Fructooligosaccharides Intake during Pregnancy Improves Metabolic Phenotype of Offspring in High Fat Diet-Induced Obese Mice

SCOPE

Obesity and metabolic diseases are closely associated, and individuals who become obese are also prone to type 2 diabetes and cardiovascular disorders. Gut microbiota is mediated by diet and can influence host metabolism and the incidence of metabolic disorders. Recent studies have suggested that improving gut microbiota through a fructooligosaccharide (FOS)-supplemented diet may ameliorate obesity and other metabolic disorders. Although accumulating evidence supports the notion of the developmental origins of health and disease, the underlying mechanisms remain obscure.

METHODS AND RESULTS

ICR mice are fed AIN-93G formula-based cellulose -, FOS-, acetate-, or propionate-supplemented diets during pregnancy. Offspring are reared by conventional ICR foster mothers for 4 weeks; weaned mice are fed high fat diet for 12 weeks and housed individually. The FOS and propionate offspring contribute to suppressing obesity and improving glucose intolerance. Gut microbial compositions in FOS-fed mothers and their offspring are markedly changed. However, the beneficial effect of FOS diet on the offspring is abolished when antibiotics are administered to pregnant mice.

CONCLUSION

The findings highlight the link between the maternal gut environment and the developmental origin of metabolic syndrome in offspring. These results open novel research avenues into preemptive therapies for metabolic disorders by targeting the maternal gut microbiota.

The Degree of Inulin Polymerization Is Important for Short-Term Amelioration of High-Fat Diet (HFD)-Induced Metabolic Dysfunction and Gut Microbiota Dysbiosis in Rats

Inulin, a non-digestible polysaccharide, has gained attention for its prebiotic properties, particularly in the context of obesity, a condition increasingly understood as a systemic inflammatory state linked to gut microbiota composition. This study investigates the short-term protective effects of inulin with different degrees of polymerization (DPn) against metabolic health deterioration and gut microbiota alterations induced by a high-fat diet (HFD) in Sprague Dawley rats. Inulin treatments with an average DPn of 7, 14, and 27 were administered at 1 g/kg of bodyweight to HFD-fed rats over 21 days. Body weight, systemic glucose levels, and proinflammatory markers were measured to assess metabolic health. Gut microbiota composition was analyzed through 16S rRNA gene sequencing. The results showed that inulin27 significantly reduced total weight gain and systemic glucose levels, suggesting a DPn-specific effect on metabolic health. The study also observed shifts in gut microbial populations, with inulin7 promoting several beneficial taxa from the Bifidobacterium genera, whilst inducing a unique microbial composition compared to medium-chain (DPn 14) and long-chain inulin (DPn: 27). However, the impact of inulin on proinflammatory markers and lipid metabolism parameters was not statistically significant, possibly due to the short study duration. Inulin with a higher DPn has a more pronounced effect on mitigating HFD-induced metabolic health deterioration, whilst inulin7 is particularly effective at inducing healthy microbial shifts. These findings highlight the benefits of inulin as a dietary adjuvant in obesity management and the importance of DPn in optimizing performance.

Effects of Different Types of Dietary Fibers on Lipid Metabolism and Bile Acids in Weaned Piglets

The aim of this study was to investigate the effects of dietary fiber on the serum biochemistry, bile acid profile, and gut microbiota in piglets. Twenty-four pigs (initial body weight: 10.53 ± 1.23 kg) were randomly divided into three treatments with eight replicate pens of one pig per pen for 21 d. The dietary treatments consisted of the following: (1) a fiber-free diet (NS); (2) a fiber-free diet + 3% fructooligosaccharides (SI); (3) a fiber-free diet + 3% dietary fiber mixture (fructooligosaccharides, long-chain inulin, and microcrystalline cellulose at the ratio 1:1:1; MIX). The results showed that compared with the NS group, the 3% SI diet reduced the serum total cholesterol (TC) concentration of the piglets (p < 0.05). The metabolomics results showed that the 3% SI diet increased the level of taurohyocholic acid (THCA) and α-muricholic acid, and the 3% MIX diet increased the level of THCA and cholic acid (p < 0.05). The use of 3% SI or MIX decreased the glycodeoxycholic acid (GDCA) level in the bile of the piglets (p < 0.05). The correlation analysis shows that the GDCA was positively related to the TC. The 16S rRNA gene sequencing results showed that UCG-002 and Holdemanella were enriched in the SI group, while Bacteroides was enriched in the MIX group. The microbial function prediction indicated that SI supplementation tended to elevate the relative abundance of gut bacteria capable of expressing bile acid-metabolizing enzymes. To sum up, the regulatory effect of dietary fiber on lipid metabolism is related to bile acids in piglets. Compared with MIX, SI is more likely to regulate bile acids through the gut microbiota.

Non-Thermal Supercritical Carbon Dioxide Processing Retains the Quality Parameters and Improves the Kinetic Stability of an Araticum Beverage Enriched with Inulin-Type Dietary Fibers

Fruit-based beverages have been considered excellent food vehicles for delivering prebiotics. However, the conventional thermal processes currently used to microbiologically and enzymatically stabilize these products may cause significant losses in their sensory, physicochemical, nutritional, and bioactive characteristics. Thus, in this study, we evaluate the effect of different levels of pressure (8, 15, and 21 MPa) and temperature (35 and 55 °C) on the characteristics of an inulin-enriched araticum beverage processed with non-thermal supercritical carbon dioxide (SC-CO₂) technology. The temperature showed a significant effect on total soluble solids, pH, particle size distribution, and kinetic stability. In contrast, pressure affected only the particle size distribution. The interaction between pressure and temperature influenced the total soluble solids, pH, and particle size distribution. Color parameters, ζ-potential, and glucose and fructose contents were not modified after all SC-CO₂ treatments. Moreover, the SC-CO₂ treatments preserved the inulin molecular structure, thus maintaining its prebiotic functionality. Overall, the SC-CO₂ treatment did not alter the sensory, nutritional, and functional quality of the beverage, while improving its physical stability during storage. Therefore, non-thermal SC-CO₂ treatment can be an alternative to current conventional processes for stabilizing inulin-enriched fruit-based beverages.

A Strategy for Rapid Acquisition of the β-D-Fructofuranosidase Gene through Chemical Synthesis and New Function of Its Encoded Enzyme to Improve Gel Properties during Yogurt Processing

A chemical gene synthesis strategy was developed in order to obtain β-D-fructofuranosidase, and a novel gene, AlFFase3, was characterized from Aspergillus luchuensis and expressed in Escherichia coli. The recombinant protein was purified, showing a molecular mass of 68.0 kDa on SDS-PAGE, and displaying a specific activity towards sucrose of up to 771.2 U mg^-1, indicating its exceptional enzymatic capacity. AlFFase3 exhibited stability between pH 5.5 and 7.5, with maximal activity at pH 6.5 and 40 °C. Impressively, AlFFase3, as a soluble protein, was resistant to digestion by various common proteases, including Flavourzyme, acidic protease, pepsin, neutral protease, Proteinase K, alkaline proteinase, and trypsin. AlFFase3 also demonstrated significant transfructosylation activity, with a yield of various fructooligosaccharides up to 67%, higher than almost all other reports. Furthermore, we demonstrated that the addition of AlFFase3 enhanced the growth of probiotics in yogurt, thereby increasing its nutritional value. AlFFase3 also improved the formation of yogurt gel, reducing the gel formation time and lowering the elasticity while increasing its viscosity, thereby improving the palatability of yogurt and reducing production costs.

Prebiotic Consumption Alters Microbiota but Not Biological Markers of Stress and Inflammation or Mental Health Symptoms in Healthy Adults: A Randomized, Controlled, Crossover Trial

BACKGROUND

Chronic stress contributes to systemic inflammation and diminished mental health. Although animal work suggests strong links with the microbiota-gut-brain axis, clinical trials investigating the effectiveness of prebiotics in improving mental health and reducing inflammation are lacking.

OBJECTIVES

We aimed to determine fructooligosaccharide (FOS) and galactooligosaccharide (GOS) effects on biological markers of stress and inflammation and mental health symptoms in adults. Secondary outcomes included fecal microbiota and metabolites, digestive function, emotion, and sleep.

METHODS

Twenty-four healthy adults (25-45 y; 14 females, 10 males; BMI, 29.3 ± 1.8 kg/m²) from central Illinois participated in a 2-period, randomized, controlled, single-blinded crossover trial. Interventions included the prebiotic (PRE) treatment (237 mL/d Lactaid low-fat 1% milk, 5 g/d FOS, 5 g/d GOS) and control (CON) (237 mL/d Lactaid), which were consumed in counterbalanced order for 4 wk each, separated by ≥4-wk washout. Inflammatory markers were measured in blood plasma (>10-h fast) and cortisol in urine. The Depression Anxiety Stress Scales-42 assessed mental health symptoms. Fecal samples were collected for 16S rRNA gene (V4 region) sequencing and analysis. Emotion was measured by rating images from a computer task. Sleep was assessed using 7-d records and accelerometers. Change scores were analyzed using linear mixed models with treatment and baseline covariate as fixed effects and participant ID as the random effect.

RESULTS

There were no differences in change scores between PRE and CON treatments on biological markers of stress and inflammation or mental health. PRE increased change in percent sequences (q = 0.01) of Actinobacteriota (CON: 0.46 ± 0.70%; PRE: 5.40 ± 1.67%) and Bifidobacterium (CON: -1.72 ± 0.43%; PRE: 4.92 ± 1.53%). There were also no differences in change scores between treatments for microbial metabolites, digestive function, emotion, or sleep quality.

CONCLUSIONS

FOS+GOS did not affect biological markers of stress and inflammation or mental health symptoms in healthy adults; however, it increased Bifidobacterium.

CLINICAL TRIAL REGISTRY

NCT04551937, www.

CLINICALTRIALS

gov.

Effects of dietary Clostridium butyricum and fructooligosaccharides, alone or in combination, on performance, egg quality, amino acid digestibility, jejunal morphology, immune function, and antioxidant capacity of laying hens

The present study was conducted to evaluate the effects of Clostridium butyricum (CB) and fructooligosaccharide (FOS) singly or combined, on performance, egg quality, amino acid digestibility, jejunal morphology, immune function and antioxidant capacity in peak-phase laying hens. A total of 288 Hy-Line Brown laying hens (30 weeks of age) were randomly assigned to 4 dietary groups that included basal diet, basal diet +0.02% of CB (zlc-17: 1 × 10⁹ CFU/g) (PRO), basal diet +0.6% FOS (PRE), and basal diet +0.02% CB + 0.6% FOS (SYN) for 12 weeks. Each treatment had 6 replicates with 12 birds each. The results demonstrated that probiotics (PRO), prebiotics (PRE) and synbiotics (SYN) (p ≤ 0.05), respectively, exerted a positive effect on the performance and physiological response of the birds. There were significant increases in egg production rate, egg weight, egg mass, daily feed intake and reduced number of damaged eggs. and zero mortality rate due to dietary PRO, PRE and SYN (p ≤ 0.05) respectively. Also, feed conversion was improved by PRO (p ≤ 0.05). In addition, egg quality assessment showed that; eggshell quality was increased by PRO (p ≤ 0.05) and albumen indices (Haugh unit, thick albumen content, and albumen height) were enhanced by PRO, PRE and SYN (p ≤ 0.05). Further analysis showed that PRO, PRE and SYN (p ≤ 0.05), reduced heterophil to lymphocyte ratio, increased antioxidant enzymes and immunoglobulin concentration. Although spleen index was higher for PRO (p ≤ 0.05) group. The significant increase in villi height, villi width, villi height to crypt depth ratio and reduced crypt depth were obvious for PRO, PRE, and SYN (p ≤ 0.05). Furthermore, improved nutrient absorption and retention evidenced by increased digestibility of crude protein and amino acids, were notable for PRO, PRE, and SYN (p ≤ 0.05) group. Collectively, our findings revealed that dietary CB and FOS alone, or combined, enhanced productive performance, egg quality, amino acid digestibility, jejunal morphology, and physiological response in peak-phase laying hens. Our results would provide direction on nutritional strategies for gut enhancers and better physiological response of peak laying hens.

A Comprehensive Chemical and Nutritional Analysis of New Zealand Yacon Concentrate

Global interest in yacon (Smallanthus sonchifolius) is growing due to its potential as a functional food, attributable to its unique profile of bioactives and high fructooligosaccharide (FOS) content, which vary between cultivars. Our objective was to conduct a comprehensive chemical and nutritional analysis of New Zealand yacon concentrate (NZYC)-a sweet syrup derived from the roots of cultivar 'New Zealand', which was first grown in the 1980s. The major minerals in NZYC were potassium, phosphorus, and calcium. The FOS content ranged from 17.6 to 52.7 g/100g. Total phenolic content ranged from 565 to 785 mg gallic acid equivalents per 100 g; chlorogenic acid and caffeic acid were the major phenolic compounds. The major amino acids were L-arginine, L-glutamic acid, L-proline, L-aspartic acid, and asparagine. The major organic acids were citric, malic, quinic, and fumaric acids. Antioxidant activity ranged from 1084.14 to 3085.78 mg Trolox equivalents per 100 g depending on the assay used. The glycaemic index (GI) value was 40 ± 0.22, classifying it as a low-GI food. These results support the classification of NZYC as a nutraceutical food product for future diet therapy applications.

Selection of Non-Mycotoxigenic Inulinase Producers in the Group of Black Aspergilli for Use in Food Processing

Research background

Inulinases are used for fructooligosaccharide production and they are of interest for both scientific community and industry. Black aspergilli represent a diverse group of species that has use for enzyme production, in particular some species are known as potent inulinase producers. Finding new potential producers from the environment is as important as improving the production with known strains. Safe use of enzymes produced by aspergilli in food industry is placed ahead of their benefit for inulinase production.

Experimental approach

Here we show a specific approach to finding/screening of newly isolated fungal inulinase producers that combines a newly developed screening method and an equally important assessment of the toxigenic potential of the fungus. In this study 39 black aspergilli collected from different substrates in Serbia were identified and assessed for inulinase production.

Results and conclusions

The most common species were Aspergillus tubingensis (51.2%), followed by A. niger (23.1%), A. welwitschiae (23.1%) and A. uvarum (2.6%). The isolates for inulinase production were selected using a cheap and easy, fast and non-hazardous alternative inulinase screening test developed in this work. Enzymatic activity of selected inulinase-producing strains was confirmed spectrophotometrically. Since some A. niger and A. welwitschiae strains are able to produce mycotoxins ochratoxin A (OTA) and fumonisins (FB), the toxigenic potential of selected inulinase producers was assessed analytically and genetically. Fungal enzyme producer can be considered safe for use in food industry only after comparing the results of both approaches for investigating toxic potential, the direct presence of mycotoxins in the enzyme preparation (analytically) and the presence of mycotoxin gene clusters (genetically). In some strains the absence of OTA and FB production capability was molecularly confirmed by the absence of complete or critical parts of biosynthetic gene clusters, respectively. The two best inulinase producers and mycotoxin non-producers (without mycotoxin production capability as additional safety) were selected as potential candidates for further development of enzyme production.

Novelty and scientific contribution

The presented innovative approach for the selection of potential fungal enzyme producer shows that only non-toxigenic fungi could be considered as useful in food industry. Although this study was done on local isolates, the approach is applicable globally.

Insights into the Structure of the Highly Glycosylated Ffase from Rhodotorula dairenensis Enhance Its Biotechnological Potential

Rhodotorula dairenensis β-fructofuranosidase is a highly glycosylated enzyme with broad substrate specificity that catalyzes the synthesis of 6-kestose and a mixture of the three series of fructooligosaccharides (FOS), fructosylating a variety of carbohydrates and other molecules as alditols. We report here its three-dimensional structure, showing the expected bimodular arrangement and also a unique long elongation at its N-terminus containing extensive O-glycosylation sites that form a peculiar arrangement with a protruding loop within the dimer. This region is not required for activity but could provide a molecular tool to target the dimeric protein to its receptor cellular compartment in the yeast. A truncated inactivated form was used to obtain complexes with fructose, sucrose and raffinose, and a Bis-Tris molecule was trapped, mimicking a putative acceptor substrate. The crystal structure of the complexes reveals the major traits of the active site, with Asn387 controlling the substrate binding mode. Relevant residues were selected for mutagenesis, the variants being biochemically characterized through their hydrolytic and transfructosylating activity. All changes decrease the hydrolytic efficiency against sucrose, proving their key role in the activity. Moreover, some of the generated variants exhibit redesigned transfructosylating specificity, which may be used for biotechnological purposes to produce novel fructosyl-derivatives.

A Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effects of Multi-Strain Synbiotic in Patients with Functional Diarrhea and High Fecal Calprotectin Levels: A Pilot Study

Synbiotics, including probiotics and prebiotics, are useful for patients with functional bowel disorders. However, which synbiotics are beneficial for patients with which diseases, especially those with functional diarrhea (FDr) with high fecal calprotectin levels, is currently unknown. FDr is an extension of irritable bowel syndrome with diarrhea (IBS-D). Although fewer studies have been conducted on FDr compared to IBS-D, its importance is increasing as its prevalence increases. The aim of this study was to evaluate the effects of a synbiotic containing a mixture of Lactobacillus and Bifidobacterium and its substrate, fructooligosaccharide, on bowel symptoms, fecal calprotectin levels, fecal microbiota, and safety in FDr patients with high fecal calprotectin levels. Forty patients were randomly assigned to either a synbiotic group or a placebo group. A total of 20 subjects in the synbiotic group and 19 subjects in the placebo group completed the study (8 weeks). Changes in FDr symptoms, fecal calprotectin levels, and gut microbiota were assessed during the intervention period. At 4 and 8 weeks, the number of bowel movements tended to increase in the synbiotic group, with a significant increase in the number of formed stools rather than loose stools (p < 0.05). Bowel movement satisfaction was significantly increased in the synbiotic group, but not in the placebo group. Intestinal flora analysis revealed that Lactobacillales at the order level was increased only in the synbiotic group at the end of the intervention. In contrast, at week 8 of the intervention, log-transformed fecal calprotectin levels were significantly decreased in the synbiotic group, although the change was not significantly different from that of the placebo group. These findings suggest that the intake of a multi-strain-containing synbiotic for 8 weeks could improve gut symptoms and the intestinal microenvironment of FDr patients with high fecal calprotectin levels.

Effects of fructooligosaccharides (FOS) on the composition of cecal and fecal microbiota and the quantitative detection of FOS-metabolizing bacteria using species-specific primers

BACKGROUND

Fructooligosaccharides (FOS) are a kind of prebiotic. Previous studies concerning the effect of FOS on intestinal microbiota have focused on Bifidobacterium and Lactobacillus. However, the presence of other FOS-utilizing bacteria makes it necessary to investigate the quantitative changes in these bacterial species in the intestine after FOS intake. In this study, the composition of cecal and fecal microbiota was analyzed using MiSeq sequencing, and the abundance of FOS-utilizing bacteria was detected using quantitative polymerase chain reaction after the oral administration of FOS.

RESULTS

Species-specific primers for FOS-utilizing bacteria were designed with superior amplification efficiency for quantification. After FOS intervention, the relative abundance of Bifidobacterium pseudolongum in feces increased to 17.37% and the abundance reached 2.28 × 10¹⁰  CFU g^-1 . The abundance of Bifidobacterium longum and Bifidobacterium breve did not change significantly. Whereas the abundance of Ligilactobacillus murinus decreased, that of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, and Lacticaseibacillus rhamnosus remained at approximately 10⁴  CFU g^-1 .

CONCLUSION

Species-specific primers for FOS-utilizing bacteria were successfully developed, and we confirmed that FOS significantly increased the relative abundance and the abundance of B. pseudolongum in mice, while decreasing the proportion of Lactobacillus. The detection of these species using 16S ribosomal DNA sequencing and quantitative polymerase chain reaction showed the same results. Further investigations are needed to reveal the response of the intestinal microbiota to different FOS compositions. These techniques will contribute to future studies about the composition and dynamics of the intestinal microflora. © 2022 Society of Chemical Industry.

Effect of a diet rich in galactose or fructose, with or without fructooligosaccharides, on gut microbiota composition in rats

Recent studies suggest that a diet rich in sugars significantly affects the gut microbiota. Adverse metabolic effects of sugars may partly be mediated by alterations of gut microbiota and gut health parameters, but experimental evidence is lacking. Therefore, we investigated the effects of high intake of fructose or galactose, with/without fructooligosaccharides (FOS), on gut microbiota composition in rats and explored the association between gut microbiota and low-grade systemic inflammation. Sprague-Dawley rats (n = 6/group) were fed the following isocaloric diets for 12 weeks (% of the dry weight of the sugars or FOS): (1) starch (control), (2) fructose (50%), (3) galactose (50%), (4) starch+FOS (15%) (FOS control), (5) fructose (50%)+FOS (15%), (6) galactose (50%)+FOS (15%), and (7) starch+olive (negative control). Microbiota composition in the large intestinal content was determined by sequencing amplicons from the 16S rRNA gene; 341F and 805R primers were used to generate amplicons from the V3 and V4 regions. Actinobacteria, Verrucomicrobia, Tenericutes, and Cyanobacteria composition differed between diets. Bifidobacterium was significantly higher in all diet groups where FOS was included. Modest associations between gut microbiota and metabolic factors as well as with gut permeability markers were observed, but no associations between gut microbiota and inflammation markers were observed. We found no coherent effect of galactose or fructose on gut microbiota composition. Added FOS increased Bifidobacterium but did not mitigate potential adverse metabolic effects induced by the sugars. However, gut microbiota composition was associated with several metabolic factors and gut permeability markers which warrant further investigations.

Successive Fermentation of Aguamiel and Molasses by Aspergillus oryzae and Saccharomyces cerevisiae to Obtain High Purity Fructooligosaccharides

Fructooligosaccharides (FOS) are usually synthesized with pure enzymes using highly concentrated sucrose solutions. In this work, low-cost aguamiel and molasses were explored as sucrose alternatives to produce FOS, via whole-cell fermentation, with an Aspergillus oryzae DIA-MF strain. FOS production process was optimized through a central composite experimental design, with two independent variables: initial sucrose concentration in a medium composed of aguamiel and molasses (AgMe), and inoculum concentration. The optimized process—165 g/L initial sucrose in AgMe (adjusted with concentrated molasses) and 1 × 10⁷ spores/mL inoculum concentration—resulted in an FOS production of 119 ± 12 g/L and a yield of 0.64 ± 0.05 g _FOS/g _GFi. Among the FOSs produced were kestose, nystose, 1-fructofuranosyl-nystose, and potentially a novel trisaccharide produced by this strain. To reduce the content of mono- and disaccharides in the mixture, run a successive fermentation was run with two Saccharomyces cerevisiae strains. Fermentations run with S. cerevisiae S227 improved FOS purity in the mixture from 39 ± 3% to 61.0 ± 0.6% (w/w) after 16 h of fermentation. This study showed that agro-industrial wastes such as molasses with aguamiel are excellent alternatives as substrate sources for the production of prebiotic FOS, resulting in a lower-cost process.

Application of oligosaccharides in meat processing and preservation

In recent decades, consumer preference and attention to foodstuff presented as healthy and with desirable nutritional information, has increased significantly. In this field, the meat industry has a challenging task since meat and meat products have been related to various chronic diseases. Functional ingredients have emerged in response to the increasing demand for healthier and more nutritious foods. On this matter, oligosaccharides such as fructooligosaccharides (FOS), xylooligosaccharides (XOS), galactooligosaccharides (GOS), and chitooligosaccharides (COS) have been presented as suitable ingredients for the meat industry with the aim of obtaining healthier meat derivatives (e.g. with low fat or sugar content, reduced amount of additives, and desirable functional properties, etc.). However, studies considering application of such oligomers in the meat sector are scarce. In addition, a large number of issues remain to be solved related both to obtaining and characterizing the oligosaccharides available in the industry and to the effect that these ingredients have on the features of meat products (mainly physicochemical and sensory). The study of new oligosaccharides, the methodologies for obtaining them, and their application to new meat products should be promoted, as well as improving knowledge about their effects on the properties of functional meat foods.

Crystal Structure of Levansucrase from the Gram-Negative Bacterium Brenneria Provides Insights into Its Product Size Specificity

Microbial levansucrases (LSs, EC 2.4.1.10) have been widely studied for the synthesis of β-(2,6)-fructans (levan) from sucrose. LSs synthesize levan-type fructo-oligosaccharides, high-molecular-mass levan polymer or combinations of both. Here, we report crystal structures of LS from the G^--bacterium Brenneria sp. EniD 312 (Brs-LS) in its apo form, as well as of two mutants (A154S, H327A) targeting positions known to affect LS reaction specificity. In addition, we report a structure of Brs-LS complexed with sucrose, the first crystal structure of a G^--LS with a bound substrate. The overall structure of Brs-LS is similar to that of G^-- and G⁺-LSs, with the nucleophile (D68), transition stabilizer (D225), and a general acid/base (E309) in its active site. The H327A mutant lacks an essential interaction with glucosyl moieties of bound substrates in subsite +1, explaining the observed smaller products synthesized by this mutant. The A154S mutation affects the hydrogen-bond network around the transition stabilizing residue (D225) and the nucleophile (D68), and may affect the affinity of the enzyme for sucrose such that it becomes less effective in transfructosylation. Taken together, this study provides novel insights into the roles of structural elements and residues in the product specificity of LSs.

Beneficial Effects of Fructooligosaccharides Esterified with Lauric Acid in a Metabolic Syndrome Model Induced by a High-Fat and High-Carbohydrate Diet in Wistar Rats

Metabolic syndrome (MS) is a group of abnormalities in which obesity, insulin resistance (IR), oxidative stress, and dyslipidemia stand out. This pathology predisposes to the development of cardiovascular diseases and diabetes. The ingestion of linear fructooligosaccharides (FOS) such as inulin reduces conditions such as hyperinsulinemia, increased body fat, and triglyceridemia. When FOS are esterified with fatty acids, they present emulsifying and surfactant properties; however, there are no reports of their function at the biological level. The purpose of this investigation was to evaluate the effect of Agave tequilana Weber's FOS (AtW-FOS) and FOS esterified with lauric acid (FOS-LA) in MS markers in a rat model induced by a HFHC diet. Supplementation with AtW-FOS and FOS-LA decreased IR, improved glucose tolerance, reduced liver weight (19%), plasma triglycerides (24%), and blood pressure (16%) when compared with the untreated MS group. In conclusion, the ingestion of AtW-FOS and FOS-LA has beneficial effects in the prevention of MS alterations, showing a high potential for their application in functional foods.

Asparagus Roots: From an Agricultural By-Product to a Valuable Source of Fructans

Asparagus roots are by-products from asparagus cultivation and they could be considered one of the best sources of fructans. These polymers are interesting food ingredients for their prebiotic and immuno-stimulating characteristics. The aim of this work is to characterize the fructan profile from the roots of several asparagus varieties grown at different locations and pickled at three vegetative statuses in order to valorize these by-products as fructan source. Fructans were extracted with hot water and fractionated into three pools according to their molecular weight (MW). Their average MW was studied by HPSEC and their degree of polymerization by HPAEC. The fructan content was up to 12.5% on fresh weight basis, depending on variety and sampling date. The relative abundance of the three pools also depended on the picking moment as after the spear harvest period their total content and MW increased. The average MW of the three fractions was similar among varieties with 4.8, 8.4 and 9 sugar units, although fructans up to 30 units were identified by HPAEC. These characteristics make them similar to the commercialized Orafti^®-GR inulin, a common additive to food products. Therefore, the concept of asparagus roots as cultivation waste must be changed to a new feedstock for sustainable agriculture and industry.

A Systematic Review

Breast milk is the optimal food choice for infant growth and development. Among breast milk components, fructooligosaccharides (FOSs) are being actively studied because of their role in microbiota development. In particular, 2'-fucosyllactose is being proposed as a potential supplement/nutraceutical or component of infant formula. In this systematic review, we critically summarize the available information on FOSs and we discuss their future use in infant nutrition. We searched the main electronic databases (PubMed, Embase, and Scopus), with a final check in May 2021. Search terms were inserted individually and using the Boolean tools AND and OR. Relevant articles were identified using the following words: ("fructooligosaccharides" OR "FOS") AND ("human milk" OR "breast milk" OR "donor milk" OR "bank milk"). The search retrieved 1814 articles. After removal of duplicates, we screened 1591 articles based on title, abstract, and exclusive use of the English language. We included articles describing the concentration of FOSs in human milk and assessed the relevant ones. We excluded reviews, studies on animals, and studies exclusively carried out on adults. Also, we excluded studies that have not reported evidence either on FOSs or on galactooligosaccharides from human milk. The resulting publications were reviewed, and 10 studies were included in the systematic review. We conclude that human milk FOSs are, indeed, crucial to infant gut development and their addition to infant formula is safe, well-tolerated, and might provide immune benefits to newborns. However, we would like to underscore the scantiness of human data and the need to avoid the immediate translation of infant research to the commercialization of supplements marketed to adults.

Fructooligosaccharides on inflammation, immunomodulation, oxidative stress, and gut immune response: a systematic review

CONTEXT

Evidence shows that fructooligosaccharides (FOSs) can modulate inflammatory, oxidative, and immune activity in the gut, possibly leading to a systemic response, improving human health.

OBJECTIVE

To assess the present knowledge of the effects of FOSs on inflammation, immunomodulation, oxidative stress, and gut immune response.

DATA SOURCES

Studies published between December 2000 and January 2020 were systematically searched in four databases: MEDLINE, LILACS, Web of Science, and Scopus. After the screening of 1316 articles, 8 human studies and 20 animal models were included.

DATA EXTRACTION

Data were extracted separately by 2 reviewers. For each study, the design, population, exposures, main results, and conclusion were extracted. The research questions and the risk-of-bias information were also extracted. Additionally, the risk-of-bias were analyzed to guarantee the reliability of this review.

DATA ANALYSIS

A qualitative analysis revealed that FOSs can increase bifidobacteria counts and short-chain fatty acids in the gut, stimulate IgA secretion in the colon, and decrease proinflammatory cytokines, thus influencing metabolic diseases.

CONCLUSION

Studies suggest that FOS supplementation is positively associated with an anti-inflammatory and antioxidant effect, thus enhancing the gut immune system, which may be beneficial for the host's health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration nos 42020209865 and 42020220369.

Fructooligosaccharides Increase in Plasma Concentration of (-)-Epigallocatechin-3-Gallate in Rats

(-)-Epigallocatechin-3-gallate (EGCG) undergoes auto-oxidation at physiological pH and therefore may be poorly absorbed in the intestine. Fructooligosaccharides (FOS), comprising a group of 1-kestose, nystose, and 1^F-β fructofuranosyl-nystose, are fermentable by gut bacteria and converted mainly into lactate. This study was conducted to determine whether dietary FOS may help to increase the plasma concentration of EGCG in rats by preventing it from auto-oxidation. Rats consumed an assigned diet, either a 0.3% (w/w) EGCG diet or an EGCG diet with additional 1, 3, or 5% (w/w) FOS, for 2 weeks. The results showed that the plasma concentration of EGCG was 0.21 ± 0.05 μM for the EGCG alone group, and it was significantly higher at 0.65 ± 0.12 μM for the EGCG plus 5% FOS group. Treatments with FOS resulted in a dose-dependent increase in the cecal level of lactate and brought the cecal pH down, with an accompanying alteration in the abundance of Lactobacillus and Collinsella. Because EGCG concentrations in the cecal digesta of rats fed the FOS-containing diet maintained comparatively high levels, FOS likely contributed to the protection of EGCG from auto-oxidation. In conclusion, FOS reduced the pH of the lumen of the intestine, kept EGCG intact to a certain degree, and consequently allowed EGCG to be taken into the blood circulation from the intestine.

The Prebiotic Potential of Inulin-type Fructans: A Systematic Review

Inulin-type fructans (ITF), including short-chain fructooligosaccharides (scFOS), oligofructose, and inulin, are commonly used fibers that are widely regarded as prebiotic for their ability to be selectively utilized by the intestinal microbiota to confer a health benefit. However, the literature thus far lacks a thorough discussion of the evidence from human clinical trials for the prebiotic effect of ITF, including both effects on the intestinal microbiota composition as well as the intestinal and extraintestinal (e.g., glucose homeostasis, lipids, mineral absorption and bone health, appetite and satiety, inflammation and immune function, and body composition) benefits. Additionally, there is a lack of discussion regarding aspects such as the effect of ITF chain length on its intestinal and extraintestinal effects. The overall objective of this systematic review was to summarize the prebiotic potential of ITF based on the results of human clinical trials in healthy adult populations. Evidence from studies included in the current review suggest that ITF have a prebiotic effect on the intestinal microbiota, promoting the abundances of Bifidobacterium, Lactobacillus, and Faecalibacterium prausnitzii. Beneficial health effects reported following ITF intake include improved intestinal barrier function, improved laxation, increased insulin sensitivity, decreased triglycerides and an improved lipid profile, increased absorption of calcium and magnesium, and increased satiety. While there is some evidence for differing effects of ITF based on chain length, lack of direct comparisons and detailed descriptions of physicochemical properties limit the ability to draw conclusions from human clinical studies. Future research should focus on elucidating the mechanisms by which the intestinal microbiota mediates or modifies the effects of ITF on human health and the contribution of individual factors such as age and metabolic health to move towards personalization of prebiotic application.

Prebiotic Potential of Cereal Components

One type of functional food that has been receiving much attention is food rich in prebiotics. The old but still valid definition of prebiotics defines them as non-digestible food components that selectively stimulate the growth and/or activity of the beneficial bacteria in the colon and, as a result, improve the host health. Cereals, as one of the main components in the human diet, contain substantial levels of dietary fiber with probable prebiotic potential. In addition, dietary fiber, particularly soluble dietary fiber, has recently emerged as a promising natural highly functional food ingredient in food production. This review focuses on the prebiotic potential of cereal dietary fiber types and covers the achievements and developments regarding its isolation. First, the probiotic and prebiotic concepts will be discussed. Next, different components of dietary fiber and their effect on the host bacteria through in vitro and/or in vivo studies will be reviewed. In a last part, this paper also discusses means of boosting the prebiotic properties of cereal components and innovative strategies for the extraction of cereal dietary fiber. The review focuses on wheat as a leading cereal crop that is widely and intensely used throughout the world in food production.

Crystal Structure of a Sucrose-6-phosphate Hydrolase from Lactobacillus gasseri with Potential Applications in Fructan Production and the Food Industry

Fructooligosaccharides (FOSs) are polymers of fructose with a prebiotic activity because of their production and fermentation by bacteria that inhabit the gastrointestinal tract and are widely used in the industry and new functional foods. Lactobacillus gasseri stands out as an important homofermentative microorganism related to FOS production, and its potential applications in the industry are undeniable. In this study, we report the production and characterization of a sucrose-6-phosphate hydrolase from L. gasseri belonging to the GH32 family. Apo-LgAs32 and LgAs32 complexed with β-d-fructose structures were determined at a resolution of 1.94 and 1.84 Å, respectively. The production of FOS, fructans, 1-kestose, and nystose by the recombinant LgAs32, using sucrose as a substrate, shown in this study is very promising. When compared to its homologous enzyme from Lactobacillus reuteri, the production of 1-kestose by LgAs32 is increased; thus, LgAs32 can be considered as an alternative in fructan production and other industrial applications.

Production, properties, and applications of fructosyltransferase: a current appraisal

BACKGROUND

Fructosyltransferases (FTases) are drawing increasing attention due to their application in prebiotic fructooligosaccharide (FOS) generation. FTases have been reported to occur in a variety of microorganisms but are predominantly found in filamentous fungi. These are employed at the industrial scale for generating FOS which make the key ingredient in functional food supplements and nutraceuticals due to their bifidogenic and various other health-promoting properties.

SCOPE AND APPROACH

This review is aimed to discuss recent developments made in the area of FTase production, characterization, and application in order to present a comprehensive account of their present status to the reader. Structural features, catalytic mechanisms, and FTase improvement strategies have also been discussed in order to provide insight into these aspects.

KEY FINDINGS AND CONCLUSIONS

Although FTases occur in several plants and microorganisms, fungal FTases are being exploited commercially for industrial-scale FOS generation. Several fungal FTases have been characterized and heterologously expressed. However, considerable scope exists for improved production and application of FTases for cost-effective production of prebiotic FOS.HIGHLIGHTSFructosyltrasferase (FTase) is a key enzyme in fructo-oligosaccharide (FOS) generationDevelopments in the production, properties, and functional aspects of FTasesMolecular modification and immobilization strategies for improved FOS generationFructosyltransferases are innovation hotspots in the food and nutraceutical industries.

(Cucurbitaceae) tuberous roots

The fruits and aerial parts of Sechium edule (Jacq.) Sw. (Cucurbitaceae) are a popular cook vegetable being used in different parts of the world with ethnomedicinal and pharmacological values. However, the beneficial health attributes of the tuberous roots have been less exploited. The present study aimed to determine the prebiotic potentiality of the storage carbohydrates from this part. The carbohydrate fractions were harvested by hot-water, cold-water, hot-acid, hot-alkali, and hot 80% ethanol treatments following the standard protocol. The fractions were tested for in vitro prebiotic efficacy, hypocholesterolemic and antioxidant potentials, and in vivo health attributes in Swiss albino mice. The partial characterization was performed by high-performance thin-layer chromatography (HPTLC) and spectroscopic analyses by Fourier-transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectrometry (ESI-MS). The highest prebiotic index was observed in hot-water and ethanol (Et-OH) fractions with the antioxidant IC₅₀ values of 35.46 ± 0.33 and 32.56 ± 0.48 µg/ml, respectively. The HPTLC, FT-IR, and ESI-MS analyses showed that the hot-water and Et-OH carbohydrate fractions are rich in low-degree polymerizing inulin-like fructooligosaccharides (FOS). The fractions had a significant prebiotic index, hypocholesterolemic, and antioxidant activities. The synbiotic combination of the fractions with the probiotic LAB improved gut colonization and gut immune enhancement with significantly lowered triglycerides, serum LDL, and serum VLDL cholesterols. A significantly enhanced HDL cholesterol level proves its health beneficial attributes comparable to the commercial inulin prebiotics. Thus, this plant's novel inulin-like FOS may substitute the high-cost commercial prebiotics for our daily life. PRACTICAL APPLICATIONS: Prebiotics are low-degree polymerizing oligosaccharide food ingredients having multifaceted health benefits. For this reason, there is an ever-increasing global demand for such novel prebiotics. Therefore, finding out some novel prebiotic from conventional food sources may provide an alternative dietary source to fulfill the consumer demand. Sechium edule is a famous cook vegetable used by many ethnic communities across the globe. For the first time, the study revealed novel inulin-like fructooligosaccharides in the tuberous roots having hypocholesterolemic and synbiotic efficacy with GRAS lactic acid bacteria.

FODMAP Fingerprinting of Bakery Products and Sourdoughs: Quantitative Assessment and Content Reduction through Fermentation

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are associated with digestive disorders and with diseases such as irritable bowel syndrome. In this study, we determined the FODMAP contents of bread, bakery products, and flour and assessed the effectiveness of sourdough fermentation for FODMAP reduction. The fermentation products were analyzed to determine the DP 2-7 and DP >7 fructooligosaccharide (FOS) content of rye and wheat sourdoughs. FOSs were reduced by Acetobacter cerevisiae, Acetobacter okinawensis, Fructilactobacillus sanfranciscensis, and Leuconostoc citreum to levels below those in rye (-81%; -97%) and wheat (-90%; -76%) flours. The fermentation temperature influenced the sourdough acetic acid to lactic acid ratios (4:1 at 4 °C; 1:1 at 10 °C). The rye sourdough contained high levels of beneficial arabinose (28.92 g/kg) and mannitol (20.82 g/kg). Our study contributes in-depth knowledge of low-temperature sourdough fermentation in terms of effective FODMAP reduction and concurrent production of desirable fermentation byproducts.

Impact of encapsulating probiotics with cocoa powder on the viability of probiotics during chocolate processing, storage, and in vitro gastrointestinal digestion

Chocolates can be formulated as a functional food via enrichment with probiotics. However, the added probiotics must overcome the challenges of processing and storage conditions and the harsh gastrointestinal environment. The study aimed to overcome these challenges using two different formulations of cocoa powder as alternative encapsulants along with Na-alginate (A₁ ) and Na-alginate and fructooligosaccharides (A₂ ). Seven different probiotic strains were encapsulated individually using the new formulations and viabilities of these encapsulated probiotics were assessed prior to and after they were added to chocolates. The highest achieved encapsulation efficiencies were 93.40% for formulation A₁ (with Lactobacillus casei) and 95.36% for formulation A₂ (with Lactobacillus acidophilus La5). The encapsulated probiotics with the new formulations maintained higher viability than the recommended therapeutic level (10⁷ colony forming unit [CFU]/g) for up to 180 and 120 days of storage at 4 and 25 °C, respectively. The tested encapsulants improved probiotics survival when subjected to thermal stress and maintained about 9.0 Logs CFU/g at 60 °C. Additionally, the viable numbers of probiotics in fortified chocolates showed higher than 7 Logs CFU/g after 90 days of storage at 25 °C. Both formulations exhibited significantly (P < 0.05) high survivability of probiotics (8.0 Logs CFU/g) during the in vitro gastrointestinal digestion. This study demonstrated that cocoa powder along with Na-alginate and FOS has the potential to be used as a probiotic encapsulating material, and chocolates could be an excellent carrier for the development of healthy probiotic chocolate products. PRACTICAL APPLICATION: The introduction of cocoa powder as an effective encapsulating agent to deliver probiotics could help the chocolate industry to develop healthy and attractive functional snacks for health-conscious consumers.

Antioxidant Vitamins and Prebiotic FOS and XOS Differentially Shift Microbiota Composition and Function and Improve Intestinal Epithelial Barrier In Vitro

Human gut microbiota (HGM) play a significant role in health and disease. Dietary components, including fiber, fat, proteins and micronutrients, can modulate HGM. Much research has been performed on conventional prebiotics such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS), however, novel prebiotics or micronutrients still require further validation. We assessed the effect of FOS, xylooligosaccharides (XOS) and a mixture of an antioxidant vitamin blend (AOB) on gut microbiota composition and activity, and intestinal barrier in vitro. We used batch fermentations and tested the short-term effect of different products on microbial activity in six donors. Next, fecal inocula from two donors were used to inoculate the simulator of the human microbial ecosystem (SHIME) and after long-term exposure of FOS, XOS and AOB, microbial activity (short- and branched-chain fatty acids and lactate) and HGM composition were evaluated. Finally, in vitro assessment of intestinal barrier was performed in a Transwell setup of differentiated Caco-2 and HT29-MTX-E12 cells exposed to fermentation supernatants. Despite some donor-dependent differences, all three tested products showed beneficial modulatory effects on microbial activity represented by an increase in lactate and SCFA levels (acetate, butyrate and to a lesser extent also propionate), while decreasing proteolytic markers. Bifidogenic effect of XOS was consistent, while AOB supplementation appears to exert a specific impact on reducing F. nucleatum and increasing butyrate-producing B. wexlerae. Functional and compositional microbial changes were translated to an in vitro host response by increases of the intestinal barrier integrity by all the products and a decrease of the redox potential by AOB supplementation.

Effects of High Intakes of Fructose and Galactose, with or without Added Fructooligosaccharides, on Metabolic Factors, Inflammation, and Gut Integrity in a Rat Model

SCOPE

A high fructose and galactose intake show adverse metabolic effects in animal models and in humans, but it is yet unknown if addition of fermentable dietary fiber can mitigate such effects. This study investigate the effects of high intakes of fructose and galactose, with/without added fructooligosaccharides (FOS), on metabolic factors, inflammation, and gut integrity markers in rats.

METHODS AND RESULTS

Rats (n = 6/group) receive different carbohydrates at isocaloric conditions for 12 weeks as follows: 1) starch (control), 2) fructose, 3) galactose, 4) starch + FOS (FOS control), 5) fructose + FOS, and 6) galactose + FOS, together with a high amount of n-6 polyunsaturated fatty acids (n-6 PUFA) in all diets except for in 7) starch + olive oil (negative control). The rats fed the galactose and galactose + FOS diets exhibit lower body weight than other groups. High-galactose diets has more pronounced effects on metabolic factors and gut permeability than high-fructose diets. High-fructose diets show less pronounced effect on these selected markers. No differences in inflammatory markers are detected for any of the diets.

CONCLUSIONS

The results suggest potential adverse effects of high galactose and fructose on metabolic factors and gut integrity markers, but not on inflammation. However, several mechanisms are at play, and general net effects are difficult to determine conclusively for the conditions tested.

Yacón (Smallanthus sonchifolius) prevented inflammation, oxidative stress, and intestinal alterations in an animal model of colorectal carcinogenesis

BACKGROUND

Yacón (Smallanthus sonchifolius) roots store carbohydrate in the form of prebiotic fructooligosaccharides (FOS), which improve intestinal health. Yacon has the potential to prevent the intestinal barrier alterations associated with colorectal cancer (CRC). This study aimed to investigate the preventive effects of yacón flour (YF) on alterations promoted by CRC induced by 1,2-dimethylhydrazine in rats.

RESULTS

CRC increased tumor necrosis factor alpha levels (group CY = 10.2 ± 0.72; group C = 9.6 ± 1.0; group Y = 5.8 ± 0.54; group S = 5.95 ± 0.6 pg mL^-1 ) and short-chain fatty acid production, and decreased total antioxidant capacity (group CY = 4.7 ± 0.72; group C = 3.3 ± 0.3; group Y = 4.1 ± 0.47; group S = 6.7 ± 0.78 U mL^-1 ). Furthermore, YF treatment reduced intraluminal pH (group CY = 6.45 ± 0.47; group C = 7.65 ± 0.44; group Y = 6.75 ± 0.46; group S = 8.13 ± 0.2), lactulose/mannitol ratio, tumor necrosis factor-alpha (TNF-α)/interleukin (IL)-10 ratio, and increased secretory immunoglobulin A (group CY = 9.48 ± 1.46; group C = 10.95 ± 3.87; group Y = 15.95 ± 7.36; group S = 9.19 ± 1.52), but did not affect IL-10, IL-12, and TNF-α levels nor the IL-12/IL-10 ratio.

CONCLUSION

YF as a source of fructooligosaccharides may help to maintain the integrity of intestinal health, which is altered in induced CRC in rats. © 2020 Society of Chemical Industry.

Effects of High-Fat Diet Induced Obesity and Fructooligosaccharide Supplementation on Cardiac Protein Expression

The mechanism by which high fat-diet induced obesity affects cardiac protein expression is unclear, and the extent to which this is modulated by prebiotic treatment is not known. These outcomes were assessed in rats initially fed a high-fat diet, then the top 40% weight gain group were randomly allocated to control (CON), high-fat (HF) and HF supplemented with fructooligosaccharide (32 g; HF-FOS) treatments for 12 weeks (n = 10/group). At sacrifice, left ventricles were either frozen or preserved in formalin. Serum was stored for glucose and insulin measurements. Protein spectra was obtained using an Orbitrap analyzer, processed with Sequest and fold changes assessed with Scaffold Q +. Treatment effects for body weights, glucose and insulin were assessed using one-way ANOVA, and the differential protein expression was assessed by a Mann-Whitney U test. The Database for Annotation, Visualization and Integrated Discovery and the Kyoto Encyclopedia of Genes and Genomes identified pathways containing overrepresented proteins. Hematoxylin and eosin sections were graded for hypertrophy and also quantified; differences were identified using Chi-square analyses and Mann-Whitney U tests. HF diet fed rats were significantly (p < 0.05) heavier than CON, and 23 proteins involved in mitochondrial function and lipid metabolism were differentially expressed between HF and CON. Between HF-FOS and HF, 117 proteins involved in contractility, lipid and carbohydrate metabolism were differentially expressed. HF cardiomyocytes were significantly (p < 0.05) more hypertrophic than CON. We conclude that high-fat feeding and FOS are associated with subcellular deviations in cardiac metabolism and contractility, which may influence myocardial function and alter the risk of cardiovascular disease.

Physicochemical composition, lipid oxidation, and microbiological quality of ram mortadella supplemented with Smallanthus sonchifolius meal

This study evaluated the physicochemical, lipid peroxidation, and microbiological quality of mortadellas prepared with ram and supplemented with different amounts of Smallanthus sonchifolius meal. Three mutton mortadella formulations supplemented with 1.25%, 2.50%, and 5% yacón meal and control formulation without yacón meal was included. The physicochemical, lipid peroxidation, and microbiological analyses were carried out in the time periods 10, 45 days, three, and six month after the preparation of mortadella. The control formulation presenting lighter and more intense red tone compared with the other formulations. All formulations presenting lipid peroxidation increased 90 days after processing; already the pH and Aw values were constant for all formulations at the experimental times stipulated. All formulations had the physicochemical characterization and microbiological quality standards, according to defined in regulations for mortadella production in Brazil. The results show that mutton mortadella supplemented with yacón meal is a promising alternative in the manufacture of healthy meat products.

Separation of Fructose and Glucose via Nanofiltration in Presence of Fructooligosaccharides

Fructose and glucose are commonly present together in mixtures and may need to be separated. Current separation methods for these isomers are complex and costly. Nanofiltration is a cost-effective method that has been widely used for separating carbohydrates of different sizes; however, it is not commonly used for such similar molecules. Here, we report the separation of fructose and glucose in a nanofiltration system in the presence of fructooligosaccharides (FOS). Experiments were performed using a pilot-scale filtration setup using a spiral wound nanofiltration membrane with molecular weight cutoff of 1 kDa. We observed three important factors that affected the separation: (1) separation of monosaccharides only occurred in the presence of FOS and became more effective when FOS dominated the solution; (2) better separation was achieved when the monosaccharides were mainly fructose; and (3) the presence of salt improved the separation only moderately. The rejection ratio (R_f/R_g) in a fructose/glucose mixture is 0.92. We reported a rejection ratio of 0.69, which was observed in a mixture of 50 g/L FOS with a fructose to glucose ratio of 4.43. The separation is hypothesized to occur due to selective transport in the FOS layer, resulting in a preferential binding towards fructose.

Effect of inulin-type fructans and galactooligosaccharides on cultures of Lactobacillus strains isolated in Algeria from camel's milk and human colostrum

Bacteria from the genus Lactobacillus are responsible for spontaneous food fermentations. Some species, such as Lactobacillus casei and Lactobacillus brevis, have the "Qualified Presumption of Safety" status recognized by the European Food Safety Authority. Several of their strains are used as probiotics in foods and sometimes are included in synbiotic combinations together with prebiotics. New microbial strains isolated from different sources represent an opportunity to use them for the production of traditional food products. The capacity of three selected strains (one isolated from Camel's milk and identified by partial 16 S rRNA gene sequencing as L. brevis, and two isolated from human colostrum and identified as L. paracasei/L. casei and L. brevis, respectively) was assessed in vitro for the ability to survive in gastrointestinal conditions (low pH and high bile salts concentrations). We also tested the capacity of growth and the production of organic acids and volatile compounds by high-performance liquid chromatography and gas chromatography, respectively, when these bacteria were incubated anaerobically in the presence of inulin, fructooligosaccharides, or galactooligosaccharides as the main carbon sources. The strains were able to survive in simulated gastrointestinal conditions and to grow in inulin, fructooligosaccharides, and galactooligosaccharides. However, they displayed different profiles of organic acids and volatile compounds, mainly depending on the microbial species and the prebiotic used. The influence that the combined use of strains and different prebiotics could exert on the organic acids and volatiles formed in food and in the gut should be assessed for each synbiotic combination and food product.

Effects of prebiotic consumption on serum intestinal fatty acid-binding protein levels in patients with diabetes: A case-control study

Background

Type 2 diabetes mellitus (T2DM) is a condition involving several molecular mechanisms related to the intestinal microbiota for its development. Intestinal fatty acid‐binding protein (I‐FABP) is a sensitive marker to study enterocyte damage. A prebiotic is a non‐digestible food ingredient that improves host health by selectively stimulating the growth and/or activities of bacteria in the colon. We aimed to clarify the currently described effects of prebiotics in the prevention and management of T2DM.

Methods

In this case‐control study, we chose 68 participants with T2DM and 52 healthy participants. Both groups were further divided based on consumption of prebiotics. Forty participants with T2DM consumed prebiotics, and 28 did not; 30 healthy volunteers consumed prebiotics, and 22 did not. We used the analysis of variance to compare the inflammation levels between the case and control groups. Multiple linear regression was performed for the significantly correlated groups to estimate the influence of prebiotics on inflammation level.

Results

Age was a significant factor for difference in I‐FABP levels (standardized coefficient: 0.06; P = .047). The analysis of eating habits showed that vegetarian diets produced lower I‐FABP levels than non‐vegetarian diets (standardized coefficient: −2.55; P = .022). Results showed that patients with T2DM who consumed prebiotics expressed lower I‐FABP levels, reflecting an improvement in inflammation level, than the healthy volunteers who did not consume prebiotics (standardized coefficient: −3.20; P = .019).

Conclusions

For patients with T2DM, prebiotics supplemented produced no significant impact on serum I‐FABP levels.

Effect of temperature on the hydrolysis of levan treated with compressed hot water fluids

The hydrolysis of levan using compressed hot water for the production of functional fructooligosaccharides (FOSs) was investigated. Levans from Erwinia herbicola (EH) and Halomonas smyrnensis (HS) were characterized using scanning electron microscopy and light scattering techniques, and hydrolyzed using compressed hot water at four temperatures (120, 140, 160, and 180°C). The hydrolysates were analyzed using high-performance liquid chromatography and electrospray ionization-mass spectrometry. Levan HS showed a crystalline morphology, whereas levan EH showed an aggregated structure. Both levans had molar masses on the order of 106 g/mol, but levan EH had a smaller radius of gyration, hydrodynamic radius, and intrinsic viscosity. Levan EH hydrolyzed into FOSs at approximately 120°C, whereas levan HS required a temperature of at least 160°C, possibly because of differences in the degree of branching of the two levans. Both samples were degraded to fructose when treated at 180°C.

Impact of Prebiotics on Enteric Diseases and Oxidative Stress

In animals, the gastrointestinal microbiota are reported to play a major role in digestion, nutrient absorption and the release of energy through metabolism of food. Therefore, microbiota may be a factor for association between diet and enteric diseases and oxidative stress. The gut microbial composition and concentration are affected by diet throughout the life of an animal, and respond rapidly and efficiently to dietary alterations, in particular to the use of prebiotics. Prebiotics, which play an important role in mammalian nutrition, are defined as dietary ingredients that lead to specific changes in both the composition and activity of the gastrointestinal microbiota through suppressing the proliferation of pathogens and by modifying the growth of beneficial microorganisms in the host intestine. A review of the evidence suggests possible beneficial effects of prebiotics on host intestinal health, including immune stimulation, gut barrier enhancement and the alteration of the gastrointestinal microbiota, and these effects appear to be dependent on alteration of the bacterial composition and short-chain fatty acid (SCFA) production. The production of SCFAs depends on the microbes available in the gut and the type of prebiotics available. The SCFAs most abundantly generated by gastrointestinal microbiota are acetate, butyrate and propionate, which are reported to have physiological effects on the health of the host. Nowadays, prebiotics are widely used in a range of food products to improve the intestinal microbiome and stimulate significant changes to the immune system. Thus, a diet with prebiotic supplements may help prevent enteric disease and oxidative stress by promoting a microbiome associated with better growth performance. This paper provides an overview of the hypothesis that a combination of ingestible prebiotics, chitosan, fructooligosaccharides and inulin will help relieve the dysbiosis of the gut and the oxidative stress of the host.

Harvesting of Prebiotic Fructooligosaccharides by Nonbeneficial Human Gut Bacteria

Prebiotics are increasingly used as food supplements, especially in infant formulas, to modify the functioning and composition of the microbiota. However, little is currently known about the mechanisms of prebiotic recognition and transport by gut bacteria, while these steps are crucial in their metabolism. In this study, we established a new strategy to profile the specificity of oligosaccharide transporters, combining microbiomics, genetic locus and strain engineering, and state-of-the art metabolomics. We revisited the transporter classification database and proposed a new way to classify these membrane proteins based on their structural and mechanistic similarities. Based on these developments, we identified and characterized, at the molecular level, a fructooligosaccharide transporting phosphotransferase system, which constitutes a biomarker of diet and gut pathology. The deciphering of this prebiotic metabolization mechanism by a nonbeneficial bacterium highlights the controversial use of prebiotics, especially in the context of chronic gut diseases.

Prebiotic oligosaccharides, such as fructooligosaccharides, are increasingly being used to modulate the composition and activity of the gut microbiota. However, carbohydrate utilization analyses and metagenomic studies recently revealed the ability of deleterious and uncultured human gut bacterial species to metabolize these functional foods. Moreover, because of the difficulties of functionally profiling transmembrane proteins, only a few prebiotic transporters have been biochemically characterized to date, while carbohydrate binding and transport are the first and thus crucial steps in their metabolization. Here, we describe the molecular mechanism of a phosphotransferase system, highlighted as a dietary and pathology biomarker in the human gut microbiome. This transporter is encoded by a metagenomic locus that is highly conserved in several human gut Firmicutes, including Dorea species. We developed a generic strategy to deeply analyze, in vitro and in cellulo, the specificity and functionality of recombinant transporters in Escherichia coli, combining carbohydrate utilization locus and host genome engineering and quantification of the binding, transport, and growth rates with analysis of phosphorylated carbohydrates by mass spectrometry. We demonstrated that the Dorea fructooligosaccharide transporter is specific for kestose, whether for binding, transport, or phosphorylation. This constitutes the biochemical proof of effective phosphorylation of glycosides with a degree of polymerization of more than 2, extending the known functional diversity of phosphotransferase systems. Based on these new findings, we revisited the classification of these carbohydrate transporters.

IMPORTANCE Prebiotics are increasingly used as food supplements, especially in infant formulas, to modify the functioning and composition of the microbiota. However, little is currently known about the mechanisms of prebiotic recognition and transport by gut bacteria, while these steps are crucial in their metabolism. In this study, we established a new strategy to profile the specificity of oligosaccharide transporters, combining microbiomics, genetic locus and strain engineering, and state-of-the art metabolomics. We revisited the transporter classification database and proposed a new way to classify these membrane proteins based on their structural and mechanistic similarities. Based on these developments, we identified and characterized, at the molecular level, a fructooligosaccharide transporting phosphotransferase system, which constitutes a biomarker of diet and gut pathology. The deciphering of this prebiotic metabolization mechanism by a nonbeneficial bacterium highlights the controversial use of prebiotics, especially in the context of chronic gut diseases.

The Structure of Sucrose-Soaked Levansucrase Crystals from Erwinia tasmaniensis reveals a Binding Pocket for Levanbiose

Given its potential role in the synthesis of novel prebiotics and applications in the pharmaceutical industry, a strong interest has developed in the enzyme levansucrase (LSC, EC 2.4.1.10). LSC catalyzes both the hydrolysis of sucrose (or sucroselike substrates) and the transfructosylation of a wide range of acceptors. LSC from the Gram-negative bacterium Erwinia tasmaniensis (EtLSC) is an interesting biocatalyst due to its high-yield production of fructooligosaccharides (FOSs). In order to learn more about the process of chain elongation, we obtained the crystal structure of EtLSC in complex with levanbiose (LBS). LBS is an FOS intermediate formed during the synthesis of longer-chain FOSs and levan. Analysis of the LBS binding pocket revealed that its structure was conserved in several related species. The binding pocket discovered in this crystal structure is an ideal target for future mutagenesis studies in order to understand its biological relevance and to engineer LSCs into tailored products.

Effects of fructooligosaccharides (FOS) on growth, survival, gut microflora, stress, and immune response in Pacific white shrimp, Litopenaeus vannamei, cultured in a recirculating system

The present study investigated the effects of short-chain fructooligosaccharides (FOS) as dietary supplements on stress, immune response, gut microbiota, growth, and survivability of three different treatment groups of Pacific white shrimp, Litopaneous vennamei, cultured in a recirculating system. The experiment was conducted over a 35-day trial period. Shrimps were fed diets, 15 times a day using automated feeder, supplemented with GOS at 0%, 0.15%, and 0.30% by weight. Denaturing gradient gel electrophoresis analysis revealed that the enteric microbial community of shrimp fed the basal diet differed markedly (<80.0% similarity coefficient) from those fed FOS-supplemented diets. However, shrimp survival, weight gain, and immune responses among the treatment groups were good but not significantly different (P > 0.05), probably due to the limited length of the feeding trial.

Metagenomic Insights into the Effects of Fructooligosaccharides (FOS) on the Composition of Luminal and Mucosal Microbiota in C57BL/6J Mice, Especially the Bifidobacterium Composition

Fructooligosaccharides (FOS) are considered prebiotics and have been proven to selectively promote the growth of Bifidobacterium in the gut. This study aimed to clarify the effects of FOS intake on the composition of luminal and mucosal microbiota in mice. Briefly, mice were fed a 0% or 25% FOS (w/w)-supplemented diet for four weeks, and the composition of luminal and mucosal microbiota, especially the Bifidobacterium, was analyzed by sequencing the V3-V4 region of 16S rRNA and groEL gene, respectively. After FOS intervention, there were significant increases in the total and wall weights of the cecum and the amount of total short-chain fatty acids (SCFAs) in the cecal contents of the mice. At the phylum level, the results showed a significant increase in the relative abundance of Actinobacteria in the contents and mucosa from the cecum to the distal colon in the FOS group. Besides Bifidobacterium, a significant increase was observed in the relative abundance of Coprococcus in all samples at the genus level, which may be partially related to the increase in butyric acid levels in the luminal contents. Furthermore, groEL sequencing revealed that Bifidobacterium pseudolongum was almost the sole bifidobacterial species in the luminal contents (>98%) and mucosa (>89%). These results indicated that FOS can selectively promote B. pseudolongum proliferation in the intestine, either in the lumen or the mucosa from the cecum to the distal colon. Further studies are required to reveal the competitive advantage of B. pseudolongum over other FOS-metabolizing bacteria and the response mechanisms of B. pseudolongum to FOS.

Enzymatic Process Yielding a Diversity of Inulin-Type Microbial Fructooligosaccharides

The specificity of fructooligosaccharides as prebiotics depends on their size and structure, which in turn depend on their origin or the synthesis procedure. In this work we describe the application of an inulosucrase (IslA) from Leuconostoc citreum CW28 to produce high molecular weight inulin from sucrose alongside a commercial endoinulinase (Novozym 960) produced by Aspergillus niger for a simultaneous or sequential reaction to synthesize fructooligosaccharides (FOS). The simultaneous reaction resulted in a higher substrate conversion and a wide diversity of FOS when compared to the sequential reaction. A shotgun MS analysis of the commercial endoinulinase preparation surprisingly revealed an additional enzymatic activity: a fructosyltransferase, responsible for the synthesis of FOS from sucrose. Consequentially, the range of FOS obtained in reactions combining inulosucrase from Ln. citreum with the fructosyltransferase and endoinulinase from A. niger with sucrose as substrate may be extended and regulated.

Reduced-fat Frescal sheep milk cheese with inulin: a first report about technological aspects and sensory evaluation

This research paper aimed to evaluate the role of inulin as a fat replacer on the quality of Frescal sheep milk cheese. Sheep milk and its derivatives are a promising niche in the dairy industry, mainly due to increasing interest of consumers in diversified products. Three Frescal sheep milk cheese formulations, namely whole milk cheese (WMC), semi-skimmed cheese (SSC) and semi-skimmed cheese with 5 g/100 g inulin (SSCI) were prepared. Their composition was evaluated and the feasibility of using inulin as a fat substitute was investigated. SSC and SSCI were considered 'reduced fat' or 'reduced calorie' products. The addition of inulin to SSCI cheeses yielded textural parameters (firmness, adhesiveness, cohesiveness, and gumminess) with intermediate characteristics between SSC and WMC. All the formulations presented scores higher than 7.6 in sensory analysis. In conclusion, the use of inulin in semi-skimmed sheep cheese allowed the production of cheese with texturizing properties similar to whole milk sheep cheese, enabling the development of a foodstuff with lower caloric content and beneficial characteristics valued by consumers.

Fructooligosaccharides Ameliorating Cognitive Deficits and Neurodegeneration in APP/PS1 Transgenic Mice through Modulating Gut Microbiota

Alzheimer's disease (AD) is closely related to gut microbial alteration. Prebiotic fructooligosaccharides (FOS) play major roles by regulating gut microbiota. The present study aimed to explore the effect and mechanism of FOS protection against AD via regulating gut microbiota. Male Apse/PSEN 1dE9 (APP/PS1) transgenic (Tg) mice were administrated with FOS for 6 weeks. Cognitive deficits and amyloid deposition were evaluated. The levels of synaptic plasticity markers including postsynaptic density protein 95 (PSD-95) and synapsin I, as well as phosphorylation of c-Jun N-terminal kinase (JNK), were determined. The intestinal microbial constituent was detected by 16S rRNA sequencing. Moreover, the levels of glucagon-like peptide-1 (GLP-1) in the gut and GLP-1 receptor (GLP-1R) in the brain were measured. The results indicated that FOS treatment ameliorated cognitive deficits and pathological changes in the Tg mice. FOS significantly upregulated the expression levels of synapsin I and PSD-95, as well as decreased phosphorylated level of JNK. The sequencing results showed that FOS reversed the altered microbial composition. Furthermore, FOS increased the level of GLP-1 and decreased the level of GLP-1R in the Tg mice. These findings indicated that FOS exerted beneficial effects against AD via regulating the gut microbiota-GLP-1/GLP-1R pathway.

Amberlite IRA 900 versus calcium alginate in immobilization of a novel, engineered β-fructofuranosidase for short-chain fructooligosaccharide synthesis from sucrose

The immobilization of β-fructofuranosidase for short-chain fructooligosaccharide (scFOS) synthesis holds the potential for a more efficient use of the biocatalyst. However, the choice of carrier and immobilization technique is a key to achieving that efficiency. In this study, calcium alginate (CA), Amberlite IRA 900 (AI900) and Dowex Marathon MSA (DMM) were tested as supports for immobilizing a novel engineered β-fructofuranosidase from Aspergillus japonicus for scFOS synthesis. Several immobilization parameters were estimated to ascertain the effectiveness of the carriers in immobilizing the enzyme. The performance of the immobilized biocatalysts are compared in terms of the yield of scFOS produced and reusability. The selection of carriers and reagents was motivated by the need to ensure safety of application in the production of food-grade products. The CA and AI900 both recorded impressive immobilization yields of 82 and 62%, respectively, while the DMM recorded 47%. Enzyme immobilizations on CA, AI900 and DMM showed activity recoveries of 23, 27, and 17%, respectively. The CA, AI900 immobilized and the free enzymes recorded their highest scFOS yields of 59, 53, and 61%, respectively. The AI900 immobilized enzyme produced a consistent scFOS yield and composition for 12 batch cycles but for the CA immobilized enzyme, only 6 batch cycles gave a consistent scFOS yield. In its first record of application in scFOS production, the AI900 anion exchange resin exhibited potential as an adequate carrier for industrial application with possible savings on cost of immobilization and reduced technical difficulty.

Production of an Enzymatic Extract From Aspergillus oryzae DIA-MF to Improve the Fructooligosaccharides Profile of Aguamiel

Aguamiel is a natural sap produced by some species of agave plants, such as Agave salmiana, A. atrovirens, or A. angustifolia. It is a product with a high concentration of fructose, glucose or sucrose, although its composition may vary depending on the season in which it is produced, and may also contain agave fructans (or agavins) or fructooligosaccharides (FOS). It has been reported that FOS can be produced by enzymes that act on sucrose or inulin, transfructosylating or hydrolyzing these materials, respectively. Due to the sugar content in aguamiel, the application of an enzymatic complex produced by Aspergillus oryzae DIA MF was carried out. This complex was characterized by 1-D electrophoresis SDS-PAGE, and its transfructosylation and hydrolysis activities were determined by HPLC. In order to determine the conditions at which the concentration of FOS in this beverage increased, kinetics were carried out at different temperatures (30, 50, and 70°C) and times (0, 1, 2, 3, 4, 5, 10, and 15 h). Finally, the antioxidant and prebiotic activities were evaluated. FOS concentration in aguamiel was increased from 1.61 ± 0.08 to 31.01 ± 3.42 g/ L after 10 h reaction at 30°C applying 10% enzymatic fraction-substrate (v/v). Antioxidant activity was highly increased (34.81–116.46 mg/eq Trolox in DPPH assay and 42.65 to 298.86 mg/eq Trolox in FRAP assay) and growth of probiotic bacteria was higher in aguamiel after the enzymatic treatment. In conclusion, after the application of the enzymatic treatment, aguamiel was enriched with FOS which improved antioxidant and prebiotic properties, so it can be used as a functional food.

Tributyrin in Inflammation: Does White Adipose Tissue Affect Colorectal Cancer?

Colorectal cancer affects the large intestine, leading to loss of white adipose tissue (WAT) and alterations in adipokine secretion. Lower incidence of colorectal cancer is associated with increased fibre intake. Fructooligosaccharides (FOS) are fibres that increase production of butyrate by the intestinal microbiota. Tributyrin, a prodrug of butyric acid, exerts beneficial anti-inflammatory effects on colorectal cancer. Our aim was to characterise the effects of diets rich in FOS and tributyrin within the context of a colon carcinogenesis model, and characterise possible support of tumorigenesis by WAT. C57/BL6 male mice were divided into four groups: a control group (CT) fed with chow diet and three colon carcinogenesis-induced groups fed either with chow diet (CA), tributyrin-supplemented diet (BUT), or with FOS-supplemented diet. Colon carcinogenesis decreased adipose mass in subcutaneous, epididymal, and retroperitoneal tissues, while also reducing serum glucose and leptin concentrations. However, it did not alter the concentrations of adiponectin, interleukin (IL)-6, IL-10, and tumour necrosis factor alpha (TNF)-α in WAT. Additionally, the supplements did not revert the colon cancer affected parameters. The BUT group exhibited even higher glucose tolerance and levels of IL-6, VEGF, and TNF-α in WAT. To conclude our study, FOS and butyrate supplements were not beneficial. In addition, butyrate worsened adipose tissue inflammation.

Effects of β-Fructans Fiber on Bowel Function: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to assess the effects of β-fructan supplementation on bowel function in healthy volunteers and patients. The search process was based on the selection of publications listed in the Pubmed and EUPMC database until December 2017, plus two unpublished studies, to identify studies evaluating the impact of β-fructans on bowel movement and stool parameters. Forty-seven publications were selected for inclusion. Primary parameter was frequency of bowel movements, evaluated by the number of defecations per day during the study period. Secondary outcomes were stool consistency, stool dry and wet weights, and transit time. Short-chain (DP < 10) β-fructans contributed to increased stool frequency (0.36 defecation +/- 0.06 per day; p < 0.001), while no significant effect was reported with long-chain (DP ≥ 10) β-fructans (-0.03 +/- 0.11, p = 0.82). A minimal increase in stool wet weight was also statistically demonstrated with short-chain β-fructans. Moreover, the meta-analysis highlighted significant differences in stool consistency in contrast to fecal dry weight after β-fructan supplementation. This systematic review and meta-analysis indicates that short-chain β-fructan supplementation has a positive effect on bowel function by significantly increasing the frequency of bowel movements.

Impact of Cultivation Method and Cultivar Selection on Soluble Carbohydrates and Pungent Principles in Onions ( Allium cepa L.)

The composition of soluble carbohydrates such as fructooligosaccharides (FOS) in onions ( Allium cepa L.) plays a role regarding their digestibility, long-term storability, and processability. Qualitative and quantitative profiles of soluble carbohydrates were determined in 23 different onion samples comprising 20 cultivars grown at two different locations in 2014 and 2015. FOS concentrations were 1.1-fold higher in set grown onions than in seed grown onions ( p = 0.001). FOS levels of dehydrator cultivars were higher (overall average: 130.8 ± 42.4 g/L FOS) than those of common set and seed (61.8 ± 20.0 and 29.4 ± 14.7 g/L FOS) grown cultivars. Consequently, cultivation method (seed vs. set planting) and cultivar selection were crucial when aiming at onions with defined FOS contents. Besides FOS and other carbohydrate-related parameters, levels of alk(en)yl cysteine sulfoxides, indicating onion oil yield and pungency of onions, were determined to be different in dehydrator onions (13.1 ± 2.6 μmol/mL), seed (8.4 ± 1.3 μmol/mL), and set grown onions (7.5 ± 1.6 μmol/mL).