Effect of fractionated lotus seed resistant starch on proliferation of Bifidobacterium longum and Lactobacillus delbrueckii subsp. bulgaricus and its structural changes following fermentation

Evolution of multi-scale structure and microbiota metabolism of lentil resistant starch during the dynamic fermentation in vitro

This study investigated the structural changes of resistant starch (RS) derived from autoclaved lentil starch (ALRS) and untreated lentil starch (ULRS) during in vitro colonic fermentation, as well as their regulatory effects on the composition of the intestinal microbiota. Following in vitro fermentation, both RS samples exhibited a progressive decrease in molecular weight and a gradual increase in double helix/order. Bifidobacterium was more abundant in ULRS during the initial period of fermentation, while ALRS showed higher abundance in the later stage. ALRS demonstrated greater production of short-chain fatty acids (SCFAs) compared to ULRS, likely attributed to its higher structural order and faster fermentation pattern. The distinct surface morphologies of ULRS and ALRS played a crucial role in determining the accessibility of RS substrates for microbial fermentation. These different structural patterns also influenced the shifts in microbial composition in fecal cultures, leading to variations in SCFAs production through anaerobic fermentation.

Structural changes of rice starch-anthocyanins complexes (V-type) and its impact on gut microbiotas and potential metabolic pathways during in vitro fermentation

This study explored the differences in the in vitro fermentation properties of rice starch (RS) and rice starch-anthocyanins complexes (RS-A). Structural characterization suggested that RS and RS-A complexes showed a V-type crystalline structure. The degree of order (DO) and degree of double helix (DD) values of RS and RS-A complexes were enhanced after fermentation. Moreover, the RS-A complexes could improve the relative abundance of Bacteroidetes, Ruminococcaceae, and up-regulate gut microbiota diversity to maintain gut homeostasis. Relative abundance of potential metabolic pathways, such as energy metabolism, digestion system, and carbohydrate degradation overexpressed in the presence of RS-A complexes. The results demonstrated that the RS-A complexes had slower fermentation rates contributing to the transport of the formed short-chain fatty acid (SCFA) to the end of the colon and that the crystallinity might be a factor influencing the utilization of the starch matrix by the gut microbiota for SCFA formation.

New insights into starch, lipid, and protein interactions - Colon microbiota fermentation

Starch, lipids, and proteins are essential biological macromolecules that play a crucial role in providing energy and nutrition to our bodies. Interactions between these macromolecules have been shown to impact starch digestibility. Understanding and controlling starch digestibility is a key area of research. Investigating the mechanisms behind the interactions of these three components and their influence on starch digestibility is of significant practical importance. Moreover, these interactions can result in the formation of resistant starch, which can be fermented by gut microbiota in the colon, leading to various health benefits. While current research has predominantly focused on the digestive properties of starch in the small intestine, there is a notable gap in understanding the colonic microbial fermentation phase of resistant starch. The benefits of fermentation of resistant starch in the colon may outweigh its glucose-lowering effect in the small intestine. Thus, it is crucial to study the fermentation behavior of resistant starch in the colon. This paper investigates the impact of interactions among starch, lipids, and proteins on starch digestion, with a specific focus on the fermentation phase of indigestible carbohydrates in the colon. Furthermore, valuable insights are offered for guiding future research endeavors.

A multihole nozzle controls recrystallization of high-moisture extruded maize starches: Effect of cooling die temperature

Hot extrusion is utilized for starch modification due to its high mechanical input and product output. Amylose recrystallization commences and primarily depends on intermolecular interactions after conventional extrusion. Hence, the design of a new component based on the existed extrusion system was aimed at facilitating molecular aggregation, potentially accelerating starch recrystallization. In this study, a nozzle sheet comprising 89 holes was integrated into the cooling die. The impact of the multihole nozzle on the structure and in vitro digestibility of extruded maize starches after retrogradation was examined at varying cooling die temperatures. The results showed that the nozzle-assembled extrusion system operated effectively without additional mechanical or yield losses. At 50 °C, the crystallinity of nozzle-produced starch was approximately 70 % higher than that of conventionally extruded starch, predominantly owing to the B-type allomorph of the amylose double helix. Recrystallized amylopectin was also found in these nozzle-produced starches, indicating that multihole nozzle-induced uniaxial elongational flow resulted in the rapid starch crystallization. The increased formation of recrystallized amylose led to improved molecular order in starch structures while reducing their digestibility. These findings revealed a new approach to improve starch crystallinity by incorporating a nozzle sheet in the extrusion process.

Effect of lotus seed resistant starch on the bioconversion pathway of taurocholic acid by regulating the intestinal microbiota

Taurocholic acid (TCA) is abundant in the rat intestine and has multiple health benefits. In the gut, intestinal microbiota can transform TCA into different bile acid (BA) derivatives, with the composition of microbiota playing a crucial role in the transformation process. This study aims to investigate how lotus seed resistant starch (LRS) can regulate microbiota to influence BA transformation. A fecal fermentation study was conducted in vitro, using either LRS, high-amylose maize starch (HAMS), or glucose (GLU) to analyze microbiota composition, BA content, and metabolic enzyme activities over different fermentation times. Bioinformatics analysis found that LRS increased the relative abundance of Enterococcus, Bacillus, and Lactobacillus, and decreased Escherichia-Shigella, compared with HAMS and GLU. LRS also reduced total BA content and accelerated the conversion of TCA to cholic acid, deoxycholic acid, and other derivatives. These results reveal that LRS and GLU tend to mediate the dehydroxy pathway, whereas HAMS tends to secrete metabolic enzymes in the epimerization pathway. Therefore, the evidence that LRS may regulate TCA bioconversion may benefit human colon health research and provide an important theoretical basis, as well as offer new concepts for the development of functional foods.

Research Progress in Modifications, Bioactivities, and Applications of Medicine and Food Homologous Plant Starch

Starchy foods are an essential part of people's daily diet. Starch is the primary substance used by plants to store carbohydrates, and it is the primary source of energy for humans and animals. In China, a variety of plants, including edible medicinal plants, such as Pueraria root, yam tuber and coix seed, are rich in starch. However, limited by their inherent properties, kudzu starch and other starches are not suitable for the modern food industry. Natural starch is frequently altered by physical, chemical, or biological means to give it superior qualities to natural starch as it frequently cannot satisfy the demands of industrial manufacturing. Therefore, the deep processing market of modified starch and its products has a great potential. This paper reviews the modification methods which can provide excellent functional, rheological, and processing characteristics for these starches that can be used to improve the physical and chemical properties, texture properties, and edible qualities. This will provide a comprehensive reference for the modification and application of starch from medicinal and edible plants.

Addition of Canna edulis starch and starch nanoparticles to stabilized Pickering emulsions: In vitro digestion and fecal fermentation

Starch nanoparticles (SNPs) were prepared through acid hydrolysis of Canna edulis native starch and modified with octenyl succinic anhydride (OSA) to yield OS-starch and OS-SNPs. These modified particles were used to stabilize curcumin-loaded Pickering emulsions. Effects on gut microbiota during in vitro fecal fermentation were examined. The surface of OS-starch exhibits a porous structure, while OS-SNPs display layered grooves. OSA modification was confirmed by Fourier transform infrared spectroscopy (with peaks at 1728 cm-1 and 1573 cm-1) and proton nuclear magnetic resonance spectra (0.5-2 ppm). The degree of substitution for OS-starch and OS-SNPs is 0.0106 ± 0.0004 and 0.0079 ± 0.0003, respectively. Following modification, the crystallinity decreased from 35.69 ± 0.46 % (native starch) to 30.17 ± 0.70 % (OS-starch), SNPs decreased from 45.87 ± 0.89 % to 43.63 ± 0.64 % (OS-SNPs). Contact angles for OS-starch and OS-SNPs are 77.47 ± 1.78 and 55.57 ± 0.21, respectively. OS-SNPs exhibited superior emulsification properties compared to OS-starch, forming stable Pickering emulsions with pseudoplastic fluid behavior and enhanced curcumin storage protection over 14 days (60.88 ± 4.26 %) with controlled release. Stabilizing Pickering emulsions with OS-starch and OS-SNPs positively affected on gut microbiota and improved the intestinal environment, showing promise for their application in transportation systems and innovative prebiotic food formulations.

New plant-based fermented beverage made of baru nut enriched with probiotics and green banana: composition, physicochemical and sensory properties

This study aimed to evaluate the influence of potential functional ingredients-green banana starch, green banana pulp flour or whole green banana flour-on the composition, physicochemical and sensory properties of plant-based fermented beverages made of baru nuts. The incorporation of green banana-derived ingredients, especially the whole flour, increased protein (2.44-2.81 g/100 g), fibre (1.53-2.32 g/100 g), resistant starch (0.15-0.33 g/100 g) and ash (0.36-0.61 g/100 g) content in fermented beverages. The total phenolic content and antioxidant capacity were higher in beverages added with pulp or whole flour. The main polyphenols identified were catechin (0.75-4.97 mg/100 g), gallic acid (0.29-0.52 mg/100 g) and ferulic acid (0.17-0.64 mg/100 g). All beverages showed to be rich in unsaturated fatty acids (68%) as omega-3, omega-6, and conjugated linoleic acid. The incorporation of green banana in beverages enhanced the probiotic bacteria growth indicating the potential prebiotic effect of the unripe fruit. The sensory acceptance of fermented beverages was also improved after adding green banana. Overall, whole green banana flour stood out as the main factor that increased the nutritional value of baru nut fermented beverage. Green banana was used for the first time as a potential prebiotic ingredient in a plant-based beverage. This novel product represents a potential symbiotic non-dairy alternative that could offer health benefits to consumers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05781-5.

Effect of resistant starch types as a prebiotic

Since the role of intestinal microbiota in metabolism was understood, the importance of dietary components such as fibres and prebiotics, which affect the modulation of microbiota, has been increasing day by day. While all prebiotic components are considered dietary fibre, not every dietary fibre is considered a prebiotic. While fructooligosaccharides, galactooligosaccharides, inulin, and galactans are considered prebiotics, other fermentable carbohydrates are considered candidate prebiotic components based on in vitro and preclinical studies. Resistant starch, one of such carbohydrates, is considered a potential prebiotic component when it is made resistant to digestion naturally or chemically. In this review, both in vitro and in vivo studies in which the prebiotic capacity of type II, type III, and type IV resistant starch isolated from food and produced commercially was assessed were analyzed. According to the results of current studies, certain types of resistant starch are thought to have a high prebiotic capacity, and they may be candidate prebiotic components although positive results have not been achieved in all studies. KEY POINTS: • Resistant starch is undigested in the small intestine and is fermented in the large intestine. • Resistant starch fermentation positively affects the growth of Bifidobacterium and Lactobacillus. • Resistant starch can be considered a prebiotic ingredient.

Dietary enrichment of resistant starches or fibers differentially alter the feline fecal microbiome and metabolite profile

BACKGROUND

Cats are strict carnivores but possess a complex gastrointestinal (GI) microbial community that actively ferments dietary substrates that are not digested and reach the colon. The GI microbiota responses to dietary inclusion of resistant starches versus fibers have not been tested in cats. Thus, our objective was to evaluate the effects of diets enriched in resistant starch or fibers on the fecal characteristics, microbiome, and metabolite profiles of cats. Twelve healthy adult domestic shorthair cats (age = 9.6 ± 4.0 year; body weight = 3.9 ± 1.0 kg) were used in a replicated 3 × 3 Latin square design to test diets that were enriched with: (1) resistant starch (ERS), (2) a fiber-prebiotic-probiotic blend (FPPB), or (3) a fiber-prebiotic-probiotic blend + immune-modulating ingredients (iFPPB). In each 28-day period, 22 days of diet adaptation was followed by fecal and blood sample collection. Fecal samples were used for shotgun metagenomic sequencing. In addition, fecal and blood metabolite measurements and white blood cell stimulation was performed to assess immune function.

RESULTS

A total of 1690 bacterial species were identified, with 259 species differing between fiber-rich and ERS treatments. In comparison with fiber-rich treatments that increased diversity and promoted Firmicutes and Bacteroidetes populations, resistant starch reduced microbial diversity and fecal pH, led to a bloom in Actinobacteria, and modified Kyoto Encyclopedia of Genes and Genomes orthology (KO) terms pertaining to starch and sucrose metabolism, fatty acid biosynthesis and metabolism, epithelial cell signaling, among others. Resistant starch also differentially modified fecal metabolite concentrations with relevance to GI and overall host health (increased butyrate; decreased propionate and protein catabolites - branched-chain fatty acids; phenols and indoles; ammonia) and reduced blood cholesterol, which correlated strongly with microbial taxa and KO terms, and allowed for a high predictive efficiency of diet groups by random forest analysis.

CONCLUSION

Even though domestic cats and other carnivores evolved by eating low-carbohydrate diets rich in protein and fat, our results demonstrate that the feline microbiome and metabolite profiles are highly responsive to dietary change and in directions that are predictable.

Difference in the adhesion of Bifidobacterium breve to lotus seed resistant starch is attributable to its structural performance conferred by the preparation method

Resistant starch (RS) is a kind of important carbon source for colonic microorganisms. Its structure-function relationship is helpful to understand the mechanism of dietary nutrition in the body. In this paper, lotus seed resistant starches (LRS) prepared by microwave-power method (MP-LRS3-1 and MP-LRS3-2) and water-bath method (WB-LRS3-1 and WB-LRS3-2) were used to determine the structural changes and establish their nutritional interactions with Bifidobacterium breve. The results showed that four types all formed scale- and gully-like surface microstructures, B-type crystal structures, and lightly variable double helix structures. However, greater diffraction peak intensity was observed of MP-LRS3 at 18° and 19° compared with WB-LRS3, and higher crystallinity and tighter double helix were detected in MP-LRS3-1 than others. Meanwhile, MP-LRS3-1 showed the most effective proliferation promoting capability and highest adhesion value to B. breve. It might be related to specific surface microstructure and crystallinity differences of LRS caused by different preparing methods. There was also a positive correlation between the adhesion and the ability to promote proliferation, and it could be speculated this structural difference makes MP-LRS3-1 having highest adhesion ability and the most proliferative effect. This result can provide theoretical bases for improving the metabolism and probiotic action of RS.

Influence of corn resistant starches type III on the rheology, structure, and viable counts of set yogurt

The study intended to explore the influence of corn resistant starches type III (RS3s) prepared by autoclave, debranching, and microwave heat on the rheology, structure, and viable counts of set yogurt. The rheological analysis suggested that RS3s enhanced the elastic and viscous modulus of yogurt, and that microwave-heated RS was the most effective for improving viscoelasticity. Fitting the creep data using the Burger model showed that yogurt with microwave-heated RS increased the structural strength of yogurt, which displayed the highest instantaneous and viscoelastic deformations. The confocal laser scanning microscopy and scanning electron microscopy micrographs demonstrated that autoclaved and debranched RS3s formed large fragments and disrupted the continuity of the milk protein structure; however, microwave-heated RS evenly filled the gel network and formed an interpenetrating network with proteins. The bacterial count and acidity of yogurt indicated that microwave-heated and debranched RS3s promoted the growth of lactic acid bacteria and accelerated the fermentation process of yogurt. The results of this study demonstrated that microwave-heated RS is a favorable supplement to the microstructure and rheological properties of yogurt compared with autoclaved and debranched RS3s.

Viability of Lactobacillus delbrueckii in chocolates during storage and in-vitro bioaccessibility of polyphenols and SCFAs

This study evaluated the viability of encapsulated Lactobacillus delbrueckii subsp. bulgaricus in chocolate during storage and in-vitro gastrointestinal transit. Flavonoid contents and short chain fatty acids (SCFAs) production during gastrointestinal transit were also assessed. Encapsulated L. delbrueckii subsp. bulgaricus survived well in chocolates >7 logs both after 120 days of storage at 4 °C and 25 °C, and during in-vitro gastrointestinal transit. The release of SCFAs through in-vitro gastrointestinal digestion and colonic fermentation revealed that probiotic-chocolates could be an excellent source of nutrients for the gut microbiota. Encapsulated probiotic in chocolates with 70% cocoa produced significantly (P < 0.05) more acetic, propionic, isobutyric, butyric and isovaleric acids than that with 45% cocoa. The bioconversion results of a specific polyphenol by L. delbrueckii subsp. bulgaricus exhibited that chocolate polyphenols could be utilized by probiotics for their metabolism. These findings confirmed that chocolate could be successfully fortified with L. delbrueckii subsp. bulgaricus encapsulation to improve health promoting properties of chocolates.

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Chocolates enhance the biosynthesis of SCFAs and Vit B₁₂ in colonic fermentation.

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Chocolates served as a prebiotic source for gut microbiota proliferation.

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Chocolate with probiotics would favor the bioconversion of a specific polyphenols.

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Chocolates nutritional value can be enhanced via fortification with probiotics.

Synergistic Effects of Lotus Seed Resistant Starch and Sodium Lactate on Hypolipidemic Function and Serum Nontargeted Metabolites in Hyperlipidemic Rats

The synergistic effects of lotus seed resistant starch (LRS3) and sodium lactate (SL; a postbiotics of RS3) on hypolipidemic function and serum nontargeted metabolites of hyperlipidemia rats were investegated. Rats fed a high-fat diet were orally administered with LRS3 (HLRS group) or SL (HSL group) either alone or in combination (HLRSSL group) for consecutive 4 weeks. HLRSSL was found to control weight gain, regulate blood lipid levels, reduce accumulation of fat in liver cells, and improve lesions in rat cardiac arteries, liver, small intestine, and colon tissues more effectively compared to HLRS or HSL group alone. Compared to the high-fat control group (HMC), l-phenylalanine and LysoPC(22:6(4Z,7Z,10Z,13Z,16Z,19Z)) in serum were upregulated in HLRSSL rats, while aconitic acid and suberic acid were decreased. Correlation analysis showed that SM(d18:0/16:1(9Z)), taurochenodeoxycholic acid, LysoPC(22:6(4Z,7Z,10Z,13Z,16Z,19Z)), oleic acid, and retinol were negatively correlated with total cholesterol (TCHO), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) and positively correlated with high-density lipoprotein cholesterol (HDL-C). Moreover, glutamic acid and serine showed a significant positive correlation with LDL-C and negative correlation with HDL-C. These differential metabolites were associated with reducing serum lipid levels in hyperlipidemia rats potentially through metabolic pathways such as linoleic acid, glutamine and glutamate, pyruvate, citric acid cycle, and glycerophospholipid.

Effects of a traditional Chinese medicine formula containing the Coix seed and Lotus seed on the intestinal morphology and microbiota of local piglets

A traditional Chinese medicine formula based on the Coix seed and Lotus seed has been used as a general treatment of malnutrition, excessive fatigue, dysfunction of the spleen and stomach, and disorders of water transport in humans in China. However, there is limited information on its effects on the gut microbiota of piglets in vivo. In this study, the mix of Coix seed and Lotus were added the diet of forty weaned piglets (local piglets), and then evaluated it's affected on the gut microbiota of piglets and on the relations within the gut bacterial community. The results indicated that this traditional Chinese medicine formula (LM) and the extract of the traditional Chinese medicine formula (LMT) downregulated pH of succus gastricus and raised pH of the ileum, and LMT obviously decreased the feed conversion ratio. Further study showed LMT and LM also significantly increased the thick and long of gastrointestinal villi. And then, 16S ribosomal DNA sequencing revealed that groups LMT and LM have higher relative abundance of the genus Lactobacillus in the colon, succus gastricus, and jejunum, which are beneficial bacteria sold as dietary supplements to aid digestion or to augment health. Meanwhile, the relative abundance levels of Prevotellaceae, Alloprevotella, and Prevotella in the colon and Clostridium in succus gastricus and jejunum were lower. These experiments highlight the usefulness of the traditional Chinese medicine formula based on the Coix seed and Lotus seed for decreasing pH in succus gastricus, for improving the structure of intestinal villi and gut microflora, and then for achieving improvements in pig production performance.

Soluble Dietary Fiber, One of the Most Important Nutrients for the Gut Microbiota

Dietary fiber is a widely recognized nutrient for human health. Previous studies proved that dietary fiber has significant implications for gastrointestinal health by regulating the gut microbiota. Moreover, mechanistic research showed that the physiological functions of different dietary fibers depend to a great extent on their physicochemical characteristics, one of which is solubility. Compared with insoluble dietary fiber, soluble dietary fiber can be easily accessed and metabolized by fiber-degrading microorganisms in the intestine and produce a series of beneficial and functional metabolites. In this review, we outlined the structures, characteristics, and physiological functions of soluble dietary fibers as important nutrients. We particularly focused on the effects of soluble dietary fiber on human health via regulating the gut microbiota and reviewed their effects on dietary and clinical interventions.

Synergistic effect of lotus seed resistant starch and short-chain fatty acids on mice fecal microbiota in vitro

This study aimed to investigate the synergistic effect of lotus seed resistant starch (LRS) and short-chain fatty acids (SCFAs) on mice fecal bacterial flora and the contents of SCFAs in vitro. Following 24 h of fermentation, 16S rRNA analysis revealed several differences in the fecal microbiota community structure among primal bacteria (PB), LRS and different SCFAs combined with LRS groups (SCFAs-LRS). The LRS group increased the relative abundance of Lactobacillus, Allobaculum, Clostridium, Bacteroides and Prevotella. Among the SCFAs-LRS group, AA-LRS increased the relative abundance of Prevotella, and Bacillus. PA-LRS increased abundance of Sphingomonas and the BA-LRS group significantly increased the relative abundance of Rhizobiales, Brucellaceae and Ochrobactrum. Meanwhile, propionic acid and BA productions significantly increased in the BA-LRS group. The SCFAs-LRS group elicited a beneficial effect on the fecal microbiota by increasing production of SCFAs. We highlight the fact that the combination of LRS and SCFA can increase the contents of SCFAs produced by mice fecal microbiota. In short, the combination of LRS and SCFA can influence intestinal flora by promoting the growth of beneficial bacteria and can serve as new prebiotics for promoting health and disease management.

Isolated Pea Resistant Starch Substrates with Different Structural Features Modulate the Production of Short-Chain Fatty Acids and Metabolism of Microbiota in Anaerobic Fermentation In Vitro

Resistant starches (RSs) with different structural features were isolated from both native and pullulanase-debranched and acid-hydrolyzed pea starches. Their microscopic changes, short-chain fatty acids (SCFA) composition, microbiota communities, and structural characteristics of the corresponding fermenta residues by the end of 24 h of the in vitro fermentation period were investigated. The microbial fermentation clearly caused numerous cracks and erosion on the RS granule surface. In comparison to the positive control, significantly higher levels of butyrate, propionate, and total SCFA were produced after 24 h of in vitro fecal fermentation when resistant starches were used as substrates. The RS substrates with different structural characteristics enabled varying growth of Bifidobacterium spp., Eubacterium spp., and Faecalibacterium spp. The discrepancy in microbiota communities associated with the differences in SCFA from the fermentation of RS with different structural features would be critical toward the rational design of foods containing resistant starch with targeted health benefits.

Homology- and cross-resistance of Lactobacillus plantarum to acid and osmotic stress and the influence of induction conditions on its proliferation by RNA-Seq

In this study, homology- and cross-resistance of Lactobacillus plantarum L1 and Lactobacillus plantarum L2 to acid and osmotic stress were investigated. Meanwhile, its proliferation mechanism was demonstrated by transcriptomic analysis using RNA sequencing. We found that the homologous-resistance and cross-resistance of L. plantarum L1 and L. plantarum L2 increased after acid and osmotic induction treatment by lactic acid and sodium lactate solution in advance, and the survival rate of live bacteria was improved. In addition, the count of viable bacteria of L. plantarum L2 significantly increased cultivated at a pH 5.0 with a 15% sodium lactate sublethal treatment, compared with the control group. Further study revealed that genes related to membrane transport, amino acid metabolism, nucleotide metabolism, and cell growth were significantly upregulated. These findings will contribute to promote high-density cell culture of starter cultures production in the fermented food industry.

RS5 Produced More Butyric Acid through Regulating the Microbial Community of Human Gut Microbiota

The objective of this research was to compare the in vitro fermentability of three resistant starches (RS2, RS3, and RS5). Structural analyses showed that there were small changes in the long- and short-range ordered structure of three RSs after fermentation by human gut microbiota. The fermentation of RSs by gut microbiota produced large amounts of short-chain fatty acids, with RS5 producing more butyric acid and RS3 producing more lactic acid. RS3 and RS5 decreased the pH of the fermentation culture to a greater extent compared with RS2. Moreover, RS5 increased significantly the relative abundance of Bifidobacterium, Dialister, Collinsella, Romboutsia, and Megamonas. The results suggested that the form of RS was the main factor affecting the physiological function of RS and that RS5, as a recently recognized form of resistant starch, could be a better functional ingredient to improve health compared with RS2 and RS3.

Influence of guabiroba pulp (campomanesia xanthocarpa o. berg) added to fermented milk on probiotic survival under in vitro simulated gastrointestinal conditions

In fermented milks inoculated with two thermophilic strains (Lactobacillus bulgaricus and Streptococcus thermophilus), guabiroba pulp (Campomanesia xanthocarpa O. Berg) was added in different concentrations: 5% (I5 sample) and 10% (I10 sample), compared to a control sample, with no pulp addition. In these fermented milks, Bifidobacterium BB-12 was added and the samples were submitted to a progressive gastrointestinal simulation in vitro. The cells count was performed, including the survival rates for all the progressive steps of the simulated digestion. Total phenolic content (TPC) and antioxidant activity analysis by FRAP (Ferric Reducing Antioxidant Power) and DPPH (2,2-diphenyl-1-picrylhydrazyl) were performed in all the gastrointestinal steps. Before and during the entire gastrointestinal tract, the Bifidobacterium BB-12 count was 8-9 log CFU g^-1, above the recommended for a probiotic product, with a highlight in intestinal colon steps. The I10 sample showed the highest viable cell count, the highest total phenolic content and antioxidant activity throughout the entire gastric steps (p < 0.05). The fermented milk proved to be an effective matrix for the probiotic stability and incorporation of guabiroba components. Bioactive compounds present in the guabiroba pulp may have occasioned a prebiotic and protective effect on Bifidobacterium BB-12 after gastric conditions. The possible bioconversion of these compounds in more active forms can contribute to the absorption in epithelial cells, enhancing fermented milks with guabiroba pulp as important sources of dietary accessible bioactive compounds.

Lactobacillus plantarum relieves diarrhea caused by enterotoxin-producing Escherichia coli through inflammation modulation and gut microbiota regulation

Lactobacillus plantarum can relieve diarrhea caused by enterotoxigenic Escherichia coli (ETEC), but the remission mechanism has not been fully explained. This study compares the ability of four Lactobacillus plantarum strains from different niches to alleviate diarrhea caused by ETEC infection and explores their potential remission manner. The results showed that Lactobacillus plantarum CCFM1143 had the most obvious protective effect on diarrhea caused by ETEC. FGDLZ1M5, FCQNA30M6 and CCFM1143 reduced tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin (IL)-6 as well as jejunal injury. Moreover, FCQNA30M6 and CCFM1143 increased the aquaporin AQP3, and CCFM1143 increased interleukin (IL)-10 and decreased heat-stable enterotoxin (ST), while FGDLZ1M5 reduced the toll-like receptor (TLR4). The gut microbiota analysis demonstrated that ETEC increased Proteus and Pseudomonas and reduced Bifidobacterium, Odoribacter, Allobaculum and Blautia. A supplement of Lactobacillus plantarum could reconstruct the unbalanced gut microbiota. Furthermore, CCFM1143 significantly increased butyric acid, acetic acid, propionic acid and isobutyric acid, while FGDLZ1M5 only increased butyric acid. In summary, Lactobacillus plantarum alleviated ETEC-induced diarrhea by regulating the inflammatory cytokines, rebalancing the gut microbiota and modulating short-chain fatty acids (SCFAs) generation, which could provide the foundation and support for subsequent clinical trials and probiotic products.

Comprehensive analysis of AGPase genes uncovers their potential roles in starch biosynthesis in lotus seed

BACKGROUND

Starch in the lotus seed contains a high proportion of amylose, which endows lotus seed a promising property in the development of hypoglycemic and low-glycemic index functional food. Currently, improving starch content is one of the major goals for seed-lotus breeding. ADP-glucose pyrophosphorylase (AGPase) plays an essential role in regulating starch biosynthesis in plants, but little is known about its characterization in lotus.

RESULTS

We describe the nutritional compositions of lotus seed among 30 varieties with starch as a major component. Comparative transcriptome analysis showed that AGPase genes were differentially expressed in two varieties (CA and JX) with significant different starch content. Seven putative AGPase genes were identified in the lotus genome (Nelumbo nucifera Gaertn.), which could be grouped into two subfamilies. Selective pressure analysis indicated that purifying selection acted as a vital force in the evolution of AGPase genes. Expression analysis revealed that lotus AGPase genes have varying expression patterns, with NnAGPL2a and NnAGPS1a as the most predominantly expressed, especially in seed and rhizome. NnAGPL2a and NnAGPS1a were co-expressed with a number of starch and sucrose metabolism pathway related genes, and their expressions were accompanied by increased AGPase activity and starch content in lotus seed.

CONCLUSIONS

Seven AGPase genes were characterized in lotus, with NnAGPL2a and NnAGPS1a, as the key genes involved in starch biosynthesis in lotus seed. These results considerably extend our understanding on lotus AGPase genes and provide theoretical basis for breeding new lotus varieties with high-starch content.

Effect of lotus seed resistant starch on tolerance of mice fecal microbiota to bile salt

We investigated the effect of lotus seed resistant starch (LRS) on mice fecal microbiota tolerance to bile salt by culturing organisms compared to inulin (INU) glucose (GLU) and waxy corn starch (WAX). Operational taxonomic units (OTUs) and diversity indices in LRS and INU groups were increased in the presence of 0.03% to 0.3% bile salt, while they were decreased in GLU, and OTUs were decreased in WAX. Specifically, LRS promoted proliferation of Lactobacillus, which potentially used bile acid, and inhibited growth of the potentially harmful bacteria Enterococcus and Staphylococcus. Moreover, Lactobacillus was negatively correlated with Salinicoccus and Granulicatella in GLU, LRS and INU groups at 1.5% bile salt. With LRS, amino acid metabolic pathways were increased while pathogens causing certain diseases were decreased. LRS increased the tolerance of mice fecal microbiota to bile salt by promoting the proliferation of bacteria utilizing bile acid and inhibiting the growth of harmful bacteria.

The preparation, formation, fermentability, and applications of resistant starch

Resistant starch (RS) cannot be digested in the small intestine but can be fermented by microflora in the colon. To meet the demand for RS, effective methods and advanced equipment for preparing RS have emerged, but further development is needed. RS contents are affected by different prepared methods, starch source and certain nutrients such as protein, phenols, and hydrocolloids interacted with RS. As a beneficial fermentation substrate, RS modifies and stabilizes the intestinal flora to balance the intestinal environment and improve intestinal tract health and function. RS is also a kind of ingredient with potential physiological function, even better than that dietary fiber, but also in terms of providing various health benefits. RS has good food-processing characteristics as well and can thus be widely used in the food industry.

Effects of nanobubble water on the growth ofLactobacillus acidophilus1028 and its lactic acid production

Nanobubbles (NBs) in the culture medium may offer a new way of accelerating bacterial growth in the lag and logarithmic phases.