Lactulose: Properties, techno-functional food applications, and food grade delivery system

Production of lactulose from lactose using a novel cellobiose 2-epimerase from Clostridium disporicum

Lactulose is a semisynthetic nondigestive sugar derived from lactose, with wide applications in the food and pharmaceutical industries. Its biological production routes which use cellobiose 2-epimerase (C2E) as the key enzyme have attracted widespread attention. In this study, a set of C2Es from different sources were overexpressed in Escherichia coli to produce lactulose. We obtained a novel and highly efficient C2E from Clostridium disporicum (CDC2E) to synthesize lactulose from lactose. The effects of different heat treatment conditions, reaction pH, reaction temperature, and substrate concentrations were investigated. Under the optimum biotransformation conditions, the final concentration of lactulose was up to 1.45 M (496.3 g/L), with a lactose conversion rate of 72.5 %. This study provides a novel C2E for the biosynthesis of lactulose from low-cost lactose.

Metabolites 13,14-Dihydro-15-keto-PGE2 Participates in Bifidobacterium animalis F1-7 to Alleviate Opioid-Induced Constipation by 5-HT Pathway

SCOPE

People suffer from constipation caused by many factors, including constipation (Opioid-Induced Constipation, OIC) during analgesic treatment. Microorganisms may be a potent solution to this problem, but the mechanism is still unclear.

METHODS AND RESULTS

Based on models in vivo and in vitro, the potential mechanism involving Bifidobacterium animalis F1-7 (B. animalis F1-7), screened in the previous studies, is explored through non-targeted metabonomics, electrophysiological experiment and molecular level docking. The results showed that B. animalis F1-7 effectively alleviates OIC and promotes the expression of chromogranin A (CGA) and 5-hydroxytryptamine (5-HT). The metabolite 13,14-dihydro-15-keto-PGE2 related to B. animalis F1-7 is found, which has a potential improvement effect on OIC at 20 mg kg BW-1 in vivo. At 30 ng mL-1 it effectively stimulates secretion of CGA/5-HT (408.95 ± 1.18 ng mL-1 ) by PC-12 cells and changes the membrane potential potassium ion current without affecting the sodium ion current in vitro. It upregulates the target of free fatty acid receptor-4 protein(FFAR4/β-actin, 0.81 ± 0.02).

CONCLUSION

The results demonstrate that metabolite 13,14-dihydro-15-keto-PGE2 participated in B. animalis F1-7 to alleviate OIC via the 5-HT pathway.

Production of high-purity lactulose via an integrated one-pot boronate affinity adsorbent based adsorption-assisted isomerization and simultaneous purification

High-purity lactulose is mandatory for its medical uses and food applications. This work developed an efficient lab-scale strategy for the synthesis of high-purity lactulose by combining lactose-to-lactulose isomerization with simultaneous recovery of lactulose, which was conducted concurrently and semi-continuously in a boronate affinity adsorbent-packed column. The first step covers the boronate affinity adsorbent-based adsorption-assisted lactose-to-lactulose isomerization. Under optimized conditions, in situ selectively binding of the newly formed lactulose onto the boronate affinity adsorbent enables a much-enhanced lactulose yield up to 80.20% with the lowest byproducts yield of 6.30%. Afterward, over 90% of the adsorbed lactulose can be recovered through sequential desorption with purity >98%. The net outcome of the applied strategy was the yield of high-purity lactulose up to 72.31%, the highest value ever reported. Moreover, the packed column displayed excellent operational stability. The encouraging results validate the high potential of this approach in the sustainable production of high-purity lactulose.

Natural Deep Eutectic Solvents for Solubility and Selective Fractionation of Bioactive Low Molecular Weight Carbohydrates

Natural deep eutectic solvents (NADESs) have been shown to be selective and environmentally friendly solvents for the extraction of bioactive compounds. However, studies on the solubility of low-molecular-weight carbohydrates (LMWCs) in NADESs are scarce. In this work, new solubility data of LMWCs in NADESs are provided and a new approach based on the use of these solvents for the efficient fractionation of bioactive carbohydrates was explored for the first time. Several mono- and disaccharides and three NADESs based on choline chloride (ChCl) and different donors (2-ethylene glycol (EtG), glycerol (Gly) and ethanedioic acid dihydrate (Eth)) were considered. While the degradation of carbohydrates, mainly ketoses, was detected with ChCl:Eth due to its acidic nature, ChCl:EtG and ChCl:Gly were found to be useful alternatives for selectively separating bioactive ketoses and their corresponding aldoses (e.g., lactulose/lactose and tagatose/galactose) present in equimolar binary mixtures. In addition, the usefulness of ChCl:EtG for the selective enrichment of lactulose to be used as food ingredient or nutraceutical was proven (from a 25% in the reaction mixture to a 56% in the purified sample). NADESs could be used for the selective fractionation of value-added carbohydrates from interfering sugars for several applications, including food science, engineering or pharmaceuticals.

Regulatory effect of lactulose on intestinal flora and serum metabolites in colitis mice: In vitro and in vivo evaluation

Lactulose is a common component in foods. However, the effect of lactulose on intestinal flora and overall metabolic levels remains unclear. Therefore, this study aims to explore the regulative role of lactulose on intestinal flora and serum metabolites via in vitro simulated colonic fermentation model and in vivo colitis mouse model. The results showed that lactulose significantly enriched beneficial bacteria including Dubosiella and Bifidobacterium, and reduced pathogenic bacteria such as Fusobacterium. Moreover, lactulose significantly inhibited dextran sodium sulfate-induced body weight loss, colon shortening, colonic inflammatory infiltration, and pro-inflammatory cytokines IL-6, TNF-α, IL-17, and IL-1β. Lactulose significantly affected serum metabolome in colitis mice and total 24 metabolites representing a high inter-group difference were obtained. Correlation analysis revealed that the changes in serum metabolites were closely associated with the role of intestinal flora, and thus affected phenotypic indicators. Our study provides a reference for nutritional characteristics and application scenarios of dietary lactulose.

Characterization and valorization of soybean residue (okara) for the development of synbiotic ice cream

There is an increasing challenge in probiotic viability and stability during food product formulation, processing, and storage. However, synbiotic functional foods have promising potential to deliver the targeted benefits. This study aimed to isolate the okara from soybean residue, and obtained okara flour was further characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Synbiotic ice cream was developed by fortification with Lactobacillus rhamnosus GG and okara at different concentrations (1-3%). Additionally, the synbiotic ice cream was subjected to physicochemical and sensory attributes over 60 days of storage. High viability of L. rhamnosus GG (8.17 log CFU/mL) was observed during storage at 3% okara. Moreover, adding okara at 2% or higher improved viscosity, reduced overrun, and maintained probiotic viability. When compared to the control (ice cream without okara), synbiotic ice cream exhibited a higher protein content and a lower fat level. The synergistic combination of probiotics and okara in ice cream is a potentially novel approach for developing functional ice cream. The addition of okara is not only helpful in increasing the nutritional value of the ice cream but will also be a way forward to minimize agricultural waste. Synbiotic ice cream developed in this study may be considered a potential functional food rich in protein and low in fat.

Computer-aided design of novel cellobiose 2-epimerase for efficient synthesis of lactulose using lactose

Cellobiose 2-epimerase (CE) is ideally suited to synthesize lactulose from lactose, but the poor thermostability and catalytic efficiency restrict enzymatic application. Herein, a non-characterized CE originating from Caldicellulosiruptor morganii (CmCE) was discovered in the NCBI database. Then, a smart mutation library was constructed based on FoldX ΔΔG calculation and modeling structure analysis, from which a positive mutant D226G located within the α₈/α₉ loop exhibited longer half-lives at 65-75 °C as well as lower K_m and higher k_cat/K_m values compared with CmCE. Molecular modeling demonstrated that the improvement of D226G was largely attributed to the rigidification of the flexible loop, the compactness of the catalysis pocket and the increment of substrate-binding capability. Finally, the yield of synthesizing lactulose catalyzed by D226G reached 45.5%, higher than the 35.9% achieved with CmCE. The disclosed effect of the flexible loop on enzymatic stability and catalysis provides insight to redesign efficient CEs to biosynthesize lactulose.

The effect of lactose and its isomerization product lactulose on functional and structural properties of glycated casein

Lactulose is an isomer of lactose, formed under thermal processing of milk. Alkaline conditions favor the isomerization of lactose. As reducing sugar, lactose and lactulose could participate in the Maillard reaction and cause protein glycation in milk products. In this study, the influence of lactose and lactulose on the functional and structural properties of glycated casein was investigated. The results demonstrated that compared with lactose, lactulose led to severer changes in molecular weight, more disordered spatial structure and decrease of tryptophan fluorescence intensity of casein. Besides, the glycation degree and advanced glycation end products (AGEs) results suggested that lactulose exhibited stronger glycation ability than lactose due to the higher proportion of open chain in solution. Furthermore, higher glycation degree induced by lactulose resulted in lower solubility, surface hydrophobicity, digestibility and emulsifying capacity of casein-glycoconjugates compared with lactose. The results of this study are essential for tracking the effects of harmful Maillard reaction products on the quality of milk and dairy products.

Effect of Malva neglecta and lactulose on survival of Lactobacillus fermentum and textural properties of synbiotic stirred yogurt

Yogurt is a popular dairy product and its consumption has been progressively growing over the past few decades by raising consumers' health-consciousness. As yogurt is growing in popularity, manufacturers are continuously seeking for bioactive components such as probiotics and prebiotics, to produce functional yogurt with more beneficial health effects. Therefore, this study aimed to evaluate the effect of Malva neglecta (MN, 0, 5, 10 and 15%) and lactulose (0, 1 and 2%) as prebiotic substances on survival of Lactobacillus fermentum in a half-fat synbiotic stirred yogurt. The results revealed that with increasing MN and lactulose concentrations, the count of Lb. fermentum significantly increased (p < 0.05). At the end of 21-day cold storage, the count of probiotics in yogurt sample having 2% lactulose and 10-15% MN significantly was higher than control (8.37-8.4 vs. 7.73 Log cfu/g). With increasing the amount of MN and lactulose, firmness and chewiness of yogurt samples decreased while adhesiveness increased (p < 0.05). Scanning electron microscopy assessment shown that addition of MN and lactulose resulted in a higher moisture retention in the void spaces. The results revealed that by incorporating lactulose and MN in yogurt formulation, an appropriate synbiotic yogurt could be produced as a novel functional product.

Fermented Foods in the Management of Obesity: Mechanisms of Action and Future Challenges

Fermented foods are part of the staple diet in many different countries and populations and contain various probiotic microorganisms and non-digestible prebiotics. Fermentation is the process of breaking down sugars by bacteria and yeast species; it not only enhances food preservation but can also increase the number of beneficial gut bacteria. Regular consumption of fermented foods has been associated with a variety of health benefits (although some health risks also exist), including improved digestion, enhanced immunity, and greater weight loss, suggesting that fermented foods have the potential to help in the design of effective nutritional therapeutic approaches for obesity. In this article, we provide a comprehensive overview of the health effects of fermented foods and the corresponding mechanisms of action in obesity and obesity-related metabolic abnormalities.

Ameliorative Effect of Chitosan Oligosaccharides on Hepatic Encephalopathy by Reshaping Gut Microbiota and Gut-Liver Axis

This study investigated the influence of chitosan oligosaccharides (COSs) on a thioacetamide-induced hepatic encephalopathy (HE) Wistar rat model. COS treatment statistically reduced the false neurotransmitters and blood ammonia in HE rats, along with the suppression of oxidative stress and inflammation. The disbalanced gut microbiota was detected in HE rats by 16S rDNA sequencing, but the abundance alterations of some intestinal bacteria at either the phylum or genus level were at least partly restored by COS treatment. According to metabolomics analysis of rat feces, six metabolism pathways with the greatest response to HE were screened, several of which were remarkably reversed by COS. The altered metabolites might serve as a bridge for the alleviated HE rats treated with COS and the enhanced intestinal bacterial structure. This study provides novel guidance to develop novel food or dietary supplements to improve HE diseases due to the potential beneficial effect of COS on gut-liver axis.

Functionality of glycomacropeptide glycated with lactose and maltodextrin

The Maillard reaction (MR), under proper environmental conditions, has been used to improve protein functionality. In the present work, 2 high temperatures (50-80°C) and water activity (Aw; 0.45-0.67) were used to promote exogenous glycosylation of glycomacropeptide (GMP) while minimizing processing times (0, 8, 24, 48, and 96 h at 50°C; 0, 2, 4, 8, and 24 h at 80°C). Maltodextrin, a polysaccharide commonly used in the food industry as a functional ingredient, was used as a reducing sugar, and compared with lactose, a native milk sugar. The progression of MR was evaluated by tracking changes in molecular weight using SDS-PAGE, the formation of Amadori compounds, and browning. Aqueous glycosylated GMP solutions (5 to 20% wt/vol) were tested for solubility, rheological properties, and foam formation. As expected, MR progression was faster with Aw = 0.67 and 80°C. Glycosylated GMP powders showed no change in their solubility after MR. However, the apparent viscosity ( γ˙ = 30 s^-1) of the 20% wt/vol suspensions exhibited a slight increase when GMP was glycosylated with maltodextrin for 24 h at 80°C, and a 2-log increase when GMP was glycosylated with lactose, with a high browning development in both cases. The foam expansion index of the resuspended glycosylated powders was increased by between 25 and 66% compared with the nonglycosylated powders. Better foam stability (approximately 2 h) and no browning development were observed for GMP glycosylated with maltodextrin for 2 h at Aw = 0.67 and 80°C. The results show that GMP has undergone further glycosylation by means of controlled MR, which improves viscosity and foaming index without negatively affecting solubility. These preliminary studies provide a basis for the future creation of a new ingredient with GMP and reducing sugars.

Lactulose production from lactose isomerization by chemo-catalysts and enzymes: Current status and future perspectives

Lactulose, a semisynthetic nondigestive disaccharide with versatile applications in the food and pharmaceutical industries, has received increasing interest due to its significant health-promoting effects. Currently, industrial lactulose production is exclusively carried out by chemical isomerization of lactose via the Lobry de Bruyn-Alberda van Ekenstein (LA) rearrangement, and much work has been directed toward improving the conversion efficiency in terms of lactulose yield and purity by using new chemo-catalysts and integrated catalytic-purification systems. Lactulose can also be produced by an enzymatic route offering a potentially greener alternative to chemo-catalysis with fewer side products. Compared to the controlled trans-galactosylation by β-galactosidase, directed isomerization of lactose with high isomerization efficiency catalyzed by the most efficient lactulose-producing enzyme, cellobiose 2-epimerase (CE), has gained much attention in recent decades. To further facilitate the industrial translation of CE-based lactulose biotransformation, numerous studies have been reported on improving biocatalytic performance through enzyme mediated molecular modification. This review summarizes recent developments in the chemical and enzymatic production of lactulose. Related catalytic mechanisms are also highlighted and described in detail. Emerging techniques that aimed at advancing lactulose production, such as the boronate affinity-based technique and molecular biological techniques, are reviewed. Finally, perspectives on challenges and opportunities in lactulose production and purification are also discussed.

Valorization of dairy waste and by-products through microbial bioprocesses

Waste is an inherent and unavoidable part of any process which can be attributed to various factors such as process inefficiencies, usability of resources and discarding of not so useful parts of the feedstock. Dairy is a burgeoning industry following the global population growth, resulting in generation of waste such as wastewater (from cleaning, processing, and maintenance), whey and sludge. These components are rich in nutrients, organic and inorganic materials. Additionally, the presence of alkaline and acidic detergents along with sterilizing agents in dairy waste makes it an environmental hazard. Thus, sustainable valorization of dairy waste requires utilization of biological methods such as microbial treatment. This review brings forward the current developments in utilization and valorization of dairy waste through microbes. Aerobic and anaerobic treatment of dairy waste using microbes can be a sustainable and green method to generate biofertilizers, biofuels, power, and other biobased products.

Trends in lactose-derived bioactives: synthesis and purification

Lactose obtained from cheese whey is a low value commodity despite its great potential as raw material for the production of bioactive compounds. Among them, prebiotics stand out as valuable ingredients to be added to food matrices to build up functional foods, which currently represent the most active sector within the food industry. Functional foods market has been growing steadily in the recent decades along with the increasing awareness of the World population about healthy nutrition, and this is having a strong impact on lactose-derived bioactives. Most of them are produced by enzyme biocatalysis because of molecular precision and environmental sustainability considerations. The current status and outlook of the production of lactose-derived bioactive compounds is presented with special emphasis on downstream operations which are critical because of the rather modest lactose conversion and product yields that are attainable. Even though some of these products have already an established market, there are still several challenges referring to the need of developing better catalysts and more cost-effective downstream operations for delivering high quality products at affordable prices. This technological push is expected to broaden the spectrum of lactose-derived bioactive compounds to be produced at industrial scale in the near future.

Graphical abstract

Recent trends and developments on integrated biochemical conversion process for valorization of dairy waste to value added bioproducts: A review

In this review article, discuss the many ways utilized by the dairy sector to treat pollutants, emphasizing their influence on the quality and efficiency with which contamination is removed. It focuses on biotechnology possibilities for valorizing dairy waste in particular. The findings revealed that dairy waste may be treated using physicochemical, biological, and biotechnological techniques. Notably, this article highlighted the possibility of dairy waste being used as a feedstock not only for the generation of biogas, bioethanol, biohydrogen, microbial fuel cells, lactic acid, and fumaric acid via microbial technology but also for the production of biooil and biochar by pyrolysis. In addition, this article critically evaluates the many treatment techniques available for recovering energy and materials from dairy waste, their combinations, and implementation prospects. Valorization of dairy waste streams presents an opportunity to extend the dairy industry's presence in the fermented functional beverage sector.

Edible coatings and films with incorporation of prebiotics -A review

Prebiotics are compounds naturally present in some foods or can be synthesized by microorganisms and enzymes. Among the benefits associated with prebiotic consumption are the modulation of the intestinal microbiota that increase the production of short chain fatty acids and prevent the development of some disorders such as colon cancer, irritable bowel syndrome, diabetes, obesity, among others. Traditionally, prebiotics have been used in diverse food formulations to enhance their healthy potential or to improve their technological and sensory properties. However, different alternatives for the production of prebiotic products are being explored, such as edible coatings and films. Therefore, this review aims to highlight recent research on edible coatings and films incorporated with different prebiotics, the concept of prebiotics, the general characteristics of these materials, and the main production methods, as well as presenting the perspectives of uses in the food industry. Current works describe that polyols and oligosaccharides are the most employed prebiotics, and depending on their structure and concentration, they can also act as film plasticizer or reinforcement agent. The use of prebiotic in the coating can also improve probiotic bacteria survival making it possible to obtain fruits and vegetables with synbiotic properties. The most common method of production is casting, suggesting that other technologies such as extrusion can be explored aiming industrial scale. The use of film and coating carried of prebiotic is an emerging technology and there are still several possibilities for study to enable its use in the food industry. This review will be useful to detect the current situation, identify problems, verify new features, future trends and support new investigations and investments.

Lactulose Improves Neurological Outcomes by Repressing Harmful Bacteria and Regulating Inflammatory Reactions in Mice After Stroke

Background and Objective

Gut microbiota dysbiosis following stroke affects the recovery of neurological function. Administration of prebiotics to counteract post-stroke dysbiosis may be a potential therapeutic strategy to improve neurological function. We aim to observe the effect of lactulose on neurological function outcomes, gut microbiota composition, and plasma metabolites in mice after stroke.

Methods

Male C57BL/6 mice (20–25 g) were randomly divided into three groups: healthy control, photothrombotic stroke + triple-distilled water, and photothrombotic stroke + lactulose. After 14 consecutive days of lactulose administration, feces, plasma, and organs were collected. 16S rDNA sequencing, plasma untargeted metabolomics, qPCR, flow cytometry and Elisa were performed.

Results

Lactulose supplementation significantly improved the functional outcome of stroke, downregulated inflammatory reaction, and increased anti-inflammatory factors in both the brain and gut. In addition, lactulose supplementation repaired intestinal barrier injury, improved gut microbiota dysbiosis, and partially amended metabolic disorder after stroke.

Conclusion

Lactulose promotes functional outcomes after stroke in mice, which may be attributable to repressing harmful bacteria, and metabolic disorder, repairing gut barrier disruption, and reducing inflammatory reactions after stroke.

Probiotics, Prebiotics and Postbiotics on Mitigation of Depression Symptoms: Modulation of the Brain-Gut-Microbiome Axis

The brain–gut–microbiome axis is a bidirectional communication pathway between the gut microbiota and the central nervous system. The growing interest in the gut microbiota and mechanisms of its interaction with the brain has contributed to the considerable attention given to the potential use of probiotics, prebiotics and postbiotics in the prevention and treatment of depressive disorders. This review discusses the up-to-date findings in preclinical and clinical trials regarding the use of pro-, pre- and postbiotics in depressive disorders. Studies in rodent models of depression show that some of them inhibit inflammation, decrease corticosterone level and change the level of neurometabolites, which consequently lead to mitigation of the symptoms of depression. Moreover, certain clinical studies have indicated improvement in mood as well as changes in biochemical parameters in patients suffering from depressive disorders.

Dietary intervention with sialylated lactulose affects the immunomodulatory activities of mice

Four sialylated lactuloses [N-acetylneuraminic acid-α2,3-lactulose (Neu5Acα2,3lactulose), N-acetylneuraminic acid-α2,6-lactulose (Neu5Acα2,6lactulose), deaminoneuraminc acid-α2,3-lactulose (Kdnα2,3lactulose), and deaminoneuraminc acid-α-2,6-lactulose (Kdnα2,6lactulose)] were reported to modulate the immunity of mice. The influences of cytokine expression, cell immunity, humoral immunity, and nonspecific immunity were investigated in our study using several techniques. Analysis via ELISA showed that cytokine expression was induced by sialylated lactulose treatment consistently in the serum and spleen. Among the 4 tested sialylated lactuloses, Neu5Acα2,6lactulose performed the best, simultaneously and appropriately promoting the expression of proinflammatory and anti-inflammatory factors in the serum and spleen. Kdnα2,3lactulose showed the best antioxidant activity according to detection of the activity of superoxide dismutase, myeloperoxidase, peroxidase, and alkaline phosphatase. Flow cytometry revealed that only Kdnα2,3lactulose significantly boosted the CD3⁺ T lymphocyte ratio similarly to that of lactulose. Analysis of the hemolysin content to characterize humoral immunity revealed that Kdnα2,3lactulose notably increased hemolysin content compared with that in the control group. To evaluate the nonspecific immune effects of the 4 sialylated lactuloses, a fluorescence microsphere phagocytosis assay was used to analyze the phagocytosis of macrophages. Kdnα2,3lactulose still performed the best in enhancing the phagocytosis of macrophages, showing markedly increased phagocytic percentage and phagocytic index values compared with those in the control and lactulose groups. Comparing the differences of these 4 sialylated lactuloses in affecting immunity in mice revealed that Kdnα2,3lactulose had the best overall performance in influencing cytokine expression, cell immunity, humoral immunity, and nonspecific immunity. This study provides critical support for use of sialylated lactuloses as potential immunomodulators in foods.

The β-galactosidase immobilization protocol determines its performance as catalysts in the kinetically controlled synthesis of lactulose

In this paper, 3 different biocatalysts of β-galactosidase from Kluyveromyces lactis have been prepared by immobilization in chitosan activated with glutaraldehyde (Chi_Glu_Gal), glyoxyl agarose (Aga_Gly_Gal) and agarose coated with polyethylenimine (Aga_PEI_Gal). These biocatalysts have been used to catalyze the synthesis of lactulose from lactose and fructose. Aga-PEI-Gal only produces lactulose at 50 °C, and not at 25 or 37 °C, Aga_Gly_Gal was unable to produce lactulose at any of the assayed temperatures while Chi_Glu_Gal produced lactulose at all assayed temperatures, although a lower yield was obtained at 25 or 37 °C. The pre-incubation of this biocatalyst at 50 °C permitted to obtain similar yields at 25 or 37 °C than at 50 °C. The use of milk whey instead of pure lactose and fructose produced an improvement in the yields using Aga_PEI_Gal and a decrease using Chi_Glu_Gal. The operational stability also depends on the reaction medium and of biocatalyst. This study reveals how enzyme immobilization may greatly alter the performance of β-galactosidase in a kinetically controlled manner, and how medium composition influences this performance due to the kinetic properties of β-galactosidase.

Biosynthesis of Nondigestible Galactose-Containing Hetero-oligosaccharides by Lactobacillus plantarum WCFS1 MelA α-Galactosidase

This work describes the high capacity of MelA α-galactosidase from Lactobacillus plantarum WCFS1 to transfer galactosyl residues from melibiose to the C6-hydroxyl group of disaccharide-acceptors with β-linkages (lactulose, lactose, and cellobiose) or α-linkages (isomaltulose and isomaltose) to produce novel galactose-containing hetero-oligosaccharides (HOS). A comprehensive nuclear magnetic resonance characterization of the transfer products derived from melibiose:lactulose reaction mixtures revealed the biosynthesis of α-d-galactopyranosyl-(1 → 6)-β-d-galactopyranosyl-(1 → 4)-β-d-fructose as the main component as well as the presence of α-d-galactopyranosyl-(1 → 3)-β-d-galactopyranosyl-(1 → 4)-β-d-fructose and α-d-galactopyranosyl-(1 → 6)-α-d-galactopyranosyl-(1 → 6)-β-d-galactopyranosyl-(1 → 4)-β-d-fructose. Melibiose-derived α-galactooligosaccharides (α-GOS), manninotriose and verbascotetraose, were also simultaneously synthesized. An in vitro assessment of the intestinal digestibility of the novel biosynthesized HOS revealed a high resistance of α-galactosides derived from lactulose, lactose, cellobiose, and isomaltulose. According to the evidence gathered for conventional α-GOS and certain disaccharides used as acceptors in this work, these novel nondigestible α-galactosides could be potential candidates to selectively modulate the gut microbiota composition, among other applications, such as low-calorie food ingredients.

Influence of the innovative prebiotic complex on physiological state of pigs and quality indicators of pork

The article presents an analysis of the use of antibiotic therapy in pig breeding and offered an alternative to them in the form of prebiotic supplements. Studies were conducted on the effect of probiotic drugs on the body of large white pigs in the farm-breeding plant Named after Lenin of Surovikinsky District of Volgograd Region and lasted until 180 days of age. For the experiment, 2 groups of Large White piglets of 2 months of age were formed. Each experimental group consisted of 15 pigs. Animals of the control group received standart farm animal diet (SD), analogs of the first experimental group SD + mixture of dietary supplements “LactuVet-1” and “Chlorelact” at a dosage of 0.2 mg / kg of live weight each. Deep studies were conducted on the effect of probiotic supplements to live weight gain, natural resistance, immunoglobulin reactivity, and slaughter indicators of piglets. Superiority of pigs from the experimental group in almost all the studied indicators over the peers of the control group was established.

Effect of Maillard reaction conditions on the solubility and molecular properties of wheat gluten-maltose conjugates

In this experiment, the conjugation reaction between gluten and maltose via Maillard reaction under dry-heated condition was studied. The process conditions for the preparation of protein-maltose conjugates with optimum solubility were optimized by using Box-Behnken model. The conjugation reaction and the structure changes of the protein-maltose conjugates were confirmed by infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the process conditions for the preparation of protein-maltose conjugates with optimum solubility were as follows: temperature 50.72°C, time 1.92 days, and gluten/maltose (W/W) 267.36%. The infrared spectroscopy showed that the structure of the modified protein had a very obvious change, including the decrease in β-fold and β-turn and the increase in α-helix at a certain degree. But the conjugation reaction has little effect on the irregular coiled structure. The scanning electron microscopy showed that the microstructure of gluten is small grainy, but gluten-maltose conjugate looks sheet with bigger volume.

Potential of "coalho" cheese whey as lactose source for β-galactosidase and ethanol co-production by Kluyveromyces spp. yeasts

The present study evaluated the co-production of β-galactosidase and ethanol by Kluyveromyces marxianus ATCC 36907 and Kluyveromyces lactis NRRL Y-8279 using as carbon source the lactose found on "coalho" cheese whey. Cheese whey was subjected to partial deproteinization, and physicochemical parameters were assessed. Cultivations were carried out in an shaker to evaluate two carbon/nitrogen (C:N) ratios. The best C:N ratio (1.5:1) was carried to 1.5-L bioreactor cultivation in order to increase co-production yields. The stability of β-galactosidase was assessed against different temperatures and pH, and in the presence of metal ions. Concerning the co-production of β-galactosidase and ethanol, K. lactis proved to be more efficient in both the C:N ratios, reaching 21.09 U·mL^-1 of activity and 7.10 g·L^-1 of ethanol in 16 h. This study describes the development of a viable and value-adding biotechnological process using a regional cheese by-product from Northeast Brazil for co-production of biomolecules of industrial interest.

AN INNOVATIVE TECHNOLOGY OF WAFFLES WITH FUNCTIONAL PROPERTIES

The high-priority tasks of today’s confectionery industry include the development and introduction of functional-purpose confections. These products are supposed to be of high technological qualities, be effective in production to the extent possible, and have physiological functional properties due to the physiologically valuable ingredients in their composition. These ingredients include the synbiotic complex composed of probiotics (bifidobacteria, lactobacilli) and prebiotics (inulin and lactulose). This complex has been studied in this research. The paper gives reasons why waffles with fatty fillings are the ones to which the synbiotic complex should be added. It has been established what mass fraction of the ingredients at what stage of fatty filling production should be added. It has been studied how the synbiotic complex affects the structural and mechanical properties of the fatty filling: its effective viscosity, adhesive strength, and critical shear stress. It has been found that the maximum shear rate that still allows obtaining a high-quality filling is 5.4 s-1. The specific pull-off force of the fatty filling with the synbiotic added becomes lower compared to that of the control sample. This helps reduce the energy consumed in the course of moulding waffles. An innovative manufacturing technology for waffles with synbiotic supplements has been developed and proved practical. It includes the stages of preparing microencapsulated microorganisms and adding prebiotics, and provides the technological parameters of fatty filling preparation. It has been established that the synbiotic included into the composition of the new fatty filling decreases the maturation of waffle blocks by 40–45%, and allows reducing the layer of filling to 1–1.5 mm. It has been proven that the synbiotic complex as an ingredient in the fatty filling of waffles will allow developing and manufacturing confections that improve human microflora. These new specialised products will be socially significant, as they will help solve a topical and important task of the confectionery industry: prevent gastrointestinal diseases.

Functional and biological properties of Maillard conjugates and their potential application in medical and food: A review

Protein and peptides are usually sensitive to environmental stresses, such as pH changes, high temperature, ionic strength, and digestive enzymes amongst other, which limit their food and medicinal applications. Maillard reaction (also called Maillard conjugation or glycation) occurs naturally without the addition of chemical agents and has been vastly applied to boost protein/peptide/amino acid functionalities and biological properties. Protein/peptide-saccharide conjugates are currently used as emulsifiers, antioxidants, antimicrobials, gelling agents, and anti-browning compounds in food model systems and products. The conjugates also possess the excellent stabilizing ability as a potent delivery system to enhance the stability and bioaccessibility of many bioactive compounds. Carbonyl scavengers such as polyphenols are able to significantly inhibit the formation of advanced glycation end products without a significant effect on early Maillard reaction products (MRPs) and melanoidins, which are currently applied as functional ingredients. This review paper highlights the technological functionality and biological properties of glycoconjugates in food model systems and products. Recent applications of MRPs in medical sciences are also presented.

Biological reduction of aflatoxin B1 in yogurt by probiotic strains of Lactobacillus acidophilus and Lactobacillus rhamnosus

The present study was conducted to investigate the ability of two probiotic strains, L. acidophilus PTCC 1643 and L. rhamnosus PTCC 1637, to bind aflatoxin B₁ (AFB₁, 20 ng/ml) in comparison with yogurt starter cultures, at equal bacterial count (~ 10⁹ LogCFU/ml) during a 21-day storage period at 4 °C. All assessed treatments exhibited high percentages of AFB₁-binding, ranged from 64.56 to 96.58%. However, the ability of probiotic bacteria was statistically higher than yogurt starter cultures. Aflatoxin binding ability of the selected lactic acid bacteria was dependent on both time and bacteria species. The highest and the lowest percentages of AFB_1-removal was observed at 11th day of cold storage by L. rhamnosus (96.58 ± 3.97%) and at the first day of storage for yogurt starter cultures (64.56 ± 5.32%), respectively. The stability of bacterial cells-AFB₁ complex was remarkable, since only 0.84-26.75% of bounded AFB₁ was released from bacterial cells after 3 times washing during the storage period.

In vitro and in vivo inhibition of maillard reaction products using amino acids, modified proteins, vitamins, and genistein: A review

Maillard reaction is known to result in loss of nutrients, particularly that of essential amino acids; decrease in digestibility and safety issues due to the development of toxic compounds. Maillard reaction products are also known to cause oxidation of tissues and inflammation, thus increasing the risk of cardiovascular diseases and diabetes. The aim of this review is to present a detailed information about the role of foodborne constituents as antibrowning agents to significantly reduce the harmful compounds like advanced glycation end products (AGEs) during food processing. This review includes strategies involving addition of amino acids, aromatic compounds, vitamins, modification of amino acids, and reducing sugars as antibrowning agents to reduce the AGEs. The role of Food borne functional ingredients such as catechin, epicathechin, luteolin, and ferulic acids as inhibitors of AGEs is also discussed. Among the naturally occurring inhibitors, genistein could be a crucial and safe agent to reduce reactive intermediates. PRACTICAL APPLICATIONS: Maillard reaction leads to changes in food color, protein functionality, protein digestibility, and loss of nutrient from foods. Maillard reaction products (MRPs) is also reported to be associated with various inflammatory conditions and may contribute to the progress of chronic diseases, including diabetes. It is hence necessary to reduce the MRPs, in both food and biological products, to offset this phenomenon. Among the strategies adopted till date, chemical agents could inhibit reactive carbonyl species and reactive oxygen species, but also are known to elicit serious side effects. Dietary flavonoids could be a very good inhibitor of MRPs both in biological and in food systems. It could be suggested that dietary flavonoids and isoflavones can be used as antibrowning agents in food and pharmaceutical industries particularly for targeted and sustained release of hypoglycemic drug in the intestines.

Cheese Whey Processing: Integrated Biorefinery Concepts and Emerging Food Applications

Cheese whey constitutes one of the most polluting by-products of the food industry, due to its high organic load. Thus, in order to mitigate the environmental concerns, a large number of valorization approaches have been reported; mainly targeting the recovery of whey proteins and whey lactose from cheese whey for further exploitation as renewable resources. Most studies are predominantly focused on the separate implementation, either of whey protein or lactose, to configure processes that will formulate value-added products. Likewise, approaches for cheese whey valorization, so far, do not exploit the full potential of cheese whey, particularly with respect to food applications. Nonetheless, within the concept of integrated biorefinery design and the transition to circular economy, it is imperative to develop consolidated bioprocesses that will foster a holistic exploitation of cheese whey. Therefore, the aim of this article is to elaborate on the recent advances regarding the conversion of whey to high value-added products, focusing on food applications. Moreover, novel integrated biorefining concepts are proposed, to inaugurate the complete exploitation of cheese whey to formulate novel products with diversified end applications. Within the context of circular economy, it is envisaged that high value-added products will be reintroduced in the food supply chain, thereby enhancing sustainability and creating "zero waste" processes.

Rapid HPLC method for monitoring of lactulose production with a high yield

An HPLC method suitable for rapid monitoring of lactulose production by isomerization from lactose was developed. The separation of lactose and lactulose under hydrophilic interaction liquid chromatography (HILIC) mode was achieved with resolution 1.5 within 5 min. Since isocratic elution was used, there is no extra time necessary for the column equilibration. Application of the method was illustrated on monitoring lactulose isomerization with catalysis of sodium hydroxide in the presence of sodium tetraborate at 70 °C (pH = 11). The conversion yield obtained for lactulose was 86%, and corresponding purity 76%. For the first time, a polyhydroxy stationary phase for separation of lactose and lactulose is reported.

Effects of a Lactulose-Rich Diet on Fecal Microbiome and Metabolome in Pregnant Mice

Lactulose, a safe and beneficial molecule, can be used in food as a prebiotic and as an osmotic laxative during pregnancy. This work evaluated the effects of dietary lactulose on the gut microenvironment of pregnant mice using the fecal microbiota and metabolomic profiling. After 2 weeks of feeding, the Bifidobacterium and Bacteroides abundances in the mouse feces were significantly increased in the LAC-high (the diet supplemented with 15% lactulose) group. A total of 15 metabolites, including 1-monoolein, glucose-6-phosphate, and short-chain fatty acids, were increased significantly in the LAC-high group. The serum glucose and total cholesterol concentrations were significantly decreased, while the progesterone level was significantly increased in the lactulose-fed mice. In the LAC-high group, the colonic pH and intestinal permeability were decreased, while the immunoglobulins in the colonic epithelial cells and the small intestinal absorption capacity were significantly increased. These findings indicated that lactulose supplementation benefitted pregnancy performance in mice.

Antioxidant potential and antimicrobial activity of chitosan-inulin conjugates obtained through the Maillard reaction

Chitosan (1%) was glycated with inulin (0.5, 1, and 2%) via the Maillard reaction at various initial pH values (5, 5.5, and 6). Higher pHs led to a greater pH drop and increase in the intermediate products and browning intensity (BI). The chitosan-inulin conjugates were then classified into three levels of low, medium, and high BI through K-means clustering in order to investigate the effect of BI development on the antioxidant and antimicrobial attributes of the conjugates. Covalent linkage between chitosan and inulin was confirmed by fourier transform infrared spectroscopy. High BI chitosan-inulin conjugate had significantly higher antioxidant property compared to chitosan and other conjugate fractions. In addition, the conjugates obtained at low pH values mainly presented greater antimicrobial activities than those prepared at high pHs. It can be concluded that chitosan-inulin Maillard-born conjugates can be used as novel antioxidant and antimicrobial prebiotic-based ingredients for food applications.

Zein-CMC-PEG Multiple Nanocolloidal Systems as a Novel Approach for Nutra-Pharmaceutical Applications

Purpose: Hydrophobic nutraceuticals are suffering from water solubility and physicochemical stabilities once administered to the body or food matrixes. The present study depicts the successful formulation of a zein-carboxymethyl cellulose (CMC) complex to stabilize a water in oil (W/O) emulsion to protect them from environmental and gastrointestinal conditions. The formulated water in oil in water (W/O/W) system was used for nanoencapsulating of hydrophobic nutraceutical, rutin, via protein-polysaccharide complexes. Methods: Zein nano particles smaller than 100 nm were produced using poly ethylene glycol (PEG 400) and Tween 80, which eliminates the use of ethanolic solutions in preparation of zein nanoparticles (ZN). CMC was then added to the ZN under magnetic stirrer to provide zein-CMC complex. A concentration of 20% CMC showed the smallest particle size (<100 nm). Rutin was dispersed in water in oil in water (W/O/W) emulsion stabilized by zein-CMC complex. A set of experiments such as encapsulation efficiency (EE%), encapsulation stability (ES%), and releasing rate of rutin were measured during 30 days of storage at 4°C. Results: Results showed that, produced multiple emulsion prepared with lower concentrations of Tween 80 (0.5%), ethanol: PEG: water ratio of 0:80:20 showed smaller size (89.8±4.2 nm). ES% at pH values of 1.2, 6.8, and 7.4 were 86.63±6.19, 91.54±3.89, and 97.13±2.39 respectively, indicating high pH tolerability of formulated W/O/W emulsions. Conclusion: These findings could pave a new approach in stabilizing W/O/W emulsions for encapsulating and controlling the release of water insoluble nutraceuticals/drugs.

Continuous enzymatic synthesis of lactulose in packed-bed reactor with immobilized Aspergillus oryzae β-galactosidase

Lactulose synthesis from fructose and lactose in continuous packed-bed reactor operation with glyoxyl-agarose immobilized Aspergillus oryzae β-galactosidase is reported for the first time. Alternative strategies to conventional batch synthesis have been scarcely explored for lactulose synthesis. The effect of flow rate, substrates ratio and biocatalyst-inert packing material mass ratio (M_B/M_IM) were studied on reactor performance. Increase in any of these variables produced an increase in lactulose yield (Y_Lu) being higher than obtained in batch synthesis at comparable conditions. Maximum Y_Lu of 0.6 g·g^-1 was obtained at 50 °C, pH 4.5, 50% w/w total sugars, 15 mL·min^-1, fructose/lactose molar ratio of 12 and M_B/M_IM of 1/8 g·g^-1; at such conditions yield of transgalactosylated oligosaccharides (Y_TOS) was 0.16 g·g^-1, selectivity (lactulose/TOS molar ratio) was 5.4 and lactose conversion (X_Lactose) was 28%. Reactor operation with recycle had no significant effect on yield, producing only some decrease in productivity.