In vitro digestion of polysaccharides: InfoGest protocol and use of small intestinal extract from rat

Unraveling the development of Maillard reaction indicators in popped cereal grains

Popped grains, subjected to high temperatures (180 to 310 °C), may undergo the Maillard reaction (MR). This study, for the first time, assessed MR indicators in popped sorghum and maize using two methods: traditional hot salt (310 °C) and the industrial hot air process (210 °C), at initial (furosine), intermediate (Hydroxymethylfurfural "HMF") and advanced stages (browning index), while monitoring changes in carbohydrates and color parameters (L*, a*, b*, ΔE). A browner color was observed in popped grains, with a higher ΔE in the hot salt treatments which showed the highest furosine (37.0 to 81.0 mg/100 g) and HMF (4.0 to 10.8 mg/100 g) contents. Both popping methods triggered the MR, with either the temperature difference and/or the salt potentially acting as catalysts. These findings highlight the importance of optimizing processing techniques and maximizing the potential contributions to food quality, paving an approach for higher-quality and healthier grain-based products.

Citrus endogenous components as prebiotics: Advances in extraction, digestion, mechanisms, and delivery

The large number of by-products during the processing of citrus fruits exert significant pressure on the environment. Citrus by-products contain a variety of bioactive compounds that promote gut health and maintain microbial homeostasis. Therefore, recycling and reuse of these by-products is considered an excellent way to reduce environmental pressure. The purification and characterization methods of bioactive compounds (such as pectin, dietary fiber, polyphenols, essential oils, and limonin) extracted from citrus by-products in recent years are summarised. Subsequently, we summarize the digestive behavior (digestion, absorption, metabolism, and excretion) of these components, focusing on the mechanisms of action through which they exert prebiotic activity. This highlights the interactions between citrus by-product bioactives and gut microbiota, as well as the health effects on the host gut. Additionally, we provide a brief overview of the delivery systems for the active ingredients based on pectin from citrus sources. The results show that extraction methods can significantly affect the composition and structure of citrus by-products, which in turn affects digestive properties and eventually leads to differences in prebiotic activity. Notably, gut microbiota plays a key role in the metabolism and bioactivity of citrus actives. Besides, the innovative embedding methods can markedly enhance their prebiotic potential. Therefore, a comprehensive understanding of the relationship between the extraction, structure, and prebiotic activity of citrus by-products, as well as their delivery methods, is essential to advancing the use of citrus by-products in human health.

Regulating Effects of Three Polysaccharides on Gut Microbiota in Felines and Canines: Insights from In Vitro Digestion, Fecal Fermentation, and Lactic Acid Bacterial Fermentation

This study evaluated the effects of laminaria polysaccharide (FU), aloe polysaccharide (AL), and yeast β-glucan (YG) on in vitro digestion, fecal fermentation, and lactic acid bacterial fermentation in felines and canines. FU (Mw 27 713 g/mol), AL (44 425 g/mol), and YG (29 296 g/mol) were primarily composed of glucose, galacturonic acid, and glucuronic acid. The FU strongly promoted the fermentation of Bifidobacterium, Lactobacillus, and Pediococcus. The AL slightly supported Lactobacillus. The YG showed minimal activity. Molecular weights decreased after digestion with negligible monosaccharide release. The FU and AL were almost completely metabolized during fecal fermentation, while YG had ∼50% utilization. The FU produced the highest lactate concentration. The YG significantly increased SCFA levels, especially in canines, surpassing fructooligosaccharides. The FU:AL:YG mixture (0.8:0.2:1, FAY) achieved the best overall effects. 16S rRNA analysis revealed the enrichment of SCFA-producing genera (e.g., Megamonas, Parabacteroides) and suppression of odor-related bacteria (e.g., Fusobacterium, Desulfovibrio). Metabolomics showed reduced levels of odor compounds (e.g., 2-oxindole, 5-hydroxyindole) and increased secondary bile acids (e.g., deoxycholic acid, glycocholic acid). The FU, AL, and FAY upregulated bile secretion, neuroactive pathways, and arachidonic acid metabolism, while YG activated the ABC transporter pathway.

Ultrasonic-assisted aqueous two-phase extraction and purification of polyphenols from hawk tea (Litsea coreana var. lanuginose): Investigating its impact on starch digestion

Hawk tea, a conventional herbal beverage, is renowned for its beneficial properties in enhancing digestion and mitigating hyperglycemic tendencies. However, the extraction methodology for hawk tea polyphenols (HTP) has been understudied thus far, impeding its progress and broader application. To develop an efficient approach for HTP extraction, the present study introduced and optimized the application of ultrasonic-assisted aqueous two-phase extraction. Under optimal extraction conditions, the extraction yield of polyphenols from raw HTP was 7.86 %. During purification, LX-B14 was selected due to the highest adsorption and desorption abilities. Then in an in vitro simulated digestion system, HTP significantly reduced the expected glycemic index, raised the content of resistant starch, and decreased the activities of α-amylase and α-glucosidase, indicating its potential for alleviating starch digestion. Accordingly, the results provide an alternative approach for efficiently obtaining phenolic compounds from hawk tea, facilitating the advanced utilization of HTP within the food industry.

Rat small intestine extract as a source of mammalian α- and β-glycosidases to study polyphenol bioaccessibility and deglycosylation in vitro: A case study with matrix-devoid and matrix-defined apple fractions

Most polyphenols are glycosylated, affecting their uptake, metabolism, and biological activity. However, the attached sugar must be removed before absorption and functionality can take place. Yet, despite the biological and chemical implications of polyphenol (de-)glycosylation, most in vitro digestion assays omit the utilization of intestinal brush border α- and/or β-glycosidases to study polyphenol bioaccessibility and deglycosylation. This study investigated the effect of rat small intestine extract (RSIE) as an affordable source of mammalian α- and β-glycosidases in different food matrices: matrix-devoid whole apple extract, whole apple, apple juice, and apple pomace. Using the INFOGEST 2.0 model, transepithelial polyphenol absorption, UHPLC-ESI-QTOF-MS/MS, and the inclusion of RSIE at the 15 U*mL-1 maltase activity reported in the human epithelium, the role of RSIE in polyphenol bioaccessibility and deglycosylation was explored. Moreover, the effect of the plant cell wall (PCW) matrix on the role of RSIE was mechanistically investigated by comparing whole apple (or pomace) with their respective extracts. 36 glycosylated polyphenols were identified, including 33 β-O-glycosides and 3 α-O-glycosides. The content of bioaccessible polyphenol β-O-glycosides and α-O-glycosides was significantly lower (p < 0.001) when RSIE was present, which resulted in a concomitant generation of the aglycone forms (phloretin, quercetin, ferulic acid, caffeic acid and p-coumaric acid). However, the concentration of aglycones was much lower than the reduction in the concentration of glycosylated polyphenols, strongly suggesting that polyphenols bind to RSIE. Matrix-devoid whole apple extract, or pomace extract, exhibited higher polyphenol bioaccessibility than whole apple or pomace, likely due to reduced interactions between polyphenols and the food matrix. Importantly, these differences in bioaccessibility diminished with RSIE, suggesting that RSIE α-glycosidases cleaved α-glucans and disrupted the PCW structure.

In vitro gastrointestinal digestion and fecal fermentation behaviors of pectin from feijoa (Acca sellowiana) peel and its impact on gut microbiota

This study investigated the digestion and fermentation characteristics of pectin from feijoa peel (FPP) and its effect on gut microbiota via in vitro simulated digestion and fecal fermentation. The gastrointestinal results showed that the molecular weight (Mw) of FPP kept stable with small production of reducing sugar and free monosaccharides, indicating that FPP was basically not degraded during digestion. However, during the fecal fermentation, the Mw of FPP significantly decreased with the release of free monosaccharides, which were further utilized by gut microbiota. The content of reducing sugar showed a trend of increasing at first and then decreasing. The production of gases and short-chain fatty acids (SCFAs) increased with the utilization of FPP, along with the pH decrease in fecal culture. Meanwhile, FPP regulated the composition of gut microbiota by suppressing enteropathogenic bacteria (genera Escherichia-Shigella and Fusobacterium) and promoting beneficial bacteria (genera Lactiplantibacillus and Bifidobacterium). Significantly positive correlation was found between SCFAs and bacteria including Lactiplantibacillus and Bifidobacterium. These results suggested that FPP had potential prebiotic functions to promote human intestinal health.

Comprehensive evaluation of Flammulina velutipes residues polysaccharide based on in vitro digestion and human fecal fermentation

Flammulina velutipes residues (FVR) are the waste culture medium derived from the collection of Flammulina velutipes fruiting bodies, with an annual output that remains largely unexplored. The characteristics of digestion and fermentation of Flammulina velutipes residues polysaccharide (FVRP) are still relatively unknown. This study investigated the structure of the gut microbiota through 16 s rDNA gene sequencing and analyzed changes in short-chain fatty acid (SCFA) content via targeted metabolome analysis. The aim was to explore the prebiotic activity of FVRP based on a simulated digestion model combined with an in vitro anaerobic fermentation model. The results demonstrated that FVRP did not exhibit significant changes during in vitro digestion and fermentation but did enhance antioxidant activity. Furthermore, FVRP was found to rapidly reduce the pH value and increase SCFA production in the fermentation broth from lactic acid bacteria and human feces. Notably, FVRP altered the gut microbiota structure, significantly increasing the relative abundance of Firmicutes and Bacteroidota. Thus, FVRP could be considered a promising prebiotic food and feed additive that promotes the generation of short-chain fatty acids by modulating gut microbiota.

Functions and mechanisms of nonstarch polysaccharides in monogastric animal production

As natural active ingredients, polysaccharides are a class of biological macromolecules that are ubiquitous in living organisms and have antibacterial, antioxidant, antitumor and intestinal flora-regulating functions. Nonstarch polysaccharides (NSPs) are an important class of polysaccharides that include both soluble and insoluble nonstarch polysaccharides. As green feed additives, NSPs play important roles in promoting immunity and disease resistance in the body, regulating the intestinal microbial balance and improving the quality of animal products. NSPs regulate cell signal transduction mainly via interactions between short-chain fatty acids and G protein-coupled receptors and inhibiting the histone deacetylation pathway to protect the intestinal barrier in animals. In this paper, the composition, physiological functions, and molecular mechanisms of the gut protective effects of NSPs are reviewed to provide a reference for the application of NSPs in monogastric animal production.

Catalytic action of alternansucrase on sucrose under in vitro simulated gastric conditions

Alternansucrase, a glucosyltransferase, is currently used to produce slowly digestible alternan oligosaccharides or maltooligosaccharides from sucrose. These oligosaccharides are popular for food fortification to lower postprandial glucose levels. This study aimed to explore the enzymatic reaction of alternansucrase in simulated in vitro gastric reaction conditions. Under the studied conditions, SucroSEB (a model enzyme for alternansucrase) hydrolyzed the sucrose and transglycosylated the glucose to produce glucans, both in the absence and presence of acceptors. The preference of the acceptor was maltose˃ raffinose˃ lactose. The rate of sucrose hydrolysis was significantly higher in the presence of maltose (p = 0.024). The glucans formed during the reaction included oligomers (DP 3-10) and polymers (DP ≥ 11), both of which increased over time. These glucans contained α-1,3 and α-1,6 glycosidic linkages, confirmed by 1H and 13C NMR. They were slowly and partially digestible in the presence of rat intestinal extract in contrast to the complete and rapid digestion of starch. The glucans formed after a longer gastric reaction time exhibited higher dietary fiber potential (19.145 ± 4.77 %; 60 min) compared to those formed during the initial phase (2.765 ± 0.19 %; 15 min). Overall, this study demonstrated the efficacy of SucroSEB in converting sucrose to slowly and partially digestible glucans under simulated in vitro gastric conditions.

Replacement of Native with Malted Triticale (x Triticosecale Wittmack) Flour in Dry Pasta: Technological and Nutritional Implications

The use of native and malted triticale (MT) flour in dry pasta has been limited despite the potential of triticale in cereal-based food production. In this study, triticale-based dry spaghetti with increasing levels of substitution (0, 25, 50, and 75 g/100 g w/w) of MT flour were formulated and analyzed. Samples were analyzed for technological and nutritional traits, including the in vitro starch and protein digestions. The gradual substitution of native triticale flour with MT increased (p < 0.05) the total dietary fiber content, whereas total starch decreased (p < 0.05). Adding MT flour increased the cooking loss and the stickiness of cooked pasta (p < 0.05). Using MT flour modulated the in vitro starch digestion, lowering the slowly digestible and resistant starch contents. The in vitro protein digestibility was positively affected using MT at the highest substitution level. Overall, MT could be used to formulate dry pasta products being the substitution to native triticale up to 50 g/100 g, a good compromise between nutritional quality and technological characteristics.

Application of In Vitro Digestion Models in the Evaluation of Dietary Supplements

Nowadays, dietary supplements are a permanent part of our diet. Using various simulated in vitro digestive models, the bioavailability of dietary supplement ingredients has also been investigated. In most cases, static models are used instead of dynamic ones. This article focuses on the division of applications of in vitro methods, such as assessing the quality of dietary supplements (in chemical and pharmaceutical form), the impact of diet on the assessment of the bioavailability of product ingredients, the impact of supplement ingredients on the state of intestinal microflora, and the development of new products using various encapsulation methods. The review included publications from 2000 to 2024 showing the use of in vitro methods in dietary supplements containing polysaccharides, proteins, elements, vitamins, and bioactive substances, as well as probiotic and prebiotic products. The impact of components in dietary supplements on the human digestive tract and their degree of bioaccessibility were determined through the use of in vitro methods. The application of in vitro methods has also become an effective tool for designing new forms of dietary supplements in order to increase the availability and durability of labile ingredients in these products.

Changes in the structure and enzyme binding of starches during in vitro enzymatic hydrolysis using mammalian mucosal enzyme mixtures

Starches are hydrolyzed into monosaccharides by mucosal α-glucosidases in the human small intestine. However, there are few studies assessing the direct digestion of starch by these enzymes. The objective of this study was to investigate the changes in the structure and enzyme binding of starches during in vitro hydrolysis by mammalian mucosal enzymes. Waxy maize (WMS), normal maize (NMS), high-amylose maize (HAMS), waxy potato (WPS), and normal potato (NPS) starches were examined. The order of the digestion rate was different compared with other studies using a mixture of pancreatic α-amylase and amyloglucosidase. NPS was digested more than other starches. WPS was more digestible than WMS. Hydrolyzed starch from NPS, NMS, WPS, WMS, and HAMS after 24 h was 66.4, 64.2, 61.7, 58.7, and 46.2 %, respectively. Notably, a significant change in the morphology, reduced crystallinity, and a decrease in the melting enthalpy of the three starches (NPS, NMS, and WPS) after 24 h of hydrolysis were confirmed by microscopy, X-ray diffraction, and differential scanning calorimetry, respectively. The bound enzyme fraction of NPS, NMS, and WPS increased as hydrolysis progressed. In contrast, HAMS was most resistant to hydrolysis by mucosal α-glucosidases in terms of digestibility, changes in morphology, crystallinity, and thermal properties.

Unveiling the significance of gastric digestion in gastrointestinal fate of octenylsuccinylated starch-stabilized emulsions

The importance of gastric digestion in starch-based emulsion is often overshadowed compared to intestinal digestion, despite acknowledging the activity of salivary α-amylase in the stomach. This study aimed to address this gap by investigating the digestion of starch-based emulsions through orogastrointestinal digestion experiments. Our observations revealed the crucial role of salivary α-amylase, which hydrolyzed ∼8 %, ∼56 %, and ∼ 28 % of starch in emulsions stabilized by octenylsuccinylated maize starch (OMS-E), gelatinized OMS (GOMS-E), and retrograded OMS (ROMS-E), respectively, during the gastric phase. Consequently, ∼23 % of the oil in GOMS-E underwent lipolysis during this phase, whereas ∼13 and ∼ 6 % of the oil was lipolyzed in OMS-E and ROMS-E, respectively. These phenomena significantly influenced their small intestinal digestion and the bioaccessibility of encapsulated curcumin. Notably, GOMS-E exhibited ∼28 % lower curcumin bioaccessibility than that of curcumin encapsulated in OMS-E or ROMS-E. This difference was attributed to premature gastric digestion and subsequent encapsulant release in the case of GOMS-E. This understanding can be utilized to manipulate the delivery and digestion of starch-based emulsions. Importantly, our findings highlight the necessity of considering gastric amylolysis and lipolysis when investigating the gastrointestinal fate of starch-based emulsions.

In vitro gastric digestion of polysaccharides in mixed dispersions: Evaluating the contribution of human salivary α-amylase on starch molecular breakdown

The aim of this work was to investigate the impact of the addition of salivary α-amylase on starch hydrolysis in protein-containing dispersions during an in vitro digestion process. In vitro digestion provides useful insights on the fate of nutrients during gastro-intestinal transit in complex food matrices, an important aspect to consider when developing highly nutritious foods. Many foods contain polysaccharides, and as their disruption in the gastric stage is limited, salivary α-amylase is often neglected in in vitro studies. A reference study on the effect of salivary α-amylase using one of the most advanced and complex in vitro digestion models (INFOGEST) is, however, not available. Hence, this work reports the gastrointestinal breakdown of three mixed dispersions containing whey protein isolate with different polysaccharides: potato starch, pectin from citrus peel and maize starch. The latter was also studied after heating. No polysaccharide or salivary α-amylase-dependent effect on protein digestion was found, based on the free NH2 and SDS-PAGE. However, in the heat-treated samples, the addition of salivary α-amylase showed a significantly higher starch hydrolysis compared to the sample without α-amylase, due to the gelatinization of the starch granules, which improved the accessibility of the starch molecules to the enzyme. This work demonstrated that the presence of different types of polysaccharides does not affect protein digestion, but also it emphasizes the importance of considering the influence of processing on food structure and its digestibility, even in the simplest model systems.

In vitro gastrointestinal digestion methods of carbohydrate-rich foods

The trend toward healthier food products has led to an increase in the research of in vitro gastrointestinal digestion methods. Among the most used models, static models are the simplest. Most static models have three stages: oral, gastric, and intestinal, simulating the enzymatic, electrolyte, pH, temperature, and bile salt conditions. The studies that have taken the most notice are those related to antioxidant activity, followed by those dealing with proteins and carbohydrates using most of them static in vitro digestion models. The number of these studies has increased over the years, passing from 45 to 415 in a 10-year period (2012-2023) and showing an interest in knowing the impact of food on human health. Nevertheless, published papers report different methodologies and analytical approaches. This review discusses the similarities and differences between the published static in vitro gastrointestinal digestion methods, with a focus on carbohydrates, finding that the most used protocol is Infogest, but with differences, mainly in the type of enzymes and their activity. Regarding in vitro gastrointestinal digestion of carbohydrates, many of the published studies are related to food and biomacromolecules, being the oral phase the most omitted, while the intestinal phase in the most diverse. Other methodologies to study the intestinal phase have been recommended, but the number of in vitro digestion studies using these methodologies (RSIE and BBMV) is still scarce but could represent a good alternative to analyze carbohydrates foods when combining with Infogest. More studies are required in this area.

Gastrointestinal metabolism characteristics and mechanism of a polysaccharide from Grifola frondosa

Grifola frondosa polysaccharide (GFP) is mainly composed of α-1,4 glycosidic bonds and possesses multiple pharmacological activities. However, the absence of pharmacokinetic studies has limited its further development and utilization. Herein, GFP was labeled with 5-DTAF (FGFP) and cyanine 5.5 amine (GFP-Cy5.5) to investigate its gastrointestinal metabolism characteristics and mechanism. Significant distributions of the polysaccharide in the liver and kidneys were observed by near infrared imaging. To investigate the specific distribution form of the polysaccharide, in vitro digestion models were constructed and revealed that FGFP was degraded in saliva and rat small intestine extract. The metabolites were detected in the stomach and small intestine, followed by further degradation in the distal intestine in the in vivo experiment. Subsequent investigations showed that α-amylase was involved in the gastrointestinal degradation of GFP, and its metabolite finally entered the kidneys, where it was excreted directly with urine.

The Effects of Fermented Feed on the Growth Performance, Antioxidant Activity, Immune Function, Intestinal Digestive Enzyme Activity, Morphology, and Microflora of Yellow-Feather Chickens

This experiment was conducted to investigate the effects of fermented feed on growth performance, antioxidant activity, immune function, intestinal digestive enzyme activity, morphology, and microflora of yellow-feather chickens. A total of 240 one-day-old female yellow-feathered (Hexi dwarf) chickens were randomly divided into two treatment groups, with six replicates per group and 20 chickens per replicate. The control group (CK) received a basal diet, whereas the experimental group was fed a basal diet of +2.00% fermented feed (FJ). The trial lasted for 22 days. Compared with the CK, (1) the growth performance was not affected (p > 0.05); (2) immunoglobin a, immunoglobin g, immunoglobin m, interleukin-1β, and interleukin-6 were affected (p < 0.05); (3) liver superoxide dismutase, glutathione peroxidase, and catalase were higher (p < 0.05); (4) trypsin activity in the duodenum and cecal Shannon index were increased (p < 0.05); (5) the relative abundance of Actinobacteriota in cecum was increased (p < 0.05); (6) the abundance of dominant microflora of Bacteroides as well as Clostridia UCG-014_norank were increased (p < 0.05). In summary, the fermented feed improved the growth performance, antioxidant activity, immune function, intestinal digestive enzyme activity, morphology, and microflora of yellow-feather chickens.

Transglycosylation catalysed by Caco-2 membrane disaccharidases: A new approach to understand carbohydrates digestibility

Under appropriate experimental conditions, some glycoside hydrolases can catalyze transglycosylation reactions; a hypothesis associated with this is that the glycosidic linkages formed will be preferentially hydrolyzed under optimal conditions. Therefore, the hydrolytic and transglycosylation activities of isolated membranes from differentiated Caco-2 cells on sucrose, maltose and isomaltulose were evaluated. After the enzymatic reactions, the di- and trisaccharides obtained were identified by gas chromatography coupled to a mass spectrometer. Differentiated Caco-2 cell membranes exerted hydrolytic and transglycosylation activities towards the studied disaccharides. The obtained di- and trisaccharides were detected for the first time using human cell models. Due to the absence of maltase-glucoamylase complex (MGAM) in Caco-2 cells, and the known hydrolytic activity of sucrase-isomaltase (SI) towards sucrose, maltose and isomaltulose, it is plausible that the glycosidic linkages obtained after the transglycosylation reaction, mainly α-glucosyl-fructoses and α-glucosyl-glucoses, were carried out by SI complex. This approach can be used as a model to explain carbohydrate digestibility in the small intestine and as a tool to design new oligosaccharides with low intestinal digestibility.

The digestive behavior of pectin in human gastrointestinal tract: a review on fermentation characteristics and degradation mechanism

Pectin is widely spread in nature and it develops an extremely complex structure in terms of monosaccharide composition, glycosidic linkage types, and non-glycosidic substituents. As a non-digestible polysaccharide, pectin exhibits resistance to human digestive enzymes, however, it is easily utilized by gut microbiota in the large intestine. Currently, pectin has been exploited as a novel functional component with numerous physiological benefits, and it shows a promising prospect in promoting human health. In this review, we introduce the regulatory effects of pectin on intestinal inflammation and metabolic syndromes. Subsequently, the digestive behavior of pectin in the upper gastrointestinal tract is summarized, and then it will be focused on pectin's fermentation characteristics in the large intestine. The fermentation selectivity of pectin by gut bacteria and the effects of pectin structure on intestinal microecology were discussed to highlight the interaction between pectin and bacterial community. Meanwhile, we also offer information on how gut bacteria orchestrate enzymes to degrade pectin. All of these findings provide insights into pectin digestion and advance the application of pectin in human health.

Sourdough "Biga" Fermentation Improves the Digestibility of Pizza Pinsa Romana: An Investigation through a Simulated Static In Vitro Model

Baked goods manufacturing parameters and fermentation conditions interfere with the nutrients content and affect their gastrointestinal fate. Pinsa Romana is a type of pizza that, recently, has been commercially rediscovered and that needed elucidation from a nutritional and digestibility perspective. In this study, six types of Pinsa Romana (five made with indirect method and one produced with straight dough technology) were characterized for their biochemical and nutritional features. Several variables like indirect (biga) Pinsa Romana production process, fermentation time and use of sourdough were investigated. The Pinsa Romana made with biga including sourdough and fermented for 48 h at 16 °C ((PR_48(SD)) resulted in the lowest predicted glycemic index, in the highest content of total peptides, total and individual free amino acids and gamma-amino butyric acid (GABA), and in the best protein quality indexes (protein efficiency ratio and nutritional index). The static in vitro digestion showed that the digesta from PR_48(SD) confirmed a reduced in vitro glycemic response after intake, and it showed a lower bioavailability of hydrophilic peptides. Furthermore, the inclusion of sourdough in biga enhanced the bioavailability of protein-related end-products including human health promoting compounds such as essential amino acids.

Glycated α-lactalbumin based micelles for quercetin delivery: Physicochemical stability and fate of simulated digestion

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ALA-dextran conjugates were fabricated by Maillard reaction.

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The conjugates had the high encapsulation efficiency on loading quercetin.

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The micelles showed excellent pH, ionic strength and photothermal stability.

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The micelles exhibited sustained release of quercetin by the resistance to enzymes.

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The excellent stability made the conjugates promising materials for oral delivery.

Glycated protein is a kind of promising material that can improve the bioavailability of bioactive compounds and achieve sustained release under digestion. In this study, the α-lactalbumin (ALA)-dextran conjugates synthesized by Maillard reaction were fabricated to load and protect quercetin. Quercetin-loaded micelles stabilized by the ALA-dextran conjugates 1:4 showed the smallest size (428.57 ± 5.64 nm) with highest encapsulation efficiency (94.38% ± 0.50%) of quercetin. Compared to ALA/dextran mixture complex, the conjugates-based micelles had better pH, ionic strength and photothermal stability. Furthermore, the micelles composed of the conjugates 1:2 and 1:4 showed the best controlled release effect during the simulated digestion, releasing 62.41% and 66.15% of quercetin from the total encapsulated contents, respectively, which was mainly related to the resistance of glycated ALA to the enzymes. The findings indicated that ALA-dextran conjugates could be effectively designed for the ideal delivery system of hydrophobic bioactive compounds in food industry.

Sweet Biotechnology: Enzymatic Production and Digestibility Screening of Novel Kojibiose and Nigerose Analogues

In view of the global pandemic of obesity and related metabolic diseases, there is an increased interest in alternative carbohydrates with promising physiochemical and health-related properties as a potential replacement for traditional sugars. However, our current knowledge is limited to only a small selection of carbohydrates, whereas the majority of alternative rare carbohydrates and especially their properties remain to be investigated. Unraveling their potential properties, like digestibility and glycemic content, could unlock their use in industrial applications. Here, we describe the enzymatic production and in vitro digestibility of three novel glycosides, namely, two kojibiose analogues (i.e., d-Glc_p-α-1,2-d-Gal and d-Glc_p-α-1,2-d-Rib) and one nigerose analogue (i.e., d-Glc_p-α-1,3-l-Ara). These novel sugars were discovered after an intensive acceptor screening with a sucrose phosphorylase originating from Bifidobacterium adolescentis (BaSP). Optimization and upscaling of this process led to roughly 100 g of these disaccharides. Digestibility, absorption, and caloric potential were assessed using brush border enzymes of rat origin and human intestinal Caco-2 cells. The rare disaccharides showed a reduced digestibility and a limited impact on energy metabolism, which was structure-dependent and even more pronounced for the three novel disaccharides in comparison to their respective glucobioses, translating to a low-caloric potential for these novel rare disaccharides.

Chlorella pyrenoidosa Polysaccharides as a Prebiotic to Modulate Gut Microbiota: Physicochemical Properties and Fermentation Characteristics In Vitro

This study was conducted to investigate the prebiotic potential of Chlorella pyrenoidosa polysaccharides to provide useful information for developing C. pyrenoidosa as a green healthy food. C. pyrenoidosa polysaccharides were prepared and their physicochemical characteristics were determined. The digestibility and fermentation characteristics of C. pyrenoidosa polysaccharides were evaluated using in vitro models. The results revealed that C. pyrenoidosa polysaccharides were composed of five non-starch polysaccharide fractions with monosaccharide compositions of Man, Rib, Rha, GlcA, Glc, Gal, Xyl and Ara. C. pyrenoidosa polysaccharides could not be degraded under saliva and the gastrointestinal conditions. However, the molecular weight and contents of residual carbohydrates and reducing sugars of C. pyrenoidosa polysaccharides were significantly reduced after fecal fermentation at a moderate speed. Notably, C. pyrenoidosa polysaccharides could remarkably modulate gut microbiota, including the promotion of beneficial bacteria, inhibition of growth of harmful bacteria, and reduction of the ratio of Firmicutes to Bacteroidetes. Intriguingly, C. pyrenoidosa polysaccharides can promote growth of Parabacteroides distasonis and increase short-chain fatty acid contents, thereby probably contributing to the promotion of intestinal health and prevention of diseases. Thus, these results suggested that C. pyrenoidosa polysaccharides had prebiotic functions with different fermentation characteristics compared with conventional prebiotics such as fructooligosaccharide, and they may be a new prebiotic for improving human health.

Orange Pectin with Compact Conformation Effectively Alleviates Acute Colitis in Mice

A comprehensive understanding of the relationships between the structure and function is critical for the targeted preparation of functional pectins. In this study, we compared the alleviating effects of five orange pectins (200 mg/kg) extracted using acid (P2), alkali (P10), cellulase (C), acid + cellulase (P2 + C), and alkali + cellulase (P10 + C) on dextran sodium sulfate-induced acute colitis. The physiological and histopathological indicators revealed that the alleviating effects were most significant for P10 + C, followed by P10, P2 + C, P2, and C. P10 + C increased the diversity and relative abundance of Akkermansia, leading to increased generation of colonic short-chain fatty acids as well as mRNA and protein expressions of GPR43, GPR109A, claudin-1, ZO-1, and occludin. Therefore, proinflammatory cytokines were decreased, and anti-inflammatory cytokines were increased. A compact conformation of P10 + C contributed to the alleviation effects on acute colitis. Alkali + cellulase-extracted orange pectin with a compact conformation has potential as adjuvant treatment for intestinal inflammation.

Advances in static in vitro digestion models after the COST action Infogest consensus protocol

In vitro digestion models are essential to predictively evaluate the bioaccessibility and bioactivity of food molecules or natural products. Dynamic models better simulate the gastrointestinal conditions as they reproduce similar physiological environments. Despite this, static methods, also known as biochemical methods, represent a simple and useful approach for the study of different types of molecules, with a broad applicability in the nutritional, pharmaceutical, and toxicological fields. In addition, static models can be validated, avoiding the disadvantage of a difficult reproducibility of dynamic in vitro systems and inter-individual variations of in vivo experiments. A crucial point in the standardization of static models was the COST Action Infogest in 2014, which elaborated an international consensus static digestion method to harmonize experimental conditions and has general guidelines, thus allowing the comparison of studies and data. The aim of our review is to underline the impact of the Infogest consensus method and the development and evolution of in vitro static methods in the following years, with a focus on food applications.

Mechanism of Lentinan Intestinal Absorption: Clathrin-Mediated Endocytosis and Macropinocytosis

Lentinan (LNT), a typical triple helix β-glucan extracted from Lentinus edodes, has been widely used as a functional food and an orally administered drug. However, its oral pharmacokinetics has been rarely reported. The aim of this work is to systematically study the pharmacokinetics and intestinal absorption mechanism of LNT after oral administration. Radioactive 99m-technetium (^99mTc) was introduced to label LNT to determine the plasma concentration, tissue distribution, and excretion of the β-glucan in rats after oral administration. The results confirmed the absorption of LNT, with the maximal plasma concentration reached at 1 h. 5-([4,6-Dichlorotriazin-2-yl]amino)fluorescein (DTAF) was used to label LNT to explore the absorption mechanism of LNT, utilizing both a Ussing chamber and a monolayer of Caco-2 cells. These transport assays showed that LNT could penetrate through the intestine and epithelial monolayer, which was mediated by macropinocytosis and clathrin-mediated endocytosis. These findings provide a pharmacokinetic reference for LNT and help provide a greater understanding of the absorption of β-glucans in general.