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Background; The structure of many plant- and fungal-based foods is determined by cell walls which are the primary source of dietary fiber. Several studies have shown that consumption of cell wall fibers from plants and fungi can modulate digestion leading to health-promoting effects such as increasing satiety and reducing the risk of cardiovascular diseases and type-2 diabetes. Scope and Approach; We focus on the impact of the food structure determined by plant and fungal cell walls on digestion and subsequent physiological responses. The underlying mechanisms promoting health effects may differ between plant and fungal cell walls, considering their different structural and biochemical organizations. Fungal cell walls have been vastly understudied compared to plant cell walls in this regard. Therefore, we highlight differences and similarities of plant- and fungal-based foods that may underlie the observed health benefits. Key Findings and Conclusions; The ability of the plant cell walls in our diet to influence digestion and improve human health has been intensely investigated over many years. The health outcomes observed following plants and fungi consumption appear similar, despite fundamental differences between the two kingdoms of life. The possible mechanisms underlying the health effects are the control of nutrient bioaccessibility, binding and sequestration of digestive components, increasing viscosity, and colonic fermentation. Mechanisms by which cell walls influence bioaccessibility of nutrients from fungal and plant cell walls are discussed. Moreover, consistent evidence for the fungal counterpart is still lacking, and further studies focusing on the whole structure of fungi are required. • Cell walls are the main source of dietary fiber and linked to disease prevention. • Cell walls from fungi and plants have different composition and structure. • Similar health outcomes are linked with both plant and fungal fiber consumption. • The release of digested nutrients may vary between plant and fungal cell walls. • Research on fungal cell walls and health is lacking compared to those of plants. [ABSTRACT FROM AUTHOR]

Personalisation of foods opens for improving individuals' quality of life. In the personalised food approach, the focus of research is food, its components and the possibilities of different processes throughout the food value chain to impact on individuals and their needs. In this paper, we will provide an overview of how research from a personalised food perspective can benefit consumers that require special food offerings. The paper is structured along the food chain addressing the following topics: i) Food raw material and components, ii) Food processing and culinary aspects, iii) Food digestion and microbiota, iv) Food perception. The paper highlights how food and its composition influence personal requirements, and how processing of the foods can contribute to optimised products for consumer groups. Furthermore, much attention has been accorded how digestion and microbiota are sensitive to food consumed and how this vary with consumer group. Finally, consumers' perceptions and preferences play an important part in how foods are presented and chosen. More research is needed to utilise the possibilities of personalising foods to improve life for consumers with different needs. • Personalisation of food can be addressed throughout the value chain of food. • Food raw material can be selected, modified and treated for personalisation. • Food processing techniques can improve nutrient availability of personalised food. • Food digestion and gut microbiota influence personalisation of food. • Sensory attributes are important for personalisation of food. [ABSTRACT FROM AUTHOR]

Solutions of okra gum and mucin were studied during pH cycling (7–3–7), as to model the interactions between these components in the oral-gastrointestinal tract. Okra gum aggregates with mucin at pH close to 3, while they redissolve back at pH 7 due to electrostatic interactions. Fluorimetry shows that complexes form at low pH, and break-up upon return to pH 7. At pH 3 both static and transient complexes are detected. Shear viscosities reduce upon pH lowering from 7 to 3 pH 3 and then are partially restored back at pH 7, suggesting a hysteresis in the macromolecular rearrangement after pH cycling. Hysteresis is more pronounced in the extensional rheology, leading to Trouton ratios with a strong dependence on the pH. Thus flow can be regulated in different ways in compartments with different pH (mouth, stomach, intestine). Image 1 • Okra gum and mucin in solution form pH-dependent complexes. • Okra gum–mucin interactions are generally pH-reversible at the molecular level. • Shear viscosity is reversible upon pH cycling. • Extensional rheology shows hysteresis during pH cycling due to surface phenomena. • The relative importance of shear vs. extensional rheology changes during pH cycling. [ABSTRACT FROM AUTHOR]

The current allergenicity assessment of novel proteins is based on the EFSA GMO guidance. Recently, EFSA launched a new guidance document on allergenicity assessment of GM plants (2017). This document describes, amongst other topics, the new scientific and regulatory developments on in vitro protein digestibility tests. The EFSA GMO Panel stated that for in vitro protein digestibility tests, additional investigations are needed before any additional recommendation in the form of guidance can be provided. To this end, an interim phase is considered necessary to evaluate the revisions to the in vitro gastrointestinal digestion test, proposed by EFSA. This prompted the establishment of a joint workshop through two COST Action networks: COST Action ImpARAS and COST Acton INFOGEST. In 2017, a workshop was organised to discuss the relevance of digestion in allergenicity risk assessment and how to potentially improve the current methods and readouts. The outcome of the workshop is that there is no rationale for a clear readout that is predictive for allergenicity and we suggest to omit the digestion test from the allergenicity assessment strategy for now, and put an effort into filling the knowledge gaps as summarized in this paper first. • Protein digestion is relevant for allergenicity of some proteins, but not for all. • It is not clear yet how different factors exactly influence digestion and how these factors can be included. • Including all factors will complicate the elaboration of a simple and predictive digestion assay. • There is no rationale for a clear readout that is predictive for allergenicity. • We suggest to omit the digestion test from the allergenicity assessment for now and put effort into filling the knowledge gaps. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ enzyme treatments can be exploited to generate low-sugar functional foods. • Fructo-oligosaccharides (FOS) were enzymatically synthesized at 60 ℃ and pH 5.0. • A strawberry preparation with 50 % (w/w) FOS and less 80 % sucrose was obtained. • The caloric value of the prebiotic-treated preparations was lowered in 26–31 %. • More than 90 % of the FOS resisted to the in vitro digestion. Food industry has been pressed to develop products with reduced sugar and low caloric value, while maintaining unchanged their rheological and physicochemical properties. The development of a strawberry preparation for the dairy industry, with prebiotic functionality, was herein investigated by in situ conversion of its intrinsic sucrose content into prebiotic fructo-oligosaccharides (FOS). Two commercial enzymatic complexes, Viscozyme® L and Pectinex® Ultra SP-L, were evaluated for the synthesis of FOS. Operational parameters such as temperature, pH, and enzyme:substrate ratio (E:S) were optimized to maximize FOS yield. The rheological and physicochemical properties of the obtained strawberry preparation were evaluated. For functional analysis, the resistance of FOS to the harsh conditions of the gastro-intestinal digestion was evaluated by applying the standardized INFOGEST static protocol. At optimal conditions (60 ℃, pH 5.0), Pectinex® produced 265 ± 3 g·L−1 FOS, yielding 0.57 ± 0.01 g FOS ·g initial sucrose −1 after 7 h reaction (E:S: 1:40); and Viscozyme® produced 295 ± 1 g·L−1 FOS, yielding 0.66 ± 0.00 g FOS ·g initial sucrose −1 after 5 h (E:S: 1:30). The obtained strawberry preparations contained more than 50 % (w/w) prebiotic FOS incorporated (DP 3–5), with 80 % reduction of its sucrose content. The caloric value was therefore reduced by 26–31 %. FOS showed resistance to gastrointestinal digestion being only slightly hydrolysed (<10 %). 1F-Fructofuranosylnystose was not digested at any phase of the digestion. Although the physicochemical properties of the prebiotic preparations were different from the original one, parameters such as the lower °Brix , water activity, consistency and viscosity, and its different color, may be easily adjusted. Results indicate that in situ synthesis strategies are efficient alternatives in the manufacture of reduced sugar and low-caloric food products with prebiotic potential. [ABSTRACT FROM AUTHOR]

Background In vitro digestion models show great promise in facilitating the rationale design of foods. This paper provides a look into the current state of the art and outlines possible future paths for developments of digestion models recreating the diverse physiological conditions of specific groups of the human population. Scope and approach Based on a collective effort of experts, this paper outlines considerations and parameters needed for development of new in vitro digestion models, e.g. gastric pH, enzymatic activities, gastric emptying rate and more. These and other parameters are detrimental to the adequate development of in vitro models that enable deeper insight into matters of food luminal breakdown as well as nutrient and nutraceutical bioaccessibility. Subsequently, we present an overview of some new and emerging in vitro digestion models mirroring the gastro-intestinal conditions of infants, the elderly and patients of cystic fibrosis or gastric bypass surgery. Key findings and conclusions This paper calls for synchronization, harmonization and validation of potential developments in in vitro digestion models that would greatly facilitate manufacturing of foods tailored or even personalized, to a certain extent, to various strata of the human population. [ABSTRACT FROM AUTHOR]

[Display omitted] • DTB and BF were conjugated to beads for ratiometric imaging. • The probe was favorable for monitoring dextranase activity in the agarose gel. • A linear relationship of I green / I red was obtained against C / C 0. • I green / I red increased more rapidly with a greater diffusion coefficient of dextranase. Molecular bioimaging of enzyme activity is rapidly emerging as a powerful strategy for accurate disease diagnostics. This work aims to prove that bioimaging of enzyme activity in food digestion with a fluorescent probe is feasible. In this study, a dual-labeled fluorescent probe with dextran-tetramethylrhodamine (TMR)-biotin conjugate (DTB) as the enzyme-cleavable unit, and biotin-(5-fluorescein) conjugate (FB) as the reference unit, was developed. It was immobilized in the agarose gel (the model food matrix) for the fluorescence quantification of dextranase activity. The probe manifested significantly ratiometric fluorescent signals (I green / I red) in response to the enzyme-active reaction. Linear relationships of I green / I red were obtained against the dextranase concentration ratio (C / C 0). I green / I red increased more rapidly with a greater dextranase diffusion rate, also supported by the more significant diffusion coefficient of fluorescently labeled dextranase in 0.5 wt% agarose gel (1.87 × 10-6 cm2 s−1). Our work provides more mechanistic evidence for enzyme activity imaging in food digestion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quantitative analysis of peptide release kinetics during chymotrypsin hydrolysis. • Broad specificity with preference towards F, Y, W and to a lower extent M, L. • Hydrolysis rates of individual cleavage sites (selectivity) differed a lot. • Hindrance by proline when occupying positions P 3, P 1′ or P 2′ but not in P 2 and P 3′. • Other neighbouring amino acids had no major effects on selectivity. Chymotrypsin is one of the major proteases in intestinal protein digestion. Observations about the type of bonds that are hydrolysed (specificity and preference) were in the past derived from the peptide composition after digestion or hydrolysis rates of synthetic peptides. In this study, the path of hydrolysis by bovine chymotrypsin, i.e formation and degradation of peptides, were described for α-lactalbumin, β-lactoglobulin and β-casein. The peptide compositions, determined with UPLC-PDA-MS at different time points were used to determine the digestion kinetics for individual cleavage sites. It was evaluated how statements on (secondary) specificity from literature were reflected in the release kinetics of peptides. β-Lactoglobulin reached the highest degree of hydrolysis (10.9 ± 0.1 %) and was hydrolysed fastest (28 ± 1 mM peptide bonds /s/mM enzyme), regardless of its globular (tertiary) structure. Chymotrypsin showed a preference towards aromatic amino acids, methionine and leucine, but was also tolerant to other amino acids. For the cleavage sites within this preference, ̴73% of the cleavage sites were hydrolysed with high or intermediate selectivity. For the missed cleavages within the preference, 45 % was explained by hindrance of proline, which affected hydrolysis only when in positions P 3, P 1′ or P 2′. No clear indication (based on primary structure) was found to explain the other missed cleavages. A few cleavage sites were hydrolysed extremely efficient in α-lactalbumin (F9, F31, W104) and β-casein (W143, L163, F190). This study gave unique and quantitative insight in peptide formation and degradation by chymotrypsin in the digestion of proteins. The approach used showed potential to explore the path of hydrolysis for other proteases with less defined specificity. [ABSTRACT FROM AUTHOR]

High blood glucose and insulin concentrations, even if within the normal range, are associated with an increased risk to develop type 2 diabetes and cardiovascular diseases. Dietary carbohydrates are the main determinants of blood glucose levels in the postprandial period; therefore, the effects of dietary carbohydrates on human health are strongly related to their rate of digestion in the small intestine. This has raised much interest on food properties able to retard carbohydrate digestion and absorption. This review is focused to examine food properties which influence carbohydrate digestion in order to predict their potential influence on health markers. Among them, it is worth to underline the role of viscosity, the physical form of the food, cooking methods and processing, the type of starch (amylose or amylopectin), the presence of anti-nutrients and the amount of fiber, fat, and proteins. In this respect particularly relevant is the type of starch present in the food, since amylose is slowly digested by intestinal α-amylases while the digestion of amylopectin is faster. However, the food component that has the strongest impact on digestion and absorption of dietary carbohydrates is dietary fiber that modulates the postprandial glucose rise by multiple mechanisms. In fact, dietary fibers may increase ingesta viscosity, thus delaying the gastric emptying time and slowing both carbohydrate digestion and the rate of glucose transport to enterocytes. In addition, they can influence the composition of the gut microbiota and induce the production of short-chain fatty acids that beneficially affect glucose and lipid metabolism. In short, the knowledge of food characteristics able to retard carbohydrate digestion and absorption in the intestine can help modify food properties with the aim of improving their functionality. [ABSTRACT FROM AUTHOR]

Two whey protein emulsion gels containing 10 mM NaCl (soft gel) or 200 mM NaCl (hard gel) were formed and subjected to sequential digestion, including an in vitro gastric step followed by an in vitro intestinal step. The breakdown of gel particles, stability of oil droplets, microstructure and free fatty acid release during digestion were examined. The results showed that after 60 and 240 min gastric digestion the digesta of both gels had different physicochemical forms. The 60 min gastric digesta of both gels was mainly composed of gel particles ranging from ∼1 to ∼1000 μm. The 240 min gastric digesta of the soft gel mainly consisted of individual oil droplets and small gel particles (∼10 μm) while that of the hard gel mainly consisted of small gel particles (∼10 μm). During intestinal digestion, the breakup and coalescence of oil droplets occurred simultaneously for all gastric digesta. The remaining network structure of gel particles hindered their breakdown especially in the hard gel during intestinal digestion, which delayed lipid digestion significantly. Lipolytic products appeared to accumulate around oil droplet surfaces. Needle-shaped crystals that may be composed of free fatty acids were also found during intestinal digestion. [ABSTRACT FROM AUTHOR]

We have cloned the cDNA and genomic DNA of an active intronless cathepsin L from Metapenaeus ensis. The encoded enzyme has the shortest prosequence among cathepsin L subgroup. It was predominantly expressed in hepatopancreas with an expression level of at least 10 times higher than in any other tissues. It also has expression in stomach, intestine, eye, testis, ovary and muscle. Western blots visualized the mature enzyme in hepatopancreas and a procathepsin L in ovary, intestine and stomach. Metapenaeus cathepsin L (MeCatL) is localized in the large digestive vacuole of the digestive B cell of hepatopancreas. MeCatL has a role in food digestion. An interesting finding is that it exists in the nucleus of oocyte. MeCatL might have a specified physiological role in the nucleus of oocyte. MeCatL might also have a house-keeping function as is suggested for mammalian cathepsin L. [Copyright &y& Elsevier]

Nanocellulose (NC) has become a topic of increasing interest in recent years due to its special characteristics (including viscous properties and large specific surface area) and potential wide applications. Currently NC has been widely used in a number of fields, including textile, pharmacy, cosmetics, medicine and packaging. However, so far there are limited studies on the behavior of NC along gastrointestinal tract (GIT) if consumed as a fiber source. NC has not yet been approved by FDA as a generally recognized as safe (GRAS) material. Therefore, future studies are needed in order to aid in a better understanding of the safety of NC as well as foster decision-making regarding the usage of NC as a food-grade fiber source. This review overviews current studies on the behavior of NC along GIT as well as its influence on food digestion and nutrient absorption, and highlights the existing knowledge gaps. • Intrinsic and extrinsic factors that influence the fate of NC along GIT are summarized. • Characterization of the fate of NC along GIT utilizing multiple techniques is discussed. • The influence of NC on food digestion and mineral absorption is overviewed. • The effects of NC on intestinal cells, microbiota and mucus are summarized. • The existing knowledge gaps are brought forward as suggestions for future studies. [ABSTRACT FROM AUTHOR]

The resistance of Bifidobacterium, Lactobacillus , and Bacillus strains with claimed probiotic properties in different food matrices was evaluated. Lactobacillus paracasei PXN 37, Lactobacillus acidophilus La-5, Bifidobacterium animalis subsp. lactis Bb-12, Bifidobacterium breve PXN 25, Bacillus subtilis PXN 21, Bacillus coagulans GBI30 6086 and Bacillus coagulans MTCC 5856 strains were inoculated in "requeijão cremoso" cheese, pasteurized orange juice, and bread. Further, the counts of the strains with claimed probiotic properties were determined throughout the products' shelf-life. Additionally, the survival (%), at the beginning and at the end of their shelf-life, of each strain with claimed probiotic properties inoculated in the three foods was estimated by using a static in vitro system simulating the gastric (pH 2), enteric I (pH 5) and enteric II (pH 7) phases of gastrointestinal tract (GIT). Overall, it has been found that the Bacillus strains with claimed probiotic properties showed greater viability than probiotic Bifidobacterium and Lactobacillus strains no matter the food studied. The percentage of survival of the Bacillus strains with claimed probiotic properties were always above 83%. The Bacillus strains with claimed probiotic properties were able to survive well in all the food matrices tested. Therefore, this study shows that these strains of Bacillus may comprise a feasible strategy for expanding the range of "probiotic food" choices given their high resistance to the composition of foods, manufacturing steps, and resistance to simulated GIT conditions. Unlabelled Image • Fate of seven probiotic strains of Lactobacillus, Bifidobacterium and Bacillus during food storage • Survival of the seven probiotic strains in three food matrices through in vitro gastrointestinal (GIT) conditions • Probiotic Bacillus strains showed higher viability than Lactobacillus and Bifidobacterium during storage and GIT conditions • The resistance of the probiotic Bacillus strains varied with food matrix, but <1 log CFU/ or mL of these microorganisms were observed. • The reduction in the counts of probiotic Bacillus strains during storage and GIT conditions were always <1 log CFU/g or mL • Survival rate of probiotic Bacillus during GIT conditions was >80%, even at the end of the shelf life of the tested foods [ABSTRACT FROM AUTHOR]