Michael Gidley

Mucoadhesive functionality of cell wall structures from fruits and grains: Electrostatic and polymer network interactions mediated by soluble dietary polysaccharides

Publisher: Springer Science and Business Media LLC

Date: 17-11-2017

DOI: 10.1038/S41598-017-16090-1

Abstract: We demonstrate the enhancement of intestinal mucin (Muc2) binding to plant cell wall structures from fruit (parenchymal apple tissue) and grain (wheat endosperm) mediated by soluble dietary fibers embedded within cellulose networks. Mucin binding occurs through two distinct mechanisms for pectin polysaccharides characteristic of fruits and vegetables, it is governed by molecular mucoadhesive interactions, while for neutral polysaccharides, arabinoxylan and β -glucan characteristic of cereal grains, the interaction stems from the properties of their polymer network. Based on microrheological and microscopic measurements, we show that neutral dietary fiber polysaccharides do not adhere to intestinal mucin, but are capable of disrupting the mucin network, which facilitates interpenetration of mucin molecules into the polysaccharide mesh. This effect becomes significant in the context of ‘whole foods’, where soluble fibers are incorporated within the gel-like matrix of cellulose-reinforced plant cell wall structures. The result of mucoadhesion assay and analysis of microscopy images points to the critical role of entanglements between mucin and polysaccharides as a lock-in mechanism preventing larger mucin from escaping out of plant cell wall structures. These results provide the first indication that non-pectin soluble dietary fiber may influence mucosal interactions, mucus barrier properties, and transmucosal transport of nutrients.

Towards personalised saliva spectral fingerprints: Comparison of mid infrared spectra of dried and whole saliva samples

Publisher: Elsevier BV

Date: 05-2021

DOI: 10.1016/J.SAA.2021.119569

Rheology and microstructure characterisation of small intestinal digesta from pigs fed a red meat-containing Western-style diet

Publisher: Elsevier BV

Date: 02-2015

DOI: 10.1016/J.FOODHYD.2014.09.036

Digestion of isolated legume cells in a stomach-duodenum model: Three mechanisms limit starch and protein hydrolysis

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C7FO00086C

Abstract: Retention of intact plant cells to the end of the small intestine leads to transport of entrapped macronutrients such as starch and protein for colonic microbial fermentation, and is a promising mechanism to increase the content of resistant starch in diets.

Interactions among macronutrients in wheat flour determine their enzymic susceptibility

Publisher: Elsevier BV

Date: 12-2016

DOI: 10.1016/J.FOODHYD.2016.05.026

Anti-staling of high-moisture starchy food: Effect of hydrocolloids, emulsifiers and enzymes on mechanics of steamed-rice cakes

Publisher: Elsevier BV

Date: 10-2018

DOI: 10.1016/J.FOODHYD.2018.05.028

Pasting properties of high-amylose wheat in conventional and high-temperature Rapid Visco Analyzer: Molecular contribution of starch and gluten proteins

Publisher: Elsevier BV

Date: 10-2022

DOI: 10.1016/J.FOODHYD.2022.107840

Altering starch branching enzymes in wheat generates high-amylose starch with novel molecular structure and functional properties

Publisher: Elsevier BV

Date: 07-2019

DOI: 10.1016/J.FOODHYD.2019.01.041

In vitro fermentation profiles of undigested fractions from legume and nut particles are affected by particle cohesion and entrapped macronutrients

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D2FO00250G

Abstract: Insoluble undigested food residues are the predominant dietary form of ‘fibre’ from food plants, with the potential for fermentation by microbial species resident within the large intestine.

Extracellular depolymerisation triggers fermentation of tamarind xyloglucan and wheat arabinoxylan by a porcine faecal inoculum

Publisher: Elsevier BV

Date: 12-2018

DOI: 10.1016/J.CARBPOL.2018.08.089

Abstract: Arabinoxylan (AX) and xyloglucan (XG) are important components of primary cell walls of cereal grains and vegetables/fruits, respectively. Despite the established health benefits of these non-starch polysaccharides, the mechanisms of their utilisation by the gut microbiota are poorly understood. In this study, the mechanisms of solubilised wheat AX and tamarind XG degradation were investigated under in vitro fermentation conditions using a porcine faecal inoculum. Through structural analysis of the polymers, we demonstrate that depolymerisation by microbial surface accessible endo-degrading enzymes occurs prior to active fermentation of AX or XG. Breakdown products are released into the medium and potentially utilised cooperatively by other microbes. Acetate and propionate are the main fermentation products and are produced concurrently with polysaccharide depletion. Butyrate, however, is produced more slowly consistent with it being a secondary metabolite.

Predicting Satiety from the Analysis of Human Saliva Using Mid-Infrared Spectroscopy Combined with Chemometrics

Publisher: MDPI AG

Date: 28-02-2022

DOI: 10.3390/FOODS11050711

Abstract: The aim of this study was to evaluate the ability of mid-infrared (MIR) spectroscopy combined with chemometrics to analyze unstimulated saliva as a method to predict satiety in healthy participants. This study also evaluated features in saliva that were related to in idual perceptions of human–food interactions. The coefficient of determination (R2) and standard error in cross validation (SECV) for the prediction of satiety in all saliva s les were 0.62 and 225.7 satiety area under the curve (AUC), respectively. A correlation between saliva and satiety was found, however, the quantitative prediction of satiety using unstimulated saliva was not robust. Differences in the MIR spectra of saliva between low and high satiety groups, were observed in the following frequency ratios: 1542/2060 cm−1 (total protein), 1637/3097 cm−1 (α-amino acids), and 1637/616 (chlorides) cm−1. In addition, good to excellent models were obtained for the prediction of satiety groups defined as low or high satiety participants (R2 0.92 and SECV 0.10), demonstrating that this method could be used to identify low or high satiety perception types and to select participants for appetite studies. Although quantitative PLS calibration models were not achieved, a qualitative model for the prediction of low and high satiety perception types was obtained using PLS-DA. Furthermore, this study showed that it might be possible to evaluate human/food interactions using MIR spectroscopy as a rapid and cost-effective tool.

Mechanisms of utilisation of arabinoxylans by a porcine faecal inoculum: competition and co-operation

Publisher: Springer Science and Business Media LLC

Date: 14-03-2018

DOI: 10.1038/S41598-018-22818-4

Abstract: Recent studies show that a single or small number of intestinal microbes can completely degrade complex carbohydrates. This suggests a drive towards competitive utilisation of dietary complex carbohydrates resulting in limited microbial ersity, at odds with the health benefits associated with a erse microbiome. This study investigates the enzymatic metabolism of wheat and rye arabinoxylans (AX) using in vitro fermentation, with a porcine faecal inoculum. Through studying the activity of AX-degrading enzymes and the structural changes of residual AX during fermentation, we show that the AX-degrading enzymes are mainly cell-associated, which enables the microbes to utilise the AX competitively. However, potential for cross-feeding is also demonstrated to occur by two distinct mechanisms: (1) release of AX after partial degradation by cell-associated enzymes, and (2) release of enzymes during biomass turnover, indicative of co-operative AX degradation. This study provides a model for the combined competitive-co-operative utilisation of complex dietary carbohydrates by gut microorganisms.

High amylose wheat starch structures display unique fermentability characteristics, microbial community shifts and enzyme degradation profiles

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0FO00198H

Abstract: In vitro fermentation of wheat starch depends on amylose content in cooked but not granule forms, and shows that high amylose wheat is a promising source of fermentable carbohydrate in the large intestine.

Hemicellulose-bacterial cellulose ribbon interactions affect the anisotropic mechanical behaviour of bacterial cellulose hydrogels

Publisher: Elsevier BV

Date: 03-2023

DOI: 10.1016/J.FOODHYD.2022.108283

Metabolism of Black Carrot Polyphenols during In Vitro Fermentation Is Not Affected by Cellulose or Cell Wall Association

Publisher: MDPI AG

Date: 21-08-2020

DOI: 10.3390/FOODS9121911

Abstract: Fruit and vegetable polyphenols are associated with health benefits, and those not absorbed could be fermented by the gastro-intestinal tract microbiota. Many fermentation studies focus on “pure” polyphenols, rather than those associated with plant cell walls (PCW). Black carrots (BlkC), are an ideal model plant food as their polyphenols bind to PCW with minimal release after gastro-intestinal digestion. BlkC were fractionated into three components—supernatant, pellet after centrifugation, and whole puree. Bacterial cellulose (BCell) was soaked in supernatant (BCell& S) as a model substrate. All substrates were fermented in vitro with a pig faecal inoculum. Gas kinetics, short chain fatty acids, and ammonium production, and changes in anthocyanins and phenolic acids were compared. This study showed that metabolism of BlkC polyphenols during in vitro fermentation was not affected by cellulose/cell wall association. In addition, BCell& S is an appropriate model to represent BlkC fermentation, suggesting the potential to examine fermentability of PCW-associated polyphenols in other fruits/vegetables.

Holistic approach to effects of foods, human physiology, and psychology on food intake and appetite (satiation & satiety)

Publisher: Informa UK Limited

Date: 19-10-2022

DOI: 10.1080/10408398.2022.2134840

Abstract: Appetite (satiation and satiety) is an essential element for the control of eating behavior, and as a consequence human nutrition, body weight, and chronic disease risk. A better understanding of appetite mechanisms is necessary to modulate eating behavior and food intake, and also provide a practical approach for weight management. Although many researchers have investigated the relationships between satiation/satiety and specific factors including human physiology, psychology, and food characteristics, limited information on the interactions between factors or comparisons between the relative importance of factors in contributing to satiation/satiety have been reported. This article reviews progress and gaps in understanding in idual attributes contributing to perceived satiation/satiety, the advantages of considering multiple factors together in appetite experiments, as well as the applications of nondestructive sensing in evaluating human factors contributing to relative appetite perception. The approaches proposed position characterization of appetite (satiation and satiety) for personalized and precision nutrition in relation to human status and healthy diets. In particular, it is recommended that future studies of appetite perception recognize the inter-dependence of food type and intake, appetite (satiation and satiety), and in idual status.

Molecular interactions of a model bile salt and porcine bile with (1,3:1,4)-β-glucans and arabinoxylans probed by 13C NMR and SAXS

Publisher: Elsevier BV

Date: 04-2016

DOI: 10.1016/J.FOODCHEM.2015.10.104

Abstract: Two main classes of interaction between soluble dietary fibres (SDFs), such as (1,3:1,4)-β-D-glucan (βG) and arabinoxylan (AX) and bile salt (BS) or diluted porcine bile, were identified by (13)C NMR and small angle X-ray scattering (SAXS). Small chemical shift differences of BS NMR resonances were consistent with effective local concentration or dilution of BS micelles mostly by βG, suggesting dynamic interactions whilst the reduced line widths/intensities observed were mostly caused by wheat AX and the highest molecular size and concentrations of βG. SAXS showed evidence of changes in βG but not AX in the presence of BS micelles, at >13 nm length scale consistent with molecular level interactions. Thus intermolecular interactions between SDF and BS depend on both SDF source and its molecular weight and may occur alone or in combination.

Intact cellular structure in cereal endosperm limits starch digestion in vitro

Publisher: Elsevier BV

Date: 08-2018

DOI: 10.1016/J.FOODHYD.2018.02.027

High-amylose wheat tortillas with reduced in vitro digestion and enhanced resistant starch content

Publisher: Elsevier BV

Date: 04-2023

DOI: 10.1016/J.FOODHYD.2022.108321

Rheological characterisation of cell walls from wheat flour and endosperm: Effects of diferulate crosslink hydrolysis

Publisher: Elsevier BV

Date: 03-2019

DOI: 10.1016/J.FOODHYD.2018.10.004

In vitrofermentation gas kinetics and end-products of soluble and insoluble cereal flour dietary fibres are similar

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C7FO01724C

Abstract: Similar in vitro fermentation rates, extents, and levels of short chain fatty acid metabolites suggest that soluble and insoluble fibre fractions from refined flour (and models for baking and extrusion) are likely to have similar large intestinal nutritional functionality.

Enzymatic arabinose depletion of wheat arabinoxylan regulates in vitro fermentation profiles and potential microbial degraders

Publisher: Elsevier BV

Date: 09-2023

DOI: 10.1016/J.FOODHYD.2023.108743

In vitro digestion of pectin- and mango-enriched diets using a dynamic rat stomach-duodenum model

Publisher: Elsevier BV

Date: 06-2017

DOI: 10.1016/J.JFOODENG.2017.01.011

Molecular brewing: Molecular structural effects involved in barley malting and mashing

Publisher: Elsevier BV

Date: 02-2019

DOI: 10.1016/J.CARBPOL.2018.11.018

Abstract: Ten barley s les containing varied protein contents were subject to malting followed by mashing to investigate molecular effects of both barley starch and starch- protein interactions on malting and mashing performances, and the underlying mechanism. Starch granular changes were examined using differential scanning calorimetry and scanning electron microscopy. The molecular fine structures of amylose and amylopectin from unmalted and malted grain were obtained using size-exclusion chromatography. The results showed that both amylose and amylopectin polymers were hydrolyzed at the same time during malting. Protein and amylose content in both unmalted and malted barley significant negatively correlated with fermentable sugar content after mashing. While protein content is currently the main criterion for choosing malting varieties, this study shows that information about starch molecular structure is also useful for determining the release of fermentable sugars, an important functional property. This provides brewers with some new methods to choose malting barley.

High-amylose wheat starch: Structural basis for water absorption and pasting properties

Publisher: Elsevier BV

Date: 10-2020

DOI: 10.1016/J.CARBPOL.2020.116557

Isolation of wheat endosperm cell walls: Effects of non-endosperm flour components on structural analyses

Publisher: Elsevier BV

Date: 03-2017

DOI: 10.1016/J.JCS.2017.02.004

Rice starch granule amylolysis – Differentiating effects of particle size, morphology, thermal properties and crystalline polymorph

Publisher: Elsevier BV

Date: 2015

DOI: 10.1016/J.CARBPOL.2014.08.091

Abstract: The underlying mechanism of amylolysis of rice starch granules was investigated using isolated starch granules from wild-type, as well as SBEIIb mutant and down-regulated lines. Fused granule agglomerates isolated from mutant and transgenic lines were hydrolysed at similar rates by amylases, and had similar crystalline patterns and thermal properties as in idual granules. Surface pores, a feature previously only reported for A-polymorphic starch granules, were also observed in B- and C-polymorphic rice starch granules. Although the microscopic patterns of hydrolysis among granules with different crystalline polymorphs were qualitatively similar, the extent and the rate of amylolysis were different, suggesting that B-type crystalline polymorphs are intrinsically more resistant to enzymatic hydrolysis than A-type in rice starch granules. It is proposed that the slightly longer branch lengths of amylopectin which leads to the formation of more stable B-type double helical structures compared to their A-type counterparts is the major parameter, with other factors such as granule size, surface pores and interior channels having secondary roles, in determining the rate of enzymatic hydrolysis of rice starch granules.

Quantitative structural organisation model for wheat endosperm cell walls: Cellulose as an important constituent

Publisher: Elsevier BV

Date: 09-2018

DOI: 10.1016/J.CARBPOL.2018.05.041

Abstract: The cell walls of cereal endosperms are a major source of fibre in many diets and of importance in seed structure and germination. Cell walls were isolated from both pure wheat endosperm and milled flour.

Rheological and microstructural properties of porcine gastric digesta and diets containing pectin or mango powder

Publisher: Elsevier BV

Date: 09-2016

DOI: 10.1016/J.CARBPOL.2016.04.037

Abstract: Hydrated polysaccharides and their assemblies are known to modulate gastric emptying rate due to their capacity to change the structural and rheological properties of gastric contents (digesta). In the present study, we investigated the rheological and microstructural properties of gastric digesta from pigs fed with diets incorporating mango powder or pectin, and compared results with those from hydrated diets of the same water content, in order to investigate the origins for rheological changes in the pig stomach. All of the hydrated diets and gastric digesta were particle-dominated suspensions, generally showing weak gel or more solid-like behavior with the storage modulus (G') always greater than loss modulus (G") under small deformation oscillatory measurements, and with small deformation viscosity greater than steady shear viscosity (i.e. non-Cox-Merz superposition). Although significant rheological differences were observed between the hydrated diets, rheological parameters for gastric digesta were similar for all diets, indicative of a rheological homeostasis in the pig stomach. Whilst the addition of gastric mucin (20mg/mL) to control and mango diets altered the rheology to match the gastric digesta rheology, the effect of mucin on the pectin-containing diet was negligible. The viscous effect of pectin also hindered the action of alpha amylase as observed from relatively less damaged starch granules in pectin digesta compared to mango and control digesta. Based on the experimental findings that the rheology of gastric digesta differs from hydrated diets of the same water content, the current study revealed composition-dependent complex behavior of gastric digesta in vivo, suggesting that the rheology of food products or ingredients may not necessarily reflect the rheological effect when ingested.

High-amylose wheat bread with reduced in vitro digestion rate and enhanced resistant starch content

Publisher: Elsevier BV

Date: 02-2022

DOI: 10.1016/J.FOODHYD.2021.107181

Composition and functional profiles of human faecal microbiota fermenting plant-based food particles are related to water-holding capacity more than particle size

Publisher: Elsevier BV

Date: 08-2023

DOI: 10.1016/J.FOODHYD.2023.108714

Exploring relationships between satiation, perceived satiety, and plant‐based snack food features

Publisher: Wiley

Date: 25-05-2021

DOI: 10.1111/IJFS.15102

Abstract: We aimed to identify relations between satiation and subsequent satiety for six plant‐based foods (apple, avocado, banana, carrot, chick pea and macadamia) using a panel of ten healthy participants and a complete crossover randomised design. Food was served as a mid‐morning snack ad libitum over 20 min until participants were comfortably full, and subsequent satiety was monitored for up to 180 min. Carrot and macadamia had significantly higher perceived fullness during eating, but also significantly lower perceived satiety per gram than other foods. Food energy factors had no strong relationship with perceived fullness, but were significantly positively correlated with satiety. Mastication number had significant effects on both perceived fullness (negative) and satiety (positive). This pilot study showed that plant food factors affecting perceived fullness during eating and subsequent satiety are different, and suggests how portion control through satiation for different plant‐based snacks may influence both energy intake and subsequent satiety.

Absolute abundance values reveal microbial shifts and co-occurrence patterns during gut microbiota fermentation of dietary fibres in vitro

Publisher: Elsevier BV

Date: 06-2022

DOI: 10.1016/J.FOODHYD.2021.107422

Investigation of the micro- and nano-scale architecture of cellulose hydrogels with plant cell wall polysaccharides: A combined USANS/SANS study

Publisher: Elsevier BV

Date: 11-2016

DOI: 10.1016/J.POLYMER.2016.07.015

Wheat cell walls and constituent polysaccharides induce similar microbiota profiles upon in vitro fermentation despite different short chain fatty acid end-product levels

Publisher: Royal Society of Chemistry (RSC)

Date: 2021

DOI: 10.1039/D0FO02509G

Abstract: Similar microbial communities but different fermentation rates and relative end-product amounts from wheat cell walls and component polysaccharides.

Molecular, mesoscopic and microscopic structure evolution during amylase digestion of extruded maize and high amylose maize starches

Publisher: Elsevier BV

Date: 03-2015

DOI: 10.1016/J.CARBPOL.2014.11.025

Abstract: Extrusion processing of cereal starch granules with high (>50%) amylose content is a promising approach to create nutritionally desirable resistant starch, i.e. starch that escapes digestion in the small intestine. Whilst high amylose content seems to be required, the structural features responsible for the slow digestion of extrudates are not fully understood. We report the effects of partial enzyme digestion of extruded maize starches on amylopectin branch length profiles, double and single helix contents, crystallinity and lamellar periodicity. Comparing results for three extruded maize starches (27, 57, and 84% apparent amylose) that differ in amylase-sensitivity allows conclusions to be drawn concerning the rate-determining features operating under the digestion conditions used. Enzyme resistance is shown to originate from a combination of molecular and mesoscopic factors, including both recrystallization and an increase in very short branches during the digestion process. This is in contrast to the behaviour of the same starches in the granular form (Shrestha et al., 2012) where molecular and mesoscopic factors are secondary to microscopic structures in determining enzyme susceptibility. Based on the structure of residual material after long-time digestion (>8h), a model for resistant starch from processed high amylose maize starches is proposed based on a fringed micelle structure with lateral aggregation and enzyme susceptibility both limited by attached clusters of branch points.

In vitro fermentation outcomes of arabinoxylan and galactoxyloglucan depend on fecal inoculum more than substrate chemistry

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/D0FO01103G

Abstract: The production of SCFA and promotion of bacteria, during fermentation of soluble polysaccharides, depend on the initial composition of the host large intestinal microbiota more than the type of polysaccharide.

Mechanical properties of bacterial cellulose synthesised by diverse strains of the genus Komagataeibacter

Publisher: Elsevier BV

Date: 08-2018

DOI: 10.1016/J.FOODHYD.2018.02.031

Interaction of cellulose and xyloglucan influences in vitro fermentation outcomes

Publisher: Elsevier BV

Date: 04-2021

DOI: 10.1016/J.CARBPOL.2021.117698

Tribology of swollen starch granule suspensions from maize and potato

Publisher: Elsevier BV

Date: 2017

DOI: 10.1016/J.CARBPOL.2016.08.064

Abstract: The tribological properties of suspensions of cooked swollen starch granules are characterised for systems based on maize starch and potato starch. These systems are known as granule 'ghosts' due to the release (and removal) of polymer from their structure during cooking. Maize starch ghosts are less swollen than potato starch ghosts, resulting in a higher packing concentration and greater mechanical stability. In a soft-tribological contact, maize ghost suspensions reduce friction compared to the solvent (water), generate bell-shaped tribological profiles characteristic of particle entrainment and show a marked concentration dependence, whereas potato ghost suspensions exhibit lubrication behaviour similar to water. Microscopy analysis of the s les following tribological testing suggests that this is due to the rapid break-up of potato ghosts under the shear and rolling conditions within the tribological contact. A reduction in the small deformation moduli (associated with a weak gel structure) is also observed when the potato ghost suspensions are subjected to steady shear using parallel plate rheometry both microscopy and particle size analysis show that this is accompanied by the partial shear-induced breakage of ghost particles. This interplay between particle microstructure and the resultant rheological and lubrication dynamics of starch ghost suspensions contributes to an enhanced mechanistic understanding of textural and other functional properties of cooked starches in food and other applications.

Microstructure and mechanical properties of arabinoxylan and (1,3;1,4)-β-glucan gels produced by cryo-gelation

Publisher: Elsevier BV

Date: 10-2016

DOI: 10.1016/J.CARBPOL.2016.06.038

Abstract: The interactions between heteroxylans and mixed linkage glucans determine the architecture and mechanical properties of cereal endosperm cell walls. In this work hydrogels made of cross-linked arabinoxylan with addition of β-glucan were synthesised by cryogelation as a biomimetic tool to investigate endosperm walls. Molecular and microstructural properties were characterised by nuclear magnetic resonance ((13)C NMR), scanning electron microscopy (SEM) and immunolabelling/confocal laser scanning microscopy (CLSM). The response to mechanical stress was studied by compression-relaxation experiments. The hydrogels consisted of a scaffold characterised by dense walls interconnected by macropores with both hemicelluloses co-localised and homogeneously distributed. The gels showed a high degree of elasticity reflected in their ability to resist compression without developing cracks and recover 60-80% of their original height. Our results highlight the compatibility of these hemicelluloses to coexist in confined environments such as cell walls and their potential role in determining mechanical properties in the absence of cellulose.

Determination of glucosinolates and isothiocyanates in glucosinolate-rich vegetables and oilseeds using infrared spectroscopy: A systematic review

Publisher: Informa UK Limited

Date: 10-04-2023

DOI: 10.1080/10408398.2023.2198015

Independent fermentation and metabolism of dietary polyphenols associated with a plant cell wall model

Publisher: Royal Society of Chemistry (RSC)

Date: 2020

DOI: 10.1039/C9FO02987G

Abstract: The metabolic pathways of polyphenol degradation are not influenced by the presence of plant cell walls during in vitro fermentation, but co-fermentation of cell walls may lead to faster microbial metabolism of polyphenols.

Inhibition of α-amylase activity by cellulose: Kinetic analysis and nutritional implications

Publisher: Elsevier BV

Date: 06-2015

DOI: 10.1016/J.CARBPOL.2015.01.039

Abstract: We report on inhibition of α-amylase activity by cellulose based on in vitro experiments. The presence of cellulose in the hydrolysing medium reduced the initial velocity of starch hydrolysis in a concentration dependent manner. α-Amylase adsorption to cellulose was reversible, attaining equilibrium within 30min of incubation, and showed a higher affinity at 37°C compared to 20 and 0°C. The adsorption was almost unchanged in the presence of maltose (2.5-20mM) but was hindered in the presence of excess protein, suggesting non-specific adsorption of α-amylase to cellulose. Kinetic analyses of α-amylase hydrolysis of maize starch in the presence of cellulose showed that the inhibition is of a mixed type. The dissociation constant (Kic) of the EI complex was found to be ca. 3mg/mL. The observed inhibition of α-amylase activity suggests that cellulose in the diet can potentially attenuate starch hydrolysis.

Mucin gel assembly is controlled by a collective action of non-mucin proteins, disulfide bridges, Ca2+-mediated links, and hydrogen bonding

Publisher: Springer Science and Business Media LLC

Date: 11-04-2018

DOI: 10.1038/S41598-018-24223-3

Abstract: Mucus is characterized by multiple levels of assembly at different length scales which result in a unique set of rheological (flow) and mechanical properties. These physical properties determine its biological function as a highly selective barrier for transport of water and nutrients, while blocking penetration of pathogens and foreign particles. Altered integrity of the mucus layer in the small intestine has been associated with a number of gastrointestinal tract pathologies such as Crohn’s disease and cystic fibrosis. In this work, we uncover an intricate hierarchy of intestinal mucin (Muc2) assembly and show how complex rheological properties emerge from synergistic interactions between mucin glycoproteins, non-mucin proteins, and Ca 2+ . Using a novel method of mucus purification, we demonstrate the mechanism of assembly of Muc2 oligomers into viscoelastic microscale domains formed via hydrogen bonding and Ca 2+ -mediated links, which require the joint presence of Ca 2+ ions and non-mucin proteins. These microscale domains aggregate to form a heterogeneous yield stress gel-like fluid, the macroscopic rheological properties of which are virtually identical to that of native intestinal mucus. Through proteomic analysis, we short-list potential protein candidates implicated in mucin assembly, thus paving the way for identifying the molecules responsible for the physiologically critical biophysical properties of mucus.

Effects of diverse food processing conditions on the structure and solubility of wheat, barley and rye endosperm dietary fibre

Publisher: Elsevier BV

Date: 2016

DOI: 10.1016/J.JFOODENG.2015.08.037

Wood hemicelluloses exert distinct biomechanical contributions to cellulose fibrillar networks

Publisher: Springer Science and Business Media LLC

Date: 17-09-2020

DOI: 10.1038/S41467-020-18390-Z

Abstract: Hemicelluloses, a family of heterogeneous polysaccharides with complex molecular structures, constitute a fundamental component of lignocellulosic biomass. However, the contribution of each hemicellulose type to the mechanical properties of secondary plant cell walls remains elusive. Here we homogeneously incorporate different combinations of extracted and purified hemicelluloses (xylans and glucomannans) from softwood and hardwood species into self-assembled networks during cellulose biosynthesis in a bacterial model, without altering the morphology and the crystallinity of the cellulose bundles. These composite hydrogels can be therefore envisioned as models of secondary plant cell walls prior to lignification. The incorporated hemicelluloses exhibit both a rigid phase having close interactions with cellulose, together with a flexible phase contributing to the multiscale architecture of the bacterial cellulose hydrogels. The wood hemicelluloses exhibit distinct biomechanical contributions, with glucomannans increasing the elastic modulus in compression, and xylans contributing to a dramatic increase of the elongation at break under tension. These erging effects cannot be explained solely from the nature of their direct interactions with cellulose, but can be related to the distinct molecular structure of wood xylans and mannans, the multiphase architecture of the hydrogels and the aggregative effects amongst hemicellulose-coated fibrils. Our study contributes to understanding the specific roles of wood xylans and glucomannans in the biomechanical integrity of secondary cell walls in tension and compression and has significance for the development of lignocellulosic materials with controlled assembly and tailored mechanical properties.

Characterisation of bacterial cellulose from diverse Komagataeibacter strains and their application to construct plant cell wall analogues

Publisher: Springer Science and Business Media LLC

Date: 27-01-2017

DOI: 10.1007/S10570-017-1203-3

Determination of glucosinolates in broccoli (Brassica oleracea var. italica) by combining mid‐infrared (MIR) spectroscopy with chemometrics

Publisher: Wiley

Date: 09-2023

DOI: 10.1111/IJFS.16664

Abstract: Glucosinolates (GSLs), compounds with potential chemo‐preventative properties, can be affected by pre‐ and post‐harvest processes. Therefore, monitoring their content is important for the food and agricultural industries. This study evaluates the application of mid‐infrared (MIR) spectroscopy for the determination of GSLs in commercial broccoli ( Brassica oleracea var. italica ). Broccoli (n=53) from different varieties were analysed using MIR spectroscopy and high‐performance liquid chromatography to develop partial least squares models for six in idual GLSs, total indolic glucosinolates, and total GSLs. The coefficient of determination in cross‐validation (R 2 CV ) of 0.50‐0.78 whereas residual predictive deviation (RPD) values of 1.35‐2.19 for different GSLs. Cross‐validation models developed using Tenderstem® broccoli yielded an R 2 CV of 0.41‐0.91 and an RPD of 0.81‐2.97. This study showed that MIR spectroscopy can be considered for the determination of some broccoli GSLs. Differences in the loadings between the models demonstrated that variations in broccoli composition can influence the cross‐validation models for GSLs.

Regrinding large particles from milled grains improves growth performance of pigs

Publisher: Elsevier BV

Date: 11-2017

DOI: 10.1016/J.ANIFEEDSCI.2016.08.004

Microstructural properties of potato chips

Publisher: Elsevier BV

Date: 04-2018

DOI: 10.1016/J.FOOSTR.2018.03.001

In Vitro Digestion of Apple Tissue Using a Dynamic Stomach Model: Grinding and Crushing Effects on Polyphenol Bioaccessibility

Publisher: American Chemical Society (ACS)

Date: 10-12-2019

DOI: 10.1021/ACS.JAFC.9B05649

Abstract: Food structure is a key determinant for the release of phenolic compounds during gastric and intestinal digestion. We evaluated the bioaccessibility of polyphenols from apple tissue during gastric digestion in vitro from bio-mechanical perspectives including the effects of gastric juice and mucin on the apple tissue matrix under simulated stomach peristalsis. The gastric model system was effective in releasing polyphenols because of simultaneous compression and extrusion, with 3 times higher release from coarse than from fine particles. However, bioaccessibility of polyphenols was reduced up to 44% in the presence of both cell walls and gastric mucin. Most in idual phenolic molecules were gradually released and were stable in the gastric environment, except for procyanidin B2. The study suggests that the bioaccessibility of polyphenols from apples in the upper digestive tract is dependent on mechanical disintegration and the residual matrix present in the swallowed bolus.

Multi-scale model for the hierarchical architecture of native cellulose hydrogels

Publisher: Elsevier BV

Date: 08-2016

DOI: 10.1016/J.CARBPOL.2016.03.098

Abstract: The structure of protiated and deuterated cellulose hydrogels has been investigated using a multi-technique approach combining small-angle scattering with diffraction, spectroscopy and microscopy. A model for the multi-scale structure of native cellulose hydrogels is proposed which highlights the essential role of water at different structural levels characterised by: (i) the existence of cellulose microfibrils containing an impermeable crystalline core surrounded by a partially hydrated paracrystalline shell, (ii) the creation of a strong network of cellulose microfibrils held together by hydrogen bonding to form cellulose ribbons and (iii) the differential behaviour of tightly bound water held within the ribbons compared to bulk solvent. Deuterium labelling provides an effective platform on which to further investigate the role of different plant cell wall polysaccharides in cellulose composite formation through the production of selectively deuterated cellulose composite hydrogels.

Claret Bioscience

Location: United States of America

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Discovery Projects - Grant ID: DP0558067

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