In-situ disintegration of egg white gels by pepsin and kinetics of nutrient release followed by time-lapse confocal microscopy

Somaratne, Geeshani; Nau, Françoise; Ferrua, Maria J.; Singh, Jaspreet; Ye, Aiqian; Dupont, Didier; Singh, R. Paul; Floury, Juliane

doi:10.1016/j.foodhyd.2019.105228

Cited by 20 publications

(10 citation statements)

References 32 publications

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“…Therefore, the result was greater changes of the microstructure of pH 5 EWG, and a larger effect on the weakening and disintegration of this gel. Another factor possibly contributing to the greater resistance of the pH 9 EWG to breakdown under the stomach conditions could be the higher initial pH of the gel (Somaratne, Nau, et al, 2019b). Indeed, this could locally induce high pH despite the addition of gastric fluid, thus limiting the proteolytic action of pepsin on the pH 9 gel proteins in agreement with the observations of Nau et al (2019).…”

Section: Tablesupporting

confidence: 72%

“…On the other hand, EWGs became softer and then likely easier to break apart after diffusion of gastric juice. Then, as reported in Somaratne, Nau, et al (2019a, 2019b, pepsin diffusivity was higher inside the flexible, highly anisotropic, porous and the granular network of the pH 5 EWG than inside the rigid, highly isotropic, less porous and smooth network of the pH 9 EWG. Therefore, the result was greater changes of the microstructure of pH 5 EWG, and a larger effect on the weakening and disintegration of this gel.…”

Section: Tablesupporting

confidence: 65%

“…pH 9 EWG had a significantly higher initial hardness compared to the pH 5 EWG (4.83 ± 0.13 N compared to 2.39 ± 0.07 N), likely due to the more compact and microstructurally homogeneous gel formed by egg white proteins at pH 9 (Somaratne, Nau, et al, 2019a, 2019b. In contrast, the microstructure of the pH 5 EWG was characterised by a spatially heterogeneous loose protein matrix made of larger aggregate particles (Somaratne, Nau, et al, 2019a, 2019b, which lead to a lower initial hardness. Throughout the gastric digestion, pH 9 EWG maintained a higher hardness compared to pH 5 EWG.…”

Section: Softening Kinetics Of Ewgs During Gastric Phase Is Influenced By the Initial Ewg Characteristicsmentioning

confidence: 96%

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Egg white gel structure determines biochemical digestion with consequences on softening and mechanical disintegration during in vitro gastric digestion

Somaratne

Nau

et al. 2020

Food Research International

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The aim of this work was to investigate the role of biochemical digestion on softening and disintegration kinetics of pH 5 and pH 9 egg white gel (EWGs) during in vitro gastric digestion. EWG samples (5 mm length cubes) underwent in vitro digestion by incubation in simulated gastric fluid at different time intervals for up to 240 min. The hardness was measured using a Texture Analyser; softening kinetics was fit to the Weibull model. Results revealed that pH 9 EWG had the highest softening halftime (458 ± 86 min), indicating the slowest softening, whereas pH 5 EWG had the lowest softening halftime (197 ± 12 min), indicating the quickest softening. The digested samples were immediately exposed to mechanical forces generated by the human gastric simulator (HGS) for 10 min to investigate the influence of gastric juice on the breakdown behaviour of EWG cubes. The breakdown behaviour of the disintegrated samples was characterized by fitting the cumulative distributions of particle surface areas to a mixed Weibull function (R 2 > 0.99). The weight of fine particles (α) showed that regardless of gastric juice diffusion, the pH 5 EWG (α = 0.22 ± 0.03) disintegrated into more fine particles than those resulting from pH 9 EWG disintegration (α = 0.07 ± 0.02). As expected, the diffusion of gastric juice enhanced erosion of the EWG particles into fine particles. Result obtained from the particle surface area distribution is in good agreement with the softening kinetics of EWGs during simulated in vitro gastric phase.

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Section: Tablesupporting

confidence: 72%

Section: Tablesupporting

confidence: 65%

Section: Softening Kinetics Of Ewgs During Gastric Phase Is Influenced By the Initial Ewg Characteristicsmentioning

confidence: 96%

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Egg white gel structure determines biochemical digestion with consequences on softening and mechanical disintegration during in vitro gastric digestion

Somaratne

Nau

et al. 2020

Food Research International

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“…In contrast, pH 9-EWG has a less porous and a more rigid structure due to the formation of linear aggregates of egg white protein at pH 9, , which likely hinders the water mobility within the structure. This fact could be further strengthened using the results reported in our previous studies in which the loosened microstructure in the pH 5-EWG may lead to faster pepsin diffusion and subsequent gel disintegration compared to the smooth-gel structure of pH 9-EWG. , …”

Section: Resultsmentioning

confidence: 99%

“…This fact could be further strengthened using the results reported in our previous studies in which the loosened microstructure in the pH 5-EWG may lead to faster pepsin diffusion and subsequent gel disintegration compared to the smooth-gel structure of pH 9-EWG. 34,35 To confirm the diffusion mechanism, the data were fitted with the power law model. 24 The model parameters and goodness of fit (R 2 > 0.94) are shown in Table 5.…”

Section: Journal Of Agricultural and Food Chemistrymentioning

confidence: 99%

Mapping the Spatiotemporal Distribution of Acid and Moisture in Food Structures during Gastric Juice Diffusion Using Hyperspectral Imaging

Somaratne

Reis

Ferrua

et al. 2019

J. Agric. Food Chem.

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This study investigated the feasibility of using hyperspectral imaging (HSI) to characterize the diffusion of acid and water within food structures during gastric digestion. Two different sweet potatoes (steamed and fried) and egg white gel (pH5 and pH9 EWGs) structures were exposed to in vitro gastric digestion before scanning by HSI. Afterward, the moisture or acid present in the digested sample was analyzed for calibration purposes. Calibration models were subsequently built using partial least-squares (PLS). The PLS models indicated that the full-wavelength spectral range (550−1700 nm) had a good ability to predict the spatial distribution of acid (R cal 2 > 0.82) and moisture (R cal 2 > 0.88). The spatiotemporal distributions of moisture and acid were mapped across the digested food, and they were shown to depend on the food composition and structure. The kinetic data revealed that the acid and moisture uptakes are governed by Fickian diffusion or by both diffusion and erosion-controlled mechanisms. Article pubs.acs.org/JAFC Cite This: J. Agric. Food Chem. XXXX, XXX, XXX−XXX

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Interactions Between Isolated Pea Globulins and Purified Egg White Proteins in Solution

et al. 2023

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In the present work, the interactions and associations between low denatured pea globulins (PPI) and purified main egg white proteins (ovalbumin (OVA), ovotransferrin (OVT), and lysozyme (LYS)) were studied at pH 7.5 and 9.0 by using isothermal titration calorimetry (ITC), dynamic light scattering (DLS), laser granulometry and confocal laser scanning microscopy (CLSM). From ITC, we detected strong exothermic interactions between PPI and LYS at both pHs, which led to aggregation. At these pH values, the net positive charge of lysozyme favored electrostatic interactions with negative charges of pea proteins, and oligomers were formed during titration experiments. Furthermore, DLS, laser granulometry, and CLSM data showed that the particle size of the mixture increased with increasing LYS to PPI molar ratio (from 0.8 to 20). Large irregular aggregates up to 20-25 µm were formed at high molar ratios and no complex coacervate was observed. No or very weak interactions were detected between OVT or OVA and PPI whatever the pH. These results suggest the role of electrostatic interactions between LYS and PPI when considering protein mixtures.

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In-situ disintegration of egg white gels by pepsin and kinetics of nutrient release followed by time-lapse confocal microscopy

Cited by 20 publications

References 32 publications

Egg white gel structure determines biochemical digestion with consequences on softening and mechanical disintegration during in vitro gastric digestion

Egg white gel structure determines biochemical digestion with consequences on softening and mechanical disintegration during in vitro gastric digestion

Mapping the Spatiotemporal Distribution of Acid and Moisture in Food Structures during Gastric Juice Diffusion Using Hyperspectral Imaging

Interactions Between Isolated Pea Globulins and Purified Egg White Proteins in Solution

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