Effect of human and simulated gastric juices on the digestion of whey proteins and carboxymethylcellulose-stabilised O/W emulsions (original) (raw)

2014, Food chemistry

In this study, we analysed the impact of carboxymethylcellulose (CMC) on lipid digestion and physicochemical properties of whey proteins (WP)-stabilised emulsions during in vitro digestion with either artificial or human gastrointestinal juices. The emulsions were made by adsorbing WP on the fat droplets and subsequently adding CMC, which does not interact with the adsorbed proteins. The limited hydrolysis of lipids and their higher physical stability was recorded for WP-stabilised emulsions in the presence of CMC under simulated gastrointestinal conditions. The possible mechanism by which CMC lowers the digestion of WP-stabilised emulsions is related to the limited interaction of fat droplets with gastrointestinal fluids due to the extended thickening network formed by CMC in the continuous phase. The digestion of WP- and CMC-stabilised emulsions in the in vitro model with human gastric fluids led to greater lipid hydrolysis, although the enzymatic activity in both in vitro models ...

The Effect Of Carboxymethyl Cellulose On The Stability Of Emulsions Stabilized By Whey Proteins Under Digestion In Vitro And In Vivo

2013

In vitro gastro-duodenal digestion model was used to investigate the changes of emulsions under digestion conditions. Oil in water emulsions stabilized by whey proteins (2%) and stabilized by whey proteins (2%) with addition of carboxymethyl cellulose (0.75%) as gelling agent of continuous phase were prepared at pH7. Both emulsions were destabilized under gastric conditions; however the protective role of carboxymethyl cellulose was indicated by recording delay of fat digestibility of this emulsion. In the presence of carboxymethyl cellulose whey proteins on the interfacial surface of droplets were more resistant to gastric degradation causing limited hydrolysis of fat due to the poor acceptability of lipids for the enzymes. Studies of emulsions using in vivo model supported results from in vitro studies. Lower content of triglycerides in blood serum and higher amount of fecal fat of rats were determined when rats were fed by diet containing emulsion made with whey proteins and carb...

Rheological behavior and droplet size distribution of emulsions stabilized by whey proteins and chitosan during ex vivo digestion

The effect of type of emulsifier, 2 w/w% whey protein concentrate (WPC) or 2 w/w% WPC and 0.1 w/w% chitosan (CH) on the rheological changes and droplet size distribution during the ex vivo digestion of oil in water emulsions (pH 2) containing 1 w/w% rapeseed oil (RSO) were investigated. The procedure was used to mimic the human gastro duodenal digestion in two steps, gastric phase at pH 2 for 30 min followed by the duodenal phase at pH 7 for 60 min. With regard to viscosity, the emulsion, either WPC or WPC-CH showed an increase from gastric phase to duodenal phase (p<0.001) and then it was stable until the end of digestion. The viscosity of WPC-CH emulsions during the whole digestion (with/without added HGJ/HDJ) process was higher than the respective WPC emulsions. At pH 7 (duodenal juice addition), the droplet diameters stabilized by WPC emulsion showed a bimodal distribution with droplet sizes in the range of 0.05-1.7 µm and 200-500 µm. A significant change (p<0.01) in the o...

Impact of the Simulated Gastric Digestion Methodology on the In Vitro Intestinal Proteolysis and Lipolysis of Emulsion Gels

Foods, 2021

The aim of this work was to study the impact of the methodology of in vitro gastric digestion (i.e., in terms of motility exerted and presence of gastric emptying) and gel structure on the degree of intestinal proteolysis and lipolysis of emulsion gels stabilized by whey protein isolate. Emulsions were prepared at pH 4.0 and 7.0 using two homogenization pressures (500 and 1000 bar) and then the emulsions were gelled by heat treatment. These gels were characterized in terms of texture analysis, and then were subjected to one of the following gastric digestion methods: in vitro mechanical gastric system (IMGS) or in vitro gastric digestion in a stirred beaker (SBg). After gastric digestion, the samples were subjected to in vitro intestinal digestion in a stirred beaker (SBi). Hardness, cohesiveness, and chewiness were significantly higher in gels at pH 7.0. The degree of proteolysis was higher in samples digested by IMGS–SBi (7–21%) than SBg–SBi (3–5%), regardless of the gel’s pH. For...

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