Impact of caseins and whey proteins ratio and lipid content on in vitro digestion and ex vivo absorption. (30th July 2020)

• Record Type: Journal Article
• Authors: Mulet-Cabero, Ana-Isabel; Torcello-Gómez, Amelia; Saha, Shikha; Mackie, Alan R.; Wilde, Peter J.; Brodkorb, André
• Is Part Of: Food chemistry. Volume 319(2020)
• Publication Date: 2020-07-30
• Subjects: Dairy proteins -- Caseins -- Whey proteins -- Gastric digestion -- Semi-dynamic model -- Digestion kinetics; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.126514
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Caseins and whey mixtures were digested differently using a semi-dynamic model. Caseins (≥50%) formed solid coagula and whey proteins were more soluble. The different gastric behaviour was the main factor controlling digestion rates. Caseins delayed but whey proteins accelerated bioaccessibility and absorption. Foods with different nutrient digestion rates can address specific populations needs. Abstract: Caseins and whey proteins are known as 'slow' and 'fast' proteins, respectively, based on their amino acid absorption rate. However, there is limited understanding of the mechanisms controlling their behaviour during gastro-intestinal transit. A protein model system (8% total protein) with varying casein:whey protein ratios (0:100, 20:80, 50:50 and 80:20) were subjected to in vitro gastro-intestinal digestion using a semi-dynamic gastric model, a static intestinal model and an ex vivo absorption model (Ussing chambers). The casein-rich (≥50%) samples showed the formation of solid coagula that were persistent throughout gastric digestion, which caused a delay in nutrient emptying, slower digestion and leucine absorption kinetics. In contrast, whey proteins formed more soluble aggregates during the gastric phase, which led to faster gastric emptying, rapid intestinal hydrolysis, and higher and faster leucine absorption. This work shows the key role of the gastric restructuring for the overall digestive mechanism and kinetics of food, in particular proteins.