Structural mechanism and kinetics of in vitro gastric digestion are affected by process-induced changes in bovine milk

Mulet-Cabero, Ana-Isabel, Mackie, Alan R., Wilde, Peter J., Fenelon, Mark and Brodkorb, André (2019) Structural mechanism and kinetics of in vitro gastric digestion are affected by process-induced changes in bovine milk. Food Hydrocolloids, 86. pp. 172-183. ISSN 0268-005X

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    Abstract

    Bovine milk is commonly exposed to industrial processing, which can alter the structure, biochemical composition, physico-chemical properties and sensory quality. While many of these changes have been studied extensively, little is known about their effect on digestive behaviour. In this study, heat treatments of pasteurisation at 72 °C for 15 s or Ultra-High-Temperature (UHT) treatment at 140 °C for 3 s and homogenisation at pilot-plant scale were applied to whole milk. The gastric behaviour was investigated using a recently developed semi-dynamic adult in vitro model. The emptied digesta were analysed to assess the nutrient delivery kinetics, changes in microstructure and protein digestion. All samples showed protein aggregation and coagulum formation within the first 15 min of gastric digestion at which time the pH ranged from 5.5 to 6. Homogenised samples creamed regardless of heat treatment, whereas all non-homogenised samples exhibited sedimentation. The consistency of the coagulum of the heated samples was more fragmented compared to those of the non-heated samples. Rheological analysis showed that the higher the temperature of the heat treatment, the softer the obtained coagulum and the higher the protein hydrolysis at the end of digestion. The study also confirmed that gastric emptying of caseins from milk is delayed due to coagulation in the stomach, while β-lactoglobulin was emptied throughout the gastric phase, except for UHT-treated milk. The gastric behaviour also had an impact on the lipid and protein content of the emptied chyme. The homogenised samples seemed to release more nutrients at the end of gastric digestion.

    Item Type: Article
    Uncontrolled Keywords: milk,homogenisation,heat treatment,gastric behaviour,nutrient delivery,protein digestion
    Faculty \ School: Faculty of Science > School of Biological Sciences
    Faculty of Science > School of Pharmacy
    Related URLs:
    Depositing User: Pure Connector
    Date Deposited: 04 Apr 2018 11:30
    Last Modified: 01 Jan 2019 04:30
    URI: https://ueaeprints.uea.ac.uk/id/eprint/66653
    DOI: 10.1016/j.foodhyd.2018.03.035

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