Heat treatment and homogenization of bovine milk loosened gastric curd structure and increased gastric emptying in growing pigs
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Date
2023-04
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Ltd
Rights
(c) 2022 The Author/s
CC BY 4.0
CC BY 4.0
Abstract
During gastric digestion, bovine milk forms a curd, which consists largely of proteins and lipids. However, it is unknown how processing-induced changes to curd structure affects the gastric emptying of milk proteins and lipids. This study aimed to determine the impact of heat treatment and homogenization on gastric curd formation, and gastric emptying of dry matter (DM), proteins and lipids from bovine milk fed to pigs as a human model. Growing pigs (n = 180, mean ± standard error of the mean (SEM) bodyweight 22.4 ± 0.13 kg) consumed raw, or pasteurized non-homogenized (PNH), or pasteurized homogenized (PH), or ultra-high temperature treated homogenized (UHT) milk diets. A protein-lipid-free lactose (PLFL) solution was also fed as a test diet. At 0, 20, 60, 120, 180 and 300 min postprandially the entire gastrointestinal tract was dissected out. The gastric chyme (curd and liquid) fractions were collected after separation using a mesh screen. The DM, protein, and lipid contents of these fractions were quantified. Confocal, transmission electron microscopy, cryo-scanning electron microscopy and rheological analyses were conducted to determine the micro- and macrostructure of the curd. Overall, both heat treatment and homogenization influenced the in vivo gastric curd structure formed of bovine milk, although to different extents. The gastric emptying of DM, proteins, and lipids increased with the extent of processing. Gastric emptying rates of DM and proteins followed the pattern UHT > PH > PNH = raw, while emptying rates of lipid also differed between PNH and raw milk. Curd structure was the main gastric parameter affected in PNH milk.
Description
Keywords
Bovine milk, Processing, Gastric curd formation, Gastric emptying, Curd microstructure
Citation
Ahlborn NG, Montoya CA, Hodgkinson SM, Dave A, Ye A, Samuelsson LM, Roy NC, McNabb WC. (2023). Heat treatment and homogenization of bovine milk loosened gastric curd structure and increased gastric emptying in growing pigs. Food Hydrocolloids. 137.