Structural changes in milk from different species during gastric digestion in piglets

Abstract

This study investigated the structural and physicochemical changes that occur in milk, a naturally designed complex structured emulsion, during gastric digestion using the bottle-fed piglet as an animal model. The gastric digestions of cow, goat, and sheep milk were compared in male piglets euthanized at different postfeeding times to collect the stomach chyme. The cow and noncow milks separated into curd (aggregated caseins) and liquid (mostly soluble whey) phases in the piglet's stomach. For milk from all the species, the curd remained longer in the stomach because of its slow disintegration, whereas the liquid phase emptied readily. The majority of the fat globules were found to be entrapped within the protein network of the curd. The rate of release of fat globules was strongly dependent on the breakdown of the surrounding protein network of the curd. The consistency of the gastric curds changed as digestion progressed, with goat and sheep milk curds having relatively softer curd consistency and less fused protein networks, especially toward the end of digestion. This might have led to the lower protein and fat retention in the goat and sheep milk curds and relatively faster gastric emptying of these nutrients from goat and sheep milk in comparison to cow milk. This in vivo study provided new and enhanced understanding of the mechanisms of the gastric digestion of milk from different species. It may have implications for developing bioinspired structures for the controlled digestion and delivery of nutrients.

Milk coagulation and gastric emptying in women experiencing gastrointestinal symptoms after ingestion of cow's milk

“…In this study, overall GE was not affected by coagulation, but the liquid phase emptied quicker while the solid phase was retained longer, as there was a significantly higher percentage of coagulum and a lower percentage of liquid in the group of people with gastrointestinal problems. This is in line with previous animal in vivo research 62 . Future research should include blood sampling to track amino acid uptake, to see whether this is the case.…”

“…This is in line with previous animal in vivo research. 62 Future research should include blood sampling to track amino acid uptake, to see whether this is the case. Indeed, a recent study with similar inclusion criteria showed that less efficient digestion of milk proteins, leading to a different pattern of peptides reaching the lower gut which might explain GI problems in healthy people after milk consumption.…”

Comparison of four digestion protocols on the physical characteristics of gastric digesta from cooked couscous using the Human Gastric Simulator

“…Previous in vivo digestion studies revealed that the gastric secretion rate varied in terms of the digestion time, food structure and composition, 9 buffering capacity, 41 quantity of diet, and frequency of feeding. 42 For instance, Nadia et al 9 found that pigs fed with cooked couscous had a higher moisture addition rate (due to gastric secretions) after 30 min of gastric digestion (15.18 ± 1.09 g min −1 ) that was significantly reduced to 1.40 ± 0.33 g min −1 after 240 min gastric digestion. As part of the same study, when pigs were fed with another wheat-based meal (semolina), the gastric secretion ranged between 6.48 ± 1.44 g min −1 and 3.41 ± 0.63 g min −1 at 30 and 240 min, respectively.…”

“…Previous in vivo digestion studies revealed that the gastric secretion rate varied in terms of the digestion time, food structure and composition, 9 buffering capacity, 41 quantity of diet, and frequency of feeding. 42 For instance, Nadia et al 9 found that pigs fed with cooked couscous had a higher moisture addition rate…”

Gastric emptying and nutrient absorption of pea protein products differing in heat treatment and texture: a randomizedin vivocrossover trial andin vitrodigestion study

“…Gastric emptying is largely determined by the chemical characteristics of food, such as the energy density and macronutrient content, but also by physical characteristics, such as texture (Camps, Mars, De Graaf, & Smeets, 2016; Marciani, et al, 2001; Roy, et al, 2022). The food matrix plays an important role in digestibility because of its influence on the kinetics of transit and hydrolysis of macronutrients.…”