Projects - Q (Qing) Ren
Milk is an important source of high quality protein in the human diet because of its high level of essential amino acids, as well as its high digestibility(van Lieshout et al., 2019). However, heat load that is necessarily applied in milk industry will lead to modifications of the milk proteins, which can change the digestion and overall physiological impact of these proteins (Schaafsma et al., 2012). Different changes occur to milk proteins, including denaturation, aggregation and glycation, depending on the heating conditions (temperature, time, water activity). In literature, some data on these topics is already available, but this is mainly limited to bovine milk. With goat being a mammal that receives increasing interest, especially with regard to its use for infant nutrition, it would thus be highly relevant to study the specific consequences of heating for the physicochemical and functional properties of goat milk.
Aim
The aim of this research is to study in more detail the effects of heating of goat milk on the physical-chemical and functional properties of its milk proteins. And this project will try to find the differences between goat milk and bovine proteins during the whole project. Related bovine milk immune proteins studies are ongoing in our research group, so this connection will increase the understanding of findings on both milk types. And the immunological differences between goat milk and bovine milk will be compared based on these findings.
Methods
This project focus on the effects of heating on milk protein so we need to remove the milk fat first. The aim of this project is to study the effects of heating on goat milk whey protein so the caseins in goat milk need to be removed considering the PI value of caseins. Complete denaturation of whey proteins can occur when the heating condition is 85? for 30mins(Pesic, M. B.et al.,2012). So different temperatures below to 85? will be chosen to achieve different levels of denaturation. For the dry heating, goat’s milk protein powder is heated at low temperature and high temperature respectively. Next, some parameters including the protein denaturation, aggregation, glycation, digestion as well as immunogenicity will be detected.
References
1. van Lieshout, G. A. A.; Lambers, T. T.; Bragt, M. C. E.; Hettinga, K. A., How processing may affect milk protein digestion and overall physiological A systematic review. Crit Rev Food Sci Nutr 2019, 1-24.
2. Schaafsma; Gertjan, Advantages and limitations of the protein digestibility-corrected amino acid score (PDCAAS) as a method for evaluating protein quality in human diets. British Journal of Nutrition 2012, 108 (S2), S333-S336.
3. Pesic, M. B.; Barac, M. B.; Stanojevic, S. P.; Ristic, N. M.; Macej, O. D.; Vrvic, M. M., Heat induced casein–whey protein interactions at natural pH of A comparison between caprine and bovine milk. Small Ruminant Research 2012, 108 (1-3), 77-86.
