Bovine milk is the complex colloidal system containing nano to micrometer scale components. Earlier, our research group reported the structural changes in bovine casein micelles in the temperature range of 10-40 °C by small-angle X-ray scattering (SAXS) [H. Takagi, T. Nakano, T. Aoki and M. Tanimoto, Food Chem., 2022, , 133389]. In this study, we extend our previous research by investigating the temperature-associated structural alterations in casein micelles over a wide spatial scale using SAXS and ultra-SAXS (USAXS). Furthermore, the temperature dependences of various physical properties of the casein micelles were investigated by analyzing the SAXS intensities. The USAXS results showed that micelles formed 1-dimensional aggregates and that these aggregate structures did not change in the temperature range of 10-40 °C. Changes in electron densities calculated from SAXS intensities showed that the voluminosity reduced and the weight fraction of protein inside the micelles increased during the heating process. The number of water domains in a micelle decreased when the temperature increased from 10 to 40 °C, but did not substantially change in the cooling run at a rate of 1 °C min. The number of colloidal calcium phosphate () in a micelle can also be calculated from the SAXS intensities; increases upon heating. This study on the behavior of casein micelles with respect to temperature change in milk over a wide spatial scale showed that the casein micelle structure was sensitive to temperature and can change dramatically with temperature variations.
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http://dx.doi.org/10.1039/d3sm00146f | DOI Listing |
Int J Biol Macromol
January 2025
College of Food and Nutrition, Joint Research Center for Food Nutrition and Health of IHM, Anhui Agriculture University, Hefei, Anhui 230036, China. Electronic address:
Micelle systems using safe food-grade biopolymers are of particular interest for the encapsulation and delivery of nutrition components. Micellar casein (MC) was assembled using transglutaminase (TGase) to couple with phosphoserine peptide, which enhance the stability of docosahexaenoic acid (DHA) from algae oil. The mechanism behind the construction of MC-phosphoserine peptide and the encapsulation of DHA was explored.
View Article and Find Full Text PDFFood Chem
January 2025
Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, College of Food Science, Southwest University, Chongqing 400715, China,. Electronic address:
Baked milk is subjected to prolonged high-temperature processing, which often undermines its dispersion stability. While carrageenan is known to inhibit milk demixing, its role in stabilizing heat-induced protein aggregates remains inadequately understood. In this study, we isolated casein micelles (CM), whey protein-casein aggregates (WPCA), and whey protein aggregates (WPA) from baked milk through centrifugation.
View Article and Find Full Text PDFFoods
January 2025
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, Moscow 119991, Russia.
The hydrolysis of proteins by proteases (proteolysis) plays a significant role in biology and food science. Despite the importance of proteolysis, a universal quantitative model of this phenomenon has not yet been created. This review considers approaches to modeling proteolysis in a batch reactor that take into account differences in the hydrolysis of the individual peptide bonds, as well as the limited accessibility (masking) for the enzymes of some hydrolysis sites in the protein substrate.
View Article and Find Full Text PDFFood Res Int
January 2025
Institut Numecan, INSERM, INRAE, Univ Rennes, Rennes, France. Electronic address:
Dietary protein reduces energy intake in following meals by signaling directly or indirectly to the brain. We recently observed differences in plasma amino acid kinetics and intra-gastric behavior between micellar casein (MC) and sodium caseinate (SC) in pigs, two factors that impact food intake. Our objective was to clarify whether the supramolecular structure of casein, given as a preload to pigs, impacts on subsequent food intake.
View Article and Find Full Text PDFFront Nutr
December 2024
Riddet Institute, Massey University, Palmerston North, New Zealand.
The gastric digestion behavior of different commercial Stage 1 infant formulae (for 0-6 months) with different formulation backgrounds was investigated using an dynamic infant human gastric simulator (iHGS). The microstructural arrangements of the protein and lipid, colloidal stability and protein hydrolysis during digestion were elucidated. During gastric digestion, casein-dominant formulations showed a higher extent of aggregation due to their high proportion of casein micelles that underwent coagulation upon acidification and via the action of pepsin.
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