High pressure processing is the technology by which a product is treated at or above 100 MPa. Pressure is transmitted uniformly and instantaneously throughout the food, which allows very homogeneous products to be obtained. Pressurization does not change the nutrient content, odor, and taste. The food structure by itself probably performs a baroprotective effect and so the rate of surviving microorganisms increases. It is likely that modifications in cytoplasmic membrane (the primary site of pressure damage) are the main cause of sublethal injury generated by pressure treatment to some microorganisms. High pressure processing effectively inactivates the spoilage microbiota of several foods, and important foodborne pathogens such as Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp. Foods can be pasteurized at low or moderate temperatures under pressure. Pressurization at high temperature can sterilize foods. Pressure treatment is of special interest for products or meals containing ingredients that are extensively modified by heat.
The influence of thermal and high-pressure treatments on caprine casein micellar structure and,
in particular, on the micellar serum distribution of whey proteins, caseins, and calcium phosphate
was studied by ultracentrifugation and transmission electron microscopy. Quantification of the
major whey proteins and caseins was achieved using reverse-phase HPLC, and the extent of
denaturation of the whey proteins was determined by gel permeation FPLC. Thermal treatment
of goat's milk had little effect on the micellar serum distribution of caseins, but pressure treatment
at 20 °C caused disruption of micelles into smaller particles and gave an increase in the amount of
serum casein. Pressure treatments between 300 and 350 MPa at 45 °C caused the formation of
very large micelles and gave an increase in the level of serum κ-casein. Higher pressure at 45 °C,
however, caused disruption of the micelles, with the formation of smaller, less easily sedimented
fragments. On pressure treatment, βLg was most easily denatured, and appreciable denaturation
of the immunoglobulins and α-lactalbumin only occurred at the higher pressures, particularly at
45 °C.
Keywords: Caseins; micelle; high pressure; goat's milk
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.