EFFECT OF MICROWAVE IRRADIATION VS HEATING BY CONVENTIONAL METHOD ON THE IN VITRO DIGESTIBILITY OF BOVINE WHEY
I. Bouchikhi Ann Nutr Metab 2013;63(suppl 1):1873
Thermal processing of milk, is a common practice. Heating induces several chemical and physical changes in whey proteins. Microwave irradiation
(MWI) is an alternative method to a conventional heating. Although MWI effects on bovine milk proteins were studied, there is a lack of information about its effect on digestibility. The purpose of this study was to determine MWI effects on the in vitro digestibility of bovine whey proteins compared to conventional heating effects.
Methods: The bovine whey, reconstituted in phosphate buffer, was submitted to microwave irradiation or heated by conventional method. The study of the in vitro protein digestibility was carried out by hydrolysis using pepsin, trypsin and chymotrypsin enzymes. Whey protein alteration was assessed with sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS).
Results: MWI did not alter whey protein susceptibility to pepsin. Whereas it led to their partial hydrolysis by either trypsin and chymotrypsin enzymes. This hydrolysis was more pronounced when microwaves were applied at high power but for a shorter duration. Heated whey by conventional method were resistant to pepsic hydrolysis but was observed to be susceptible to chymotrypsic and trypsic hydrolysis. This improvement of enzymatic hydrolysis was more pronounced when heating takes only shorter duration.
Conclusions: MWI or heating by conventional method accelerates whey proteins hydrolysis. This effect was more pronounced with heating using conventional method.
