Zawartosc aminokwasow siarkowych [ cysteiny, metioniny ], tryptofanu oraz wolnych grup sulfhydrylowych w mleku spozywczym

Oznaczono zawartość dostępnej cysteiny, metioniny, tryptofanu oraz wolnych grup sulfhydrylowych w mleku utrwalonym metodą UHT o różnej zawartości tłuszczu. W celach porównawczych przeprowadzono te same badania w mleku surowym, pasteryzowanym i zagęszczonym.

Available cysteine, methionine, tryptophan and free sulfhydryl group levels were determined in 108 different milk samples (raw, pasteurized, UHT-processed, condensed milk). Some UHT samples were stored for 14 days at + 18°C and + 4°C to examine the effect of storage on SH group levels. The highest availability of aminoacids from analysed milk protein was observed in raw milk samples. Aminoacid content of the pasteurized and UHT milk lower than that of raw milk. The lowest nutritive value of protein was determined for the condensed milk. The average free sulfhydryl group content was 0.12 mmol/dm3 in the raw, pasteurized and UHT milk, and 0.37 mmol/dm3 in the condensed milk.