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HEAT-STABLE PROTEASES FROM PSYCHROTROPHS IN MILK.

Author(s) : GEBRE-EGZIABHER A., HUMBERT E. S., BLANKENAGEL G.

Type of article: Article

Summary

TWELVE GRAM-NEGATIVE PSYCHROTROPHIC BACTERIA PRODUCING HEAT-RESISTANT PROTEASES THAT HYDROLYSED CASEIN WERE ISOLATED FROM REFRIGERATED RAW MILK. THE ENZYMES OF THE SIX MOST PROTEOLYTIC CULTURES WERE EXAMINED FURTHER. GEL ELECTROPHORESIS INDICATED THAT ONLY A SINGLE ENZYME WAS PRESENT IN THE PREPARATION. THE MOLECULAR WEIGHT OF MOST OF THE PROTEASES WAS APPROXIMATELY 45,000. ALL SIX ENZYMES RETAINED SOME ACTIVITY AFTER BEING HEATED AT 384 K (121 C) FOR 10 MIN AND CASEIN WAS HYDROLYZED AT PH LEVELS FOUND IN NORMAL MILK AND MANY CULTURED DAIRY PRODUCTS. ALTHOUGH PROTEOLYSIS WAS HIGHEST AT ABOUT 313 K (40 C), CONSIDERABLE ACTIVITY WAS EVIDENT AT REFRIGERATION TEMPERATURES.

Details

  • Original title: HEAT-STABLE PROTEASES FROM PSYCHROTROPHS IN MILK.
  • Record ID : 1981-0180
  • Languages: English
  • Source: Journal of Food Protection - vol. 43 - n. 3
  • Publication date: 1980/03
  • Document available for consultation in the library of the IIR headquarters only.

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