THE COMBINED EFFECTS OF ENVIRONMENTAL-CONDITIONS ON LIPOLYSIS OF PORKFAT BY LIPASES OF THE MEAT STARTER CULTURE ORGANISMS STAPHYLOCOCCUS-XYLOSUS AND DEBARYOMYCES-HANSENII

The effects of environmental conditions on lipolysis by cell-free extr acts from the meat starter culture organisms Staphylococcus xylosus an d Debaryomyces hansenii were studied using pork fat emulsions as model systems. For the individual effects of temperature and pH it was foun d that the optimal conditions for the lipolysis by S. xylosus lipase w ere 37 degrees C and pH 7.0. and 37 degrees C and pH 6.5 for the lipol ysis by D. hansenii lipase. For the combined effects of conditions rel evant to meat fermentation, i.e, 10-30 degrees C, pH 4.7-6.0, 2.5-7.5% (w/v) NaCl and incubation times of 2-6 days, the empirical models ind icated that temperature, pH and incubation time had important effects on total lipolysis whereas NaCl concentration had little effect. For b oth cultures lipolysis was strongly inhibited at conditions of meat fe rmentation compared to optimal conditions. For any set of the conditio ns which were examined the total lipolysis caused by D. hansenii lipas e was lower than that caused by S. xylosus lipase.