Hydrolytic action of Lactobacillus casei CRL 705 on pork muscle sarcoplasmic and myofibrillar proteins

Lactobacillus casei CRL 705 was screened, among other meat isolates, for it s proteinase and aminopeptidase activities toward synthetic substrates and, according to that, selected for specific assays on muscle proteins. The hy drolytic effects of whole cells, cell free extracts (CFE), and the combinat ion of both on muscle sarcoplasmic and myofibrillar protein extracts was ev aluated by SDS-PAGE and reverse phase HPLC analyses. The proteinase activit y of whole cells caused the degradation of a great number of sarcoplasmic p rotein bands. A partial hydrolysis was also associated with CFE that when c ombined with whole cells showed an important additional degradation. Peptid e profiles from sarcoplasmic protein extracts were greatly modified regardl ess of the addition of whole cells or CFE, although their combination inten sified these changes. The generation of free amino acids was remarkable whe n whole cells and CFE were incorporated together to sarcoplasmic protein ex tracts.