Production of cheddar cheese using a Lactococcus lactis ssp. Cremoris SK11 derivative with enhanced aminopeptidase activity
1995; Elsevier BV; Volume: 5; Issue: 4 Linguagem: Inglês
10.1016/0958-6946(94)00009-e
ISSN1879-0143
AutoresJeffrey E. Christensen, M.E. Johnson, J. L. Steele,
Tópico(s)Peptidase Inhibition and Analysis
ResumoA Lactobacillus helveticus CNRZ32 DNA fragment encoding aminopeptidase N (PepN) was cloned into pIL253 to construct pSUW34. The cell-free extract general aminopeptidase activity of Lactococcus lactis ssp. cremoris SK11 transformed with the pSUW34 construct was increased approximately 100-fold relative to L. lactis ssp. cremoris SK11 wild type and pIL253 transformants. Cheddar cheese was manufactured with L. lactis ssp. cremoris HP in combination with either SK11(pIL253) or SK11(pSUW34). A 99% reduction in viable SK11 derivatives occurred within 2 weeks of ripening. The SK11(pSUW34)/HP cheese had approximately 1000-fold greater aminopeptidase activity and elevated levels of TCA and PTA soluble nitrogen. The increased accumulation of particular free amino acids in the SK11(pSUW34)/HP cheese varied between 15% (methionine) and 230% (lysine). Both the SK11(pSUW34)/HP and SK11(pIL253)/HP cheeses were non-bitter and had no significant sensory differences. Thus, the increased free amino acid pool in the SK11(pSUW34)/HP cheese did not result in accelerated flavor development.
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