Lipolysis of semi-hard cheese made with a lacticin 481-producing Lactococcus lactis strain and a Lactobacillus helveticus strain.

摘要

Free fatty acids (FFA) liberated from milk fat by lipases and esterases during cheese ripening affect cheese flavour directly, or indirectly by acting as precursors for the synthesis of other volatile flavour compounds. The effect of the lacticin 481-producing strain Lactococcus lactis subsp. lactis INIA 639 (BP) on the release of intracellular esterases from a Lactobacillus helveticus strain used as adjunct culture and on FFA levels during ripening of semi-hard cheese was investigated. The cheese was manufactured using either L. lactis subsp. lactis INIA 639, the bacteriocin non-producing strain L. lactis subsp. lactis INIA 437, or a combination of both strains, as mesophilic starter cultures. The Lactobacillus strain, sensitive to lacticin 481, was added to all vats. Batches of cheese made with the BP strain exhibited on day 50 esterase activity values up to 29% higher than those of cheese made without the BP strain. Levels of most individual FFA in cheese were increased by milk inoculation with the BP strain. On day 50, total (C4:0-C18:2) FFA contents were in the range 628-638 mg/kg in cheese batches made with the BP strain, and 576 mg/kg in cheese made without the BP strain, mostly due to the higher accumulation of FFA from day 25 to day 50 in the former batches. Bacteriocin-mediated lysis of the Lactobacillus strain and subsequent release of its esterases appeared to be responsible for accelerated lipolysis in cheese.