Effect of a bacteriocin-producing Lactococcus lactis strain and high-pressure treatment on the esterase activity and free fatty acids in Hispanico cheese

The effect of milk inoculation with a bacteriocin-producing (BP) culture and of high-pressure (HP) treatment of 15-day-old Hispanico cheeses (400 MPa, 5 min, 10 degrees C), separately or combined, on the release of intracellular esterases and cheese lipolysis was investigated. Esterase activity and free fatty acids (FFAs) content increased during ripening of Hispanico cheese and palmitic, oleic and stearic acids being the most abundant FFAs. On day 15, the highest esterase activity was recorded for HP-treated BP cheese. The activity for HP-untreated BP cheese was the next highest. No difference in the activities was found between HP-treated and untreated cheeses made without BP culture. Total FFAs on day 15 were at a lower concentration in BP cheeses than in cheeses made without BP culture, probably due to the lower pH values of the former. The rate of total FFA accumulation from day 15 to day 50 was higher in BP cheeses (31.1-32.1 % increase) than in cheeses made without BP culture (19.3-21.7% increase). The highest total FFA concentration on day 50 (612mgkg(-1)) was found for HP-untreated cheese made without BP culture. (C) 2007 Elsevier Ltd. All rights reserved.