Effects of the addition of Enterococcus faecalis in Cebreiro cheese manufacture

Ten batches of Cebreiro, a fresh or short-ripened acid-curd cheese, produce d in the Galician mountains (NW Spain) were prepared from pasteurized milk inoculated with microorganisms isolated from raw-milk cheese. Two control b atches were made with a Lactococcus lactis subsp. lactis starter; 8 batches were made with the lactococcal starter plus one of eight Enterococcus faec alis cultures: 4 E. faecalis var. liquefaciens (EFLB) and 4 E. faecalis var . faecalis (EFFB). Whey dry matter in the EFLB was notably higher than in t he control batches and this was related to lower cheese yields. After over 15 days storage the highest counts of both aerobic bacteria and lactic acid bacteria were observed for the EFLB. The lower content in protein on dry m atter was found in the EFLB. The beta-casein broke down to a greater extent in the EFLB than in the EFFB, the lowest values being obtained for the con trol batches. The higher level of hydrolysis of alpha(s1)-casein and maximu m peptide alpha(s1) - I/alpha(s1) -casein ratio were obtained for EFFB at d ay 15 of storage. In all the batches made with enterococci soluble nitrogen was higher than in the control batches, with the highest values in the EFL B. In all the batches made with enterococci, volatile free fatty acid, long -chain free fatty acids and diacetyl and acetoin contents at days 10 and 15 of storage were higher than in the control batches, the highest values bei ng obtained for EFLB. Acetic acid in all batches accounted for the main pro portion of the volatile free fatty acids. Butyric and caproic acids were no t detected in the volatile free fatty acids fractions of the control batche s, but both acids were detected in most of the batches made with enterococc i. The more intense acid taste was found in the EFFB and control batches, t he most bitter taste being found in the EFLB. Buttery, rancid and spicy fla vors were more evident in the EFLB. The rancid and spicy flavors were posit ively correlated with the contents of volatile free fatty acids and long-ch ain free fatty acids. The cheeses of EFLB proved to be more crumbly than th e EFFB, whereas the stickiness and deformability were higher in the EFFB. T he batches with similar organoleptic characteristics to those of traditiona l cheese were the batch IV made with the less proteolytic strain of E. faec alis var. liquefaciens, and the batch VI made with a moderate lipolytic act ivity strain of E. faecalis var. faecalis. (C) 1999 Elsevier Science B.V. A ll rights reserved.