Biochemical and microbiological changes throughout the ripening of Argentinean fresh goat's milk cheeses made with native cultures

Abstract

Two different cultures with native lactic acid bacteria (LAB) were designed, S (starter culture consisting of Lactobacillus (L.) rhamnosus UNSE308, L. delbrueckii subsp. bulgaricus UNSE309, Streptococcus (S). thermophilus UNSE314, S. thermophilus UNSE321) and A (starter culture S plus adjunct culture consisting of L. plantarum UNSE316, L. plantarum UNSE317, Pediococcus (P). pentosaceus UNSE22, P. pentosaceus UNSE253). Cultures S, A and C (lyophilized commercial culture of Streptococcus thermophillus) were used to manufacture fresh goat cheeses (CS, CA and CC) from pasteurized milk. The impact of these cultures on the microbiological, biochemical and physicochemical parameters were evaluated during ripening (30 days). Results evidenced that CC, CA and CS did not show significant differences in protein and fat content, NaCl, acidity, fat acidity and aw, at the same time of ripening. All experimental cheeses underwent moderate lipolysis since moderate levels of free fatty acids (FFA) at the end of ripening were detected (~1.5 g kg-1) and made an important contribution to characteristic flavour and aroma. In all cases, a slight proteolysis was detected; CC showed the lowest levels during ripening. Values of NaCl (1.27%) were in accordance with those reported in most cheeses. During ripening, mesophilic LAB counts in MRS agar increased nearly 1 log cycle, total coliforms per gram at 30°C showed counts below the maximum allowed by Argentinean legislation. Overall impression of CS and CA was qualified as good compared to CC that was scored as regular. The fresh goat cheeses made with native cultures presented suitable typical flavour and satisfying overall sensorial characteristics.