Esterase Activities and Biochemical Properties of Lactic Acid Bacteria Isolated from Goat＇s Milk Cheese in Argentina

Twenty-two lactic acid bacteria （LAB） strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus （UNSE314）, Lactobacillus （L.） delbrueckii subsp, bulgaricus （UNSE309）, L. rhamnosus （UNSE308）, L. plantarum （UNSE287, UNSE316, UNSE317） and Pediococcus pentosaceus （UNSE315） strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity （ESA） was detected on ct-naphthyl （ct-NA） acetate and 13-naphthyl （[3-NA） acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.

Effect of Garlic Paste on the Physicochemical Attributes of Cheese

Cheese has recently gained a lot of popularity around the world. This experiment was carried out to make cheese from skim milk with the addition of garlic paste. This study focused on the impact of garlic paste on the physicochemical properties of cheese. Cheese samples S1, S2, S3, and S4 were prepared with 0%, 1%, 3%, and 5% garlic paste, respectively, where S1 was the control sample. Compared to sample S1, the higher proportion of garlic paste incorporation resulted in higher viscosity and water holding capacity;nevertheless, lower values for syneresis were obtained. Although no significant change was observed in the pH values, samples S4 (5% garlic) and S1 (0% garlic) exhibited the highest and lowest pH, respectively. The results in this investigation revealed that garlic inclusion had a substantial impact on the physicochemical parameters of the skim milk cheese.