Technological properties ofLactobacillus plantarumstrains isolated from Siahmazgi cheese

Abstract

In this study, the technologic properties of Lactobacillus plantarum strains isolated from Siahmazgi cheese were investigated. A significant difference in pH reduction was observed among L. plantarum strains, for example, the pH reduction for SC9 and SE4 strains was 1.98 and 0.81 unit, respectively, during 24 hr. The SD6 and SC6 strains exhibited the highest proteolysis (0.98 mg Tyr/5 ml milk) and lipolysis (17.5 U) activities, respectively. All the L. plantarum strains investigated in this study produced diacetyl. None of the L. plantarum strains produced gas from glucose and ammonia from arginine. Furthermore, none of the L. plantarum strains could grow at 45 °C, and pH = 3 and 9.6. No significant relationship was observed between Ph decrease and specific growth rate at 30 °C. SC9 strain exhibited good acid production, proteolytic activity and tolerance to a variety of environmental conditions, thus it is recommended to be used as a starter culture. Practical applications Analyzing the technologic properties of wild strains of lactic acid bacteria isolated from artisanal cheeses is required for selection of suitable strains as starter or adjunct culture to produce fermented dairy products with consistent quality and original organoleptic properties on industrial scale under hygienic conditions.