Caractérisation des aptitudes technologiques d’un Lactobacillus delbrueckii subsp. lactis isolé des produits laitiers locaux

Abstract

This study aimed to characterize the technological properties of Lactobacillus delbrueckii subsp. lactis strains isolated from local dairy products in order to evaluate their potential use in the manufacture of fermented dairy products. After isolation and identification, several technological properties were evaluated, including heat resistance at 63.5°C for 30 min, growth at 15°C and 45°C, tolerance to pH 4.5 and 9.6, tolerance to 4% and 6.5% NaCl, acidifying activity, proteolytic activity, fermentation type, and aroma compound production. The results showed that the studied strains adapted well to the tested technological conditions. They exhibited significant acidifying activity, reflected by a decrease in pH and an increase in Dornic acidity, as well as satisfactory proteolytic activity. The strains also showed a homofermentative profile, and some produced aromatic compounds. A yogurt-making trial was carried out in association with Streptococcus thermophilus. The resulting yogurt showed good coagulation, a homogeneous texture, and good sensory acceptability. These findings indicate that Lactobacillus delbrueckii subsp. lactis is a promising technological starter culture for the development and improvement of fermented dairy products.