INFLUENCE OF SPRAY DRYING PARAMETERS ON THE VIABILITY OF LACTIC ACID BACTERIA IN BIOYOGURT

Abstract

Introduction. Spray drying technology to obtain dehydrated products in the food industry and particularly in dairy industry continues to grow. In fermented milks, this method causes some impact on the viability of lactic acid bacteria, reducing the microbial population in the order to 10² and 10³ CFU/g, and the most affected are the Lactobacillus species. Bioyoghurt is a fermented milk, which is consumed around the world for the nutritional and physiological benefits, providing to consumers a source of probiotics microorganism. The most important disadvantage on spray dried procedure are the effect of inlet and oulet air temperature on the viability of lactic acid bacteria.  Objective. The main objective of this research was to evaluate the influence of maltodextrin and temperature parameters in the spray draying procedure on bioyogurt, to preserve the viability of lactobacterias (Streptococcus thermophilus and Lactobacillus acidophilus). The procedure of spray dried on fermented milks is no precedent in our country. Materials and methods.  The drying process were carried out in a minilab dryer Büchi B-190 using factorial design rotary central.  The parameters evaluated were inlet air temperature (160-170 ⁰C), outlet air temperature at 70 ⁰C as well as the maltodextrin concentration (20-30 % m/m) and the influence on the viability lactobacilli was evaluated. Results. It was shown that at 160 ⁰C inlet air temperature, 70 ⁰C outlet temperature and 30 % m/m maltodextrin, decreased the viability of Lactobacillus in two logarithmic cycles because of its thermosensibility