POTENCIAL TECNOLÓGICO E PROBIÓTICO DA MICROBIOTA DE LEITE A2A2 DE VACAS JERSEY

Abstract

Lactic acid bacteria are natural constituents of various foods microbiota, including A2A2 in natura milk, and play important roles in industries. They are a group of microorganisms that play a significant role in a variety of fermentation processes. They ferment dietary carbohydrates and produce lactic acid as the main fermentative product. Furthermore, the degradation of proteins and lipids and the production of various alcohols, aldehydes, acids, esters, and sulfur compounds contribute to the development of specific flavors in different fermented food products. They also play a significant health role when used as probiotics by improving intestinal microbial balance. The present work aims to characterize the lactic microbiota of A2A2 milk from Jersey cows from a rural property located in Cidade Occidental -GO and evaluate its technological potential. Samples were collected from pooled milk in sterile bottles and sent to the microbiology laboratory at the Instituto Federal Goiano – Campus Rio Verde. The analyzes were carried out by identifying the lactic microbiota present in the milk samples, determining the technological properties regarding acidification capacity, proteolytic activity, exopolysaccharide formation and diacetyl production. The evaluations of the probiotic potential were carried out from the development of bacteria isolated in different pH values and different bile concentrations. To determine the genetic diversity of the samples, genomic sequencing was carried out. 44% of isolates contain morphological characteristics of LABs, preventing the prevention of target strains (S. enteritidis, E. coli, S. aureus and L. sakei). In technological potential assessments, 7% of the strains demonstrated acidification capacity below pH 6 within 6 hours of incubation and 22% of the strains were capable of acidification after 24 hours of incubation. Proteolytic activity was observed in 20% strains, while none of the tested strains were able to produce exopolysaccharides from lactose, and 13% achieved diacetyl production capacity. The evaluation of the ability to develop at different pH values predicted 58% of the strains at acidic pH (1 to 3), but only 33% were predicted during the 12 hours of evaluation. 41% were able to withstand concentrations of 1% and 2% bile salt concentrations. The genera Lactobacillus and Leuconostoc mesenteroides were identified through sequencing of the gene encoding the 16S ribosomal RNA. Results obtained in this research revealed that the lactic microbiota of A2A2 milk from Jersey cows has technological potential contributing to the development of articles that can add more importance to this milk as well as the possibility of producing derivatives.