Technological characterization of lactic acid bacteria isolated from sheep milk for potential use as non-starter cultures

• Autor(a) principal: Dias, Maria Rita Souto
• Data de Publicação: 2019
• Outros Autores: Fusieger, Andressa, Motta, Amanda de Souza
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista do Instituto de Laticínios Cândido Tostes
• Texto Completo: https://www.revistadoilct.com.br/rilct/article/view/725
• topic: Food Science; Lactococcus; Enterococcus; technological properties; Lactococcus; Enterococcus; propriedades tecnológicas.

Sheep milk has different physicochemical properties, which means that its derived products have a high added value. Part of these properties is conferred by lactic bacteria which play important activities in the raw milk. This research aimed to analyze five lactic bacteria that were previously identified and evaluated for parameters as their acidification, proteolysis, diacetyl and exopolysaccharides production, potential antimicrobial activity and the safety parameters. The 16S rDNA gene identification by sequencing showed an agreement with the data obtained by MALDI-TOF/MS. The bacteria were identified as Lactococcus lactis MRS1, Lactococcus lactis MRS2, Lactococcus lactis MRS5, Lactococcus lactis MRS6, and Enterococcus faecalis M173. All isolates showed the same acidification profile, maintaining pH at 4.5 from 6 h of incubation along, under the conditions employed. Proteolytic activity, coexistence capacity, and production of exopolysaccharides were observed in all the isolates tested. Diacetyl production was only evident in the isolates Lactococcus lactis MRS1 and Lactococcus lactis MRS2. Regarding the presence of antimicrobial activity, Lactococcus lactis MRS6 and Enterococcus faecalis M173 isolates inhibited all tested cultures. In the evaluation of the safety parameters, none of the isolates presented high-level resistance to clinically important antibiotics and did not present gelatinase production and hemolytic activity. These results provide an important information on the potential bacteria to be exploited for the application in sheep milk-derived products, in a condition of starters or adjunct cultures.