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Kerala Veterinary and Animal Sciences University, Wayanad

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20201
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Subject: Dairy Microbiology × Author: AMRUTHA T A × Thesis Type: M.Tech. ×
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    ThesisItemOpen Access
    EVALUATION OF FUNCTIONAL CHARACTERISTICS OF EXOPOLYSACCHARIDE PRODUCING LACTIC ACID BACTERIA
    (COLLEGE OF DAIRY SCIENCE AND TECHNOLOGY MANNUTHY, THRISSUR, 2020-11-01) AMRUTHA T A; A K Beena
    EPS producing LAB were isolated from indigenous sources suchas goat milk, tender-coconut water, Vechur cow milk, passion fruit and potato. All the five isolates were biochemically characterised and 16SrRNA sequencing identified the isolates as Pediococcus pentosaceus, Weissella cibaria, Lactobacillus fermentum, Weissella cibaria and Lactococcus lactis respectively. Pediococcus pentosaceus, from goat milk, Weissella cibaria from tender coconut water, Weissella cibaria from passion fruit and Lactococcus lactis from potato are deposited in NCBI with accession no MK368400, MH782084,MK368397 and MK368420 respectively. As a part of assessing the probiotic potential, isolates were exposed to the harsh conditions of acid and bile. Only P.pentosaceus and W.cibaria (passion fruit) showed growth even after 3h of exposure to pH 2.0. All the isolates except L.lactis showed remarkable tolerance to 0.6% bile salts .To evaluate the adhesion potential cell surface hydrophobicity (CSH) and auto aggregation were determined. The maximum value for CSH(89.2%) and auto aggregation(90%) was exhibited by P.pentosaceus. The extent of increase in autoaggreagtion percentage on extended incubation was also maximum for this isolate. The observation of this isolate as non-haemolytic and negative for gelatin liquefaction indicates the possible absence of virulence factors.DPPH scavenging activity of P.pentosaceus was found to be 35.48%.P.pentosaceus produced EPS maximally when grown in nutrient broth that was supplemented with two percent maltose at pH 7.0. The optimum rate of inoculation was two percent.EPS recovery .was maximum after incubation at37 0C for 24h .DPPH assay showed that, 0.03mg of EPS exhibited antioxidant activity of 38.71%. Technological properties of the isolate were evaluated by looking into rate of acid productionand the physicochemical characteristics of the products prepared using the isolate.Syneresis value reduced remarkably when P. pentosaceous was included as starter. The observations in this study endorses the use of P. pentosaceus as an adjunct culture for the preparation of fermented milk products with better textural properties.