LACTIC ACID BACTERIA AND THE ROLE OF INDIGENOUS DAIRY FERMENTATION KERANDANG (Canavalia virosa): CHANGES AND ACTIVITIES oligosaccharides and antioxidant isoflavones
ABSTRACT: Canavalia virosa plants are classified as legumes. This plant can be found in Africa, South America, Australia, India, and Asia (Philiphina and Indonesia). Canavalia virosa plants are able to grow on a nutrient-poor soil and dryness resistant. In the dry season, these plants survive to grow in the sand land. This plant grows to spread, produce pods and seed. In Indonesia, especially in Yogyakarta, Canavalia virosa plants are often found on the sand land in Kulonprogo and Bantul Regency. Surrounding communities are call this plant as a kerandang, can be utilized the flowers and young pods of this plant can be utilized as vegetable and old seeds can be utilized as raw material for tempeh and tofu. Lactic acid bacteria have been used in fermented of nuts milk. The use of lactic acid bacteria in fermented foods provide benefits, i.e. can improve product safety, improve the nutritional value and providing specific flavor in fermented products. The main objective of this study was to know the role of indigenous lactic acid bacteria in kerandang milk fermentation, so that increase the functional value of lactic fermented of kerandang milk (free oligosaccharides and contain of isoflavone aglycones with high antioxidant activity and anticancer). More specific the aims of this study were 1) to know bio-diversity of indigenous lactic acid bacteria from Indonesia indigenous fermented food based on 16S rRNA gene sequences, 2) to choose the indigenous lactic acid bacteria isolated from Indonesian indigenous fermented food based on β-glucosidase activity and can hydrolyze raffinose and isoflavones, 3) to conducted the pretreatment optimization of kerandang seed as raw material for kerandang milk, 4) to study the oligosaccharides and isoflavones changes during fermentation of kerandang milk by indigenous lactic acid bacteria and 5) to evaluate the anticancer activity of crude extract isoflavones from kerandang milk fermented by indigenous lactic acid bacteria. This study consist of four steps : The first steps was identification of indigenous lactic acid bacteria based on 16S rRNA gene sequences, the second step was selection of indigenous lactic acid bacteria that produce β-glucosidase and have β-glucosidase activity, the third was optimize of pretreatment of kerandang seed as raw material for kerandang milk and the four step was fermentation of kerandang milk using indigenous lactic acid bacteria. The results showed that indigenous lactic acid bacteria are classified to the genus Lactobacillus and Pediococcus. Sixteen strains are classified to the L. plantarum-pentosus and L. plantarum species, one strain is classified to the L. paracasei subsp. paracasei species and one strain is classified to the P. pentosaceus species with similarity values above 99%. Five strains of Lactobacillus have higher β-glucosidase activity than the other strains, namely L. plantarum-pentosus T14; L. plantarum-pentosus T20; L. plantarum T33; L. plantarum-pentosus T35 and L. plantarum T32. Fifth strains of indigenous lactic acid bacteria are able to hydrolyze or transform the 100% raffinose in media MRS-raffinose 1% to sucrose, glucose, fructose and galactose. In addition, β- glucosidase from the five strains are also able to hydrolyze the β glycosidic bond in isoflavone glucosides to isoflavone aglycones, so that increase isoflavone aglycone and increased antioxidant activity. Soaking beans for 3 hr is the best way to soften the seed and reduce the HCN content as much as 41.04% before kerandang milk processing. During fermentation of kerandang milk by L. plantarum-pentosus T14 and L. plantarum-pentosus T35, consist oligosaccharides changes, particularly raffinose. In line, consist the isoflavones glucosides change into aglycones and increase the antioxidant activity of kerandang milk. The hydrolyze ability of raffinose and isoflavone by L. plantarum-pentosus T14 better than L. plantarum-pentosus T35. In line, the increase of isoflavone aglycone, so increase antioxidant activity and have positively correlated with coefisient correlation above 0.9%. Methanol extract isoflavones of kerandang milk fermented by L. plantarum-pentosus T14 and L. plantarum-pentosus T35 showed anticancer activity against Colon 26 cancer cells. Thus, kerandang milk fermented by indigenous lactic acid bacteria have functional value.
