Characterization of Exopolysaccharide Produced by Lactobacillus casei AL15 Isolated from Sap of Arenga pinnata

Exopolysaccharide (EPS) is a polymer of a reducing sugar which has a high molecular weight. This polysaccharide is usually produced by lactic acid bacteria, and has a very large usability for food products and pharmaceutical products. Lactobacillus casei AL15 is a type of lactic acid bacteria isolated from sap of Arenga pinnata and has a great potential to produce EPS. Productivity in producing EPS of L. casei AL15 in MRS broth medium is about 14.1 mg/L. Furthermore, component of carbon was a highest composition of the EPS tested by SEM. The image of SEM showed that the shape of EPS were round to ellipse shape with smooth surface texture and white yellowish color. The spectrum of FTIR produced the wavenumber in the range of 3338 cm-1 – 1056 cm-1. The spectrum indicated the presence of O-H in 3338.78 cm-1, C-H in 2962.66 cm-1, C=O in 1649,14 cm-1 and C-O-C in 1056.99 cm-1. Those bonds indicated that EPS produced by L. casei AL15 was heteropolysaccharide (HePS), since the FTIR spectrum had a same spectrum with sucrose and glucose. This result was also supported by HPLC analysis, which showed that the hydrolyzed EPS was composed by sucrose and glucose. Overall results showed that L. casei EPS AL15 was HePS. Keywords: characterization, exopolysaccharide, Lactobacillus casei AL15, Arenga pinnata

The Effect of Mixed Inoculum Addition Concentration and Fermentation Time on the Characteristics of Dry Cocoa Beans (Theobroma cacao L.)

The fermentation process has an important role in determining the quality of cocoa beans by forming taste, color, aroma, and appearance. The purpose of this study was to determine the effect of inoculum concentration and fermentation time on the characteristics of dry cocoa beans and determine the best conditions for both inoculum addition concentration and fermentation time to produce dry cocoa beans under Indonesian national standards. The research used completely randomized design with two factors; the first factor was the starter concentration consisting of controls (0%), 0.5%, 1%, 1.5%, and 2% (v/w). The second factor is the fermentation time, namely 1 day, 2 days, 3 days, 4 days, and 5 days. Treatment was repeated twice to get 50 units of the experiment. The results showed that the addition concentration of mixed inoculum (Saccharomyces cerevisiae and Lactobacillus plantarum) had a significant effect on changes in temperature and pH during fermentation, and it also had a significant effect on total unfermented beans. This study showed that time fermentation treatment had a very significant effect on all tests. The interaction of the two treatments had a significant effect on temperature changes during fermentation; it also significantly affected total unfermented beans. According to the Indonesian National Standard of cocoa beans, the best treatment, and the fastest fermentation time to produce the first quality standard (cut test) is a concentration of 1% mixed inoculum and fermentation in 3 days