Profil Bakteri Asam Laktat dan Bakteri Pembentuk Asam pada Nira Kelapa (Cocos Nucifera L.)

Abstract

Coconut sap has been widely used to produce coconut sugar in many countries. It is a liquid that coming out by tapping the unopened coconut flower. Coconut sap is rich in sugar (10~15%) and nearly at neutral pH condition. Those characteristics cause the coconut sap spontaneously fermented by certain microorganisms that present naturally in coconut flower due to unsanitary tapping process. This study aims to evaluate the profile of lactic acid bacteria and acidforming bacteria and to evaluate the effect of storage on coconut sap. Coconut sap was obtained from Sukabumi and Purbalingga. The initial amount of lactic acid bacteria and acid-forming bacteria in fresh coconut sap from Sukabumi and Purbalingga was already high. The average number of lactic acid bacteria in Sukabumi and Purbalingga fresh coconut sap respectively amounted to 7.38 log CFU/ml and 7.94 log CFU/ml, meanwhile the average number of acid-forming bacteria in Sukabumi and Purbalingga fresh coconut sap respectively amounted to 5.88 log CFU/ml and 7.95 log CFU/ml. The average pH value of fresh coconut sap from Sukabumi and Purbalingga were 5 dan 5.5 with total sugar 15 and 15.2o brix. Purbalingga coconut sap stored at room temperature for 4, 8, and 16 hours increased the number of lactic acid bacteria and acid-forming bacteria, as well as decreased its pH value. Those also happened in Sukabumi coconut sap stored for 18 hours at low temperature. Isolates from Sukabumi coconut sap was dominated by heterofermentative coccobacilli, 43 % isolated from MRSA medium and 62 % from GYC medium. Heterofermentative coccobacilli also dominated 81 % isolates in Purbalingga coconut sap obtained from MRSA medium, whereas isolates from GYC medium were dominated by heterofermentative bacilli (84%). Identification using API 50 CHL showed that coconut saps from both places were dominated by Weissella viridescens. Other lactic acid bacteria isolates were identified as Lactococcus lactis ssp lactis 1 and Leuconostoc mesenteroides ssp mesenteroides/dextranicum 1.