THE EFFECT OF INCUBATION TIME IN MOLASSES FERMENTATION (ASPERGILL US NIGER) ON CHEMICAL AND MICROBIOLOGICAL CHARACTERISTICS OF CITRIC ACID

Abstract

The purpose of this research was to find out the effect of incubation time in molasses fermentation (Aspergillus niger) on chemical and microbiological characteristics of citric acid. The material used for this research were molasses and Aspergillus niger. The method of this research was Laboratory Experiment based on Completely Randomized Design, with 6 treatments (H0 = O hour, H1 = 24 hours, H; =48 hours, H3 = 72 hours, H4 = 96 hours and H; = 144 hours). Every treatment was repeated 4 times and used the molasses used was 400 ml. The observed variables were optimum pH, optimum temperature (°C), pH, TPC (log cfu/ml), citric acid production (%), citric acid rendement (%) and citric acid activity test. The result of this research showed that incubation time was very significantly (P<0.01) influenced by pH, TPC and citric acid production (%). The incubation time on H5 was represented the best treatment on pH. The incubation time H3 was represented the best treatment on TPC. The incubation time on H5 was represented the best treatment on citric acid production. Citric acid rendement and citric acid activity test gave influence on chemical and microbiological characteristics of citric acid. The conclusion of this research were pH 7, temperature 50 "C and incubation time 72 hours had optimal influence on pH, TPC (log cfu/ml) and citric acid production (%).