By: Imaduddin Priambudi, Dwi Mega Apriliani, Muhammad Nur Cahyanto, Tyas Utami
Abstract
The objectives of this research were to study the pattern of acid production and pH decrease during the fermentation of black soybean milk with various concentration of sucrose and skim milk by lactic acid bacteria. The black soybean milk with 0%, 2%, 4%, 6%, and 8% (w/v) addition of sucrose and skim milk were inoculated with 1% (v/v) Lactobacillus plantarum Dad-13. The titratable acidity and pH were examined in every 3 hours of fermentation at 37°C. In original black soybean milk, acid and pH change occurred during the 12 hours of fermentation and likely to remain same afterwards. In variation of sucrose and skim milk concentration, acid and pH change occurred during the 24 hours of fermentation. In the end of fermentation of black soybean milk with sucrose addition, acid levels were in the range of 1.13–1.63% and pH value were in the range of 3.07–4.24. In the end of fermentation of black soybean milk with skim milk addition, acid levels were in the range of 1.07–1.86% and pH value were in the range of 4.08–4.68. Based on the research results, the time required for the fermentation of black soybean milk using L. plantarum Dad-13 was for 9–12 hours.