Fermentasi Sari Koro Pedang Putih (Canavalia ensiformis (L.) DC.) dengan Penambahan Sukrosa dan Susu Skim

Abstract

Jack bean is one of the under-utilized legumes that has not been widely explored. One of the possible applications is to ferment jack bean milk by lactic acid bacteria for fermented milk production. However, the type of carbohydrates in jack bean milk differs from cow milk’s constituent, which can affect cell growth and metabolism activities. Therefore, it is necessary to examine the ability of lactic acid bacteria to grow and produce acid in jack bean milk, as well as the effect of sucrose and skim milk addition on the fermentation performance. Lactobacillus plantarum WGK4 and Lactobacillus paracasei WGK5 isolated from water soaking of red lima bean were used as starter cultures. Each was inoculated into jack bean milk, with or without adding sucrose and skim milk and incubated at 37 °C for 24 h. Cell amount, titratable acidity, and pH were monitored before and after fermentation, then sensory characteristics were evaluated descriptively. The two isolates could grow in jack bean milk and produce acid. The addition of 2% sucrose or 2% skim milk significantly increased acid production. Sucrose reduced the pH of fermented jack bean to 3.7–4.0, while skim milk slightly elevated the pH to 4.14-4.30. The addition of 8% sucrose and 4% skim milk showed cell account, titratable acidity, and pH in the fermented milk to be 9.10 log CFU/mL, 1.19-1.26, and 4.14-4.30, respectively. After storage at 4 °C for 14 days, cell viability was relatively at the same level, but the pH decreased slightly.