Changes in microflora and biochemical composition during the Baceman stage of traditional indonesian Kecap (soy sauce) production

Abstract

Indonesian soy sauce ( kecap) is made from black soybeans in a traditional way which involves two microbiological stages: a solid-state fermentation and a brine fermentation. This study is concerned with the brine fermentation, called baceman. Samples from different kecap producers were analyzed for (bio)chemical content and micro-organisms. It was found that the final composition of the baceman differed from manufacturer to manufacturer, and even within companies large differences were found in microflora and the amounts of fermentation products, formol nitrogen and salt concentration. The main fermentation products were lactate, acetate, glycerol and ethanol. Pediococcus halophilus, staphylococci, a coryneform bacterium and yeasts belonging to Candida, Debaromyces and Sterigmatomyces were isolated from the brines. Compared to Japanese soy sauce production, fermentation by yeasts does not play an important role in Indonesian kecap production. This is due to the fact that kecap is made from whole soybeans only, which are poor in sugars. After fermentation by P. halophilus no substrates are left for growth and ethanol production by yeasts. The presence of film forming yeasts can even lead to spoilage of the product.