The effect of starter culture on bacterial profile in soybean tempeh

Abstract

The bacterial population in soybean tempeh can be affected by many factors such as hygiene and preparation procedure of the soybean. In this study, we investigate the effect of different tempeh starter culture on the bacterial profile in comparison to other factors. The bacterial profile of five commercial tempeh made with different processing techniques and three samples made with different starter culture were analyzed using quantitative polymerase chain reaction (qPCR). The phylum Verrucomicrobia was only detected in commercial tempeh from unstandardized home-scale industries. Bacteroidetes were present in commercial tempeh and samples made with starter that contains cassavabased materials. Commercial tempeh from standardized medium-scale industries contains fewer total bacteria than those from home-scale industries. The addition of starter culture for tempeh production can increase the number of total bacteria compared to uninoculated soybeans. However, there was no difference in total bacterial amount between starter culture variation. Bacterial profiles of all samples were dominated by Firmicutes except tempeh with the starter culture Cap Jago that is dominated by Gammaproteobacteria. This study showed that although the type of starter culture did not significantly contribute to total bacteria in tempeh, it can influence the bacterial profile of the product on phylum level.