Changes to the chemical and microbiological characteristics of Leucaena leucocephala seeds during tempeh fermentation in Pacitan, East Java

Abstract

Lamtoro tempeh is a traditional Indonesian fermented food made from lamtoro (Leucaena leucocephala). In Pacitan, it is usually fermented using usar (a traditional tempeh inoculum made from senggani leaves). The fermentation process takes 42 hrs and during this period, there are changes in the chemical and microbiological characteristics of the lamtoro seeds. To study these changes, samples were collected and tested for chemical characteristics (water content, ash content, dissolved protein, pH, and total acid titration) and microbiological characteristics (the number of fungi, yeast, and lactic acid bacteria) every 6 hrs during the 42 hrs fermentation. During fermentation, the water content increased significantly in the initial 6 hrs of fermentation and then tended to stabilize until the 42-hour. The ash content increased, while the dissolved protein content increased from the 0-hour to the 36-hour of fermentation but dropped at the 42-hour. The pH level of the lamtoro tempeh decreased from 0-hour until 30-hour and then increased until the end of the fermentation period. However, the level of total acid titration increased during the lamtoro tempeh fermentation. The growth of fungi, yeast and lactic acid bacteria initially declined but then gradually increased until the end of fermentation (42-hour). The fermentation time was found to affect both the number of microbes and the chemical characteristics of the lamtoro tempeh from the Pacitan area.