PROTEIN AND HYDROGEN CYANIDE CHANGES DURING JACK BEAN (Canavalia ensiformis (L) DC) TEMPE PROCESSING

Jack bean (Canavalia ensiformis (L.) DC) is a bean that can be used to make tempe because its protein althought contains hydrogen cyanide. There are several processing steps during the tempe making of jack bean, that can ameliorate hydrogen cyanide but improve protein quality of jack bean. This research was conducted with the aim to determine changes in levels of hydrogen cyanide, soluble protein and total protein during the processing of jack bean tempe. The treatment was applied on each stage of the processing of jack bean tempe with a total of six stages, namely raw material, 24 h soaking, first boiling, second boiling, inoculation, and 24 h fermentation. Hydrogen cyanide and total protein gradually lowered in line with the jack bean tempe processing, respectively. Soluble protein levels increased at the soaking stage then decreased at the boiling stage and increased from the inoculation stage to become jack bean tempe. The higher inoculum concentrations and the longer fermentation time caused hydrogen cyanide decreased.  In reverse, moisture and soluble protein content increased. Using 1.5 % (w/w) inoculum produced the highest total protein content compared to those obtained from 1.0% and 2.0% inoculum concentration both in 24 and 48 h fermentation time.