Abstract
The force-deformation curve of bulk soybean fermented with Rhizopus could be described by the equation, F=C(Δe)n. The degree of maceration of fermented soybean (a measure of softness) was estimated by the n-value of the power of the equation and depended on the Rhizopus strain used. Of the Rhizopus strains tested, R. oligosporus TISTR3001 (well known as a dominant tempeh processing species) and Rhizopus sp. LKN (isolated from a tempeh starter) gave high degrees of maceration corresponding to n=1.3 (initial value of 1.8) and 1.6 (initial value of 1.8) respectively, for 60 h of fermentation of raw soybeans at 30°C. On the other hand, the R. oligosporus TISTR3001 and Rhizopus sp. LKN for sterilized soybeans decreased to n-values of 1.5 from initial value of 1.7 and to 1.3 from initial value of 1.7, respectively, for 60 h of fermentation at 30°C. n-Values less than 1.5 were considered to indicate a considerably high degrees of maceration.
