Abstract
Processing of soybeans for industrial manufucturing of Tempe, a traditional fermented soybean food in Indonesia, was investigated. The bacterial count of Tempe prepared from peeled soybeans was lower by 2 orders than those prepared from unpeeled soybeans. The bacterial count of Tempe was lowered by soaking peeled soybeans in an aqueous solution of an organic acid. Acetic acid gave the most effective results among organic acids employed. Namely, 0.2% level of acetic acid, 1.0% level of lactic acid, succinic acid and tartaric acid, or 3.0% level of citric acid was required in order to lower the becterial count of Tempe to 10 4/g level. It was appropriate to soak peeled soybeans in an aqueous solution of acetic acid at 17 to 20°C for 3 to 4 hours. Tempe prepared from peeled and pressure-steamed soybeans was superior in taste to the one prepared from boiled soybeans. Steaming the peeled and soaked soybeans under O.8kg/cm2 for 3 to 7 minutes made the hardness of the soybeans to 1.0 to 1.5kg which gave appropriate condition to make Tempe. Satisfactory Tempe manufacturing may include the following process: peeling soybeans; soaking the peeled soybeans in 0.2% solution of acetic acid for 3 to 4 hours; draining the beans; and steaming under 0.8kg/cm2 for 3 to 7 minutes.
