PHYSICO-CHEMICAL CHARACTERISTICS OF TRIBAL BEAN (Canavalia virosa) AND ITS ALTERNATIVE TOFU AND TEMPEH FOOD PRODUCTS

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<p>Increasing price of soybean becomes a serious problem for</p> <p>producers of traditional foods such as tempeh and tofu. These</p> <p>traditional foods are important protein sources for many Indonesian</p> <p>people. Tribal bean (<em>Canavalia virosa</em>) could be used as</p> <p>a substitution of soybean for tempeh and tofu processing. This</p> <p>study aimed to determine physico-chemical characteristics of</p> <p>tribal bean and its products such as tofu and tempeh. Tribal bean</p> <p>old pods were peeled manually in the Postharvest and Agricultural</p> <p>Machinery Laboratory of the Yogyakarta AIAT. The peeled seeds</p> <p>were dried until 10% water content and their epidermis were</p> <p>removed mechanically by using an abrasive peeler to produce</p> <p>yellowish clean peeled beans. The beans were analyzed physically</p> <p>and chemically using the standard prosedure. Since the tribal</p> <p>bean seeds contained high HCN, to minimize HCN content the</p> <p>beans were presoaked for 48 hours in water. The beans were then</p> <p>mixed with soybean at a ratio of 50:50 or 25:75 and processed</p> <p>for making tempeh and tofu using traditional method. Physicochemical</p> <p>and organoleptic characteristics of the tribal bean tempe</p> <p>and tofu were analysed, involving organoleptic test with hedonic</p> <p>method, texture, as well as water, ash, protein and crude fiber</p> <p>contents. The results showed that tribal bean contained protein</p> <p>(37.30%), essential amino acids, minerals and fiber (3.1%), and</p> <p>a toxic substance HCN. Presoaking the beans in water for 48</p> <p>hours significantly reduced HCN content by 98.51%, from 1334</p> <p>ppm. Tofu made of a mixture of tribal bean and soybean at a</p> <p>ratio of 25:75 plus 2% rice vinegar as a coagulant has a white</p> <p>color and normal flavor appearances, and was accepted by</p> <p>panelists. The tribal bean tempeh contained 78.1% water, 1.21%</p> <p>ash, 8.14% protein, 3.1% crude fiber, and 44 ppm HCN. Tempeh</p> <p>made of a mixture of tribal bean and soybean at ratios of 50:50</p> <p>and 25:75 showed good characters (flavor, taste, color, and</p> <p>texture) and panelist acceptance, as well as nutrition values (76%</p> <p>water, 2.71% ash, 14% protein, 0.25% crude fiber, and 14%</p> <p>lipid). However, HCN content in the tofu was still higher (85 ppm</p> <p>HCN) than the recommended maximum value of 50 ppm. This</p> <p>study suggests that tribal bean is more suitable for tempeh than</p> <p>for tofu based on its HCN content.</p>