Physico-Chemical Characteristics of Novel Analog Rice from Fermented Sorghum Flour by Rhizopus oligosporus and Soybean Flour

Abstract

The need for food in the world is currently increasing, one of high consumption is rice. Analog rice is one of the products for rice substitute consumption to meet staple food with better nutritional value. In this research, the production of analog rice was made from fermented sorghum using Rhizopus oligosporus which has been studied previously with the addition of soybean flour fortification. Raw materials of sorghum grain were fermented using Rhizopus oligosporus to reduce tannin levels of sorghum and the addition of fortified soybean flour aims to increase the nutrition of analog rice. Analog rice production is carried out using the extrusion method with fermented sorghum flour with fortified soybean flour in a ratio of 0 to 50%. Nutritional value of analog rice (carbohydrates, protein, fat, fiber, minerals, and water), morphology, water adsorption index (WAI), water solubility index (WSI), hydrophilicity, and consumer acceptance were characterized. The best nutritional of analog rice produced was obtained from the combination of 50% sorghum (red or white sorghum) and 50% soybean flour, which contained carbohydrates, protein, fat, and fiber of 58.29%, 17.07%, 14.47%, and 7.43% respectively. The increasing portion fortified of soybean flour was reduced the WAI and increased the density of the analog rice structure. These characteristics are friendly to diabetic patients since they are rich in carbohydrates, protein, and fiber. On the other hand, this analog rice has the potential to be consumed as a main food ingredient to replace paddy rice and develop to staple food. Moreover, the insignificant effect of the WSI value and hydrophilicity of the analog rice were observed. However, adding soybean flour as a substitute for analog rice was less attractive to consumers than analog rice without substitutes.