The effects of various isoelectric points in tofu processing on physicochemical properties and antioxidant capacities

Tofu is a derivative product of soybean that is widely consumed by the society for its high nutritional content and good benefits for health. Research on the physicochemical especially antioxidant content of tofu was still rarely evaluated. The aim of this research is to increase the antioxidant effect of tofu by using Lactobacillus casei FNCC-0090 and Lactobacillus plantarum spp. as coagulants. Tofu was coagulated using Lactobacillus casei FNCC-0900 and Lactobacillus plantarum spp. to reach the isoelectric points of tofu with pH 4.8, 5 and 5.2. The physicochemical of tofu were analysed which consist of total protein content, crude fat content, carbohydrate content, moisture content, ash content, antioxidant capacities, colour, yield and texture of tofu. The results showed that there is a significant difference in moisture content, colour, protein, yield, texture and antioxidant capacities of tofu. While fat, ash, carbohydrate content of tofu did not show a significant difference between sample but showed a significant difference with control. In antioxidant capacity, the antioxidant increased by 11.21% in the radical scavenging capacity, 5.1% in the reduction capacity and 4.9% in the chelating capacity of tofu.