Comparative study of Physiochemical Properties of Soy tofu and Chickpea tofu made with two different coagulant Mgcl2 and lemon

Abstract

Soy tofu is one of the nine major foods responsible for more than 90% of food allergies in United States. Chickpeas (Cicer arietinum) are a good alternative as they lack the major allergens found in soy (Gly m5, Gly m6) and it provides good nutritional values. However, there is limited evidence available comparing physiochemical properties of soybean tofu and chickpeas tofu prepared with two different coagulant Mgcl2 and lemon. The main purpose of this study was to evaluate and compare the physiochemical properties of soybean tofu and chickpea tofu made with two different coagulant (Mgcl2 and lemon) and to assess the suitability of the chickpea tofu as an alternative to soy tofu. Two chickpeas tofu sample and one soy tofu sample were prepared using 150g raw material through soaking, blending, homogenization, filtration, sedimentation, heat treatment, and coagulation. Chickpea milk was coagulated with Mgcl2 (5mg per 1000 L) and lemon juice (20ml per 1000 L). Two soy tofu samples were used as the controls; one was purchased from the market and another prepared in the food science lab. Physiochemical analyses, including Colorimeter, pH, and water activity were performed using the calibrated instruments for tofu samples. The total yield of chickpea tofu with Mgcl2 and lemon were 72% and 62% respectively, which were significantly lower than the yield of soy tofu 117.33%. The pH of chickpea tofu made with Mgcl2 (6.83 to 6.84) was comparable to the soy tofu (lab = 6.56 – 6.62, Market place = 6.79 to 6.81) whereas chickpea tofu made with lemon has substantially lower pH (5.51 to 5.56). Water activity value of chickpea tofu (with Mgcl2 = 0.77 to 0.79, Lemon = 0.77 to 0.79) was similar to that of soy tofu (lab = 0.78 to 0.79, marketplace = 0.77 to 0.79). Soy tofu prepared in food science lab (L* = 84.21, a* =4.60, b* 1.27) and market purchased soy tofu (L* = 85.23, a* = 4.74, b* = 0.21) closely resembles with the chickpea tofu made with Mgcl2 (L* = 83.84, a* = 4.88, b* = 0.63) whereas chickpea tofu made with lemon has lower L* value and higher a* value (L* =77.62, a* = 6.28, b* = 0.64), making it more reddish and darker as compared to the soy tofu. The finding indicates that chickpea tofu made with Mgcl2 is a suitable alternative for soy tofu, with comparable physiochemical properties such as pH, water activity and color. This study supports chickpea tofu as a plant-based alternative for people who have soy allergies. Further this study also gives a valuable insight about the impact of two different coagulant Mgcl2 and Lemon on the quality of tofu yield, appearance.