Coagulants modulate the antioxidant properties & hypocholesterolemic effect of tofu (curdled soymilk)

The recent increase in Soymilk and tofu (coagulated soymilk) consumption especially in Western Country is due to the recognition of the health benefits of soy foods; consumption of soybean would prevent heart diseases. In Nigeria Calcium salt, alum and steep water from pap production are usually used as coagulant in tofu production. The effect of those coagulants on the antioxidant properties of tofu and serum cholesterol, high-density lipoproteins (HDL) and low-density lipoproteins (LDL) level of albino rats fed tofu for 14 days is been assessed. The result of the study revealed that there was no significant difference (P > 0.05) in the tofu yield (17.6-18.3%), however steep water coagulated tofu had a significantly higher (P < 0.05) total phenol (12.0 g/kg) content, reducing power (0.6 OD700) and DPPH free radical scavenging ability (69.1%) than tofu produced using other coagulants. Furthermore, feeding albino rats with tofu and water ad libitum for 14 days caused a significant decrease (P < 0.05) in the serum cholesterol and low-density lipoproteins when compared with the control, while there was no significant difference (P > 0.05) in the average daily feed intake of the rats. Conversely, there was a significant increase (P < 0.05) in the serum high-density lipoproteins when compared with the control. However, rats fed steep water coagulated tofu had the lowest serum level of cholesterol and LDL level followed by those fed CaCl2 and alum coagulated tofu respectively, while those fed with calcium chloride coagulated tofu had the highest serum HDL level, and closely followed by those fed steep water coagulated tofu. It was therefore concluded that of all the coagulant, steep water appeared to be the most promising coagulant with regard to the production of tofu with higher antioxidant and hypocholesterolemic effect.