Coagulants modulate the hypocholesterolemic effect of tofu (coagulated soymilk)

Abstract

The recent increase in soymilk and tofu (coagulated soymilk) consumption especially in western countries is due to the recognition of the health benefits of soy foods. The amount and the type of coagulated biomolecules (such as isoflavones) vary with the type of coagulant, and this will inevitable alter their biological activity. This study sought to assess the effect of some coagulants (calcium chloride, alum and steep water from pap production) commonly use in the production of tofu in Nigeria on the serum cholesterol, high-density lipoproteins (HDL) and low-density lipoproteins (LDL) level in albino rats fed tofu for 14 days. 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 (12.0 g/kg) had a significantly higher (P<0.05) total phenol content than tofu produced using other coagulants (8.0 – 9.0 g/kg). 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, 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 watercoagulated tofu had the lowest serum level of cholesterol and LDL followed by those fed CaCl₂ and alum coagulated tofu. Those fed with calcium chloride-coagulated tofu had the highest serum HDL level, closely followed by those fed steep water-coagulated tofu. It was therefore concluded that of all the coagulants, steep water appeared to be the most promising coagulant with regard to the production of tofu with high hypocholesterolemic effect base on the low serum cholesterol, LDL and high HDL.

Keywords: Coagulant, soymilk, tofu, phenol, HDL, LDL, cholesterol