EFFECT OF COAGULANTS ON THE NUTRITIONAL QUALITY AND BIOCHEMICAL RESPONSE OF RATS TO TOFU (CUDDLED SOYMILK)

Abstract

The effects of various types of locally used coagulants (calci um chloride, alum and steep water effluent from pap produced from maize) on the proximate. mineral. energy composition. digestibility (in vitro and in vivo) and biochemical response (serum enzymes and lipids) of rats fed tofu (a coagulated product of soyrnilk) for 14 days was assessed. The results of the study revealed that there was no significant difference (P>0.05) in the tofu yield by each of the coagulants (17.5 - 18.3%): however. alum coagulation gave the highest yield. while calcium chloride gave the lowest yield. The protein (17.6%), fat (6.2%). Mn (0.3). Mg (34.2). energy (6.6 cal/g) and in vitro multienzyme protein digestibility (75.8 - 77.6%) of steep water coagulated tofu was significantly higher (P<0.05) than that of other coagulants while tofu produced with alum had a significantly higher (P<0.05) Fe (1.6). Ca (23.5). and K (33.9) than that produced by other coagulants. The loll! produced by calcium chloride had the highest Zn (0.6) content but the lowest energy content (5.3 cal/g) and in vitro multienzyme protein digestibility (61.6 - 63.5%). Feeding albino rats with tofu ad libitum for 14days caused a decrease in the serum alkaline transaminase (ALT) aspartate transaminase (AST). alkaline phosphatase (ALP). cholesterol and lowdensity lipoproteins when compared with the control. while there was no significant difference (P>0.05) in the average daily feed intake and average weight gain of the rats fed tofu. Conversely. there was a significant increase (P<O.05) in the serum highdensity lipoproteins when compared with the control. However, rats fed steep water coagulated tofu had the lowest serum level of cholesterol and LDL followed by thosetofu had the highest serum HDL level, and closely followed by those fed steep water coagulated tofu. It could therefore be concluded that of all the locally used coagulants in Nigeria for tofu production. steep water (effluent from pap produced from maize) which is considered to be a waste appears to be the best with high nutritional value and hypocholesterolem ic effect though with 'the least acceptabi Iity; there is the need for further research on how to improve its sensory quality. fed CaCl-, and alum coagulated tofu, while those fed with calcium chloride coagulated