Preliminary study on the fortification of tofu with green tea catechins

Green tea catechins, especially epigallocatechin gallate (EGCG), have been linked with a number of health benefits. However, only drinking green tea may not provide a sufficient level of EGCG to achieve those health benefits. Incorporation of EGCG in tofu, which is a protein-rich food widely used in Asia, and by vegetarians in Western countries, is an alternative way of enhancing the intake of EGCG and its health promoting effects. The present study optimised the conditions necessary to obtain the optimum yield of tofu including concentration of soy protein isolate (SPI), coagulant and pressing time; it then further investigated the possibility of fortifying EGCG in tofu via the effect of EGCG on tofu production yield and the recovery of EGCG. It was possible to fortify both firm and silken tofu with EGCG. The results showed that optimum yield of firm tofu was obtained at 6% (w/w) SPI, 30 mM Nigari and 50 min pressure; and for the silken was at 6% (w/w) SPI, 30 mM GDL and 20 min pressure. EGCG recovery was higher in the silken tofu than the firm one. For both types of tofu, the EGCG addition was suggested at a level of 0.5% (w/w) to obtain the optimum yield of tofu, which resulted in 0.97 g and 0.95 g of EGCG in a serve of 100 g of firm and silken tofu, respectively.