Abstract: In this study, the effects of the processing technology on the total concentration of isoflavones and the relativeconcentrations of genistein and daidzein during the Tofu preparation were investigated. The results showed that soaking thesoybean for 12h at 20℃ and heating soy extract in a beaker up to 80℃ and holding for a few minutes to be coagulated to Tofucould increase the recoveries of isoflavones in comparison with the traditional method. The recoveries of isoflavones and the yieldof Tofu could also be increased by adding sodium alginate and gelatin. The results also showed that the firmness and other evaluationpoints of the Tofu produced with above method were proved to be of good quality. The loss of isoflavones was 22% intraditional Tofu processing, among which the aglycones isoflavones loss was less than the glucosides conjugate isoflavones loss.It was apparent that glucono-δ-lactone (GDL) was a better coagulant than CaSO4 because GDL resulted higher isoflavonesrecovery.

Key words: Tofu, isoflavones, recovery, glucono-δ-lactone (GDL), texture profile analyzer