Nutritional Quality of Fermented Soy Foods in Thailand

Soybean has been favored by many Thai people and it has been prepared by numerous different methods. Collected samples are as follows: Thua-nao paste from Chiangrai province, dried Thua-nao for Jatujak Market, Bangkok, 3 types of commercial soybean paste, soybean sauce and 2 types of fermented soybean curd cakes with other ingredients. Moisture contents of fresh and dried Thua-nao were 68.5 and 7.6%, respectively; therefore the shelf-life of dried Thua-nao can be extended to 1 year with proper packaging. The remainder of the soy foods had moisture contents of 55.4 to 64.4%. Fat contents of fresh and dried Thua-nao were 7.4 and 19.7%, respectively, whereas other samples contained less than 3%. Dried Thua-nao had the highest CHO (carbohydrates) content (37.4%); in contrast, soybean sauce contained only 4.5%. Calcium content was highest in dried Thua-nao followed by fresh Thua-nao; the other fermented soy foods had less than 44.7 mg/100 g. Salt was added to samples other than Thua-nao resulting in high Na contents. Free and total daidzein contents of dried Thua-nao were 355 and 676 ug/g; similarly free and total genistein contents were 293 and 616.5 ㎍/g, respectively.