Comparative studies on some quality attributes of firm tofu sterilized with traditional and autoclaving methods.
An innovative retort cooking method was developed for firm tofu sterilization to replace the traditional hydrogen peroxide treatment. The caramelized firm tofu was sterilized by autoclaving at 105 degrees C for 20 min, which led to a 3 log cycle reduction of total plate count. Shelf life of the processed firm tofu was extended at least 3 months. As compared with chemical treatment, thermal treatment degraded total and individual isoflavones to a lesser extent, and only minor changes were observed. The percent DPPH free radical scavenging capacity of autoclaved firm tofu was significantly higher than that of the hydrogen peroxide treated samples. Even after prolonged heat treatment, the three-dimensional network structure of the autoclaved firm tofu did not change significantly. Texture profile analysis and sensory evaluation confirmed autoclaved firm tofu to be acceptable.
Huang
Tzou-Chi
TC
Department of Food Science, National Pingtung University of Science and Technology, Taiwan. tchuang@mail.npust.edu.tw
Fu
Hui-Yin
HY
Ho
Chi-Tang
CT
D000975:Antioxidants / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D005511:Food Handling; D005519:Food Preservation; D005524:Food Technology; D006358:Hot Temperature; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007529:Isoflavones / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D011786:Quality Control; D012677:Sensation; D013025:Glycine max / Q000737:chemistry / Q000382:microbiology; D013242:Sterilization / Q000379:methods*
D000975:Antioxidants; D007529:Isoflavones; D006861:Hydrogen Peroxide