18F-8

H.-J. CHUNG¹, J. Y. Jung¹, W.-J. Kim², W.-S. Kim³, and S. Y. K. Lee⁴. (1) Dept. of Food Science and Nutrition, Daejin Univ., 11-1 Seondan-dong, Pocheon-si, Kyunggi-do, 487-711, South Korea, (2) Dept. of Food Science and Technology, Sejong Univ., 98 Kun-Ja Dong, Kwang-jin Ku, Seoul, 143747, South Korea, (3) Dept. of Culinary Science, Honam Univ., #59-1 Seobong-dong, Gwangsan-gu, Gwangju-si, South Korea, (4) Dept. of Food and Nutrition, Chung-Ang Univ., An-Sung, South Korea

Tofu whey is a byproduct waste during the process of making tofu and contains small molecular weight compounds such as isoflavones, saponins, and oligosaccharides that are regarded as functional food ingredients. The aim of this study was to propose utilization of tofu whey concentrates separated by ultrafiltration (UF) for yogurt production. The curd yogurt was prepared from whole milk added with skim milk powder and/or UF powder and fermented with lactic acid bacteria at 37 °C for 24 hr. The effects of UF powder addition on quality of yogurt in terms of titratable acidity, apparent viscosity, the number of viable cells, volatile compounds, and sensory properties were examined. Titratable acidity of all mixtures remarkably increased for the first six hr and addition of UF powder stimulated the acid production. Apparent viscosity of yogurt added with UF powder (2,623~3,189 cps) was lower than that of the control yogurt (3,196 cps). The propagation of lactic acid bacteria was stimulated by UF powder, and the number of cells after 24 hr was 9.11~9.16 log colony forming unit/ml. Gas chromatographic analysis detected acetaldehyde, diacetyl, ethanol, and organic acids, and more volatile compounds were detected in yogurts added with UF powder. Sensory analysis showed that yogurts added with UF powder were evaluated as acceptable as control yogurt. Therefore, UF powder could be substituted for skim milk powder without depressing yogurt quality.

Session 18F, Product Development: General
2:00 PM - 5:30 PM, Sunday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana