• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.71-75
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• 2009

The effects of Rhynchosia volubilis (yakong) incorporation (0%, 10%, 20%, and 30%, w/w of soybeans) on quality and shelf life of tofu were investigated. Moisture content of tofu increased slightly with the increase in the level of yakong incorporation from 10% to 30% and no apparent relationships between yakong incorporation and the yield were found. Turbidity of soybean whey tended to increase with increased level of yakong incorporation where the values of 20% and 30% samples were significantly different from those of control and 10% sample (p<0.05). The different levels of yakong incorporation were found to have significant influence (p<0.05) on all the color characteristics of tofu. Tofu texture varied with the level of yakong incorporation in consistent pattern; however, there was no significant difference (p>0.05) in most cases. Tofu incorporated with yakong ($10{\sim}30%$) had a shelf life of above at least 1 day longer than that of the control tofu.

• Food Engineering Progress
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• v.13 no.2
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• pp.99-104
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• 2009

Tofu has been playing an important role in people's daily diet in most of Asia and recently in North America due to several health-promoting functions, preventing and treating a number of chronic diseases such as cancer, coronary heart disease and osteoporosis. The objective of this study was to investigate the effect of different levels of yakong incorporation (0, 5, 10, and 15%, w/w) in preparation of firm tofu. Quality parameters such as pH, titratable, moisture content, color, and consumer preference were determined, and their correlations were analysed. There were no significant differences in pH, titratable acidity, and moisture content due to different levels of yakong incorporation studied (p>0.05). A significant decrease in L$^{*}$ and b$^{*}$-values whereas significant increase in a$^{*}$-value was observed (p<0.05). Five percent yakong tofu received the most favorable mean scores with respect to color, texture, and overall acceptability. Correlation analysis revealed that yakong incorporation was well correlated with some of physicochemical properties as well as consumer preference.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.844-849
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• 2005

The chemical composition of isoflavone, oligosaccharide and phytic acid content of three Korean soybeans, Hwanggumkong, Yakkong and Huktae cultivars, were examined. Moisture, crude fat, crude protein and ash content of soybean seeds were all in the ranges of 10.9-$12.5\%$, 15.8-$20.8\%$, 36.5-$41.1\%$ and 5.4-$5.6\%$ respectively, showing differences among the cultivars. Methionine, cystein and histidine were the minor components of soybean protein and ratio of methionine to the total proteins showed significant varietal differences. The main fatty acids of total lipids were linoleic, oleic and palmitic acids, which comprised over $80\%$ of the total fatty acids. Yakkong, Hwanggumkong and Hukae contained 2491.4 $\mu$g, 2176.8 $\mu$g and 1893.5$\mu$g of isoflavone in each gram of dry matter, respectively, and existed mainly as glycoside isomers. Oligosaccharide contents were similar among the cultivars. The total concentration of phytic acid was $2.63\%$ of Hwanggumkong, $2.12\%$ of Yakkong and $2.80\%$ of Huktae.