Texture and Storage Stability of Tofu Incorporated with Rhynchosia volubilis

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.