The effect of adding kunjak gum on the Chemical, textural and sensory properties of tofu

Because of their capability to form networks with protein matrices, hydrocolloids including gums hold much promise for imitating the functionalities of fat in cheeses. The present study was therefore aimed at exploring the potential of konjac gum to improve the poor textural and sensory properties of tofu. To this end, different levels of konjac gum (0.5, 1.5, and 2.5 g/kg) were incorporated into the formulation of tofu, and the textural and organoleptic characteristics of the resultant products were compared with control using a completely randomized design. The findings showed that konjac gum did not have a significant effect on both the protein and fat contents of tofu (p≥0.05). Conversely, pH and acidity of gum-containing tofu were significantly higher and lower than the control sample, respectively (p<0.05). Likewise, the moisture content of tofu was negatively affected by konjac gum (p<0.05); in fact, the higher the level of the fat-replacer, the lower the moisture content of the product. In line with moisture changes, the textural profile analysis indicated that tofu-incorporated samples had significantly higher hardness compared to the control sample (p<0.05). However, the highest level of the gum caused a reduction in hardness although the sample was still harder than the control (p<0.05). Inclusion of the fat-replacer in tofu formulation enhanced the springiness but had no significant impacts on cohesiveness and adhesiveness (p≥0.05). The results of sensory evaluation revealed that konjac gum had no significant effect on the color of the tofu (p≥0.05) but resulted in a considerable drop in product flavor at the highest level of incorporation (p<0.05). The texture of the sample containing 1.5 g/kg konjac gum was considerably most appreciated by the consumers (p<0.05). In conclusion, incorporation of 1.5 g/kg konjac gum in the formulation of tofu would result in a  product with desirable textural and sensory attributes.