Soybean Oil Volume Fraction Effects on the Rheology Characteristics and Gelation Behavior of Glucono‐δ‐Lactone and Calcium Sulfate‐Induced Tofu Gels

Abstract

Abstract The effects soybean oil volume fraction on the rheological characteristics and gelation behavior of acid and salt‐induced soft tofu‐type gels was investigated. High oil volume fraction resulted in lower gel point temperature and shorter gelation time ( t gel ) while G ′ at the gel point increased as the oil volume fraction in the gels increased. A power law relationship t gel , gel point temperature and oil concentration was found and also the plot of G ′ versus oil concentration fitted well in the model: G ′∼ C A . The exponent “ A ” was positive in salt‐induced gels but negative in acid‐induced gels. This gelation behavior trend was demonstrated by estimating the composite gel shear modulus, which showed that, in salt‐induced gels the stiffness of the oil droplets was higher than the one of the gel matrix while it was the opposite in acid‐induced gels. Furthermore, the weak gel model was used to analyze and describe the network extension and its strength. Practical Applications In this comparative study, soybean oil volume fraction effects on the rheological characteristics and gelation behavior of acid and salt‐induced soft tofu‐type gels was established. Different coagulation temperatures and coagulants were used. The study gives new insights on the protein‐to‐oil droplets interactions during gelation at different pHs in a tofu gel like product. The better understanding of the gelation mechanism, small and large scale deformations of soy protein gels with additional oil, is industrially relevant, as it will help in better process line design, monitoring and quality control which would potentially lead to the development of novel soy‐based and dairy free cheeses products. Additionally, the parameters and conditions used were closely related to the ones used during soft silken tofu making, therefore, ensuring the process implementation much easier.