2014 Volume 15 Issue 4 Pages 251-258
Food hydrogel was produced from an oil in water emulsion of soy milk and rice powder mixture, and a processing technique with freezing was investigated in terms of the rheological properties of the resultant products. The emulsion specimens were stored at 4℃, −5℃, −10℃ and −20℃ for 1 day. The time dependent changes in dynamic viscoelasticity suggested that the gel formation above freezing point, that was 4℃, allowed to form a gel network covering its bulk specimen. Whereas, when the specimens were aged in frozen state, gel formations could occur at localized positions due to the geometrical limitation by ice. The characteristics of viscous liquid could be confirmed in these specimens by the linerly increased loss tangent values, and this trend was obvious in the order of −5℃, −10℃ and −20℃. Gel specimens were cooked with an oven at 180℃ in order to observe their melting behavior. It was found that the degree of melting correlated to the rheological properties, and this correlation was obvious when gels were aged at −10℃. The results of this study suggested that freezing could be a useful processing tool for tuning rheological properties of food hydrogels, that may allow to process food functionalities.
