44F-6 |
Instant-gelation Properties of Soy Protein |
Z. WANG, Food School, Wuxi University of Light Industry, Qingsanwan, Wuxi, 214036, China Touhua is a typical Chinese snack, traditionally only available at snack bars. As convenience has become the trend of modern food industry, producing such a soy powder that could instantly gel within ten minutes after adding hot water is preferable. Weak gel texture of touhua was developed from gelation of soy protein. For the purpose to prepare instant Touhua powder, instant gelation properties of soy protein isolate (SPI) during rehydration with hot water must be studied. The objective of this paper was to investigate the effects of preheating parameters and the types of coagulants on the instant-gelation properties of SPI. Instant-gelation properties of preheated SPI solution (5.33%) was studied by dynamic rheological measurement under a two-step temperature ramp procedure that simulated the temperature change course of soy powder after hot water being added and then held at ambient temperature. The result showed that all preheated SPI solution with 0.33% glucono -d- lactone (GDL) as coagulate could gel within 300s. SPI that was preheated at 90C for 50 min. exhibited the maximum gel strength in this study. Gel strength of GDL-induced gel increased as GDL usage level increased. But gel strength of papain-induced gel followed an increase-decrease profile as more and more papain was added. Furthermore, when blend of GDL and papain was used as coagulant, gel strength was higher than when GDL or papain was used as coagulant singly. It could also be seen that gel point of SPI solution with addition of papain (less than 100s) came earlier than that with addition of GDL (about 200s), and gel time tended to be shorter as papain usage level increased. Those results suggested that instant-Touhua or even Instant-Tofu (they are different in gel strength) could be expected with proper preheat treatment combining suitable coagulant.
Session 44F, Product Development
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