Denaturation of soy protein isolate and its application in restructuring beefsteaks.

摘要

There has been no application of soy protein as a protein-protein binder in cold-set restructuring although soy protein is widely used as an additive in meat product due to their desirable properties. The objectives of study were mainly to determine the effect of heat induction on potential of soy protein isolate (SPI) as a binder in cold-set restructuring by monitoring stability and binding properties of restructured beefsteaks. Beefsteaks were restructured with 10% SPI solution which was treated at 95.5C for 30 min. This resulted in the most degree of structural changes as shown from surface hydrophobicity and free sulfhydryl groups. Beefsteaks containing SPI solution resulted in higher binding strength (p 0.05) than the control in instrumental texture analyses and sensory evaluation. Changes of TBARS values, hexanal concentration, and pH, microbiological, and visual deterioration of restructured beefsteaks stored in a simulated retail display at 3C for 9 days were determined. Stability was influenced over the storage of time (p 0.05), however, addition of SPI solution did not result in detrimental chemical, microbiological, and visual color changes (p > 0.05). Finally, binding properties and cooking parameters of the restructured beefsteaks made with denatured SPI and GDL (δ-glucono-lactone) were compared with those of the restructured beefsteaks with various commercial binding agents including calcium/alginate (CA), Fibrimex ®, Activa®, or denatured whey protein isolate (WPI). Denatured SPI treatment had better binding properties (p 0.05) than the control, Fibrimex® or denatured WPI in raw steaks. SPI increased (p 0.05) cook yield although it was not superior to CA. From the results from the present studies, heat induced SPI would be an alternative application in cold-restructuring meat.