Effects Of Exogenous Proteases On Chinese Sausage

Traditional Chinese sausage is famous for its unique cured meat flavor that comes from natural fermentation for long duration in winter. Since natural maturation is time consuming and climate limited, recently some alternative methods have been used by most commercial manufactures to shorten the process time. However, these alternative methods induce the problems associated with flavor deficiency and tough texture. Among the alternative ways, high temperature dehydration procedure has been the most popular choice. Although high temperature procedure owed the advantage of shortening processing time, it can not generate the attractive flavor as well as traditional method. Proteins are the most important constituents of Chinese sausage, the changes of proteins determined the final flavor and quality of Chinese sausage. The aims of the present study were to investigate the effects of exogenous protease on the flavor formation and edible quality in Chinese sausage. The detail content and conclusions are as follows:1. Effects of Flavourzyme and Protamex on proteolysis, antioxidant capacity and sensory attributes of Chinese sausage, and the response surface optimization test of the simultaneous addition of Flavourzyme and ProtamexTo improve the quality of Chinese sausage processed at high temperature by using exogenous protease. Effects of different levels of Flavourzyme and Protamex, on the proteolysis, antioxidant capacity and sensory attributes of Chinese sausage made at 50℃ for 48 h were studied. Results showed that Flavourzyme or Protamex addition in Chinese sausage accelerated protein degradation, which was reflected by the increase of non-protein nitrogen and appearance of new protein bands in both water-soluble and salt-soluble proteins. By adding Flavourzyme or Protamex, texture profile analysis (TPA) parameters decreased significantly, and aroma, taste and texture scores were enhanced respectively. The best sensory attributes were obtained at 8 LAPU/kg Flavourzyme dose, or 12 AU/1000 kg Protamex dose. Besides, Flavourzyme or Protamex addition enhanced antioxidant capacity, lowered water activity of Chinese sausage. Therefore, moderate Flavourzyme or Protamex addition is a novel method with great potential to improve eating properties and storage stability of Chinese sausage.The Box-Behnken response surface methodology was applied to optimize the processing parameters for Chinese sausage. Two quadratic polynomial mathematical models about reducing power and sensory attributes were built. The results indicated that the responses surface model, with Flavourzyme addition, Protamex addition and drying time as independent variables and reducing power and sensory attributes as responses, were fitted (R12=0.8314; R22=0.9640). The reducing power of Chinese sausage was significantly influenced by drying time(P< 0.01). While the sensory attribute of Chinese sausage was significantly influenced by Protamex addition (P< 0.05), drying time (P< 0.01), Flavourzyme additionxProtamex addition(P< 0.01) and Flavourzyme additionxdrying time (P< 0.01). According to the model, the optimum quality for Chinese sausage were obtained when Flavourzyme addition was 7.5 LAPU/kg, Protamex addition was 12 AU/1000 kg and drying time was 53 h. Under such conditions, the reducing power of Chinese sausage was 4 folders higher than the control, with the improvement of sensory attribute.2. Effects of Flavourzyme and Protamex simultaneous addition on volatile compounds and edible qualities of Chinese sausage during storageThe effect of Flavourzyme and Protamex simultaneous addition on volatile compounds and edible qualities of Chinese sausage were studied during the storage. The results showed that the addition of Flavourzyme and Protamex can improve the formation of excellent volatile compounds of Chinese sausage. The addition of Flavourzyme and Protamex can retard lipid oxidation and protein oxidation, which is helpful for the storage of Chinese sausage.