The Effect Of The Zein Hydrolysate On The Oxidative Stability Of Chinese Sausages

A number of researchers have reported the antioxidant activy of zein hydrolysate (ZH). However, its application in food systems has rarely been reported. In this study, the antioxidant effectiveness of zein hydrolysate in Chinese sausages, and its effects on flavour and texture of the sausages were investigated to gether valueable information for the food industry.Zein was hydrolysed by Alcalase under alkaline conditions. The antioxidative activity of zein hydrolysate was measured by testing its ABTS+? and DPPH·radical scavenging activy, reducing power, and metal ion chelation activity. Results showed that ZH possessed a strong antioxidative activity. Therefore, a large amount of zein hydrolysate was prepared in order to carry out further experiment.Different levels of ZH (0%,0.5%,1%,2% w/w) were added into Chinese sausages. Then the sausages were stored at 37℃,25℃,4℃, which represented, respectively, seasonal temperatures of summer, spring or autumn, and winter. Peroxide value (POV), acid value, and thiobarbituric acid-reactive substances (TBA value) concentration were monitored during storage. Results showed that the addition of zein hydrolysate significantly increased the oxidative stability of the sausages (p<0.05). The higher the zein hydrolysate concentration, the stronger the antioxidant activity. Furthermore, the antioxidant activity of 2% zein hydrolysate was significantly higher than that of the synthesized antioxidant, butylated hydroxyanisole (BHA) at a 0.01% level (p<0.05). Results of texture profile analysis showed that hardness, gumminess, chewiness, springiness, cohesiveness, and resilience were not affected by the addition of zein hydrolysates.In order to improve the oxidative stability of Chinese sausages to a greater extent, the combination effect of D-isoascorbic acid andα-tocopherol with ZH was studied in Chinese sausages storing at 37℃. Results showed that the oxidative stability of Chinese sausage was further enhanced by the incorporation of D-isoascorbic acid andα-tocopherol level. The POV, TBA and acid values of the sausages with 2% ZH + 0.3g/kg D-isoascorbic acid + 60mg/kgα-tocopherol were barely changed during a two-week storage period.The possibility of using the antioxidative ZH to reduce nitrite dosage in Chinese sausages was investigated. It was shown that colorimetric attributes of sausages with 2% added ZH and nitrite at a reduced level (55 ppm) were comparable to those of control with 0 ppm nitrite. The residual level of nitrite decreased rapidly during storage. After 30 days storage at 37℃, the residual level of nitrite in sausages with 55ppm added nitrite was only 2.73 ppm, which was substantially lower (p<0.05) than that in control sausage (20 ppm).