Preparation Of Chitosan And Nano-Silver OSA Starch Film And Its Effect On Beef Preservation

With the development of China's beef cattle industry,consumer demand for beef food is also increasing.Most of the storage methods for beef are frozen or refrigerated.The packaging method for beef is mainly plastic wrap or directly frozen.In order to develop environmentally friendly antibacterial packaging materials for meat products,an octenyl succinic anhydride(OSA)starch film was prepared by response surface optimization tests in this experiment.Nano-silver and chitosan OSA starch films were prepared based on the mechanical strength and scanning electron microscope results of the films.The effects of nano-silver and chitosan OSA starch film packaging on the fresh-keeping period of beef at4 ? were explored.(1)Through single factor and response surface test design,the best process for OSA starch preparation was determined as follows: the amount of OSA added was 8%,the esterification reaction time was 4h,the material-liquid ratio was 40%,and the esterification reaction pH was 8.The degree of substitution of OSA starch prepared under these conditions was 0.0199.(2)OSA starch film was prepared by casting method.Using single factor test and response surface test design,the preparation of OSA starch film was optimized,and the optimal preparation process was determined as follows: 5% addition of OSA starch,gelatinization The time was 30 minutes and the amount of glycerol added was 8%.The comprehensive score of tensile strength and elongation at break of the OSA starch film prepared under these conditions was 96.37.(3)The tensile strength of nano-silver OSA starch film and chitosan OSA starch film were measured by elongation at break and scanning electron microscope.The optimal amount of nano-silver was 0.3%.The optimal ratio of chitosan to OSA starch is 30:70.(4)The characteristics of nano-silver OSA starch film and chitosan OSA starch film were measured.The results showed that compared with the control group,the thickness of the film added with nano-silver increased,the thickness of the film added with chitosan decreased,and the nano-silver and chitosan significantly reduced the water solubility of the film.The light transmittance increased significantly with the addition of nano-silver and chitosan(P <0.05).Both chitosan and nano-silver have good free radical scavenging ability,and chitosan has the best effect.The DSC and infrared spectroscopy measurements show that both chitosan and nano-silver make the structure of OSA starch more stable.(5)The beef packaged with nano-silver and chitosan OSA starch film was used as the treatment group,and the beef packaged with ordinary plastic wrap was used as the control group.The beef was subjected to a storage test at 4 ° C,and sensory evaluation,color,and pressure were performed.Loss,total number of colonies,TVB-N,TBARS,and changes in pH were measured.The results showed that the sensory score of the beef in the treatment group was significantly higher than that in the control group(P <0.05).According to the comprehensive preservation period,the preservation period of the beef in the control group was 15 days.The fresh-keeping period of beef in the chitosan-treated group was 21 days.The results of this experiment showed that the mechanical strength and stability of the optimized OSA starch film were significantly improved.The addition of nano silver and chitosan could significantly prolong the freshness of beef,among which the nano silver OSA starch film had the best effect.