The Preparation Of ?-Plylysine Microparticles And Its Application On Fresh-cut Apple

Fresh-cut fruit during processing were peeled,some mechanical damage,such as segmentation,lead to deterioration of fruit.Therefore,how to maintain the quality of fresh cut fruits and vegetables,prolong its shelf life is a problem to be solved in fresh cut industry.With the concern about food safety,the demand for natural antimicrobial agents,which are safe and nontoxic,is increasing.The physiological and biochemical characteristics of fresh-cut fruits and vegetables were changed after fresh cut treatment,and the shelf life of fruits and vegetables was much shorter than that of whole fruits and vegetables.?-Polylysine is a kind of antibacterial which was widely used in food preservation field,because of it was nontoxicwide,and had a widely antimicrobial spectrum.This study was to optimize the preparation technology of CS-ALG microparticles by using single-factor test and response surface experiment,and analyzed the antibacterial activity ?-Polylysine microparticles.Finally,the effects of presrevative of ?-Polylysine microparticles films with on fresh cut apple was been studied.The results are summarized as follows:1.The preparation process for ?-Poly-lysine-loaded chitosan-Sodium alginate microparticles was optimized by employing a 4-factor,3-level Box-Behnken statistical design.The optimal formulation was obtained by using response surface analysis were as follows:mass ratio of Alginate to chitosan 4.43:1,mass ratio of alginate to ?-Polylysine100:8.97,pH5.34,and stirring time 30.38 min.2.microparticles were characterized using techniques such as NANO-ZS,TEM,DSC and FTIR.Transmission electron micrograph showed that ?-PL MPs were well dispersed as a near-spherical shape within the range of 200–400 nm.These results showed that response surface methodology was applicable for the optimization of preparation of ?-PL MPs.3.The antibacterial activity of ?-Poly-lysine microparticles were found through MIC andinhibition zone diameter.As compared to the free ?-PL,the ?-Poly-lysine microparticles formulation exhibited long lasting antibacterial activity in vitro,which can be depended on the synergistic effect of ?-PL and CS-ALG MPs along with slow and sustained release of the loaded ?-PL.4.Compared fresh-cut apples treated with sterile distilled water,fresh-cut apples treated with 1% alginate,1% alginate + ?-PL and 1% alginate + ?-PL MPs,could reduce respiratory rate,weight loss ratio,PPO and POD activity,L* value,and MDA content,inhibit microbial growth,maintain the sensory quality of fresh-cut apples during storage.Fresh-cut apples of1% alginate + ?-PL MPs treatment has the best preservation effect on fresh-cut apples.