Potential of chitosan films immobilized with carboxylesterase on cucumber and grape preservation in post-harvest and degradation of carbamate and organophosphorus pesticides

摘要

Introduction -Much attention has been recently drawn to improve the shelf life of fresh fruits and vegetables by using biodegradable and edible film coatings. In addition, the minimization of hazardous pesticides in these products was recently established with the immobilization of pesticide-degradable enzymes into the coating film because of a public awareness of the health risks posed by pesticide residues in fruits and vegetables. Materials and methods -The present study reports the property of novel complexes of biopolymer chitosan/ starch film-forming materials on the preservation quality of cucumber and grape fruits and degradation of carbamate and organophosphorus insecticides with immobilized pesticide-degradable enzyme (carboxylesterase, CbE) during cold storage. Principal component analysis (PCA) was performed on the data matrices consisting of two types of fruits and different sorts of parameters. The residues of tested insecticides were extracted from fruit samples using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) technique at different time intervals of cold storage. Results and discussion -The fruit quality parameters after 21 d of cold storage indicated that the chitosan coatings decreased the weight loss, total soluble solids (TSS), catalase, guaiacol peroxidase (G-POD), and polyphenol oxidase (PPO) compared to the control. However, the treatments increased the total soluble phenolics compared to the uncoated fruits. The PCA analysis reported that two (unrotated) significant principal components (PCs) explained more than 73% of the total variance in the data. The plots of component loadings showed significant groupings for tested parameters in fruits. The chitosan film-forming formulations degraded or chelated some residues of the insecticides however, the disappearance of the insecticides was increased with the formulations having CbE. The pesticides determination carried out by HPLC showed recoveries of these residues over 72%. Conclusion -These formulations could be used in coating of fresh fruits and vegetables containing low concentrations of organophosphorus and carbamate pesticides.