关键词: 聚乙烯, 保鲜, 呼吸作用, 菠菜, 乙烯-醋酸乙烯共聚物, 分子筛

Abstract: Molecular sieve was introduced into blends of polyethylene/ethylene-co-vinyl acetate (PE/EVA), based on which composite blown film was prepared as packaging film for fresh spinach. The tensile strength, elongation at break, and tearing strength of the film were examined. The sensory evaluation for the fresh-keeping effect of the film was also made. The effect of content of molecular sieve on the weight loss, fraction of soluble solids, and respiration rate of spinach were examined. At ambient conditions, with increasing content of molecular sieve the air permeation of the film increased, and the respiration rate of spinach was increasingly restrained. When, the content of molecular sieve was 7.5 %, an equilibrium concentration of O2 8.7 %~9.3 % and CO2 7.2 %~7.7 % in the package was obtained.

Key words: polyethylene, fresh-keeping, respiration, spinach, ethylene-vinyl acetate copolymer, molecular sieve