自发气调薄膜对荷兰豆保鲜的影响

Effects of Spontaneous Air Conditioning Film on Freshness Preservation of Snow Peas

目的研究PLLA/PLLA-PEG-PLLA(PLGL)自发气调共混薄膜对采后荷兰豆贮藏品质的影响,以期达到适宜的透气比,来延长荷兰豆的保鲜期。方法以市场上的荷兰豆为实验材料,分别用PLLA/PLGL10,PLLA/PLGL20,PLLA/PLGL30,PLLA,PE这5种薄膜来包装荷兰豆,观测荷兰豆在(4±1)℃下贮藏24 d过程中气体、色差值、叶绿素含量、丙二醛含量、质量损失率的变化。结果材料为PLLA/PLGL30的薄膜最适用于荷兰豆的保鲜包装,其具有良好的力学性能,断裂伸长率高达175.3%,并且有效提高了O_(2),CO_(2)的气体选择透过性和透过比,使得CO_(2)/O_(2)选择透过比由2.9提高到6.1。在贮藏第24天时,袋内气体组成为O_(2)体积分数2.8%、CO_(2)体积分数5%,有效延缓了叶绿素含量和质量损失率的下降,减少了丙二醛的积累,延长了荷兰豆的贮藏期。结论共混薄膜处理较单独的PLLA薄膜和市场PE薄膜更环保,对荷兰豆的保鲜效果更好。

The work aims to analyze the effect of spontaneous air-conditioned blend films PLLA/PLLA-PEG-PLLA(PLGL) on storage quality of postharvest snow peas and obtain the appropriate air permeability ratio to extend the fresh-keeping period of snow peas. The snow peas from the market were taken as testing materials. The five types of films including PLLA/PLGL10, PLLA/PLGL20, PLLA/PLGL30, PLLA, and PE were used to pack the snow peas to observe the changes of gas, color difference values, chlorophyll content, malondialdehyde content, and weight loss rate during 24 days of the storage of peas at(4±1)℃. The results showed that the film made of PLLA/PLGL 30 was the most suitable package for fresh-keeping peas which showed good mechanical properties. The elongation at break was as high as 175.3%. And it improved the selective permeability ratio of O_(2) and CO_(2) from 2.9 to 6.1. At the 24 th day of storage, the concentration in the bag consisted of 2.8% O_(2) and 5% CO_(2), which effectively delayed the decline of chlorophyll content and weight loss rate, reduced the accumulation of malondialdehyde, and extended the storage period of snow peas. The blended film processing is more environmentally friendly than PLLA film and PE film on the market, and possesses better preservation effect on snow peas.