微孔保鲜膜在蔬菜包装上的应用研究

发布时间：2018-03-31 05:10

  本文选题：自发气调包装　切入点：微孔包装　出处：《天津科技大学》2015年硕士论文

【摘要】：目前,对于果蔬贮藏保鲜来说,国内外使用最普遍的方法是气调包装。然而,不同果蔬对气体浓度的要求存在差异性,普通保鲜膜包装难以为果蔬提供适宜的气体条件,但微孔保鲜膜因其可控的透气性和较宽的二氧化碳／氧气透气系数比而广泛受到人们的关注。本文主要研究微孔膜的透气特性,提出果蔬微孔包装参数的理论设计和实验筛选方法,在此基础上研究微孔包装对三种常见果蔬的自发气调保鲜效果。详细研究内容如下：(1)孔边缘效应对微孔透气性的影响。设计一简易微孔包装装置,并以二氧化碳为实验气体,对微孔包装内随时间变化的二氧化碳浓度进行实际测定和动态变化规律的理论分析。结果表明,微孔包装内气体浓度的理论值远小于实际测定值,对此差异采用了孔末端效应进行分析,并提出激光制备微孔条件下的孔有效长度矫正公式。(2)微孔包装理论设计和微孔包装参数的实验筛选方法。根据孔有效长度矫正公式,提出了微孔包装设计的基本方程和针对特定果蔬的孔参数确定方法。针对该理论的局限性,提出微孔包装参数两步实验筛选法。(3)三种果蔬生菜、油麦菜和芹菜的微孔包装应用研究。根据微孔包装参数两步实验筛选法,以三种蔬菜为研究对象,采用不同数量微孔的PE保鲜袋对其进行包装,于0℃下贮藏70天,通过定期检测袋内的氧气和二氧化碳浓度、失重率、可溶性固形物含量、Vc含量、叶绿素含量、丙二醛含量、乙醇含量以及感官品质等指标,得出三种蔬菜的微孔包装参数和保鲜期。(4)不同微孔包装对三种果蔬的保鲜效果。研究表明,在50μm厚的PE保鲜袋(45×50 cm)上制备1、3、6和50个孔径为0.18mm的微孔,对生菜的保鲜效果最佳,保鲜期可达50天；在50μm厚的PE保鲜袋(40×65 cm)上制备1、3和6个微孔,贮藏50天油麦菜均具有良好的保鲜效果；20～30μm厚的PE袋(30×95 cm)能为芹菜提供较为合适的气体条件,而微孔包装对芹菜保鲜的优势并不明显,但采用PE50膜50孔包装,芹菜可保鲜40～55天。
[Abstract]:At present, the most common method used in the storage and preservation of fruits and vegetables at home and abroad is the modified atmosphere packaging. However, the requirements of different fruits and vegetables for gas concentration are different, so it is difficult to provide suitable gas conditions for fruits and vegetables by ordinary film packaging. However, due to its controllable permeability and wide carbon dioxide / oxygen permeability ratio, the microporous film has attracted much attention. The theoretical design and experimental screening method for packaging parameters of fruit and vegetable micropores were proposed. On this basis, the effects of microporous packaging on the spontaneous controlled atmosphere preservation of three common fruits and vegetables were studied. The effects of pore edge effect on the permeability of micropores were studied in detail. A simple microporous packaging device was designed, and carbon dioxide was used as experimental gas. The theoretical measurement and dynamic change of carbon dioxide concentration in microporous packaging with time were carried out. The results showed that the theoretical value of gas concentration in microporous packaging was much smaller than that measured in practice. This difference is analyzed by using the hole end effect, and the theoretical design of the effective length correction formula of the hole under the condition of laser fabrication of the micropore and the experimental screening method of the parameters of the micropore packaging are put forward, according to the correction formula of the effective length of the hole. The basic equation of microporous packaging design and the method of determining pore parameters for specific fruits and vegetables were put forward. In view of the limitations of the theory, a two-step experimental screening method of micropore packaging parameters was proposed for three kinds of fruits and vegetables lettuce. The application of microporous packaging of oatmeal and celery was studied. According to the two-step experimental screening method of microporous packaging parameters, three kinds of vegetables were packed with different quantities of PE preservative bags, and stored at 0 鈩，

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