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For a long time, China's fruit and vegetable production is more emphasis on cultivation techniques before picking, while ignoring postpartum keeping storage. China's annual loss rate in the storage and transportation process fruits and vegetables as much as 20% to 30% of the total value of the loss of nearly 80 billion yuan, while in developed countries, the loss rate of only 1.7% to 5.0%, showing that our preservation technology to be solved and improvements. Currently used in fruit and vegetable preservation, plastic wrap and plastic film, but it has its own shortcomings, not only can not be natural degradation, and bring a range of security risks to human health. Faced with this reality, people are constantly developed and launched a paper-based packaging products and biodegradable plastic material, want to be able to replace the plastic cling film because of its high cost, the price is expensive, but the end did not get a lot of promotion. Therefore, a plastic excellent performance, easy to be biodegradable, fresh material, no threat to the health of people and the cost has been a long-term research priorities and hotspots. People found that the polysaccharide film has easily biodegradable, performance, environmental health, etc., is a good substitute for plastic cling film, increasing attention has been concerned about. In this study, the choice of konjac glucomannan (Konjac glucomannan, KGM) acrylamide (Acrylamide) for materials, select the compound modified material developed konjac glucomannan / acrylamide modified membrane, tensile strength, The elongation at break of the mechanical properties of the film evaluation, explore the the KGM / acrylamide mass ratio, glycerin volume of pH, reaction time, concentration of potassium permanganate different factors modified membrane properties of konjac glucomannan / acrylamide the impact, determine the optimum conditions of the modified film formation, and provide a reference for key technologies and parameters of the film-forming process; modified membrane prepared in the the citrus storage and preservation of the actual application effect The study results are as follows: a film made of a purified konjac glucomannan flour compared with the unpurified powder film made of high tensile strength, thickness, elongation at break , bright color. This is related to the increase in the hydrogen bond interaction force and the konjac glucomannan intermolecular purified. Preliminary experiments also showed that the purified konjac glucomannan, film, film tension, water solubility, viscosity than unpurified konjac glucomannan were all improved, which is purified removed konjac glucomannan results of the sugar surface non-GLUCOMANNAN's ingredients. 2 konjac glucomannan acrylamide combined performance of the film than konjac glucomannan single film has greatly improved, the mass ratio of KGM / acrylamide, glycerin volume, pH, reaction time, concentration of potassium permanganate of membrane anti-tensile strength, elongation at break of a certain degree of performance impact. Orthogonal test analysis of the factors affecting the membrane performance, and the system was modified membrane comprehensive analysis and evaluation, and analysis to determine the optimum conditions of the film can be obtained from the results of the orthogonal experiment the optimal film process conditions, the quality of KGM / acrylamide ratio of 1:1, the amount of 0.45 mL of glycerol, pH 9.5, reaction time 1h, potassium permanganate concentration of 1.0 × 10-3 mol · L-1, 3 the KGM modified membrane is used to LuGan Preservation and use of the unmodified KGM as control membrane, to observe the practical effect of KGM modified membrane. The results show that: the modified film treatment can effectively reduce the physiological activity of citrus during storage, the biofilm membrane permeability can regulate membrane inside and outside the gas exchange, avoid citrus anaerobic respiration. During storage, the modified membrane can significantly reduce the loss of nutrients in citrus weight loss rate and respiration intensity, Vc, total acid can be maintained at a lower level. The rot was 10% in terms of the relative blank group, the modified membrane to the citrus last Languo rate control below 4%, with good preservation effect. POD activity was a significant inhibition of PPO film processing, citrus peel, the effective mitigation pericarp browning. The blank group citrus peel PPO, POD activity increased faster browning of the skin color is more serious. In the first 60 days, the blank group PPO activity than the first day increased 22.8%, POD activity increased by 51.7%, the decay rate also in this period of time is a significant increase in the incidence rate of the citrus. Relatively blank group, film processing of citrus PPO, POD activity of relatively gentle, the control membrane treatment citrus PPO activity in 60 days than an increase of 9% from the first day, POD activity increased 37.9%, the modified membrane treatment citrus PPO activity in 60 days than the first day only increased by 4.5%, POD activity increased by 25.5%. Thus, the modified film processing LuGan PPO, POD, growth is relatively small, its PPO, the POD activity of being a better inhibition, reducing the degree of browning of the citrus during storage, slowing the LuGan own generating The browning amount of the radical product, control LuGan premature browning. After film processing LuGan, SOD activity decreased throughout the storage period is small, basically able to maintain a relatively stable level. While the blank group LuGan SOD activity first soon rise, and then a sharp decline, especially in the first 40 days to 60 days, a surge in decline, more than 22%. After film processing citrus SOD activity was greatly inhibited, reducing the amount of citrus own browning and aging radical products, reducing the rate of browning of citrus during storage, The incidence of rot rate, significantly improve the appearance of citrus quality. Of KGM modified membrane with the control film in the effect of the preservation of citrus much better than that of the blank group, but the overall effect of the KGM modified membrane is superior to the unmodified control film showed that the combination of KGM and acrylamide can be optimized KGM The performance of the film and practical effect. Especially in fruit disease resistance, reduce fruit decay rate and reduce the effect of the use of the fruit during breathing strength of KGM modified membrane is significantly better than the control film, is the ideal substitute of plastic cling film, its potential commercial value and The economic benefits are substantial, broad application prospects.
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