The Research Of Effect For KGM Film On Storage And Preservation Of The "Zhonghua" Kiwi Fruit

Currently what is used traditionally in the preservation of fresh fruits and vegetables is still the plastic film, which is not biodegradable and bad for people's health, food safety as well as the protection of the environment. To solve such problems, a technology about paper packaging products was developed, which couldn't be popularized because of the high cost and the poor efficiency. It's necessary to look for a kind of fresh keeping material to take the place of paper packaging products. It should be biodegradable and edible and it should have a high quality as plastic. This has become a focus in the relevant researching field. Natural polymer film, which can be easily degraded by microorganisms, has an excellent performance. It is regarded as a good substitute of plastic film, and attracts much more attention from the people engaged in food industry. For it is biodegradable, the characteristic of it meets the requirements of the modern times, which means green, healthy, and benefitial to the environmental protection. Used as a material in this research, Konjac glucomannan (KGM) is considered one of the best natural biodegradable polymer materials. It has generally accepted advantages such as low cost, good biodegradability, better environmental performance and excellent film properties. Molecules of KGM contain a large number of the hydroxyl acetyl groups which can be modified. It can be rationally developed and widely used in food packaging, preservation of fruits and vegetables, as well as the field of edible packaging materials. This technology has very broad prospects. In this study, KGM is used in the storage and preservation of Chinese kiwi. The process and results of relevant experiments about kiwi fruit's quality and its ability of anti aging and softening are as follows:1. Based on its structure characteristics and its such advantages as good ability of film forming, biological compatibility and biodegradability, KGM is made into a new type of edible polymeric film, which is used in the storage, transportation and preservation of Kiwi fruit. An experiment on the film's effects to the quality of Kiwi fruit during the period of preservation and storage has been done. By the means of the selection of kiwi fruit, preparation of experimental materials, analysis and comparison of experimental data, the results has been gotten by the experiments: Preserved by KGM film, the respiratory rate of the fruit as well as that of the ethylene release has been effectively supressed, without a ethylene peak during the experiments; as for the keeping of high fruit quality, KGM film can effectively lower the descending rates of the fruit hardness, VC content and the fruit weightlessness. In that case the storage time of the kiwi fruit can be extened, which keeps the nutrition and quality of it for a longer time.There are some disadvantages, too. The rising rate of soluble solids content of Kiwi fruit is restrained from being preserved by KGM film, while the degradation rate of the content of titratable acid descends, which leads to bad effects to the quality of tasting because of the low level of fruit ripening, the hardness of pulp and a sour taste. 2. In view of the Kiwi fruit's strong climacteric, we coat the fruit with KGM film. And we have made experiments to get differences of biochemical indexes between control group and groups of KGM, and made a further analysis of data to draw a corresponding conclusion. It can be found that KGM coating can not only effectively inhibit the growing of negative factors such as MDA, activated LOX, activated PG and activated amylase in the fruit, but also keeps activated POD and SOD in a higher level. In addition, it's able to inhibit the morbidity of Kiwi fruit. All the advantages are showed as delaying the softeness and rottenness of Kiwi fruit, extending the storage time and keeping high nutrition of the fruit.