The Research Of Edible Coatings For The Fresh-keeping Of Agrocybe Aegerita

Agrocybe aegerita is an edible mushroom which is nutritious and good for health. It is difficult to be kept fresh under normal conditions during long-distance transport and store due to color browning, cap opening, water loss, body lignification and even deterioration and rottenness. Nowadays, more methods of fresh-keeping for mushroom such as cold storage, frozen storage, ozone processing, modified atmosphere storage, irradiation treatment, chemical preservation, storage by plant hormones and edible film coating storage are studied. Each of them has certain advantages and disadvantages which limit its use. Especially the preservation technology has been very little applied for health and safety in the place of origin and a little investment company.The advantages and disadvantages of different fresh-keeping methods of mushroom were analyzed in the paper. Edible film storage was thought to be a method which is suitable for applying in producing area with large-scale, and also a safe, high-efficient, low-cost method. At present, this method for the fresh-keeping of Agrocybe aegerita was rare reported. Therefore, the edible coatings for the fresh-keeping of Agrocybe aegerita were studied in this dissertation, so as to provide a simple technological solution for the fresh-keeping of Agrocybe aegerita in the producing area. Research results are as follows:1. Both nisin and natamycin are effectively able to relay spoilage, but their contribution to reduce water loss is slight. The films containing konjac glucomannan or carrageenin not only protect the food from losing water, but also relay spoilage. Also, the films containing glycerol or sucrose ester have the two functions abovementioned.2. The formula of coating film for the fresh-keeping of Agrocybe aegerita were 0.2% konjac glucomannan, 0.2% carrageenin, 1.0% glycerol, 0.5% sucrose ester and 0.1% nisin, 0.05% natamycin. After coating such a film, the Agrocybe aegerita packaged in polyethylene bags could be kept fresh for about three weeks.3. The bamboo juice or bamboo leaves juice have preservative effects. 0.2% konjac glucomannan, 0.2% carrageenin, 1.0% glycerol, 0.5% sucrose ester added with the bamboo juice or bamboo leaves juice were used as the coating film for the storage of Agrocybe aegerita. After coating such a film, the Agrocybe aegerita packaged in polyethylene bags could be kept fresh for about two weeks. Meanwhile, the Agrocybe aegerita coated with such a film had the fresh smell of bamboo.4. The bamboo juice or bamboo leaves juice was applied to film for preservation. It was found that 100% bamboo juice and bamboo leaves juice can inhibit the growth of bacteria from Agrocybe aegerita. But their inhibit effect was less than the combination of nisin and natamycin.