| Walnut originally derives from the west of Asia, and has been widely cultivated in the world. At present, china's walnut industry is quite in the increasingly growing stage, with the cultivated area and yield per year both ranking first all over the world. Due to its high content of protein and oil that can be easily absorbed by human body, so the health care function of walnut is obviously superior to other oil crops. However, in the past walnut was often dried to storage, sale and be processed further. But in recent years, fresh walnut, without drying and being sold only with removing its green husk, is become more and more popular among the public because its good taste, more excellently healthy care function, etc. But the storage period of fresh walnut is very short, and it easily occur with deterioration, such as the decomposition of green husk, the oxidation and rancidity of kernel oil and so on. It greatly affects the improvement of the storage life of fresh walnut and the preservation of storage quality.The paper chose "xiang-ling" and "liaohe-4" walnut strain as the raw materials: ?through determining the exterior morphology of the fresh walnut fruit and the changing regularity of nutrients in fresh walnut fruit kernel, this paper aims at identifying the opium harvest period for the purpose of storage. ? making three kinds of raw stuff including fresh walnut with green husk, fresh walnut without green husk, and fresh walnut kernel as experimental materials, this paper compared the difference in storage characteristics of three experimental materials under the condition of temperature 0?1 ? and RH 80%?90%. ? adopting three kinds of antistaling agents, referring tol-MCP, Na2S2O6, TBZ, fresh walnut with green husk were processed according to appropriate usage method and dosage respectively. The paper winnowed the most effective attistaling agent. ? making fresh walnut with green husk as experimental materials, the paper respectively using 1-MCP combining with vacuum package,1-MCP combining with modified atmosphere, and using 1-MCP regularly reprocessing combining with modified atmosphere process materials, meanwhile making the fresh walnut without any process as the contrast. Through determining significantly physiological indexes of kernel in all different groups. Besides, the browning index of green husk in different treats was also calculated and appearance of different treatment walnut was taken photos too. Finally, after storage 120 d the author evaluated the storage quality of fresh walnut fruit in appearance, kernel taste, flavor respectively. The result shows that:(1) From starting in august, the various nutrients rapidly gather in kernel and reach its peak in first ten days of September. Thus the harvest period of fresh walnut for the purpose of storage can be determined in range from 5th September to 10th September.(2) Fresh walnut with green husk can effectively prohibit the browning of green peel, the loss of kernel moisture, and the deterioration in kernel oil. So, fresh walnut with green husk is the best material for preservation.(3) 1-MCP shows its optimum effect on prohibiting the peel browning of fresh walnut, and the loss of the kernel moisture, further keeping the fresh quality of kernel.(4) during the storage the kernel peel in each group occurs with browning, and the ratio of browning is related to O2 concentration:the lower O2 concentration is, the slighter kernel peel browning is.(5) through adopting the method that 1-MCP treatment respectively combining with modified atmosphere storage to preserve fresh walnut with green husk, after 120 d the marketable fruit rate of fresh walnut with green husk is 60%, fresh walnut with peeling green husk 95%, and sensory value is also good.(6) The basic process of preserving fresh walnut is that:during the period of 5th September to 10th September when the color of walnut peel turn green to brown-green but green husk is not rupture, the fresh walnut should be harvested with carpopodium for keep the fruit walnut from mechanical damage; then the materials should be put in refrigerator to be pre-cooled at 4 ? for 48 h; putting materials and the a bit wet small paper bags inside with 1-MCP at the dose of 0.1 g/m~3 into LDPE plastic bags together, then seal the bag; after, putting bags at the condition of temperature 0?1 ?and RH80%?90% to storage, and reprocess materials again as above procedure every 20 d; after storage 120 d, the browning index of husk is only 0.42, and storage quality is good as well. |
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