| The natural fruits preservatives were recgonized as an main way of the developing of plant-pesticide.The prior research of Research and Development Center of Biorational Pesticide Northwest Agriculture and Forest University indicated that the clove leaf essential oil and cinnamon essential oil had good effect of fresh-keeping. The Dangshan pear was introduced in this paper as target to study the fresh-preparation of the two kinds essential oil,and above this,study the agent producing of the clove leaf essential oil.The main results as follows:1. Under the low temperature and coating method, taking some quality index and physical index as assessment index,screening the good fresh-preparations to Dangshan pear,among them the two compound of 40μL/L clove leaf essential oil with 1%chitosan and 60μL/L cinnamon essential oil with 1%chitosan have good preservation effect.The results of the 40μL/L clove leaf essential oil with 1%chitosan compound is:In the hole storage time,the firmness and Vc content have a lower decline of the 40μL/L clove leaf essential oil with 1%chitosan treatment. On the 30d of the storage, Superoxide dismutase (SOD) activity is increasing 95.61%, Catalase (CAT) and Peroxidase(POD) activity are 2.22 and 4.28 times compared to CK, respectively; Relative electric conductivity and Malondialdehyde(MDA) content is decreasing 28.50% and 39.08% respectively compared to CK, respectively; Respiration peak is decreasing 64.32% compared to CK. The results of the 60μL/L cinnamon essential oil with 1%chitosan compound is:the firmness of the treatment to Dangshan pear is decreasing by 12.95% on the storage of 60d,but the CK is decreasing by 20.33%;On the storage of 40d, Superoxide dismutase (SOD) and Catalase(CAT) activity is 5.17 and 2.23 times to CK,respectively,but the Peroxidase (POD) activity is 2.83 times to CK at the storage of 30d, Soluble solids content(SSC) content is decreasing by 8.00% compared to CK; Respiration peak is decreasing 66.43% compared to CK;At the 60d, Polyphenoloxidase (PPO) activity is decreasing 38.40% compared to CK.2. Through screening the solvents and surfactants,developed out an agent of 4% clove leaf essential oil and chitosan ME:clove leaf essential oil 3%(measured as eugenol 2.55%),chitosan1%,emulsifier is 11%(603#︰JFC=2︰1),solvent 15%( Isopropanol︰Acetone =2︰1),using water complemented to 100%.The quality of the agent is reaching the role of the country standard in pesticide processing.That the qality index contained the transparent temperature range is -5～56℃;the active constituent of clove leaf essential oil and chitosan's resolution ratio is 4.7% and 0.12% respectively after storaged under the tempretur of 54±1℃;under the cold tempreture of 0±2℃,the appearance of the ME is still transparent state.3. Compared 4% clove leaf essential oil and chitosan ME(DZJ) with the preservative ZGP and XBS of pear on sale,the results indicated:DZJ preservative have the best preservation effect among the treatment,which can significantly resistant firmness decrease,hold on a high level of storage period,and can increase protection enzymes activity. At the begaining of the storage,all the treatments have the good effect,but in the later time, the treatment of DZJ01 has the best effect.Finally,summarized the using technique of the preservation:putting the immature fruits to pre-cooling in cold storage under the tempreture of 10℃,then,spraying the fruits with 50x liquid medicine and getting out in natural ventilation to air drying,finally,using the PE bags to seal storage.This using technique can keep the storage period for 7 month and maintain the fruit surface brilliant and gloss. |
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