Effects of Different Storage Treatments on Physicochemical Indexes of Green Plums

[Objectives]This study was conducted to discuss the change laws and relationships of the physiological indexes in green plums treated with nisin or 1-MCP in the cold storage process.[Methods]Different storage methods on the physiological and quality indexes of green plums were investigated through two kinds of different treatment methods(treatment 1:1-MCP+cold storage,treatment 2:nisin+cold storage),with rotten fruit rate,weight loss rate,yellow ripeness index,hardness,Vc content,titratable acid,soluble solids and peroxidase(POD)activity as the evaluation indexes.[Results]The storage method of treating green plums with 1-MCP combined with cold storage could delay the quality decline of green plums after harvest,while the effect of nisin treatment was slightly inferior.1-MCP treatment followed by cold storage could more effectively delay the senescence of green plums,delay the decrease of fruit hardness and soluble solid content to the greatest extent,and maintain the titratable acid and Vc contents at relatively good levels.It further reduced weight loss rate and rotten fruit rate,postponed the time of the peak of POD enzyme activity,and reduced the loss of nutrients in the fruit,thereby maintaining good commercial properties of the fruit.[Conclusions]This study plays an important role in the post-harvest storage,preservation and transportation,as well as the development of the green plum industry.

QSPR Analysis of the Physicochemical Properties for Phthalic Acid Esters

Based on quantitative structure-property relationship （QSPR） of organic compounds, the molecular connectivity indices of 21 phthalic acid ester compounds were extracted. Relationship between the physicochemical properties （n-octanol/air partition coefficient, vapor pressure, water solubility） and the molecular connectivity indices of phthalic acid ester compounds have been established by multiple linear regression （MLR） method. The results showed that the zero-order valence connectivity index （0Xu） is the topology parameter which affects octanol/water partition coefficient and water solubility, and the topology parameter which affects vapor pressure is the first-order connectivity index （1X）. This indicated to a certain extent_that the molecular connectivity indices can be well used to express the quantitative relationship between the physicochemical properties and structure descriptions of phthalic acid ester compounds. The models constructed have good robustness and highly predictive capability.