Effects Of Temperature And Spermine On Physiology And Sucrose Metabolism Of Postharvest Vegetable Soybean

Vegetable soybean is prone to senescence and deterioration during storage,which has restricted its consumption seriously.Sucrose,fructose and glucose not only act on variety physiological metabolism processes of the vegetable soybean,but also play an important role in its sweetness and overall flavor quality.This paper detected and analyzed components and content of soluble sugar in different varieties vegetable soybean,and investigated its sucrose metabolism related enzyme activities and changes in quality under different storage temperature.Vegetable soybean treated by exogenous spermine was studied to illuminate its sucrose metabolism and physiological regulation mechanism during refrigerated storage.The results could provide theory foundation and technical support for improving quality of postharvest vegetable soybean.The main results are as follows:1.A method for determination the content of sucrose,fructose and glucose were in vegetable soybean by HPLC was developed.The method was achieved on an Agilent Zorbax carbohydrate column(150mm � 4.6mm,5 ?m),using amobile phase composed of acetonitrile and water(75:25,V/V)at a flow rate of 1.0 mL/min.Column and detector were held at 30 ?,The minimum detection limit was 1?10 ?g.The coefficient of variation was 2.89%?3.47%.The recovery rate was 99.50%?99.75%.The developed calibration curves displayed good linearity in the concentration of 10 mg/mL,with a correlation coefficient exceeding 0.9951.Significant differences of sucrose content were observed in vegetable soybean.It was up to 46.55 mg/g,while the lowest was only 13.73 mg/g.But sucrose content was account for 76.07%?92.51%of total soluble sugar.The average content of fructose and glucose were about 2 mg/g,and no significant difference among the varieties was observed.2.Weight loss rate and decay index increased gradually in vegetable soybean during storage,and VC,anthocyanin,chlorophyll,isoflavones,soluble sugar and sucrose content decreased with the extension of storage time.But cold storage inhibited the metabolism process,delayed its senescence and deterioration.The effect of 1? was better.Sucrose metabolizing enzymes of AI and NI activity showed a first increased and then decreased trend,while cold storage inhibited AI increase,but almost no influence on the activity of NI.SS activity declined rapidly,then rised sharply at 20 ?,but the change was inhibited by the lower temperature.SPS activity decreased gradually during the whole storage,and aggravated with the increase of temperature.3.Chilling injury symptoms was prone to vegetable soybean,and aggravated rapidly with the extension of storage time when storageed at 1?.But exogenous Spm treatment effectively delayed the increase of chilling injury index and cell membrane permeability,and the accumulation of MDA content,promoted the increase in the antioxidant enzymes of APX,CAT,POD and SOD activity effectively,and reduced the vegetable soybean chilling injury,lmmol/L Spm was better.Sucrose loss may lead to the chilling injury occurrence of vegetable soybean.The effects of different concentrations of Spm on NI and SS is not obvious,but 1 mmol/L Spm treatment significantly inhibited the increase of AI activity and the decrease of SPS activity,reduced sucrose loss,which may play an important role in alleviating chilling injury.