Preservation quality and physiological biochemical characteristics of abscission fruit of grape during cold storage.

【Objective】The changes of qualities and physiological biochemical indexes of abscission fruit during cold storage period were studied in order to provide theoretical references for grape preservation and fresh-keeping.【Method】Kyoho grape,the test material,were stored in freezer at-1-0 ℃.With non-abscission fruit as the control,the qualities and physiological indexes of abscission fruit were determined every thirty days.【Result】The results showed that with the extension of storage period,abscission rate was rising constantly.About 30% of all fruits dropped after 60 days,however,abscission rate reached up to 93.71% after 90 days.Single fruit weight,hardness,water content,Vc and TA(titratable acid) content of abscission fruit were falling constantly,which were lower than those of the control at the same period.TSS(total soluble solid) and TS(total sugar) content rose first and then fell,which were higher than those of the control.MDA(malonaldehyde) content and POD(peroxidase) activity of abscission fruit rose continually.They were higher than those of the control.SOD(superoxide dismutase) activity reduced,which was higher than that of the control.CAT(catalase) activity rose first and then fell.It was higher than that of the control in 30 d,while it was lower in 60 d.PE activity was dropping constantly,which was higher than that of the control.【Conclusion】During cold storage,the qualities of grape abscission fruit declined with physiological biochemical indexes towards aging constantly.Furthermore,there may be existed Vc,TA,TS,MDA content,SOD and POD vitality critical point of the Kyoho grape.When each index was above or below the critical threshold,the grapes started to fall.