Effect Of Pulsed Electric Field On Postharvest Physiology And Quality Of Cherry Tomato

Pulsed electric field has a electromagnetic biological effects on organism,which can induce the organism make a stress response and regulate the internal physiological and biochemical secondary metabolism as well as ripening and senescence.Our study focused on the effect of pulsed electric field on mature green cherry tomato,a typical climacteric fruit,and chosed the reversible PEF conditions by evaluating the changes of respiration intensity,endogenous ethylene release quantity and hardness.Another batch of mature green cherry tomato was treated by the selected beneficial PEF conditions,and the changes on active oxygen metabolism,antioxidant capacity and the firmness related indicators(pectin,cellulose,pectinase,cellulase)of mature green cherry tomato was measured toexplore the probable mechanism of PEF on ripening and senescence of mature green cherry tomato.The results showed that:1.Different PEF treatment by pulsed intensity(1,2,5 kV/cm),pulse duty ratio(0,24.5,48.8%),pulsed frequency(10.3,20.6,30.5 kHz)and treating time(5,10,20 min)could delay the appearance of respiration peak and ethylene peakof cherry tomato during storage,but had a threshold effect on fiemness.The storage properties were improved by PEF treatment with the parameter of 1 kV/cm,48.8%,30.5 kHz and 5 min.2.The activity of SOD and POD of cherry tomaro were increased after PEF treatment,no significant effect on CAT was founded,and the activity peak of SOD appeared 4d in advance compared to control.PEF inhibited the production rate of O2-and MDA of cherry tomato during storage.3.Reversible PEF treatment increased the accumulation of total phenol,DPPH scaving ability and FRAP value of cherry timato during the storage.Irreversible PEF increased the accumulation of total phenol of cherry tomato(0d),but reduced DPPH scaving ability and FRAP value of cherry timato at medium storage(12d).4.Reversible PEF could slow down the resolve of protopectin,while irreversible PEF speeded up the resolve of protopectin.No influence of the activity of pectinase,cellulose and cellulose was founed.Above all,there was a threshold of pulsed electric field treatment on cherry tomato,PEF could induce a positivesecondary metabolism to cherry tomato,and improved the storage properties of cherry tomatoes,which indicated that PEF was a promising technology to extend the storage life of cherry tomato.