Study On The Effect Of Ripening And Senescence Of Kiwifruit Treated By Microwave

Actinidia deliciosa cv. Hayward and Actinidia deliciosa cv. Wancui was chosen as experimental materials. The position and quantities that the kiwifruit put, and the microwave processing time and power output were studied. Then the two kinds of kiwifruit were processed by microwave(30 W、120 W、210 W、300 W、390 W) 60 s with the temperature of kiwifruits under 50 ℃,and the untreated kiwifruit was served as the control group.The kiwifruits were packaged with PE bags and storaged in the refrigeratory with the temperature (1 ± 0.5) ℃, humidity 95%. Regularly detect the change of the storage quality,such as the respiratory rate, hardness and reducing sugar content, titratable acid content and ascorbic acid (Vc) content, total soluble solids (TSS) content. Also regular detection of the change of enzymatic activity of superoxide dismutase (SOD), peroxidase (POD) and lipoxygenase (LOX), pectin enzyme (PG) and so on. The change of the index of cell membrane permeability, weightlessness rate and good fruit rate were also regular tested. At last, the different influence of the two kinds of kiwifruit respiratory physiology, storage quality and enzyme activity were discussed in order to investigate the influence of microwave treatment on kiwifruit mature aging mechanism.The full text main conclusions are as follow:(1) The change trend overall of respiratory physiology were similar between the two kinds of microwave processing kiwifruit during storage, first rose then fell.120 W/60 s microwave treatment group could significantly inhibit the respiratory rate of the two kinds of kiwifruit, and 120 W/60 s treatment group also could put off the appearance of respiration peak of Wancui kiwifruit.(2) There were similarities and differences between the influence of microwave treatment on the two kinds of kiwifruit.120 W/60 s treatment group could significantly inhibit the hardness of Hayward and Wancui. Significant inhibited the increase of reducing sugar and soluble solid content. It also could keep titratable acid content and Vc content, and made the two kinds of kiwifruit keep good storage quality. However, the 390W/60s treatment group had a significant damaged effect on Vc content of Hayward, which reduced its nutritional value.(3) The influence of microwave treatment on the enzyme activity of the two kinds of kiwifruit also had similarities and differences. There were no significant difference between the microwave processing group and the control group.120 W/60 s of the microwave treatment could significantly inhibit the rise of the LOX enzyme activity and PG enzyme activity, and inhibit the decreased of POD enzyme activity. And 390 W/60 s treatment group of the POD enzyme activity of Hayward,30 W/60 s,300 W/60 s and 390 W/60 s treatment group of the POD enzyme activity of Wancui were all had a significant inhibitory effect.(4) Microwave treatment group of 120 W/60 s could significantly inhibit the relative electrical conductivity of Hayward and Wancui. And the weightlessness rate were 0.95% and 1.20% respectively when 140d, and good fruit rate reached 75% and 75% respectively. Effectively delayed the mature and senescence of the two kinds of kiwifruit, prolonged the storage period.(5) Low power (120 W/60 s) microwave processing could delay the mature of the kiwifruit senescence, prolong the shelf life of the kiwifruit by influencing the kiwifruit respiration physiological (breathing intensity), storage quality (hardness, reducing sugar, total soluble solids, titratable acid, Vc), and enzyme physiological (POD, PG, LOX). While the high power microwave processing hastened the mature of kiwifruit.