Studies On The Deterioration Mechanism And Regulation Technology Of Postharvest Wampee

1.Wampee(Clausena lansium(Lour.)Skeels)is a sweet and delicious fruit,which with unique flavor,high nutritional value and medicinal value,and it is a popular and special fruit.The wampee fruit is mainly planted in southern and southwest of China,which is a non-climacteric fruit.After postharvest 2-3 d will lose edible value,which mainly postharvest problems contain water loss,browning,softening,cracking and disease,greatly affecting the storage and transportation of wampee.In this study,'Yongmi'and 'Dajixin'wampee was used as the experimental material,to investigate the effect of different storage temperature,UV-C,different kinds of acid and the comprehensive treatments on the storage quality of wampee fruit,in order to solve the problem of postharvest wampee,to extend and maintain the production quality,and provide a theoretical basis for wampee during the storage and transportation.The results of the study are as follows:1.Study on effect of different storage temperatures(0 ?,3 ?,5 ?,8 ?,12 ?,20 ?,28 ?)on the postharvest quality of 'Yongmi' and 'Dajixin' wampee fruit.The results showed that the suitable temperature(3-5 ?)storage can stay slow weight loss and browning index,delay the increase total soluble solids(Total Soluble,Solid,TSS),titratable acid(Total Acid,TA)and vitamin C(Vitamin C,Vc)degradation,and could inhibit the increase in malondialdehyde(Malondialdehyde,MDA)content,to keep the fruit storage quality.In the process of storage,' Yongmi' is more easily loss water and browning,at 5 ? storage temperature in 10 d,'Yongmi' and 'Dajixin'wampee fruit weight loss rate were 10.62,8.48%,the browning index were 2.1,1.6 respectively,.2.study on effect of physical preservation technology—UV-C irradiation treatments(0.6 kJ/m2,1.1 kJ/m2,1.7 kJ/m2,2.3 kJ/m2)on the postharvest physiology and antioxidation quality of ' Dajixin ' wampee fruit.The results showed that:compared with the control(CK),ultraviolet irradiation treatments can keep the better physiological quality of wampee,slow down the total phenol and flavonoid content degradation,delay the peak of polyphenol oxidase(Polyphenol decomposition,delayed Oxidase,PPO),superoxide dismutase(Superoxide Dismutase,SOD),chitinase(Chitinase,CHT)and ?-1,3 glucanase(?-1,3-Glucanase,GLU)activity remained at a high level,and the 1.1 kJ/m2 ultraviolet irradiation treatment is the best.3.Study on effect of green chemical preservative technology——organic acid treatment(0.3 g/L salicylic acid,0.5 g/L oxalic acid,50 mM ascorbic acid,100 mg/L gibberellic acid)on the postharvest physiology and antioxidation quality of 'Dajixin'wampee fruit.The results show that the wampee fruit storage to 10 d,VC content of CK,0.5 g/L oxalic acid,0.3 g/L salicylic acid,50 mM ascorbic acid and 100 mg/L gibberellic acid treatments were 21.50 mg/100g,24.50 mg/100g,24.67 mg/100g,23.34 mg/100g and 20.99 mg/100g,0.5 g/L oxalic acid and 0.3 g/L salicylic acid treatments were significantly higher than other treatments(p<0.05).The TSS content of 0.5 g/L oxalic acid,0.3 g/L salicylic acid,50 mM ascorbic acid treatments were decreased slowly at the end of storage,and decreased to the minimum 17.6%,17.9%,17.6%.The TSS content of CK and 100 mg/L gibberellic acid treatments were decreased faster,the TSS content were 17.18%and 16.55%at the end of storage,and the difference between treatment was poor.Different significance(p<0.05).Compared with the control,oxalic acid and salicylic acid have very good suppression of postharvest fruit ripening of wampee.Synthetically,0.3 g/L salicylic acid treatment was the best,and the 0.5 g/L oxalic acid treatment was the second.4.Study on comprehensive control technology(0.8 g/L oxalic acid+PE fresh-keeping film,1.5%chitosan+PE fresh-keeping film,1.1 kJ/J/m2 ultraviolet radiation+PE fresh-keeping film)on the postharvest physiology and antioxidation quality of 'Dajixin' wampee fruit.The results show that the wampee fruit storage to 14 d,total phenol content of 0.8 g/L oxalic acid,1.5%chitosan and 1.1 kJ/m2UV-C with packaging were higher than CK 1.82 mg/g,1.46 ?g/g and 2.15 mg/g,and significantly higher than other treatments(P<0.05).There are different effects on the comprehensive treatment of wampee,compared with CK,1.1 kJ/m2 UV-C treatment could delay the increase of weight loss rate and browning index,TSS,TA and control the degradation of VC,maintain the total phenol content,SOD and POD activity at a high level,inhibiting the activity of PPO growth.The second is 0.8 g/L oxalic acid and 1.5%chitosan effect.