Effects of different harvesting period and storage methods on Aiyuan 28 citrus fruit quality

【Objective】To study the effects of different harvesting stages and storage methods on the postharvest storage quality of Aiyuan 28 fruit,so as to provide a reference for the appropriate harvesting and storage of Aiyuan 28 in Chongqing.【Method】Aiyuan 28 fruits from three harvesting date(October 13,October 28 and November 12 in 2019)and two different ventilation storage conditions at normal temperature(20 ℃)and cold storage(4 ℃)were used as the experimental material. Fruit soluble solids,titratable acid,vitamin C,the skin color,firmness,weight loss rate,decay rate,postharvest diseases infection situation and other indicators were determined for comprehensive evaluation by principal component analysis and fuzzy membership function method.【Result】The results showed that L value of Aiyuan 28 fruit was decreased gradually with the increasing of maturity,but the fruit color did not change significantly during storage. The L value at harvesting period Ⅰ(October 13)was 62.71±2.67,and the L value at harvesting period Ⅲ(November 12)was56.87±4.28. The value of a/b increased through harvesting period delaying,but there was no significant change in the value of a/b during storage. The value of a/b at harvesting period Ⅰ was 0.51,that at harvesting period Ⅱ(October 28)was0.60,and that at harvesting period Ⅲ was 0.61. In the process of storage,fruit weight loss rate and decay rate of different harvesting periods under both storage methods increased gradually,the rate in ventilated cold storage was lower than that under normal temperature storage. The total weight loss rate was 12.62% under cold storage at harvesting period Ⅰ and33.57% under normal temperature storage at harvesting period Ⅲ. Diseases and total disease fruit rate on fruits picked in harvesting periodⅠwas less. Under different harvesting periods and storage methods,the fruit firmness increased first and then decreased,the fruit skin firmness was higher under storage at normal temperature,but the sarcocarp firmness was less. The content of titratable acid(TA)decreased gradually,but there were no stably changing pattern in the content of soluble solid and vitamin C. And then 10 fruit major quality indexes at 15,30,45 and 60 d after storing under different storage methods and under different harvesting periods were used for principal component analysis and membership function analysis respectively. It showed that fruit storage quality of early harvesting was better than that of later harvesting while the effect of ventilated cold storage was significantly better,harvesting periodⅠwith cold storage brought the best storage effect.【Conclusion】Considering the results of principal component analysis and membership function analysis,it is suggested that Aiyuan 28 in Chongqing can be properly harvested and sold in advance to the middle of October or kept fresh under ventilated cold storage soon after harvesting period.