Study On Preharvest Treatment And Preservation Technology Of Kiwifruit

This paper studied preservation technology of preharvest treatment on the“Guichang” kiwi fruit, and the influences of this technology on the qualities of kiwifruit—including soluble solid, vitamin C, taste, amino acid, element composition.The integrated preservation technology of "Guichang" kiwifruit was explored combined with preservatives.Calcium, NNA and chitosan oligosaccharide was choosed to do some further studies, which revealed a very good role in previous studies, by orthogonal test. The effects about those reagents, used before harvest,on postharvest preservation of“Guichang” kiwifruit was studied. The results showed that the best preservation effects on “Guichang” kiwifruit storage is 800 times spraying amount of natural sugar alcohol chelated calcium solution, 30 mg/L NAA and 0.5% oligochitosan every 15 days before harvest.Electronic tongue, amino acid automatic analyzer and SEM-EDX and other equipments were used to study the influences on the qualities of “Guichang” kiwifruit,including the content of soluble solid and vitamin C, taste, amino acid, trace elements.The results showed that the above treatment pre-harvest could affect the qualities of kiwifruit effectively, including delaying the decrease of vitamin C, increasing the varieties and content of amino acids, increasing the content of calcium. After preharvest treatment, kiwifruit contained 7 kinds of essential amino acids with one more than the control groups(threonine). In group D, the pulps of kiwifruit contained more amino acids that control groups with significant increment. The total amount of amino acids was 10082.8 μg/g, including 3174.99 μg/g of essential amino acids. The content of total amino acids and essential amino in control groups were 5425.1 μg/g and 1583.13 μg/g, respectively. The different preharvest treatment had little influences on micronutrient levels, only had some influences on calcium.The best preharvest treatment scheme, namely 800 times of spraying amount ofnatural sugar alcohol chelated calcium liquid +30 mg/L NAA +0.5% chitosan oligosaccharide treatment, then coated with special films postharvest. Every unit containing 100 kiwifruits was preserved in a dried carton with 15 grams of preservative immobilized preserchlorine dioxide, then stored in the fresh-keeping storehouse at 1±0.5℃ with humidity of 85%~95%. The results showed that the rate of intact fruit was 63.3% at 150 days, whereas the intact rates of control groups in refrigeratory decreased to 67% at 60 days. The intact rates could reach to 66.7% when kiwi fruit with preharvest treatment placed in refrigeratory at 120 days. The results demonstrated that comprehensive preservation plan can prolong storage life of“Guichang” kiwifruit.