Effect Of Storage Temperature And Packaging On Postharvest Physiology And Quality Of Blueberries

Blueberries (Vaccinium spp.) are a member of the heath family (Ericaceae). They are known for their colorful appearance, delicious taste and nutritional value. Blueberries are rich in antioxidant substances with high health benefit to human, therefore, they are popular with good economical prospects. However, blueberries are harvested during hot raining season which makes it easy for this soft juicy fruit to lose water and rot and then lose their market values. Storage in low temperature with modified atmosphere packaging can significantly delay the aging process of the fruit and inhibit the growth and invasion of the microbes, thus extending shelf life in various fruits and vegetables. However, little information is available on the use of this technology on the blueberries. Using blueberry cultivars planted in zhejiang province as test materials, this study investigated the effect of storage temperature and packaging method on blueberry postharvest storage quality and antioxidant properties. The results are as follows:(1) Storage in low temperature with modified atmosphere packaging can significantly extend the life of blueberries. During the35days storage, the quality of the rabbiteye blueberries produced from Anji were better than southern highbush blueberries produced from Xinchang. After14days of storage, the decay rates were21%for ’Nan yuan’ fruit,20%for ’Nanhao’ fruit, and30.5%for ’Nanjin’ fruit. Some of these fruit were soft and rotten obviously lost the commercial value. Rabbiteye blueberries produced from Anji maintained more than90%good fruit after storage for35days. Among them,’Canlan’fruit could maintain high firmness, TSS and TA content and good storage quality.(2) There were significant influence of the storage temperature on physiological and biochemical changes in PE packaged blueberries. The storage temperatures were set at0±0.5℃、5±.5℃.10±0.5℃and20±0.5℃, and all were packed in PE film. Storage in low temperature can effectively maintain fruit quality, slow down the decrease of firmness, sugars and acids. Low temperature can effectively delay the accumulation of reactive oxygen species (ROS) free radicals and reduce the degree of membrane lipid peroxidation, and maintain the integrity of the membrane system better. Higher temperature can obviously promote the increase of the antioxidant anthocyanins and total phenol, promote the increases of SOD, CAT, POD and other antioxidant enzyme activities, but the fruit quality declined greatly in the later part of the storage. Lower storage temperature can maintain blueberry antioxidant activity effectively, and can prolong the berries storage period. Therefore,0±0.5℃is an optimum storage temperature for PE packaging of blueberries.(3) Packaging methods had a certain influence on postharvest physiology and biochemistry of postharvest blueberry when stored in low storage temperature. Perforated PE film packaging and non-perforated PE film packaging both could effectively prevent the water loss, maintain the firmness and fruit quality, but the beneficial effect of non-perforated PE film packaging was significantly better than that of perforated PE film packaging. During storage, both perforated and non-perforated PE packaging effectively reduced the accumulation of O2"and H2O2and decreased MDA content. Perforated and non-perforated PE packaging have certain effect on restraining the rise of antioxidant enzyme activity and oxidation material content and delaying its peak. Comprehensive experimental results showed that the effectiveness of different packaging methods for maintaining blueberry quality was in following order:non-perforated PE film> perforated PE film>non-packaging. In5±0.5℃storage conditions, non-perforated film packaging was the most appropriate packaging method for blueberry stored for42days.