Studies On Technology And Preservation Mechanism Of Modified Atmosphere Package And High CO₂ Under Controlled Freezing Point For Grape

The Kyoho grapes (Vitis vinifera L.×V.labrusca L.) were stored in three preservation films and four high concentration (5%,10%,15%,20%) CO2 under controlled freezing point. Sensory quality, senescence, softening and storage effect of grape during storage were systematically studied and changes of grape texture during storage were also evaluated by using texure profile analysis(TPA).The main obtained results were as follows.Respiration rate and weight loss of grape were evidently inhibited and contents of TSS, TA, RS and stem chlorophyll were maintained in Modified atmosphere package (MAP) under controlled freezing point. Senescence of grape was alleviated by reducing cotents of O2-· and so on. Rate of pectin degradation was also declined by reducing PG and Cx activity. In a word, storage effect of PVC-Ⅰ film was best, the next was PVC-Ⅱ film and the last was PE film.Compared to MAP, respiration rate and weight loss of grape were more effectively restrained and maintenance of TSS, TA, RS content was different in four high concentration CO2. Browing extent of stem was also different and stems of grape in 10% and 15%CO2 were greener than those in 5% and 20%CO2. Alleviating senescence of grape in 10% and 15%CO2 was the best, the next was 5%CO2 and the worse was 20%CO2. Rising rate of restraining PG and Cx activity of grape in Four high CO2 was better than those in MAP and softening of grapes in 10% and 15%CO2 that were helpful to prolong the preservation time were more effectively inhibited than those in 5%and 20%CO2. However, Grapes in 5%CO2 tasted best and grapes in 10% and 15%CO2 tasted better than those in 20%CO2 which had made the flavour of grapes badly change.TPA test showed that texture of grapes gradually turned worse. But compared to MAP, high CO2 were more helpful to maintain hardness, springiness, cohesiveness, chewiness and resilience of grape during storage. Descending trend of texture parameters of grape were more effectively restrained in 10% and 15%CO2 than did in 5% and 20%CO2. With the storage time went by, good fruit rate, hardness and chewiness of grape had similar changing rule. So good fruit rate could be used to construct regression model to predict the hardness or chewiness of grape. Then a simple evaluation method could be provided for Kyoho grape during storage by using the correlation of good fruit rate and hardness or chewiness of grape.Verification test showed that in contrast to CK, descending trend of gapes hardness was effectively alleviated in 10% and 15%CO2. Berry drop and decay of grapes were evidently decreased and green character of grapes stem was better kept. Storability of grapes was also promoted and the grapes were preserved this time twenty days more than those in 2009. On basis of these, It was proved that it was suitable for Kyoho grape to store in such a kind of atmosphere circumstence 5%≤O2+10%-15%CO2 and Kyoho grape was the species which could tolerate high CO2.