Effect Of Ice Temperature Storage On The Quality Of Satsuma Mandarin Fruit

The experiments were carried out by using wase satsuma mandarin at full-ripening stage as main material, in order to systemically study effects of ice temperature storage on fruit quality. Six groups of experiments were designed storage period and shelf period:fruit storage at room temperature (control group), fruit storage at ice temperature with non-treatment, carboxymethyl chitosan, vitamin C, heat shock, and modified atmosphere bag. The change rules of decay rate, pigment, soluble sugar, organic acid, fruit quality variation analysis content, sensory evaluation, volatile substances were analyzed for fruit quality. And the changes of the malondialdehyde(MDA), soluble protein, superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) were evaluated for preliminary mechanism of regulation. The main results are as follows:1. The results showed that the supercooling point of the satsuma mandarin was-6.6℃, freezing point was -3.0℃. Considering refrigerator temperature fluctuate during the heating and cooling, the design temperature range of ice temperature storage was -2.5℃ to 0℃. And different freezing point adjustment methods had little effects on the satsuma mandarin freezing and supercooling point in a short time.2. Satsuma mandarin storage at ice temperature effectively inhibit fruit decay rate in the storage period, and the rates in the experimental groups were between 0.7% and 2.0% during the storage period, and were between 22.0% and 30.7% during the shelf period so that fruit could keep good commodity value, whlie the rate in the control group was 53.3% during the storage period. Exceptionally, Fruit storage at ice temperature with modified atmosphere bag produced large numbers of edema disease during the storage period and shelf period.3. Satsuma mandarin storage at ice temperature effectively inhibitted the degradation of fructose, glucose, citric acid, and had little effects on sucrose, malic acid. Besides, the fruit in the experimental groups stayed delicious initial value of sugar-acid ratio at 15.16, whlie the ratio grown to 20.68 at 90 d after storage in the control group. The fruit in the storage at ice temperature with non-treatment tasted the best, while storage with auxiliary measures tastes poor after storage and shelf stage.4. Satsuma mandarin volatiles was well distinguished in a DFA model generated by E-nose. Changes in the storage time more greatly influenced satsuma mandarin volatiles after harvest than defference of treatments. Time-varying changes in disciplines of peel main volatiles such as D-Limonene、γ-Terpinene in the experimental groups was defferent from that in the control groups identified by GC-MS and former was higher. While pulp main volatiles content in the experimental groups and control groups showed synchronous changes during the storage period, and that in the experimental groups was higher during the shelf period.5. MDA in satsuma mandarin fruit had increased slowly during the storage period, while sharply only in the peel of experimental groups during the shelf period. Compared with the contol, ice temperature storage kept peel soluble protein content increasing, and SOD enzyme activity stable. ice temperature storage kept SOD enzyme activity in the fruit as well as pulp soluble protein content, and stimulated the increasing of peel soluble protein content. POD and CAT enzyme activity of peel had growing levels stored at ice temperature, yet stable POD enzyme activity and CAT enzyme activity in the pulp sample were at all-time low referring to the control.