Carambola Storage At Low Temperature And Research On Technology Of Cold Shock Treatment

Carambola(Averrhoa Carambola L.)is widely favored by consumers in our country because it has rich nutrition and is ideal for those suffered from dry throat,thirst and cough.However,It tend to decay due to its high water content and angulate body.Carambola can only be kept for a week without preservation at room temperature,and it would lose the commercial value at lower storage temperature resulting from the chilling injury.This study mainly investigated the impact of different storage temperature on the quality of carambola,the effect of cold shock treatment to inhibit chilling injury and analyzed the effect of chilling injury on the storage quality of carambola in terms of active oxygen metabolism and antioxidant substance change.The main research contents and results are as follows:1.Effect of different storage temperature on the postharvest quality of carambolaFresh carambola were stored at(3±0.5)?,(5±0.5)?,(7±0.5)? and(9±0.5)? to study the impact of different storage temperature on decay rate,weight-loss ratio,firmness,total soluble solids and other indicators of carambola fruit.The results showed that there was a significant impact of storage temperature on physiological indicators of carambola(P<0.05).The storage temperature of 3? and 5? could effectively inhibit thewater-loss rate,prevent the skin shrinks wilting and delay the consumption of nutrients.However,storing at 3? would cause the chilling injury and delay the ripe of carambola after 20 days.During this period,the peroxidation of cell membrane lipid was found to produce a large number of MDA,which can accelerate fruit rot.It is easy to decay when carambola were respectively stored at 7? and 9? for 25 days and 20 days because of losing the original flavor and high temperature.Therefore,within the experimental temperature range,5? is the optimum storage temperature of carambola and the decay rate is only 3.3%after storing 30 days.2.Effect of cold shock treatment on chilling injury of carambola during the cold storage.Carambola were placed in 0? refrigerator and 0? cold ice water for 6 h,9 h,12 h respectively,while blank group was done without any treatment,then stored at 3?.The results showed that the chilling injury ratio of carambola which using the treatment of 0? refrigerator for 9 h and 0? cold ice water for 6 h were 35%and 30%after storing 25 days.At the same time,the accumulation of free proline and soluble protein was stimulated,the loss of total soluble solids,soluble sugar and ascorbic acid significantly decreased.Therefore,cold shock treatment could effectively reduce the occurrence of chilling injury of carambola,enhance its adaptability to low temperature,and maintain the flavor and nutrients as well.3.Effect of cold shock treatment on the antioxidant ability of carambola.Fresh carambola which were treated with 0? refrigerator for 9 h,0? cold ice water for 6h and the control group were used as materials to study the changes of ascorbic acid content and total phenolics content.The results showed that using cold shock treatment the antioxidants of carambola were effectively kept,the degradation of ascorbic acid were slower,as well as the smaller loss of total phenols and flavonoids at the late period of storage reduced.Therefore,the cold shock treatment played a positive role for maintaining antioxidant capacity of carambola during the period of storage at low temperature.4.The reactive oxygen metabolism of carambola resulting from cold shock treatment.Carambola which were respectively treated with 0? refrigerator for 9h,0? cold ice water for 6h and the control group,were then used as materials to study the effect of cold shock treatment on active oxygen metabolism at 3?.The results showed that cold shock treatment can effectively reduced the accumulation of active oxygen free radicals of carambola during the storage.In addition,cold shock treatment can increased the activity of SOD,CAT,APX,alleviated the chilling injury of carambola and had important implications for further research on preservation technology of carambola.