Effects Of EBR On Physiology And Storage Quality Of Capsicum Postharvest

In this test,four pepper varieties ‘hui jiao 7’,‘hui jiao 8’,‘hui jiao 18’ and ‘hao nong 11’ were used as experimental materials.Firstly,2,4-epibrassinosteroids(EBR)solutions of 1μM,10μM,20μM and 30μM were used at(4±1℃)and 70%-80%relative water content(RH)respectively.The fruits were stored at(25±1℃)and70%-80% relative moisture content(RH),and the weight loss rate,decay rate and chilling damage index of the fruits were determined.According to above index,the optimal treatment combination of(4±1℃)+20μM brassinolactone(EBR)was selected.Then,four varieties of pepper were stored under four conditions:(4±1℃)+20μM brassinolide(EBR),(4±1℃),(25±1℃)+20μM brassinolide(EBR)and(25±1℃),and some physiological and quality changes of pepper fruits were measured during storage.The results were as follows:1.Under the condition of 25℃ or 4℃,20μM EBR solution compared to several other concentration of solution can effectively reduce the chili decay rate and the weightlessness rate at the end of the storage.Under 4℃,the storage weightlessness rate and the decay rate reached 3.69% and 26.71% respectively by 20μM EBR treatment in‘huijiao7’pepper,while the weightlessness rate and rotting rate were5.46% and 44.99% under 25℃respectively.The weight loss rate and decay rate under25℃ by EBR treatments were higher than that under 4℃.Compared with 25℃,the cold damage index of pepper fruits treated with 20 u M/L EBR is significantly lower than that of other pepper varieties treated with other concentrations.2.At the end of storage,the vitamin C content of pepper treated with ‘huijiao7’varied significantly.The maximum content was 30.05mg/100 g under 4℃+EBR,while the minimum value was 19.3mg/100 g under 25℃,which were decreased by18.15mg/100 g and 28.90mg/100 g respectively.3.Under the four treatment conditions of the four varieties,the total phenol content on the whole showed a trend of rising first and then falling.the rise range in four varieties was the lowest under 4℃+EBR treatment,with the minimum of0.45mg/100 g and the maximum of 2.74mg/100 g under the control condition of 25℃.The total antioxidant capacity of pepper under 4℃+EBR showed a decreasing trend.4.The chlorophyll content of pepper decreased rapidly under the two conditions of25℃+ EBR and 25℃,while the chlorophyll content decreased slowly under the two conditions of 4℃ and 4℃+EBR.After 21 days of storage,only 0.07mg/g of pepper treated at 25℃ for ‘huijiao18’,and 0.45mg/g at 4℃+EBR for‘huijiao7’,were respectively 7.95% and 70.31% of the initial values.Carotenoids generally showed an increasing trend,and the pepper treated with 4℃+EBR rose slowly.5.the carbohydrates treated by 4℃+EBR decreased slowly,while those treated at4℃,25℃+EBR and 25℃ decreased rapidly.Sucrose content decreased slowly in the storage process,while fructose decreased rapidly.6.The soluble protein content showed a decreasing trend during storage,but the decreasing trend of several treatments was not significant.The soluble protein content of several varieties of pepper treated with 4℃+EBR decreased slightly.The free amino acids gradually increased,and the pepper of huijiao no.8 variety increased and then decreased in the later storage period.7.The polygalacturonase activity increased and then decreased during storage,and the turning point occurred around 15 d.Malondialdehyde content varied greatly during storage,and ‘huijiao7’ showed a most extent.After 21 days of storage,malondialdehyde content in 4℃+EBR,4℃,25℃+EBR,and 25℃ treatments waere3μmol/g FW,3.48μmol/g FW,3.58μmol/g FW,and 4.46μmol/g FW,respectively,about 2.4 times,2.78 times,2.86 times,and 3.56 times to their initial value.In conclusion: this experiment studied the changes of physiological indexes and nutrient quality of different varieties of pepper during storage after brassinolide treatment,and concluded that 4℃+EBR treatment could effectively reduce the loss of nutrients during storage and prolong the shelf life of pepper.The mechanism of quality change of pepper was further studied to provide some theoretical support for postharvest storage of pepper.