Studies On Mechanism Of Ethanol Accumulation And Prediction Models For Fruit Decay Of Strawberry And Chinese Bayberry

In this paper, freshly harvested strawberries (Fragaria ananassa Duch cv. FengXiang and Fragaria ananassa Duch cv. HongYan) and Chinese bayberries (Myrica rubra sieb.et Zucc. Cv. Wumei) was used to investigate the mechanism of ethanol accumulation and the relationship between ethanol content and fruit decay. The strawberries and Chinese bayberries were inoculated with pathogens to corrigenda to parameter values of the prediction model for decay index based on ethanol content for different varieties, cultivars and harvest dates fruits. The significant analysis for the model parameters (slopes and intercepts) of the different prediction models showed the effects of cultivars and harvest dates on the prediction models. This article lays the more comprehensive foundation for monitoring of quality of strawberry and Chinese bayberry fruits during circulate. The results were as follows:1. The mechanisms of ethanol accumulation of the "FengXiang" cultivar and "HongYan" cultivar were investigated. The results showed that the content of the ethanol of the strawberry rose during the storage time while the fruit decay increased. The content of pyruvate acid increased first and then decreased, which was higher in the "FengXiang" cultivar than in the "HongYan" cultivar of the same level treatment. The activities of PDC and ADH increased at the early storage time and then decreased, these enzyme activities were higher in inoculated group than the control group of the same cultivar strawberries and lower in "HongYan" cultivar than "FengXiang" cultivar of the same level treatment. The results suggested that the accumulation of pyruvate acid and enhancement of PDC and ADH activities were considered to be the reasons of ethanol accumulation of the harvest strawberry fruit, the abilities of ethanol accumulation were different in strawberry because of the cultivars.2. The liner prediction models for decay index of different picking time "FengXiang" cultivar and "HongYan" cultivar based on ethanol content were developed by the determinations of decay index and ethanol content of the model’s parameter tuning groups. The significant analysis for the model parameters (slopes and intercepts) of the different prediction models showed that the model parameters of "FengXiang" cultivar and "HongYan" cultivar were significantly different, while there were no profound differences between the model parameters of various picking time of the same cultivar strawberries. It was implied that the prediction models were affected by fruit cultivar not the picking time. The prediction models for decay index were verified with the control groups and the relative prediction errors between the predicted and measured values were found to be8.82%,4.72%,14.64%and10.35%, respectively. These results suggested that the decay index of the "FengXiang" cultivar and "HongYan" cultivar may be accurately predicted based on ethanol content.3. The mechanism of ethanol accumulation of the Chinese bayberry "WuZhong" was investigated and the liner prediction model for decay index based on ethanol content were developed by the determinations of decay index and ethanol content of the model’s parameter tuning groups. The results showed that, the content of the ethanol of the Chinese bayberry rose during the storage time while the fruit decay increased and showed the positive relationship with the fruit decay. The content of pyruvate acid increased first and then decreased during the storagetime, while the activities of PDC and ADH increased at the early storage time and then decreased slowly. The results suggested that the accumulation of pyruvate acid and enhancement of PDC and ADH activities were considered to be the reasons of ethanol accumulation of the harvest Chinese bayberry fruit. The liner prediction model for decay index of Chinese bayberry fruit based on ethanol content was developed by the determinations of decay index and ethanol content of the model’s parameter tuning group. The prediction model for decay index was verified with the control group and the relative prediction error between the predicted and measured value was found to be9.92%, the result showed that the prediction was acceptable. The model’s parameter of Chinese bayberry "WuZhong" was significantly different compared with strawberry "FengXiang" cultivar and "HongYan" cultivar, so the parameters of the prediction models for decay index were significantly different between strawberry and Chinese bayberry.