Charicteristic Study Of Quality Changes During The Apple Ripening

In this thesis, Qinguan and Fuji apples were as experimental material. Resperation rate and ethylene content were quantified to study the rules of apple's basic metabolism; the chlorophyll content,anthocyanidin content,carotenoid content were quantified to study the fruit appearance changing; fruit firmness,cell wall polysaccharides,cell wall degrading -enzyme and relative electric conductivity were quantified to study fruit texture changing; TSS content,organic acid content,ratio of TSS to organic aid content,starch content and amylase activity were quantified to study flavor changing during Qinguan and Fuji apples'ripening so as to know the differences of these indexes between the two apples and the factors answered for the differences. It enriched the basic theories to studying apple quality and provided references for apple's quality improvement. The results showed that:(1) Resperation rate was slightly increased at the benginning of the fruit ripening, kept very low level during the whole mid-ripening and the pinnacle appeared at the full ripe time for both Qinguan and Fuji. Change of ethylene content was similar to the resperation rate and the pinnacles of the two accured at the same date. The differences of resperation rate and the content of ethylene release change between Qinguan and Fuji apples were slight.(2) The chlorophyll content decreased gradually, anthocyanidin content increased at early stage, decreased afterwards, carotenoid content increase all along. Difference of chlorophyll content was the reason of appearance difference between Qinguan and Fuji apples, Qinguan looked dark red, and Fuji looked bright red.(3) The firmness of apple declined during the fruit ripening, especially rapidly at around the harvest time. Factors for the firmness decline were: content decrease of cell wall,cavolantly bound pectin,semi-celluloseII and cellulose; content increase of water soluble pectin and semi-celluloseI; not much changed of ionically bound pectin content; molecular weight all along decline of all the cell wall polysaccharides; went up of PG and PME activities at at early stage, went down afterwards; went up of Cx activity always; and ascend of relative electric conductivity.(4)Changes of Qinguan and Fuji apples'firmness were different, it had its inner reasons. First, the reasons for the firmness change characteristic of Qinguan and Fuji apples were different. Second, some of the cell wall polysaccharide contents had remarkable difference at...