The Changes of Fruit Cell Wall Matter and Hydrolase During Development and Maturation on Navel Orange

This study considered the effect of hydrolysis enzymes on navel oranges(Citrus sinesis(L.) Osbeck).The varieties studied were 'Newhall','Robertson',and 'Fengqi'.The testing samples were collected at each stage of development starting 65 DAA(days after anthesis).The study analyzed fruit quality,texture components,and the enzymes which affect the fruit texture of Pectinmethylesterase(PE),Polygalacturonase(PG),and β-glucosidase.Quantitative analysis of HCl soluble pectin(HP),water soluble pectin(WSP),acid detergent fiber(ADF),neutral detergent fiber(NDF),soluble dietary fiber(SDF),insoluble dietary fiber(IDF),hemicelluloses(HC) and cellulose(CEL) was done with the near-infrared spectroscopy(NIRS) method.The NIRS method that used an optimized model and cross tested with chemical methods achieved a level of precision close to that of chemical methods in the quantitative analysis of fruit texture components of sweet oranges for all the eight targets above.The model was able to accurately predict the dietary fiber in new samples.The investigation of dynamic changes in texture composition and enzyme reactivity by materials three samples from Jing'yan county showed why they had greatly different textural character when were tasted: the contents of all items above varied significantly.The Newhall' variety had fewer taste residues for lower CEL than the other two varieties.However,SDF and WSP were higher.During the fruit development and maturation,the change in textural components for Newhall' was greater as well.Enzyme reactivity for PE,PG,and β-glucosidase was stronger and had larger range for 'Newhall' than for 'Robertson' and 'Fengqi'.The key hydrolysis enzymes affecting navel orange texture were PE and PG.The role for β-glucosidase may be complementary to PE and PG.