Study On The Vidal Noble Rot Characteristics In East Foothill Of Helan Mountain Of Ningxia

The research aims to study whether the Vidal noble rot characteristics will be naturally developed in grapes by regularly checking and testing the maturing process of Vidal Blanc grapes grown at the East foothill of Helan Mountain in Ningxia.Experimental techniques of moisturizing cultivation and tissue separation adopted in the research,the experiment is conducted on the maturing black-brown grapes to identify the main microorganism's type that causes the fruit to shrink and wrinkle into the color of black-brown and to explore the physical and chemical indexes changes as well as the sensory changes trough comparing the wrinkled ones with normal grape fruit.After harvest,the aroma in fruit juice were identified by solid phase microextraction-gas chromatography-mass spectrometer(SPME-GC-MS),and brewing is made in small containers.After the brewed wine became stable,the conventional physical and chemical indicators are analyzed,the sensory character analysis were described and evaluated by a professional tasting group.The aroma in the wine is analyzed for qualitative characteristics by SPME-GC-MS.The results show:1.Blanc fruit loses water and shrinks without artificial invention,and produces strong aroma with the sensory characteristics of noble rot.In addition,compared with normal fruit,100 berries weigh less,and 100 berries volume of the black fruit are smaller with higher sugar content,and lower juice yield.2.Microbiological means such as isolation by dilution method and tissue separation adopted in the experiment,main internal strains of black fruit is identified as Botrytis cinerea.Observed with light-microscope,the shallow infection is only kept at the epidermis which corresponds to the characteristics of noble rot.Some of the Vidal grape could form noble rot in natural condition of Eastern of Helan Mountain and the main microbe was Botrytis cinerea.3.Made with the same brewing processes,the sample of noble rot wine performs well:the color is golden,the aroma is elegant,with a flavor of caramel and honey,so the wine has typical characteristics of noble rot which follows the national standards.Through SPME-GC-MS,it shows that volatile substances proportion of wine in black fruit is higher and the fragrance of black fruit juice or wine is stronger than that of ordinary ones.