Effects Of Production Period Control On The Quality Of 'Guipu No.3' Grape And Wine

Wine quality is basically determined by the quality of the material:wine grape.Meteorological factor plays a very important role in affecting the quality of wine grape.In this study,the grape of 'Guipu No.3' was used as the material,and three different pruning dates August 15th,August 30th,and September 5th were set as treatments.The abundant temperature and light resources in Guangxi enabled us to regulate different production cycles through the year.This study aims to analyze the quality of grapes growing in different periods and the wine,as well as their relationship with meteorological factors,in order to find the most suitable growing period for wine grape production in Guangxi province.Comprehensive analysis of the climate advantages of wine grape development in Guangxi would provide a theoretical basis for the development of local wine grape planting and wine industry.The results of the study are as follows:(1)The treatment pruning at August 30th was better than that on August 15th and September 5th among three pruning date treatments of 'Guuipu No.3' grapes,of which the basic physical and chemical indicators such as the total sugar content,the titratable acid content and sugar-acid ratio was better for wine making than the others.(2)There were 45,49 and 40 volatile aroma components identified in 'Guipu No.3'grapes in three pruning date treatments August 15th,August 30th,and September 5th respectively.Most of the identified volatile aroma components were esters,which relative content accounted for 67.92%,63.25%and 65.43%of the total volatile aroma components of the grape fruit in three pruning date treatments respectively.The second highest relative content for the pruning treatment in August 15th was alcohols which was 21.68%.However,for the pruning treatments in August 30th and September 5th,the relative second highest content was aldehydes,which were 22.14%and 21.86%respectively.In addition,a few aldehydes,ketones and organic acids were identified in the grapes of three treatments.(3)The indexes of the wine of 'Guipu No.3' of the treatments of pruning at August 30th and August 15th met all the national standard requirements for dry white wine.(4)There were 56,60 and 63 volatile aroma components identified in the wine of 'Guipu No.3' grapes in three pruning date treatments August 15th,August 30th,and September 5th respectively.Most of the identified volatile aroma components were esters.The total content of aroma components in the treatments of pruning at August 30th reached 9019.09 ug/L,which was significantly higher than that of 7762.48 ug/L in August 15th and 8092.10 ug/L in September 5th.Among three pruning date treatments,esters were the most volatile compounds identified in 'Guipu No.3' wine with the content of 6442.00-7085.47 ug/L,followed by alcohols of 486.88-987.09 ug/L and organic acids of 682.34-798.75 ug/L.The content of identified aldehydes,ketones and other substances were less than 50 ug/L,respectively.(5)Among three pruning date treatments,the treatment of pruning at August 30th performed best grape and wine quality,which could be associated with least precipitation,longest sunshine duration,largest daily diurnal range and highest accumulative temperature during the whole fruit growth period and especially from bagging to harvest,comparing with the other two treatments.