Effects Of The Yeast Assimilable Nitrogen On Alcohol Fermentation And Quality Of Wien

Nitrogen is the most abundant soil-derived macronutrient in a grapevine, and plays amajor role in many of the biological functions of both grapevine and microorganisms. Thegrapevine’s nitrogen nutrition has the potential to influence quality components in the grapeand wine. In addition, fermentation kinetics and formation of flavour-active metabolites arealso affected by the nitrogen status of the must.This paper was finished in chateau rongzi, we chose three different vineyards(Tuoyaopo, Dongaobei, Dongaonan),depending on the location.The soil sampling andtesting were done before the harvest. we have done the winemaking experiments of Muscat,Cabernet gernischt, cabernet sauvignon,which from Dongaobei; also cabernet sauvignonfrom Dongaobei and Dongaonan; Besiders,Dongaonan cabernet sauvignon was done ascomparison of adding nitrogen source (NutriSTART).1. According to the datas, the total nitrogen levels of vineyard were less than0.05%,belonged to sixth levels. the nitrogen fertilizer should be considered. Dongaonan showed ahigher total nitrogen and nitrate nitrogen,also the highest phenols in the grape,22.1mg/g.but the YAN was134.56mg/L, not the highest. Tuoyaopo showed the highestammonium nitrogen and YAN,146.31mg/L. the nitrogen level of Dongaobei was thelowest, YAN was136.6mg/L.It showed that the YAN of grapes may mainly related to thecontent of soil ammonium nitrogen.2. The YAN of different varieties in Dongaobei was different: Muscat,90.82mg/L;Cabernet gernischt,117.44mg/L; Cabernet sauvignon,180.32mg/L. The YAN of Cabernetsauvignon in different vineyards were different, Tuoyaopo showed the highest YAN(213.54mg/L). Due to the marceration, all of the YAN were higher than the grapes havested before..Therefore, if you need to add the nitrogen nutrients, the datas based on this time can avoidadding too much.3. Providing the same condition, The fermentation lasted7days. Cabernet gernischtshowed the highest anthocyanins, and Cabernet sauvignon showed the best aroma in wine.TuoYaopo and Dongaonan(nutriSTART) showed the higher alcohols and esters in wine.Esters of each wine mainly for ethyl butyrate, ethyl caproate, octanoic acid ethyl ester, acetic ester, etc. The alcohols chiefly were1-Propanol,2-methyl propyl alcohol,3-methylbutanol,1-Hexanol, phenylethyl alcohol, etc. This conclusion showed that the content ofesters and higher alcohols were directly proportional to the content of YAN.4. Dongaonan Cabernet Sauvignon wine, added the NutriSTART, had more2-methyl-1-propanol,3-methyl-1-butanol, and less propyl alcohol and phenylethyl alcohol. Inaddition, the rate of fermentation increased significantly, and showed more dry extract,organic acids and esters, and better texture of tasting. Therefore, The adding of NutriSTARTin Dongaonan was contribute to alcohol fermentation power and the quality of wine.5. During all of the fermentation,When the density reach to1.050, the wine barelyhave YAN. So if we need to add nitrogen source for yeast, before1.050, it is the right time.