施氮量对糯和非糯小麦原粮品质、酿酒品质及挥发性风味物质的影响

Effect of nitrogen application rate on grain quality,wine quality and volatile flavor compounds of waxy and no-waxy wheat

为研究不同施氮量对糯和非糯小麦原粮品质及酿酒品质的影响,明确酿酒专用小麦高产优质生产的适宜氮肥用量。于2019、2020连续2年在四川省成都市大邑县,以绵麦902(非糯性)和中科紫糯麦168(糯性)为材料,设置6个施氮量(0、45、90、135、180和225 kg hm^(–2)),分析其对小麦原粮品质、酿酒品质和挥发性风味物质的影响。结果表明:绵麦902产量、粉质率、灰分含量更高;中科紫糯麦168硬度、容重、蛋白质、脂肪含量相对较高,总淀粉和支链淀粉含量更高、直支比更低,除稀澥值比绵麦902高以外,其余RVA特征参数均更低。增加施氮量显著提高小麦产量,两品种产量均在225 kg hm^(–2)达最大值。粉质率和容重随施氮量增加而降低,硬度指数和蛋白质随施氮量增加而升高;脂肪和灰分含量在135 kg hm^(–2)、总淀粉和支链淀粉含量在90~135 kg hm^(–2)内较高,峰值黏度、低谷黏度在135 kg hm^(–2)后显著下降。两品种的出酒率年际间不同,2019年绵麦902的出酒率要显著高于中科紫糯麦168,2020年则相反,推测与2020年灌浆期雨水较多,中科紫糯麦168籽粒硬度指数下降、粉质率上升有关;在90~135kghm^(–2)施氮范围内两品种出酒率相对较高。绵麦902所酿制的白酒总酸、总酯含量不高,杂醇油含量也相对更低;中科紫糯麦168与之相反,但杂醇含量仍在安全范围(≤0.2 g 100 mL^(–1))。两年度绵麦902所酿白酒的总酸含量均在90 kg hm^(–2)处理下最高,2020年中科紫糯麦168的总酸含量则在135 kg hm^(–2)处理下最高。就总酯和杂醇油而言,两品种的总酯含量在135 kg hm^(–2)处理下相对较低,杂醇油含量在90kghm^(–2)下最低。与2019年相比,2020年两品种的总酸、总酯含量显著降低,这可能与该年度籽粒灌浆期降水较多,总淀粉、支链淀粉含量下降有关。中科紫糯麦168挥发性风味物质的种类和数量更多,整体酿酒特性要优于绵麦902。绵麦902的挥发性风味物质数量在90 kg hm^(–2)处理最高,综合评分最高,中科紫糯麦168的挥发性风味物质数量在225 kg hm^(–2)处理最高,综合评分最高。相关性分析和通径分析表明:总淀粉含量和支链淀粉含量与总酸、总酯含量呈极显著正相关关系,大多数淀粉理化指标通过直链淀粉、糊化温度等在总酯形成过程中起正向间接作用。研究认为,小麦出酒率受环境、粉质率影响,淀粉含量、组分、糊化特性对总酸、总酯的形成具有重要影响,酯类物质是挥发性风味物质主要成分,受品种因素影响较大。90~135 kg hm^(–2)施氮量下,糯和非糯小麦淀粉含量、组分和糊化特性较好,酿制白酒挥发性风味物质较多,是适宜酿酒小麦高产优质的适宜施氮量。

In order to study the effects of different nitrogen application rates on the quality of waxy and non-waxy wheat and brewing quality,the suitable nitrogen application rate for high yield and high-quality production of wheat for brewing was determined.Mianmai 902(non-waxy)and Zhongkezinuomai 168(waxy)were used as the experimental materials in Dayi County,Chengdu City,Sichuan Province,in 2019 and 2020.Six nitrogen application rates(0,45,90,135,180,and 225 kg hm^(–2))were set to analyze their effects on the quality of wheat raw grain,brewing quality,and volatile flavor compounds.The results showed that the yield,flour quality rate,and ash content of Mianmai 902 were higher.Zhongkezinuomai 168 had higher hardness,bulk density,protein,and fat content,higher total starch and amylopectin content,lower straight branch ratio,and lower RVA characteristic parameters except that breakdown value was higher than that of Mianmai 902.Increasing nitrogen application rate significantly increased wheat yield,and the yield of both varieties reached the maximum at 225 kg hm^(–2).Silty rate and bulk density decreased with the increase of nitrogen application rate,while hardness index and protein content increased.Fat and ash content were higher in 135 kg hm^(–2),the total starch and amylopectin content were higher in 90–135 kg hm^(–2),peak viscosity and trough viscosity decreased significantly after 135 kg hm^(–2).The wine yield of the two varieties was higher in the range of 90–135 kg hm^(–2) nitrogen application,but the inter-annual difference was different.The wine yield of Mianmai 902 was significantly higher than that of Zhongkezinuomai 168 in 2019,and the opposite was true in 2020.We speculated that it was related to the more rain at filling stage in 2020,the decrease of grain hardness index and the increase of silty rate of Zhongkezinuomai 168.The content of total acid and total ester in liquor brewed by Mianmai 902 was not high,and the content of fusel oil was relatively low.Zhongkezinuomai 168 was the opposite,but the fusel content was still in the safe range(≤0.2 g 100 mL^(–1)).The total acid content of liquor produced by Mianmai 902 was the highest under the treatment of 90 kg hm^(–2) in the two years,and the total acid content of Zhongkezinuomai 168 was the highest under the treatment of 135 kg hm^(–2) in 2020.In terms of total ester and fusel oil,the total ester content of the two varieties was relatively low under 135 kg hm^(–2) treatment,and the fusel oil content was the lowest under 90 kg hm-2 treatment.Compared with 2019,the contents of total acid and total ester of the two varieties decreased significantly in 2020,which may be related to more precipitation at grain filling stage and the decrease of total starch and amylopectin contents.Zhongkezinuomai 168 had more kinds and quantities of volatile flavor substances,and its overall brewing characteristics were better than that of Mianmai 902.The number of volatile flavor compounds of Mianmai 902 was the highest at 90 kg hm^(–2),and the comprehensive score was the highest.The number of volatile flavor compounds of Zhongke Zinuomai 168 was the highest at 225 kg hm^(–2),and the comprehensive score was the highest.Correlation analysis and path analysis showed that total starch content and amylopectin content were significantly positively correlated with the total acid and total ester content.Most starch physicochemical indexes played a positive indirect role in the formation of the total ester through amylose and gelatinization temperature.The results showed that the wine yield of wheat was affected by interannual factors and flour quality rate.Starch content,composition,and gelatinization characteristics had important effects on the formation of total acid and total ester,esters were the main components of volatile flavor substances,greatly affected by variety factors.Under the nitrogen application rate of 90–135 kg hm^(–2),waxy and non-waxy wheat had better starch content,composition and pasting properties,and more volatile flavor substances in liquor-making,which was suitable for high yield and high quality of liquor-making wheat.