## 1 Introduction  
The wine volatile profile consists of numerous aromatic components derived from grapes, wine fermentation and aging. It contributes greatly to the flavor features of wine [1]. Accumulation of volatile compounds in grapes greatly influences wine aroma quality, which is determined by the varietal characteristics of grapes and can also be altered by environmental conditions, vineyard management practices and berry maturity [2, 3]. Grapes can contribute aromatic compounds in free or bound forms to wines, which involve monoterpens, C13-norisoprenoids, C6 compounds and methoxypyrazines (MPs) [4, 5, 6]. The free aromatic compounds in the berry can be directly transferred into the wine during the winemaking process, while the bound forms, mainly glycosidic precursors, can be converted into volatile compounds during the winemaking process through enzymatic hydrolysis or acid hydrolysis to contribute to the wine aroma [7, 8, 9]. Grape maturity can be followed using various indicators, e.g., sugars, pH, tartaric acid, sugars/acids ratio, phenolic compounds, seed tannins, berry detachment and aroma. Aroma maturity is a decisive factor in determining the flavor quality of wine. Since the aromatic compounds and their precursors in grapes are synthesizing continuously during berry development, the varietal aromatic components accumulate differently at diversified maturity stages [10, 11]. It has been discovered that the maturity of the berry affects the content of monoterpens, alcohols, aldehydes, etc. The content of monoterpens in the berry starts to increase after fruit set, decreases near the veraison and then starts to accumulate again and increases as the berry ripens and sugar accumulates; the content of alcohols in the berry also maintains an increasing trend during the ripening process after veraison, while aldehydes show a constant decrease in content [12; 13]. During ripening, aroma glycosides also accumulate, and the content of aroma glycosides increase from veraison and reach a peak at ripening time, but decrease during the over-ripening of the grapes [8; 14; 15]. In addition, IBMP is an aroma compound that is highly correlated with berry maturity because it usually brings green pepper and grass to the wine and has a very low sensory threshold of 10 ng/L [16; 17]. IBMP in grapes is synthesized and accumulates before veraison, and its level decreases continuously during the subsequent ripening process [18]. Although many studies have revealed the changes of aroma compounds during grape ripening, the influence of different regions and grape varieties on the accumulation of volatile compounds in grapes cannot be neglected. Ningxia Helan Mountain's east foothill is located between the alluvial plain of the Yellow River and the alluvial fan of the Helan Mountains in Ningxia, China, at 37\({}^{\circ}\)-39\({}^{\circ}\) N and 105\({}^{\circ}\)-106\({}^{\circ}\) E. With the advantages of abundant sunshine, heat, low precipitation and a large temperature difference between day and night, it has become one of the largest wine-producing regions in China [19]. The majority of wine grape varieties grown in the Ningxia region are _Vitis vinifera_ L. cv, which were introduced from Europe. _Vitis vinifera_ L. cv Cabernet Sauvignon, Cabernet Gernischet, Cabernet Franc and Merlot are the most planted red wine grape varieties in this region. Cabernet Gernischet (_Vitis vinifera_ L.) is a wine grape variety widely cultivated in China, although it is very rare in other producing areas in the world. Although several vineyards and wineries have been initiated in the Ningxia region, no information on the evolution of their volatile profiles during grape ripening has been reported. Improving the aromatic quality of wine by determining the best harvest time and winemaking strategies (macceration and blending) remains challenging.