This study investigated the effect of mixed culture fermentations with non-Saccharomyces strains and Saccharomyces cerevisiae on the aroma quality of ‘Cabernet Sauvignon’ wine from the eastern foothill of Helan Mountain in Ningxia in order to determine the optimum inoculation scheme for mixed culture fermentation. Three non-Saccharomyces strains were tested, including Hanseniaspora uvarum YUN268, Pichia fermentans Z9Y-3 and Pichia kluyveri C735. The proportions of mixed cultures were 10:1 and 1:1 between non-Saccharomyces and S. cerevisiae.Two inoculation schemes were used, namely sequential (48 hours apart) and simultaneous inoculation. Inoculation with S. cerevisiae alone was used as a control. The physicochemical and aroma properties of the resultant wine samples were evaluated. The results showed that compared with the control group, the mixed culture fermentation treatments increased the glycerol yield by 0.38–1.11 g/L and reduced the alcohol content by 0.33%–1.9%. In addition to ensuring successful completion of alcoholic fermentation, simultaneous inoculation of P. fermentans Z9Y-3 and S. cerevisiae at a mixing ratio of 10:1 significantly increase the dry extract content by 23.6% and the glycerol content by 4.6%. Moreover, this inoculation scheme maximized the ability of the two strains to produce aroma compounds, significantly increasing the contents of 30 different aroma compounds, including linalool, β-damascenone, ethyl octanoate, phenethyl acetate, methyl decanoate, isoamyl octanoate increasing the total amountof volatile compounds by 45%, and enhancing the berry-like, tropical fruit-like, floral and nutty aroma of wine. Therefore, this mixed culture fermentation scheme can be used as an ideal one for the production of ‘Cabernet Sauvignon’ wine in the eastern foothill of Helan Mountain.

To clarify the quality characteristics of natural dry red wine from the Eastern Foothill of Helan Mountain, the physicochemical indexes, flavor substances and sensory profile of naturally fermented ‘Merlot’ dry red wines produced at three different regions in the Eastern Foothill of Helan Mountain were analyzed. The results showed that there was no significant difference in the basic oenological parameters such as alcohol content, residual sugar, dry extract, total acid, or pH between the naturally fermented wine and that prepared by the traditional process, while the former had lower contents of glycerol and malic acid and higher amounts of volatile acids and lactic acid. The concentrations of total phenols, tannins and anthocyanins were relatively lower in the naturally fermented wine, and the chroma and red hue were weaker, whereas the yellow hue and hue angle were not significantly different from those of the traditional one. The total amount of aroma compounds and the contents of esters of medium- and short-chain fatty acids in the natural wine were lower than those in the traditional one, while the proportions of higher alcohols, long-chain fatty acid esters with more than ten carbon atoms and phenols were slightly higher in the natural wine. Moreover, clustering analysis on aromatic components clearly distinguished the natural wine from the traditional one. In terms of olfactory properties, the chroma of the natural wine was slightly weaker, but no significant difference in taste was found. Despite having weaker fruity aroma, the natural wine had morecomplex flavors such as almond-like, pepper-like and vanilla-like aromas and had a higher overall score. In summary, the natural dry red wine has more prominent sensory quality and a unique style.

Challenges arise in global viticulture due to low temperatures. To ensure the sustainable and high-quality development of the wine industry, it is essential to breed wine grape varieties that are not only of high quality but also possess cold hardiness. Intraspecific recurrent selection in Vitis vinifera can enhance cold hardiness while maintaining fruit quality. In this study, we used ‘Ecolly ’as an intermediary grape variety for crossing with ‘Cabernet Sauvignon’, ‘Marselan’, and ‘Dunkelfelder’, including three reciprocal crosses and a total of 1,657 intraspecific hybrids. We characterized the cold hardiness of these intraspecific hybrids and analyzed the genetic aspects of cold hardiness, ultimately identifying excellent strains with cold hardiness. Parameters like mean high-temperature exotherm (mHTE), mean low-temperature exotherm (mLTE), bound/free water ratio, water loss ratio in vitro, frost damage grades, and overall performance displayed partially normal distributions. In intraspecific hybrids, there was a maternal advantage in traits related to bound/free water ratio and water loss ratio. Some hybrid populations exhibited values for mHTE, mLTE, and water loss ratio that were lower than the low parent's values, while bound/free water ratio showed values higher than the high parent's values. Among the 1,657 intraspecific hybrids, 52 strains could bud under stress at −18 ℃, and seven of these strains excelled in three important cold hardiness measures. Our study revealed that cold hardiness in V. vinifera is influenced by multiple genes and is a quantitative trait. Intraspecific hybridization can produce a small number of superior strains with enhanced cold hardiness.