## 3 Results and Discussions
### Fermentative Aroma Compounds  
The content of fermentative aroma compounds in S-Ew, H-Ew, F-Ew, S/H-Ew, S/F-Ew, H/F-Ew and S/H/F-Ew (338.21-514.14 mg/L) was significantly higher than in SCw (221.66 mg/L). S/H/F-Ew contained the highest aroma compounds (514.14 mg/L) (Table 3). Among the fermentative aroma compounds, the content of benzene derivatives (93.70-136.26 181 mg/L), higher alcohols (188.42-336.42 mg/L) and esters (29.84-48.31 mg/L) in wines with added crude extract of \(\beta\)-glucosidase were higher, compared with those of SCw, but the content of fatty acids and carbonyl compounds showed no significant difference (Figure 3). Although many studies have reported that the addition of \(\beta\)-glucosidase impacted the fermentation aroma, \(\beta\)-glucosidase from different strains affected the fermentation aroma differently [29]. It was shown that \(\beta\)-glucosidaseidase from _H. warrant_ and _Candidia easanensis_ JK8 increased the contents of benzene derivatives in wines [30; 31]. Phenyl ethanol was the most abundant compound in five benzene derivatives, which is one of the aglycons of aroma precursors in grapes and could be released by \(\beta\)-glucosidase [32; 33]. Moreover, phenyl ethanol was the synthetic material for phenylethyl acetate and phenylacetaldehyde generated from phenylalanine by the Strecker degradation pathway, which may be affected by amino acid content and composition in musts [34]. Higher alcohols play a crucial role in wine aroma and could enhance floral and fruity flavor in wines [35]. It was reported that \(\beta\)-glucosidaseidase from _H. warrant_ and _Kloeckera apiculata_ increased the higher alcohol content of wine, especially isoamyl alcohol [2; 36]. However, according to [PERSON] et al. (2020) [10], adding SLY-4E, F2-24E and HX-13E decreased the higher alcohol content. These differences could be attributed to the grape must used in this study containing a high amount of nitrogen. It was confirmed that amino acids could be transformed into higher alcohols via the Ehrlich pathway, and increased nitrogen in musts can result in higher alcohol contents  
Figure 2: PCA of varietal aroma compounds from wines. in wines [37]. Esters present fruity and floral characteristics to wine, contributing to the presence of wine flavor [38]. \(\beta\)-glucosidase from different origins resulted in various levels of increase in the content of esters, showing high strain-dependent variations. Crude \(\beta\)-glucosidase from _Pichia fermentatus_ and _H. warrant_ increased the content of ethyl octanoate, ethyl decanoate and ethyl laurate, which are medium-chain fatty acids esters [9; 30]. On the other hand, \(\beta\)-glucosidase from _Pichia anomala_ could increase the concentrations of ethyl hexanoate and ethyl decanoate [39]. It is possible that the substrate specificity of \(\beta\)-glucosidase varies from the different yeast strains and became more suitable for substrate hydrolysis in the ester formation biosynthetic pathways [40]. These results showed that adding \(\beta\)-glucosidase to wines could change the fermentative aroma profiles by increasing the content of benzene derivatives, higher alcohols and esters. Wines were classified into five groups (Figure 4), which include (i) SCw, (ii) F-Ew, (iii) H/F-Ew, S/H-Ew and S/F-Ew, (iv) S/H/F-Ew, and (v) S-Ew and H-Ew. Hierarchical cluster analysis (HCA) showed that all the detected fermentative aroma compounds were classed into I, II, III and IV. SCw was abundant in Class I, which contained nonanal, 2-methylbutyric acid and isopentanoic acid and presented herb aroma. S-Ew and H-Ew were abundant in Class I and Class IV, which contained phenylacetaldehyde, ethyl heptanoate, 2-methyl-1-butanol and carbonyl compounds (2,3-pentanedione, decanal and 2,4-dimethoxyybenzaldehyde). F-Ew was abundant in Class III and IV, including short- and medium-chain fatty acid esters, acetate esters and carbonyl compounds.