The aroma-active compounds in Chinese bayberry were identified using gas chromatography-olfactometry (GC-O) and GC-mass spectrometry techniques. The volatile compounds were extracted using Liquid-liquid extraction, solvent-assisted flavor evaporation and headspace solid-phase microextraction (HS-SPME), respectively. On the basis of odor intensity, the most important aroma compounds in Chinese bayberry samples were caryophyllene, menthol, 4-terpineol, linalool oxide, linalool, benzyl alcohol, α-methylbenzyl alcohol, β-phenylethanol, 3-methylbutanoic acid and acetic acid, and so on. Moreover, HS-SPME technique was employed to investigate the aroma compounds among immature and mature waxberry fruits. The results showed that terpenes (for example, β-caryophyllene) was predominant and its concentration represented over 89.9% of the overall compounds, and alcohols, aldehydes, ketones, esters, acids, and others were typically present in lesser amounts. Finally, principal component analysis revealed that there was also significant difference between immature and mature waxberry fruits.

Important "floral" aromas naturally occur in grapes predominantly as flavourless glycoconjugate precursors. Since these aroma compounds can be released by hydrolysis, different glycosidase enzymes can potentially contribute different aromas to wines. In this paper, we first established a procedure for profiling the free and bound volatile compounds in grape using GC-MS combined with headspace solid-phase microextraction (HS-SPME). Comparison of the free and bound aroma compounds revealed that non-volatile glycosides, known as aroma precursors, occur in high concentrations in musts. Among all compounds identified, 11 were fully quantified according to established standard calibration curves, while others were semi-quantified. Using three different glycosidase enzymes, a total of 38 bound volatile compounds were identified in Muscat grape, including terpenes, higher alcohols, C-6 compounds, and phenols, among others. The different enzymes had significant effects on the varietal aroma. Principal component analysis indicated that the characteristic aroma hydrolyzed by the commercial enzyme AR2000 was clearly different from that produced by other enzymes.

This study investigated β‐D‐glucosidase activity in the indigenous wine yeast present on grape berries in Yantai in Shandong Province, China. Yeast population profiles from the Yantai production area in China were examined. Among the ten species identified by RFLP analysis of the 5.8S rRNA gene, four exhibited higher β‐glucosidase activity, namely, Hanseniaspora uvarum, Trichosporon asahii, Pichia fermentans and Saccharomyces cerevisiae. The β‐glucosidases from the four representative strains were chosen to hydrolyse the glycosidic precursors of Cabernet Sauvignon. After enzymatic hydrolysis, 31 compounds were identified and quantified, including terpenes, C13‐noriso‐prenoid, C6 compounds, alcohols, aldehydes and volatile phenols. Results showed that different strains exhibited different hydrolytic abilities on the bound aroma precursors. The main variables included C6 compounds, terpenes and alcohols. The concentration of the 14 compounds showed significant differences between enzymatic treatments, with 11 treated using the β‐glucosidase of the F6 strain (T. asahii). These findings may have some applicative value for utilizing the strains or their β‐glucosidases, which are able to complement and optimize wine quality.

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