Effect of Power Ultrasound Treatment on Free and Glycosidically-Bound Volatile Compounds and the Sensorial Profile of Red Wines.

This study presents the effect of the application of high-power ultrasound to crushed grapes, at a winery-scale, on the content of varietal volatile compounds (free and glycosidically-bound) in musts and on the overall aroma of wines. Two different frequencies (20 kHz and 28 kHz) were tested and the combination of grape sonication and different maceration times on wine aroma was also evaluated. The volatile compounds were isolated by solid phase extraction and analyzed by gas chromatography-mass spectrometry, carrying out a sensory evaluation of wines by quantitative descriptive analysis. Sonication produced an increase in the concentration of free varietal compounds such as C6 alcohols, terpenes and norisoprenoids in musts and also in wines made by 48 h of skin maceration, being less efficient in the extraction of the bound fraction. Fermentation compounds were also positively affected by ultrasound treatment, although this effect was variable depending on the frequency used, the maceration time and the type of compound. All the wines made from sonicated grapes had better scores in the evaluated olfactory attributes with respect to the control wines. Our results indicate that sonication could produce an increase in the content of some volatile compounds of sensory relevance, obtaining wines with an aroma quality similar or higher than those elaborated with longer maceration times.

Mango by-products as a natural source of valuable odor-active compounds.

BACKGROUND: The aromatic potential of mango by-products was evaluated to seek natural and cheap sources of odor-active compounds. Volatile compounds in mango peel and seed were chemically characterized and compared with those in mango pulp using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME/GC-MS). RESULTS: More than 60 volatile compounds were detected in mango by-products, whose aromatic activity was estimated using odorant activity values (OAVs). The results indicated that mango peel was a valuable matrix of odor-active compounds, which were found in even larger quantities than in edible mango fractions. 3-Carene was the predominant compound, although other compounds such as decanal, 1-octen-3-one, nonanal, limonene, ß-damascenone, and 2-nonenal were the most odor-active compounds in mango peel. The greatest aromatic impact was obtained from mango peel, with sensorial features described as fresh / herbaceous, fruity, floral and resinous. CONCLUSION: The exceptional flavoring potential of mango peel by-product opens a door for its use and revalorization as a natural flavoring ingredient in the food and cosmetic industries. © 2020 Society of Chemical Industry.