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Syrah grape skin valorisation using ultrasound‐assisted extraction: Phenolic compounds recovery, antioxidant capacity and phenolic profile

Mazza, Karen E. L., Santiago, Manuela C. P. A., do Nascimento, Luzimar S. M., Godoy, Ronoel L. O., Souza, Erika F., Brígida, Ana Iraidy S., Borguini, Renata G., Tonon, Renata V.
International journal of food science & technology 2019 v.54 no.3 pp. 641-650
anthocyanins, antioxidant activity, citric acid, grapes, phenolic acids, ultrasonic treatment
The influence of ultrasound power (1000–3000 W/L), citric acid concentration (0–3%) and solid:liquid ratio (1:5–1:15) on the phenolic compounds recovery and antioxidant capacity of Syrah grape skin extracts were evaluated. Total phenolic compounds varied from 6485 to 11732 mg gallic acid/100 g and monomeric anthocyanin content from 453 to 685 mg malvidin‐3‐glucoside/100 g. The antioxidant capacity measured by ORAC and ABTS methods ranged from 230 to 516 μmol Trolox/g and from 442 to 939 μmol Trolox/g, respectively. The most suitable conditions chosen for extraction, within the studied ranges, were 3000 W/L of power, 2.5% citric acid and solid:liquid ratio of 1:15. The extraction yield was satisfactory, with a recovery of 59% of the quantified phenolic compounds, with only 3 min of processing. Ultrasound was considered a suitable method as compared to the conventional extraction, improving the extraction of phenolic acids and facilitating their release.