Combined ultrasound and low temperature pretreatment improve the content of anthocyanins, phenols and volatile substance of Merlot red wine.

[Display omitted] • Evaluate the effect of ultrasound combined with low temperature pretreatment on wine. • Pretreatment could increase the contents of anthocyanins and phenols. • Pretreatment affected the color of wine. • Pretreatment significantly improve its antioxidant capacity. • Pretreatment could affect the volatile components and improve the aftertaste. Ultrasound combined with low temperature treatment is a new food processing technology. In this study, low temperature, three ultrasound power levels, and their combinations were adopted in the must before fermentation to study their effects on Merlot red wine. The results showed that ultrasound combined with low temperature pretreatment increased the total and monomer contents of anthocyanins and phenols, affected the color of the wine, and significantly increased its antioxidant capacity. In particular, 240 W of ultrasound combined with low temperature pretreatment reduced the bad odors (caprylic acid, benzaldehyde, and 1-ethanol content) and improved the flower and fruit aroma (1-octanol and phenethyl acetate), as well as the aftertaste, thus improving the quality of the wine. Ultrasound combined with low temperature pretreatment positively affected the quality of Merlot red wine. [ABSTRACT FROM AUTHOR]