Study of the Effect of Thermoultrasound on the Antioxidant Compounds and Fatty Acid Profile from Blackberry (<em>Rubus fruticosus spp</em>) Juice

Abstract

Blackberry (Rubus fruticosus spp) is a fruit that has a significant antioxidant activity, due to its content in anthocyanins and antioxidant compounds. Emerging technologies are required as the thermoultrasound technique that ensures microbial reduction and release of compounds with antioxidant properties. The objective of this study was to evaluate changes in the antioxidant content and fatty acid profile of blackberry juice when it is subjected to conservation treatment (pasteurization and thermoultrasound). The blackberry juice and the extracted oil of blackberry juice with n-hexane (control, pasteurized and thermoultrasonicated) were evaluated in antioxidant activity, fatty acid profile and antioxidant content. The thermoultrasound juice had the highest (p < 0.05) amount of total phenols (1011 mg GAE/L), anthocyanins (118 mg Cy-3-GlE/L); antioxidant activity by ABTS (44 mg VCEAC/L) and DPPH (2665 µmol TE/L) compared to the control and pasteurized samples, as well as, as well as, oil extract of obtained of the thermoultrasound juice presented high antioxidant activity (177.54 mg VCEAC/L to ABTS and 1802.60 µmol TE/L to DPPH). The fatty acid composition of the oil extract showed the presence of myristic, linolenic, stearic, oleic, and linoleic acid, the fatty acid profile was similar in the different samples with the exception of stearic acid where this was higher in control sample. The thermoultrasound treatment can be an alternative to pasteurization treatments because keeps and releases antioxidant bioavailable compounds, preserving their fatty acids.