Quality characteristics of the processed dates vinegar under influence of ultrasound and pulsed electric field treatments.

This research aimed to evaluate the influences of the pulsed electric field (PEF), ultrasound (US), and combination between them (PEF + US) on the quality of vinegar processed from date palm fruits compared with untreated vinegar (UT). Physicochemical properties, free amino acids (FAA), volatile components, organic acids, total phenolics and flavonoids, and sensory analysis were determined. The results showed that there were no significant differences in pH, total titratable acidity, ethanol content, and total sugar in all treated vinegar compared with UT. However, the values were found to be decreased (PEF + US < PEF < US < UT). Twenty-eight compounds were identified in the vinegar treated by PEF + US as the highest number of components, followed by PEF and US (23 and 22 components, respectively), compared with 19 compounds identified in UT. Compared with UT, there was a significant increase (p < 0.05) in the total FAA in dates vinegar among all treated samples (UT < US < PEF < PEF + US). Total phenolic and flavonoids contents results indicated that there was a significant increase (p < 0.05) in the treated vinegar compared with UT. Sensory analysis results indicated that no significant difference (p < 0.05) in all the parameters, except for a quite significant difference (p < 0.05) in the overall acceptability between the treated vinegar. In this study, vinegar was successfully produced from date palm fruits. Therefore, PEF + US are capable not only in enhancing the extraction process but also in the production of vinegar with good quality.