Assessing the impact of ultra-sonication and thermo-ultrasound on antioxidant indices and polyphenolic profile of apple-grape juice blend

摘要

Apple-grape juice blend (50:50) were subjected to blanching (thermal), high temperature-short time (72℃: 15 s), ultra-sonication (5 & 10 min), thermo-ultrasound (5 min,40℃; 10 min, 40℃), and thermo-ultrasound (5 min, 50℃; 10 min, 50℃) and were comparedto control treatment for the antioxidant indices. Furthermore, one best treatmenteach from ultra-sonication (10 min), thermo-ultrasound at 40℃ (5 min), and thermoultrasoundat 50℃ (5 min) was analyzed through high performance liquid chromatographydiode array detector (HPLC-DAD) for the quantification of individual phenolic acids,flavanols, stilbenes, and anthocyanins. Polyphenolic profile (HPLC-DAD) of apple-grapejuice blends treated with ultra-sonicated (10 min), thermo-ultrasound (5 min; 40℃), andthermo-ultrasound (5 min: 50℃), resulted in identification of 23 polyphenols (9 phenolicacids; 6 flavanols; 1 stilbene; 7 anthocyanins). Results of HPLC characterization revealeda significant (p < .05) effect of tested treatments on all the polyphenols. Among phenolicacids, chlorogenic acid was observed to be highest (422.12 mg/L) in ultra-sonicated juiceblend (T_(U-10):10 min) followed by caftaric, gallic, syringic, vanillic, caffeic, ferulic, and cinnamicacids. While, content of resveratrol (stilbene), epigallocatechin gallate (flavanol),and Malvidin 3, 5-diglucoside (anthocyanin) were also found to be maximum (33.08,386.32, and 70.25 mg/L, respectively) in ultra-sonicated (10 min) apple-grape juiceblend samples. Keeping in view the polyphenolic profile and consumer preferences,ultra-sonication could be employed industrially as an alternative substitute of thermalprocessing techniques to enhance the quality of apple-grape juice blend.Practical application: For years, several nonthermal techniques are used for thepreservation and quality improvement of fresh juices mainly by preventing the microorganismsand enzymes. Among these technique, single nonthermal treatmenthas a capacity to reduce the amount of microorganism and enzymes while a combinedtechnique such as thermo-ultrasound has a better effect than single treatment,which have been investigated in this study. Therefore, this article would encouragethe juice industrialists by applying these techniques for commercialization of juiceand juice products in a more effectual manner.