Continuous and pulsed ultrasound-assisted extraction of carob’s antioxidants: Processing parameters optimization and identification of polyphenolic composition

• Published in: Ultrasonics sonochemistry 2021-08, Vol.76, p.105630, Article 105630
• Main Authors: Christou, Atalanti, Stavrou, Ioannis J., Kapnissi-Christodoulou, Constantina P.
• Format: Article
• Language: English
• Subjects: Antioxidants - chemistry; Antioxidants - isolation & purification; Carobs; Chemical Fractionation - methods; Galactans - chemistry; Galactans - isolation & purification; Mannans - chemistry; Mannans - isolation & purification; Original; Plant Gums - chemistry; Plant Gums - isolation & purification; Polyphenol extraction; Polyphenols; Polyphenols - analysis; Polyphenols - isolation & purification; Response surface methodology; Solid Phase Extraction - methods; Sonication - methods; Ultrasonic Waves; Ultrasound-assisted extraction
• ISSN: 1350-4177; 1873-2828; 1873-2828
• DOI: 10.1016/j.ultsonch.2021.105630

•CUAE and PUAE parameters were optimized by the maximization of the yield in TPC.•Compared to conventional methods, UAE offered a higher yield of antioxidants.•Gallic acid was the most abundant polyphenolic compound in carob pulp extracts.•Solvent concentration was the most influential processing parameter.•DPA-6S demonstrated the best ability to recuperate the target analytes. Polyphenols in carobs have recently attracted great attention due to their wide range of biological and health promoting effects. A comprehensive study was conducted to find an optimum method for the extraction, purification and characterization of these valuable bioactive substances. Under this framework, the ultrasound-assisted extraction (UAE) of polyphenols from carob pulp was optimized by the maximization of the yield in total phenolics using response surface methodology. In particular, the effects of solid-solvent ratio, solvent concentration, extraction time, sonication amplitude, and sonication mode were investigated and optimized using a complete experimental design. In comparison to conventional extraction techniques, UAE offered a higher yield of antioxidants and a shorter processing time. Solid-phase extraction was evaluated as a clean-up strategy prior to the electrophoretic analysis of extracts. The results from the analysis of real samples revealed the predominance of gallic acid and highlighted the great influence of the ripening stage on carobs composition.