Novel Accelerated Penetration Extraction for Polyphenol Extraction from Pomegranate Skins: Utilization of Fick’s Law
Yong Deng, Shunan Zhao, Xiaoling Yang, Haocheng Guo, Yinhui Li, Weidong Xu, Jin Chen, Zonghan Wang, Mingming Guo, Donghong Liu
Abstract
Pomegranate was a popular fruit, and the pomegranate skins (PS) contained abundant polyphenols. In this article, a novel method based on Fick’s law, accelerated penetration extraction (APE), was developed for the first time for polyphenol recovery from PS, which aimed at precipitating the polyphenols with Ca2+ in alkaline conditions to elevate the concentration gradient between the cell and solution, thus promoting the further penetration of polyphenols to solution. Under the optimal conditions of 8 mg/mL of CaCl2 and 3 mg/mL of NaOH of APE, the highest polyphenol yield of 113.5 mg GAE/g was obtained, higher than solvent extraction (SE, 92.9 mg GAE/g) by 21.6%. The comparisons of SE and APE were performed, including the polyphenol yields, UV–vis spectra, composition analysis by high-performance liquid chromatography (HPLC), and DPPH-scavenging ability. Results showed that APE was non-selective, almost all kinds of polyphenols could be precipitated by alkaline Ca2+, and the antioxidation of polyphenols could not be affected by APE. In addition, the mechanisms were discussed based on the mass transfer principle. Results indicated that APE was non-selective, efficient, easily operated, and promising in PS disposal and polyphenol extraction. Most importantly, the application of APE exploited the different concept with other methods to enhance the extraction process.