Process Development for Antioxidant Extraction from Wet Pomegranate Peel

Abstract

HighlightsA novel process for antioxidant extraction from wet pomegranate peel (WPP) was developed using water as solvent.Effects of extraction parameters on extract yield, quality, composition, and color were quantified.Extraction from WPP achieved 10% higher extract yield compared with dried peel.The WPP extraction process is more energy-efficient than extraction from dried peel.Abstract. Pomegranate peel (PP) is underused as animal feed or discarded in landfills, causing environmental pollution, even though it has a unique polyphenol profile with health-promoting properties. Past research has focused on the potential utilization of dried pomegranate peel (DPP), involving extended processing time, energy usage, and potential quality loss. The objective of this study was to develop a process to extract water-soluble antioxidants from wet pomegranate peel (WPP) and compare its antioxidant attributes with that of DPP. The WPP was sliced and ground into two sizes, and phenolics were extracted in water at different temperatures (20°C, 30°C, 40°C, 50°C, and 60°C), solvent (water) ratios (1:1, 2:1, 4:1, 6:1, and 8:1), and extraction times (2, 3, 4, 5, and 6 min). WPP extraction was compared with DPP extraction using hot air (HA, 40°C) and infrared radiation (IR, 60°C). The total phenolic yield (TPY) from WPP ranged from 10.37% to 12.80%, and the extraction rate increased significantly with increasing extraction time, temperature, and solvent ratio. DPPH scavenging activity (DSA), an important indicator of antioxidant activity, was in the range of 5.366 to 6.591 g g-1 and decreased only with the increase in temperature. Extraction using WPP particles resulted in 10% more extract yield and 2.5% more TPY compared to DPP powders with similar DSA. This study demonstrated that WPP could be used for the extraction of phenolic compounds with high antioxidant activity and without energy-intensive drying. Keywords: . Infrared drying, Peel composition, Polyphenol, Principal component analysis, Wet pomegranate peel.