Enzyme‐ and ultrasound‐assisted extractions of polyphenols from Citrus sinensis (cv. Malta) peel: A comparative study

Abstract

Response surface methodology (RSM) was employed for optimization of ultrasound‐assisted extraction (UAE) and enzyme‐assisted extraction (EAE) of bioactives from Citrus sinensis cv. Malta peel. The optimized extract was further compared with conventional solvent extraction for total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (AOX). The optimized condition for UAE was obtained at 70.89% amplitude, 40 ml/g solvent–solid (SS) ratio, and an extraction time of 35 min. Moreover, the optimized condition for EAE was 0.84% enzyme concentration, 30.94 ml/g SS ratio and 4.87 hr extraction time. The predicted TPC and TFC recoveries under the optimized conditions were significantly similar to the experimental values, indicating suitability of the employed RSM model. Phenolic profiling through HPLC confirmed the effect of extraction methods on released phenolics and AOX. EAE enhanced twofold higher yield of phenolics than UAE. Thus, it seems EAE has significant industrial implications in valorization of the waste from horticultural produce. Practical applications In the present research, we have optimized the process for extraction of bioactives using enzyme‐ and ultrasound‐assisted methods from citrus peel. Based on high recovery of phenolics and antioxidant activity, enzyme‐assisted process was found to be more efficient than ultrasound. Results suggest that enzyme‐assisted extraction process may have promising applications for processing of industrial byproducts and reducing environmental waste.

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