Optimization of microwave‐assisted extraction of polyphenols from apple pomace using response surface methodology and HPLC analysis

Abstract

A simple and efficient microwave-assisted extraction of polyphenols from industrial apple pomace was developed and optimized by the maximization of the yield using response surface methodology. A Box-Behnken design was used to monitor the effect of microwave power, extraction time, ethanol concentration and ratio of solvent to raw material (g/mL) on the polyphenols yield. The results showed that the optimal conditions were as follows: microwave power 650.4 W, extraction time 53.7 s, ethanol concentration 62.1% and ratio of solvent to raw material 22.9:1. Validation tests indicated that the actual yield of polyphenols was 62.68±0.35 mg gallic acid equivalents per 100 g dry apple pomace with RSD=0.86% (n=5) under the optimal conditions, which was in good agreement with the predicted yield and higher than those of reflux and ultrasonic-assisted extraction methods. HPLC analysis indicated that the major polyphenols of apple pomace consisted of chlorogenic acid, caffeic acid, syrigin, procyanidin B2, (-)-epicatechin, cinnamic acid, coumaric acid, phlorizin and quercetin, of which procyanidin B2 had the highest content of 219.4 mg/kg.

Fractionation and anti-inflammatory effects of polyphenol-enriched extracts from apple pomace

“…About 100 g pretreated apple pomace was extracted with a microwave experiment equipment (NJC 03-2, China) according to a previously published protocol (Bai et al, 2010). The afforded extract was concentrated under reduced pressure and lyophilized (Freezone 2.5 plus, Labconco, USA).…”

Preparation of procyanidin B2 from apple pomace and its inhibitory effect on the expression of cyclooxygenase-2 in lipopolysaccharide-treated RAW264.7 macrophages

“…About 100 g dried apple pomace was extracted with aqueous alcohol according to a previous published protocol (Bai et al, 2010). The afforded extract was concentrated under reduced pressure (Eyela NC-2000, Japan) and lyophilized (Freezone 2.5 plus, USA).…”

Mass Proportion, Bioactive Compounds and Antioxidant Capacity of Carrot Peel as Affected by Various Solvents

“…As such, considering residues/by-products or wastes from the food processing industry as abundant, inexpensive, renewable and sustainable sources of bioactive compounds is a great interest to the researchers and producers [5][6][7][8][9][10][11][12].…”