Automatic solvent extraction of sour cherry peels and storage stability of the products

Abstract

Conversion of biomass (particularly waste of agricultural and food products) into high-added value compounds has been an attractive research field recently. Therefore, developing an alternative downstream process to recover the relevant biologically active components is of great significance. In this study, waste of sour cherry has been used as a source of phenolic compounds rich in anthocyanins. As an advanced alternative technology, automatic solvent extraction has been used to recover phenolics from sour cherry peels. The process factors (immersion time, washing time, solid mass and solvent concentration) of this novel method were optimized by face-centered composite design of response surface method. Chromatographic analysis (HPLC) was also used to measure the major anthocyanin (cyanidin-3-glucoside) of the samples. The process was optimized in order to maximize the dependent factors such as total phenolic and anthocyanin content extractions measured spectrophotometrically. Maximum predicted TPC and TA yields on optimized conditions were 119.63 mg GAE/g FM and 24.31 mg cyanidin-3-glucoside/g FM, respectively (23.79 min immersion time, 52.21 min washing time, 0.47 g solid mass, 80% solvent concentration). A stability assay under different conditions (light, dark, ambient condition, refrigerator and deep freezer) has been also performed in order to monitor the stability of bioactivity profile (total phenolic and anthocyanin contents and cyanidin-3-glucoside level). All of the independent parameters (immersion time, washing time, solid mass and solvent concentration) were significant at the level of p > 0.05. The solvent concentration was identified to be the most significant parameter on the yields obtained by automatic solvent extraction.