Optimization of Sweet Cherry Extraction: Evaluation of Total Phenol Content, Protein Content, and Antioxidant Activity of Extracts

Abstract

Cherry fruits are known for their wide range of nutritive and bioactive compounds, including fibers, vitamins, and phytonutrients. Sweet cherry consumption has been associated with several health benefits against human problems such as cardiovascular diseases, cancer, diabetes, and Alzheimer’s disease. Particularly, cherries contain abundant phenolic compounds with antioxidant, anti-inflammatory, and anticancer properties as they exert a protective role against oxidative stress and free radical damages. However, there is not a specific method to fully extract all phenolics and other compounds from sweet cherries. Thus, this study aimed to optimize the extraction of cherries through different extraction procedures (maceration and ultrasound-assisted extraction) using different solvents (50% EtOH with and without HCl, and Tris buffer). The resulting cherry fruit extracts were investigated regarding their i) total phenol content - according to the Folin-Ciocalteu colorimetric method, ii) total protein content - evaluated using the Bradford protein assay, and iii) antioxidant activity – characterized by ABTS, DPPH, and FRAP assays. The ultrasound-assisted extraction using 50% EtOH and HCl (pH=2.3) demonstrated the best results for total phenol content (7.51 mg/L), DPPH inhibition (23.7%), and FRAP reducing power (24.5 mmol/g). On the contrary, the highest ABTS scavenging activity was noticed for maceration obtained extract with 50% EtOH and HCl (7.23 mg/mL). Finally, the best protein yield was obtained for cherries when extraction was performed in 0.1M Tris buffer at pH=11.2 (0.23 mg/mL). The optimization methodology in this work is used as a screening test for producing bioactive compounds-rich extracts for the food industry