Screening of Phenolic Compounds in Rejected Avocado and Determination of Their Antioxidant Potential

Abstract

Avocados are one of the important fruits in our diet, showing many health benefits. However, a significant amount of avocados become defective as they are transported throughout the supply chain and are refused by consumers, ending up at animal or pet feed manufacturers. Indeed, some previous evidence suggests that rejected avocados still present high phenolic content that can be reused in the drug or pharmacological industry. Therefore, in the present work, we measured the phenolic content from rejected avocado pulp and evaluated the antioxidant potential, followed by characterization and quantification using LC-ESI-QTOF-MS/MS and HPLC-PDA. Reed avocado pulp was highest in TPC (0.21 mg GAE/g f.w.) and TFC (0.05 mg QE/g f.w.), whereas in TCT assay, low traces of tannins were exhibited in Wurtz and Reed avocado pulp. Hass avocado pulp had the highest antioxidant potential in DPPH (0.32 AAE/g f.w.), FRAP (0.13 AAE/g f.w.), ABTS (0.32 AAE/g f.w.), •OH-RSA (0.51 AAE/g f.w.) and FICA (0.47 mg EDTA/g) assays. Wurtz avocado pulp had higher antioxidant potential in RPA (0.07 mg AAE/g) and PMA (0.27 AAE/g f.w.). A total of 64 phenolic compounds were characterized in avocado pulp, including 10 in Hass avocado pulp, 31 in Wurtz avocado pulp and 45 in Reed avocado pulp. In HPLC-PDA quantification, chlorogenic acid (21.36 mg/g f.w.), epicatechin (14.24 mg/g f.w.) and quercetin (21.47 mg/g f.w.) were detected to be the highest in Hass, Wurtz and Reed avocado pulp, respectively. Our study showed the presence of phenolic compounds in rejected avocado pulp and hence can be utilized in food and pharmaceutical industries.