Advanced recovery of bioactive polyphenols: integrated optimization of drying and green extraction for avocado seed by-products

Response surface methodology using a central composite design was applied to optimize the accelerated solvent extraction (ASE) of phenolic compounds from avocado seed and seed coat by-products. The optimal extraction conditions for both matrices were achieved at 200 °C using as extractant solvent a mixture of ethanol:water (50,50, <i>v</i>/v). Additionally, the drying process was optimized for avocado seed samples at different temperatures (45, 55, 65, 75, and 85 °C). Changes in the phenolic profiles during the drying and extraction processed were monitorized using HPLC-TOF-MS. A total of 42 and 52 phenolic compounds were individually identified and quantified in avocado seed and seed coat, respectively. The optimal drying temperature for avocado seed was 85 °C. In contrast, the seed coat exhibited different optimal temperatures depending on the phenolic group under research, with 75 °C being the most favourable for the majority of compounds evaluated.