Extraction process optimization for maximizing total polyphenol content in cashew nut testa (Anacardium occidentale L.) extract

Abstract

Cashew nut testa (Anacardium occidentale L.) is a valuable source of polyphenols known for their strong bioactivities. This study optimized the extraction conditions to obtain polyphenol-rich extracts from cashew nut testa. The effects of three key factors, extraction time, material-to-solvent ratio, and temperature, on Total Polyphenol Content (TPC, mg GAE/g extract) were investigated. Response surface methodology, using a Box-Behnken design, was applied to design the experiments and optimize the extraction process. The results showed that the relationship between TPC and extraction conditions followed a second-order model with an R² value of 0.9999. All three factors significantly influenced TPC (p < 0.05), and their interactions were also significant. The model predicted optimal conditions for maximum TPC at an extraction time of 19.85h, a temperature of 58.80°C, and a material-to-solvent ratio of 1:16.39 (w/v). Validation experiments under the optimized conditions of 20h, 59°C, and a 1:16 ratio confirmed the model's accuracy, yielding a TPC of 534.67mg GAE/g extract, statistically equivalent to the predicted value. These findings demonstrate the efficacy of the optimized conditions in maximizing polyphenol extraction from cashew nut testa.