Green accelerated solvent extraction (ASE) with solvent and temperature effect and green UHPLC-DAD analysis of phenolics in pepper fruit (Capsicum annum L.)

Abstract

The study presents for the first time, a green and efficient accelerated solvent extraction (ASE) method for phenolic compounds (GA gallic acid, QT quercetin, RT rutin, LT luteolin) with simultaneous determination using a green and effective UHPLC-DAD method. The effect of solvents (ACE acetone, EtOH ethanol, and H2O water) and temperatures (60, 80, 100 °C) Vs extract yield and phenolic recovery was investigated. The scale-up for ASE-UHPLC method was accomplished in 27 food-grade samples of Capsicum annum/pepper fruit (PF). ASE-MD (method development) showed a high extract yield (198.23 mg/g) in water (33 mL) at 100 °C within a time frame of 19.5 min. UHPLC-DAD revealed more yield for GA in ACE whereas, for RT, QT, LT in EtOH at 60 °C. Binary solvent system (ACE: EtOH; 1:1) and 60 °C was optimized the extraction set. The UHPLC-MDMV showed a run time of 5 min with individual retention times of 0.667 (GA), 1.05 (RT), 3.24 (QT), and 3.78 (LT) in the linearity range (1–100 ppm). The average for phenolics (ppm) in 27 PF-food samples was; GA (19.46) > QT (10.19) > LT (4.06) > RT (2.41). SP4 (Spanish green bell pepper) sample showed more amount of total phenolics (32.52 ppm, 25.36 %) whereas, the order for individual phenolic amount (ppm) was; GA (53.39) > QT (13.58) > RT (10.04) > LT (4.62). Multivariate analysis resulted a significant correlation for solvent*temperature with extract yield but with a lack of correlation for phenolics amount. K-mean correlation was positive for solvent Vs phenolic yield (P < 0.05) whereas, extract yield and temperature were less significant for phenolics content. Solvent established a high significant role for extraction and phenolic recovery whereas, temperature was more significant for extract yield rather than phenolic amount.