EFFECT OF DIFFERENT DRYING METHODS ON THE PHENOLIC EXTRACTION FROM BUTTERNUT SQUASH POMACE

Abstract

The objective of this study was to observe the effect of different drying methods (freeze drying, hot air, vacuum and microwave drying) on the color parameters, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (AA) of butternut squash pomace (BSP). In addition, the extraction conditions of phenolic compounds were optimized using the extract of freeze-dried BSP by Response Surface Methodology. The drying conditions were 30 and 60 °C for hot air and vacuum drying and 120 and 600 W for the microwave drying. TPC, TFC and AA of dried BSP were changed between 1.88 ± 0.01–4.86 ± 0.27 mg gallic acid equivalent/g dry matter, 1.32 ± 0.05–3.09 ± 0.29 mg catechin equivalent/g dry matter and 1.45 ± 0.15–4.27 ± 0.27 mg ascorbic acid equivalent/g dry matter, respectively. This study showed that dried BSP can be used as a functional ingredient due to its bioactive potential.