Physicochemical characterization and biological potential of Japanese quince polyphenol extract treated by different drying techniques

Abstract

Abstract The aim of this study was to determine the effect of different drying methods – freeze drying, spray drying and vacuum drying (at 50, 70, 90\xa0°C) – on the quality factors of Japanese quince polyphenol extract, including physical parameters, phenolic compounds, and in vitro biological activities (antioxidant, anti-diabetic, anti-obesity, and anticholinesterase). The highest content of bioactive compounds was observed in samples after freeze drying (total phenolic content – 912.7\xa0g/kg dry weight [dw]; flavan-3-ols – 467.3\xa0g/kg dw). The antioxidant activity measured by Oxygen Radical Absorbance Capacity (ORAC) assay was the highest for samples vacuum dried at 70\xa0°C (1455.5\xa0mol Trolox/kg dw). Moreover, strong anti-diabetic properties were obtained after vacuum drying, and the samples subjected to freeze drying and spray drying showed the most favorable anti-cholinergic potential. Unfavorable changes in color, formation of 5-hydroxymethylfurfural (5-HMF) and degradation of phenolics were noted along with the increasing drying temperature in vacuum drying. For vacuum drying, the most optimal temperature is 70\xa0°C, as the final product obtained in this way is characterized by favorable physical properties, a beneficial content of biological compounds, a low concentration of undesirable 5-hydroxymethylfurfural and satisfactory biological properties.