Persimmon peel deastringency by CO2 and ethanol combination: Product quality and polyphenols bioavailability

Persimmons are popular worldwide owning to their unique flavor and nutritional value, while for the astringent cultivars, deastringency treatment is needed before processing. The current deastringency methods are limited to CO2 and ethanol. The aim of this work was to select optimal deastringency methods and assess the bioavailability of polyphenols in persimmon peels treated with 12 different combination of CO2 and ethanol. The level of soluble and insoluble tannins, total polyphenols bioaccessibility, antioxidant properties, color, and soluble solids were also determined. Results indicated that soluble tannin contents decreased with increasing ethanol concentration, and with an increase in carbon dioxide concentration, the insoluble tannins content increased. Application of 30% ethanol solution and 80% carbon dioxide for 24 hr has a best deastringency effect, while this treatment does not show good phenolics bioaccessibility and antioxidant activity. Therefore, the combination of 30% ethanol solution with 70% CO2 fumigation for 24 hr at 10 °C is the best deastringency method. Practical applications This project invented a novel deastringency method by CO2 and ethanol combination, with a feature of applying to lower temperature. The aim of this work was to select optimal deastringency methods and assess the bioavailability of polyphenols in persimmon peels treated with 12 different combination of CO2 and ethanol.