Resumen de Ultrasound assisted low-temperature drying of kiwifruit: Effects on drying kinetics, bioactive compounds and antioxidant activity
Francisca Maria Vallespir Torrens, Óscar Rodríguez Barragán, Juan Andrés Carcel Carrión, María Carmen Rosselló Matas, Susana Simal Florindo
Low-temperature drying is considered to be a promising technique for food processing. It preserves thermolabile compounds and might be intensified by acoustic assistance. The effect of acoustic assistance (20.5 kW m?3) during low-temperature drying of kiwifruit (at 5, 10 and 15 °C, and 1 m s?1) on drying kinetics, bioactive compounds (such as ascorbic acid, vitamin E, and total polyphenols), and antioxidant activity was studied. Results Drying time was shortened by 55?65% when using power ultrasound. A diffusion model was used to evaluate the drying kinetics. The effective diffusion coefficient increased by 154 ± 30% and the external mass transfer coefficient increased by 158 ± 66% when ultrasound was applied during drying, compared with drying without ultrasound application. With regard to bioactive compounds and antioxidant activity, although samples dried at 15 °C presented significantly higher (P < 0.05) losses (39?54% and 57?69%, respectively) than samples dried at 5 °C (14?43% and 23?50%, respectively) when ultrasound was not applied, the application of ultrasound during drying at 15 °C significantly reduced (P < 0.05) those losses in all quality parameters (15?47% and 47?58%, respectively). Conclusion Overall, low-temperature drying of kiwifruit was enhanced by acoustic assistance preserving bioactive compounds and antioxidant activity, especially at 15 °C. ? 2018 Society of Chemical Industry
