Enhancement of phytochemical content and drying efficiency of onions (Allium cepa L.) through blanching.

• Autores: Feiyue Ren, Camila A Perussello, Zhihang Zhang, Michael Gaffney, Joseph P. Kerry, Brijesh K Tiwari
• Localización: Journal of the science of food and agriculture, ISSN 0022-5142, Vol. 98, Nº 4, 2018, págs. 1300-1309
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • This study investigated the effect of blanching (60, 70 and 80 °C for 1, 3, 5 and 10 min) combined with oven drying at 60 °C on the phenolic compounds, antioxidant activity, colour and drying characteristics (drying time, drying rate constant, effective moisture diffusivity and activation energy) of onion slices.; Results: Blanching of onion slices at 60 °C for 3 min and at 70 °C for 1 min prior to drying increased their bioactive compounds and antioxidant activity compared to the control samples and other treatments. Eighteen drying models were evaluated. The Modified Page and two-term exponential models best represented the drying data. The effective diffusivity ranged from 3.32 × 10-11 m2 s-1 (control) to 5.27 × 10-11 m2 s-1 , 5.01 × 10-11 m2 s-1 , and 4.74 × 10-11 m2 s-1 for onions blanched at 60 °C, 70 °C and 80 °C, respectively. The higher activation energy was observed for the control (unblanched) sample and slightly lower values were found for 1 min- and 3 min-blanched samples, confirming the higher drying efficiency as a result of the blanching pre-treatment.; Conclusion: The use of blanching as a pre-treatment before drying of onions resulted in enhanced phytochemical content and drying efficiency. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.