Drying Kinetics, Microstructure and Antioxidant Properties of Basil Treated by Ultrasound

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• 作者：Magdalena Sledz ; Artur Wiktor ; Malgorzata Nowacka and Dorota Witrowa-Rajchert
• 刊名：Journal of Food Process Engineering
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：40
• 期：1
• 全文大小：2273K
• ISSN：1745-4530

文摘

The current study is one of the first provided data on both the quality changes and the drying kinetics of herbal material affected by ultrasound (US). The aim of this study was to investigate the influence of US prior to microwave–convective drying on the drying kinetics, water diffusivity, total phenolic content, antioxidant activity and microstructure of basil leaves. The US pretreatment was applied at different frequencies (21, 35 kHz) for variable time (20, 30 min). Application of US significantly reduced the drying time up to 20% and decreased the total specific energy consumption maximally by 26.2% in the case of 35 kHz 20 min US-treated basil. Sonication modified the microstructure of basil, which was manifested in larger and elongated cellular spaces. Nonetheless, US did not alter the antioxidant activity and resulted in even significantly higher phenolic content in leaves treated by US at 21 kHz 20 min and at 35 kHz 30 min, compared with untreated sample. Drying coefficients of the model proposed to describe the dehydration kinetics indicated the process intensity due to the significant correlation between the drying rate and effective water diffusivity.