Combining ultrasound, vacuum and/or ethanol as pretreatments to the convective drying of celery slices
| Autor: | Meliza Lindsay Rojas, Alberto Claudio Miano, Pedro Esteves Duarte Augusto |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Convection
Materials science Acoustics and Ultrasonics Vacuum Kinetics QC221-246 Marangoni effect Review Inorganic Chemistry chemistry.chemical_compound Ultrasound Vegetables medicine Chemical Engineering (miscellaneous) Environmental Chemistry Radiology Nuclear Medicine and imaging Dehydration Desiccation SECAGEM DE ALIMENTOS QD1-999 Shrinkage ComputingMethodologies_COMPUTERGRAPHICS Apium Convective drying Chromatography Ethanol business.industry Organic Chemistry Acoustics. Sound medicine.disease Ethanol pretreatment Chemistry chemistry Distilled water Permeability (electromagnetism) business |
| Zdroj: | Ultrasonics Sonochemistry Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP Ultrasonics Sonochemistry, Vol 79, Iss, Pp 105779-(2021) |
| ISSN: | 1873-2828 1350-4177 |
| Popis: | Graphical abstract Highlights • Vacuum and ethanol pretreatments reduced the acoustic cavitation intensity. • Vacuum pretreatment did not affect drying of celery slices. • Ultrasound and ethanol were the best combination on reducing drying time. • Combination of technologies reduced drying time up to 38%. • Microstructure and shrinkage were considered for effects explanation. This work studied three emerging approaches to improve the convective drying (50 °C, 0.8 m/s) of celery. Celery slices of 2 mm thick were pretreated for 5 min using ultrasound (32 W/L, 40 kHz), vacuum (75 kPa vacuum pressure) and ethanol (99.8% v/v, as drying accelerator) applied individually or in combination. To evaluate individual effects of ultrasound and vacuum, the treatments were also performed with distilled water or air medium, respectively. Moreover, the cavitational level was characterized in each condition. Drying kinetics was evaluated tending into account the drying time required by each treatment and the Page’s model parameters. In addition, microstructural effects and shrinkage were evaluated. As results, ethanol combined with ultrasound significantly improved drying kinetics reducing drying time by around 38%. However, vacuum pretreatment did not affect drying kinetics even in combination with ethanol and/or ultrasound. Microstructural evaluation did not evidence cell disruption, suggesting changes in intercellular spaces, pores and/or cell wall permeability. The use of ethanol and vacuum showed a greater effect on shrinkage after pretreatment and after drying, respectively. In conclusion, at the studied conditions, the drying acceleration by vacuum and ultrasound is lower compared to the effect produced using ethanol. |
| Databáze: | OpenAIRE |
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