Title
Ultrasound and ethanol pre-treatments to improve convective drying: Drying, rehydration and carotenoid content of pumpkin
Date Issued
01 January 2020
Access level
metadata only access
Resource Type
journal article
Author(s)
Silveira I.
Augusto P.
Universidad de São Paulo
Publisher(s)
Institution of Chemical Engineers
Abstract
Among different effects, both ultrasound and ethanol technologies change the product structure and promote mass transfer when used as pre-treatments to improve the food drying. For the first time, their combined application was evaluated as pre-treatment to improve convective drying, as well as the properties of the dried food. Pumpkin cylinders were used as model food, being dried using air at 50 °C and 0.8 ± 0.1 m s−1. Effects on drying and rehydration kinetics, as well as on the energy consumption and carotenoid preservation, were studied. Compared to the Control, all pre-treatments decreased the drying time in more than 48%. The combination of ethanol and ultrasound presented the greatest reduction in both drying time (59%) and energy consumption (44%). The pre-treatments also enhanced the rehydration properties in more than 28%: higher rehydration rate and an increase of water retention were achieved. Possible mechanisms, involving structure modification and mass transfer during pre-treatment and drying process were discussed. Additionally, the extraction of carotenoids due to pre-treatments was negligible when compared to the remarkable effect in avoiding this nutrient degradation during drying. Pre-treated samples preserved ∼100% of the carotenoid content, while the Control samples presented partial degradation (23%). This was explained by the negative effects evidenced by sample thermal history during drying. The results open new perspectives about an innovative method to improve the drying process and product quality by combining ethanol and ultrasound.
Start page
20
End page
30
Volume
119
Language
English
OCDE Knowledge area
Ingeniería de producción Alimentos y bebidas
Scopus EID
2-s2.0-85074404248
Source
Food and Bioproducts Processing
ISSN of the container
09603085
Sponsor(s)
The authors are grateful to the São Paulo Research Foundation (FAPESP, Brazil) for funding the project nº 2016/18052-5; to the National Council for Scientific and Technological Development (CNPq, Brazil) for funding the project nº 401004/2014-7 and the productivity grant of P.E.D. Augusto ( 306557/2017-7 ); and to FONDECYT-CONCYTEC for the M.L. Rojas Ph.D. scholarship (grant contract number 087-2016-FONDECYT ).
Sources of information: Directorio de Producción Científica Scopus