Title
Drying Accelerators to Enhance Processing and Properties: Ethanol, Isopropanol, Acetone and Acetic Acid as Pre-treatments to Convective Drying of Pumpkin
Date Issued
01 November 2020
Access level
metadata only access
Resource Type
journal article
Author(s)
Carvalho G.R.
Silveira I.
Augusto P.E.D.
Publisher(s)
Springer
Abstract
Different drying accelerators were studied to improve vegetable drying: acetone (AC), ethanol (ET), isopropanol (ISO) and acetic acid (AA). Pre-treatments were performed by immersion of pumpkin cylinders. Convective drying was performed at 40 °C and air velocity 1 m/s. Different aspects were evaluated: drying kinetics, structural changes (microstructure and macrostructure), thermal profile and viscoelastic and rehydration behaviours. The microstructure was modified by pre-treatments, being more pronounced with AC and AA. Thinner cell walls, changes on turgor and extraction of components and air were reported, affecting the mass transfer. Moreover, the microstructural changes reinforced anisotropy and also affected the macrostructure, changing the viscoelastic behaviour. All pre-treatments resulted in a super-diffusive behaviour, decreasing the drying time from 9% (ISO) to 22% (AC). Possible relations were discussed among the compounds’ physical properties, sample temperature profile, drying kinetics and equilibrium moisture. Rehydration was improved by ET and ISO, but impaired by AA. Although AC accelerates drying, it did not affect the rehydration. The viscoelasticity reflected the structure and composition, with the pre-treatments with higher structure modifications (AA and AC) losing elastic properties. In conclusion, the pre-treatments with isopropanol and ethanol showed better results, improving drying and rehydration, and are thus recommended.
Start page
1984
End page
1996
Volume
13
Issue
11
Language
English
OCDE Knowledge area
Ingeniería de producción Alimentos y bebidas
Scopus EID
2-s2.0-85092497381
Source
Food and Bioprocess Technology
ISSN of the container
19355130
Sponsor(s)
The authors are grateful to the São Paulo Research Foundation (FAPESP, Brazil) for funding project n° 2019/05043-6, the GR Carvalho post-doctoral fellowship (2018/17844-0) and the I Silveira BSc scholarship (2019/19307-5); to the National Council for Scientific and Technological Development (CNPq, Brazil) for the productivity grant of PED Augusto (306557/2017-7); and to the Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT, Peru) from the “Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica” (CONCYTEC, Peru) for funding project n° 409-2019-FONDECYT.
Sources of information: Directorio de Producción Científica Scopus