Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes

Robert Mugabi

doi:10.31015/jaefs.2026.1.12

Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes

Abstract

Refractance window drying (RWD) has gained interest as a mild technology for producing high-value powders, but few studies have focused on beetroot, which is rich in vitamin C and bioactive pigments yet highly perishable and underutilised. This study aimed to find optimal RWD conditions for beetroot slices and to assess powder quality and drying behaviour. An I-optimal experimental design was employed with water-bath temperature (75–95 °C) and slice thickness (1.5, 2.0, and 2.5 mm) as independent variables. Moisture content and vitamin C were the main responses for response surface modelling and multi-response optimisation, while functional properties (water-holding capacity, oil-holding capacity, and rehydration ratio) were evaluated at selected conditions. Powder moisture content decreased as temperature increased and slice thickness decreased, and vitamin C content declined under more severe conditions, with greater losses at higher temperatures and thinner slices. Multi-response optimisation showed that 75 °C and 2.0 mm slice thickness provided the best overall compromise; the resulting beetroot powder had a moisture content of 9.98 ± 0.23% and vitamin C content of 81.90 ± 1.65 mg ascorbic acid/100 g dry matter. Drying curves followed falling-rate drying, and moisture ratio data were best fitted by the Haghai & Ghanadzadeh model for 1.5 mm slices and by the Henderson & Pabis and two-term models for 2.0 and 2.5 mm slices. RWD at 75 °C and 2.0 mm slice thickness appeared a viable way to produce shelf-stable beetroot powder with vitamin C retention and functional properties for use as a natural colourant and functional ingredient in value-added food products.

Keywords

Refractance window drying, Beetroot powder, Response surface methodology, Drying kinetics, Functional properties

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Details

Primary Language

English

Subjects

Drying Technologies

Journal Section

Research Article

Authors

Robert Mugabi ^*
0000-0003-3218-3684
Uganda

Early Pub Date

March 14, 2026

Publication Date

March 14, 2026

Submission Date

January 9, 2026

Acceptance Date

March 7, 2026

Published in Issue

Year 2026 Volume: 10 Number: 1

DOI

https://doi.org/10.31015/jaefs.2026.1.12

IZ

https://izlik.org/JA38ME46TE

APA

Mugabi, R. (2026). Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes. International Journal of Agriculture Environment and Food Sciences, 10(1), 101-112. https://doi.org/10.31015/jaefs.2026.1.12

AMA

1.Mugabi R. Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes. int. j. agric. environ. food sci. 2026;10(1):101-112. doi:10.31015/jaefs.2026.1.12

Chicago

Mugabi, Robert. 2026. “Refractance Window Drying of Beetroot: Modelling Drying Behaviour and Optimising Quality Attributes”. International Journal of Agriculture Environment and Food Sciences 10 (1): 101-12. https://doi.org/10.31015/jaefs.2026.1.12.

EndNote

Mugabi R (March 1, 2026) Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes. International Journal of Agriculture Environment and Food Sciences 10 1 101–112.

IEEE

[1]R. Mugabi, “Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes”, int. j. agric. environ. food sci., vol. 10, no. 1, pp. 101–112, Mar. 2026, doi: 10.31015/jaefs.2026.1.12.

ISNAD

Mugabi, Robert. “Refractance Window Drying of Beetroot: Modelling Drying Behaviour and Optimising Quality Attributes”. International Journal of Agriculture Environment and Food Sciences 10/1 (March 1, 2026): 101-112. https://doi.org/10.31015/jaefs.2026.1.12.

JAMA

1.Mugabi R. Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes. int. j. agric. environ. food sci. 2026;10:101–112.

MLA

Mugabi, Robert. “Refractance Window Drying of Beetroot: Modelling Drying Behaviour and Optimising Quality Attributes”. International Journal of Agriculture Environment and Food Sciences, vol. 10, no. 1, Mar. 2026, pp. 101-12, doi:10.31015/jaefs.2026.1.12.

Vancouver

1.Robert Mugabi. Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes. int. j. agric. environ. food sci. 2026 Mar. 1;10(1):101-12. doi:10.31015/jaefs.2026.1.12

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Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes

Refractance window drying of beetroot: modelling drying behaviour and optimising quality attributes

Abstract

Keywords

References

Details

Primary Language

Subjects

Journal Section

Authors

Early Pub Date

Publication Date

Submission Date

Acceptance Date

Published in Issue

DOI

IZ

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