Table 1.

Drying conditions and slice thickness induced effect on beetroot powder.

Drying parameter		Beetroot slice		Beetroot powder
Power level (W)	Vacuum (mm Hg)	Thickness (mm)	Drying time (min)	Moisture content (%)	Water activity (aw)
Microwave vacuum drying
160	710	1	37.00 ± 2.00ᵃ	2.49 ± 0.02ᵃ	0.42 ± 0.01ᵃ
320	710	1	14.00 ± 0.00ᶠ	1.76 ± 0.03ᶠ	0.39 ± 0.01ᶜ
160	660	1	31.33 ± 1.53ᵇ	2.02 ± 0.04ᶜ	0.40 ± 0.01ᵇ
320	660	1	13.17 ± 0.29ᶠ	1.58 ± 0.02ʰ	0.37 ± 0.01ᵉ
160	610	1	25.33 ± 1.53ᶜ	1.65 ± 0.05ᵍ	0.38 ± 0.01ᵈ
320	610	1	12.67 ± 0.58ᶠ	1.55 ± 0.03ʰ	0.35 ± 0.01ᶠ
160	710	2	38.00 ± 1.00ᵃ	3.65 ± 0.14ᵃ	0.44 ± 0.01ᵃ
320	710	2	16.67 ± 1.15ᵉ	2.29 ± 0.07ᵈ	0.41 ± 0.01ᵇ
160	660	2	32.00 ± 1.00ᵇ	2.73 ± 0.39ᵇ	0.42 ± 0.01ᵃ
320	660	2	16.33 ± 0.58ᵉ	2.11 ± 0.04ᵉ	0.39 ± 0.01ᶜ
160	610	2	26.00 ± 1.00ᶜ	2.22 ± 0.02ᵈ	0.40 ± 0.01ᵇ
320	610	2	16.00 ± 1.00ᵉ	1.94 ± 0.06ᶠ	0.37 ± 0.01ᵉ
Freeze drying (0.062 m bar, −40 °C)		1	1950.0 ± 30.0ᵇ	2.37 ± 0.31ᵈ	0.32 ± 0.01ᵍ
		2	3154.0 ± 30.8ᵃ	3.13 ± 0.15ᵇ	0.36 ± 0.02ᶠ

Different superscript small letters in each column denote significant difference at p ≤ 0.05.