The experiments on the effect of using a power
controlled microwave oven on cooked brown rice
gave the following results. Consumer panels gave
a high color acceptance score for the drying done at
300 W for 48 min. Most nutritional value of cooked
Table 1. Microwave drying for color parameters after cooked brown rice
drying
Sample L* a* b* Color liking
Fresh cooked brown rice 30.14 ± 1.71a 7.63 ± 0.98a 9.11 ± 0.61ab 7.1±0.7ab
Dried brown rice
280 W, 70 min 29.01±0.54a 6.56±0.34b 19.12±0.47ab 6.8±1.1ab
300 W, 48 min 30.50 ± 0.35a 8.54 ± 0.21a 16.49 ± 1.08a 7.5±0.9a
320 W, 32 min 18.05±0.27b 1.01±0.37c 21.44±0.54b 5.5±0.8b
a-d Mean within the column values with different letters are significantly different (P ≤0.05)
Table 2. Proximate composition of cooked brown rice at 300W for 48
min
Assay Before microwave drying
(g/100 g dry matter)*
After microwave drying
(g/100 g dry matter)*
Protein 12.95 ± 0.19a 12.70 ± 0.11a
Crude fat 2.19 ± 0.04a 1.64 ± 0.03b
Ash 1.61 ± 0.02a 1.42 ± 0.05a
Fiber 1.06 ± 0.03a 1.04 ± 0.02a
Carbohydrate 82.19 ± 0.19a 83.20 ± 0.13a
* Data represent the mean of three replicates ± standard deviation
a, b Values in the same row with different superscripts are significantly different (P < 0.05)
Table 3. Mineral composition of cooked brown rice at 300W for 48 min
Mineral Before microwave drying
(mg/100 g)*
After microwave drying
(mg/100 g)*
DRI
(mg/a day)
Potassium (K) 340.55 ± 16.55a 279.94 ± 29.61a 4700
Magnesium (Mg) 155.22 ± 7.11a 161.28 ± 12.19a 310-420
Zinc (Zn) 2.51 ± 0.09a 2.88 ± 0.88a 8-11
Manganese (Mn) 4.42 ± 0.20a 2.45 ± 0.15b 1.8-2.3
Copper (Cu) 0.23 ± 0.05a 0.14 ± 0.04b 900 µg *
Data represent the mean of three replicates ± standard deviation
a, b Values in the same row with different superscripts are significantly different (P < 0.05)
Jaroenkit et al./IFRJ 20(1): 351-355 355
brown rice could not be damaged by microwave
drying