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Table 2 Changes in the raw material (natural starch) after treating with microwave radiation

From: Microwave technology: a novel approach to the transformation of natural metabolites

Source of raw material Processing conditions Changes observed in the starch Reference
Maize Moisture content up to 30% (w/w)
2450 MHz microwave oven
Output power 1.2 kW
The content of amylopectin decreased, relative crystallinity increased initially then decrease, granules were completed, the degree of gelatinization, and digestibility increased [64]
Chickpeas 2450 MHz microwave oven
Power of 565 W (90% maximum power)
Temperature 105 °C
Mineral content decreased slightly, starch gelatinized, slow digesting starch decreased, fast digesting starch increased [40]
Lycoris Heated for 120 s at a power level of 200 W, followed by heating at 50 °C in a convection oven until the moisture content was approximately 8% Granules collapsed and developed the characteristics of a massive, rough or irregular surface; the tendency to aggregate was strong and retrogradation was poor [67]
Rice Power values of 4, 8, or 10 W/g for 3 min The number of microcrystalline and periodic amorphous structures increased and digestibility decreased [68]
Taro The moisture content was adjusted to 25%, heated for 5 min at power level 180 W Amylose content increase, the swelling and solubility of the modified starch increased, the water retention, and final viscosity increased [66]
Indian Horse chestnut Moisture content tempered to 22% ± 3% Exposure to microwave radiation for 15, 30 and 45 s The morphology of starch granules was round and ellipse, the surface was smooth, the water absorption and light transmittance increased, the apparent amylose content decreased, and the antioxidant activity increased [69]
Potato Heated for 5 min in a laboratory microwave oven (2450 MHz) at 440 or 800 W Viscosity decreases, heat treatment temperature is low, free radicals increase [70]
Millet Duration of exposure to microwave radiation was 60 s
The power level was 700 W, and the moisture content was adjusted to 30%, 35%, 40%, 45%, and 50%
The peak viscosity decreased, the swelling force decreased, the molecular order decreased, the digestibility of amylose increased, and starches gelatinized [49]
Yam Operated at 2450 MHz and full power of 700 W (130–140 °C) for 5 min, then at 100 W for 2 h (60–70 °C) The moisture content decreased, the total starch content decreased, the amylose content increased, the slow digesting starch content was high, and the swelling power decreased [71]
Operated at 2450 MHz
and full power (700 W) for 5 min (130–140 °C), and then at 100 W for 30 min (60–70°C)
The total starch content was low, the swelling force was reduced, the surface of the grain was not uniform, there were a lot of lamellar bands, the crystal structure was destroyed, and the digestible starch was increased [72]