| Combined methods including the solvent steam treatment and microwave drying were used to inhibit the activity of lipoxygenase in whole soybean. The results showed that steam treatment with 50% methanol, 50% isopropanol, 5% lactic acid or 0.1 mol/L citric acid solution could inhibit the enzyme to a certain degree. These treatments combined with microwave drying could reduce its activity by over 98%, while the solubility of the protein in treated soybean could remain 54.3%, 59.3%, 58.4% and 66.1%, respectively. The total content of beany odour substances in whole soybean treated by the combined methods decreased by 88.7%, 73.7%, 89.4% and 90.5%, respectively, of which its content of hexanal very significantly decreased, but its content of crude protein and crude fat, and internal voidage changed little and its seed hardness significantly decreased compared with those in the untreated soybean. In summary, the combined method of steam treatment with 0.1 mol/L citric acid solution and microwave drying was suitable to inhibit the activity of lipoxygenase in whole soybean. |
