The effect of gas plasma irradiation on the dehulling and resulting chemical and physical properties of soybeans

A study was made to ascertain the chemical and physical changes and the amount of dehulling induced by varying the electrical current in the gas plasma irradiation of two varieties of soybeans.

Moisture content, the amount of cracked beans and the amount of dehulling were determined on samples treated with 0, 40, 80, and 120 milliampers (ma.) and on the control. Crude lipids, total and water soluble proteins, trypsin inhibitor activity of soybeans and the iodine and peroxide numbers of soybean oil were determined on samples treated with 40 and 120 ma. and on the control.

The results of the experiment showed that gas plasma irradiation increased the number of cracked beans and improved the dehulling effect of soybeans. The treatment resulted in a loss of moisture and weight in the soybeans. Gas plasma irradiation increased the water sorption of the soybean. However, deformation and fragility were found in the soaked beans. At the lower treatment level (40 ma.), no change was found in the extractability of lipids and total and soluble protein contents in the soybeans. No difference was found in iodine and peroxide numbers of the oil from the soybeans at the two treatment levels (40 and 120 ma.). Slight decrease in extractability of lipids and total protein content were found in beans treated with 120 ma. Higher treatment intensity (120 ma.) resulted in a destruction of protein; there was both a lower soluble protein content and less trypsin inhibitor in the soybean extracts. The changes induced by the gas plasma irradiation in the Soylima beans were more manifest than that in the Lee soybeans, and the degree of changes increased as the treatment energy level was raised.