Influence of atmospheric pressure argon plasma treatment on the quality of peanut oil

Abstract

The effects of exposure to atmospheric pressure argon plasma on the quality of edible oil were studied. Peanut oil was exposed to the plasma that was generated in voltages ranging from 150–170 V and the variations of peroxide value, iodine value, acid value, and brightness of the resultant products were monitored. Besides, the storage stability of the radiated peanut oil was investigated as well. Plasma treatment did not change the acid value, but reduced the iodine value and increased the peroxide value and brightness of peanut oil in a voltage‐dependent manner. Compared with control, exposure to the plasma generated in 170 V significantly decreased the contents of oleic acid and linoleic acid by 2.14 and 2.99% respectively, but exhibited no effect on that of palmitic acid. Storage results revealed that the acid value of the treated peanut oils kept increasing in the 30‐day storage period, but the peroxide and iodine values peaked on the 14th and 4th day respectively and then declined gradually. Besides, the voltage‐dependent variation pattern was observed for all the three parameters monitored. Since the peroxide, iodine, and acid values of the treated peanut oil are still in the ranges allowed by the Codex Alimentarius standards, it is concluded that the atmospheric pressure argon plasma treatment does not deteriorate the quality of peanut oil and this technology has potential application in the edible oil industry.A total of 5 mL peanut oil is transferred to a weighing bottle (diameter 40 mm) and exposed to atmospheric pressure argon plasma at a flow rate of 0.5 L/h for 100 s. The voltage of the power supply is set to 150, 155, 160, 165, or 170 V to explore the effects of plasma density on peanut oil quality. Treatment by the plasma generated in voltages 0∼170 V shows no effect on the acid value, but significantly reduces the iodine value, increases the peroxide value, and brightness of peanut oil in a voltage‐dependent manner. Exposure to the plasma generated in 170 V significantly reduces the contents of oleic acid and linoleic acid by 2.14 and 2.99%, respectively, but exhibits no effect on that of palmitic acid.Practical applications: Peanut oil is rich in oleic acid, linoleic acid and other polyunsaturated fatty acids, as well as vitamin E and other nutrients, it also has high nutritional value and pleasant, peculiar flavor. However, aflatoxin B1 (AFB1) which comes from contaminated peanuts is often detected in peanut oil. An alternative that has been presented for the prevention and control of AFs in food is plasma. The plasma is a quasineutral gas of charged and neutral particles which exhibits collective behavior. The domestic and international research indicates that low temperature plasma has a good restraint of tumor cells, the promotion of gene transfection, coagulation and many other aspects. To our knowledge, the report about atmospheric pressure plasma treatment of aflatoxin has not been found in literature. Atmospheric pressure plasma for degradating AFs has the advantages of good safety, high efficiency, environmental friendliness, and is the developing direction of AFs control. In recent years, the development of atmospheric pressure plasma technology have outpaced the traditional low pressure plasma technology because it does not require the use of vacuum equipment, and it shows its advantage of handling large areas of objects more suited to the practical production line. Accordingly, in this paper, acid value, iodine value, peroxide value, chromatic value, fatty acid content and composition, and storage stability are chosen as detection indexes, to study the effects of atmospheric pressure plasma with different voltage on peanut oil quality, in order to provide theoretical basis for the application of atmospheric pressure plasma technology in vegetable oil industry.