Changes in α-, β-, γ- and δ-tocopherol contents of mostly consumed vegetable oils during refining process

In this study, the effect of different steps in both chemical and physical refining process on tocopherol contents of several vegetable oils (sunflower oil, corn oil, rapeseed oil, soybean oil, olive oil and refined-bleached-deodorized (RBD) palm oil) was investigated. The most commonly tocopherols found in vegetable oils were alpha- and gamma-tocopherols. Soybean contains 1328 mg/kg tocopherol, which is highest among plant oils. Total tocopherol contents gradually decreased until the end of the refining processes in all oil types. The content of alpha-, beta-, gamma- and delta-tocopherols also decreased during refining. These significant losses occurred especially after the deodorizing stage.