A Novel Spectrophotometric Method for Determining the Peroxide Value of Edible Oils

Abstract

This study introduces a novel spectrophotometric method to sensitively and specifically determine the peroxide value of edible oils, specifically engineered to overcome the significant analytical interference of carotenoid pigments that have historically compromised traditional methods. The method uses a solution containing ferrous (Fe2+) ions and either salicylic acid (SA) or sulfosalicylic acid (SSA). Next, these Fe2+ ions are reacted with a sample of edible oil in the presence of peroxide, forming ferric (Fe³⁺) ions. In the next step, the Fe³⁺ ion forms a complex with SSA (or SA), resulting in a ferrisulfosalicylate (or sulfosalicylate) complex that exhibits a unique color. This color change was utilized for measuring lipid peroxides. It provides a rapid, simple, and sensitive method for detecting and quantifying peroxides. SSA and SA can form complexes that absorb light at 505 and 525 nm, respectively. When this new method was compared to Ferrous Oxidation-Xylenol Orange (FOX) and ferrithiocyanate methods, it showed an impressive correlation (Pearson's r = 0.99). This study demonstrates that the proposed method is effective in determining the peroxide value in the various types of edible oils examined.