Comparison of five analytical methods for the determination of peroxide value in oxidized ghee.

In the present study, a comparison of five peroxide analytical methods was performed using oxidized ghee. The methods included the three iodometric titration viz. Bureau of Indian Standard (BIS), Association of Analytical Communities (AOAC) and American Oil Chemists' Society (AOCS), and two colorimetric methods, the ferrous xylenol orange (FOX) and ferric thiocyanate (International Dairy Federation, IDF) methods based on oxidation of iron. Six ghee samples were stored at 80 °C to accelerate deterioration and sampled periodically (every 48 h) for peroxides. Results were compared using the five methods for analysis as well as a flavor score (9 point hedonic scale). The correlation coefficients obtained using the different methods were in the order: FOX (-0.836) > IDF (-0.821) > AOCS (-0.798) > AOAC (-0.795) > BIS (-0.754). Thus, among the five methods used for determination of peroxide value of ghee during storage, the highest coefficient of correlation was obtained for the FOX method. The high correlations between the FOX and flavor data indicated that FOX was the most suitable method tested to determine peroxide value in oxidized ghee.