Improving the Oxidative Stability of Anhydrous Milk Fat by Adding Natural Antioxidant.

BACKGROUND: Anhydrous milk fat can be obtained in two forms, ghee and butter oil. These products are made by boiling butter at 110-120°C and melting butter at 60-80°C, respectively, to give them their distinct flavor. Ghee is the most popular fatty dairy product in India and Egypt. Lipid oxidation is a major cause of ghee and butter oil deterioration, affecting their flavor, color, and nutritional value. It has been suggested that natural antioxidants can be used, instead of synthetic antioxidants, to retard lipid oxidation. OBJECTIVE: Evaluation of the antioxidant potential of potato peel, fenugreek seed, and ginger rhizome extracts, to study their effect on reducing lipid oxidation, and to monitor changes of ghee and butter oil qualities during storage. METHOD: Ethanol extracts from potato peel, fenugreek seeds, and ginger rhizomes were prepared. Total phenolic compounds of these extracts were determined and 500 and 1000 ppm of each of these extracts were added to either ghee or butter oil treatments. RESULTS: Acid values, peroxide values, and thiobarbituric acid values decreased with the addition of plant extracts to both ghee and butter oil, while they increased during the storage period. Adding 1000 ppm from each extract was more efficient than adding 500 ppm of the same extract. CONCLUSIONS: Ginger rhizome extract was the most effective in reducing lipid oxidation. Ghee treatments were more stable than corresponding butter oil treatments against lipid oxidation. HIGHLIGHTS: This study demonstrates the use of natural antioxidants, instead of synthetic antioxidants, in preserving ghee and butter oil.