Oxysterol formation in spray-dried egg processed and stored under various conditions: Prevention and relationship with other quality parameters

A factorial arrangement was planned to study the influence of various factors (spray-drying temperature, antioxidant type, antioxidant concentration, packing conditions, and storage time) on various responses (oxysterol formation, fat UV absorptions, polyunsaturated fatty acid loss, color loss due to oxidation of carotenoids, and Maillard browning intensity) in egg powder. Positive correlations were found between oxysterol formation and the other responses. Use of low spray drying temperatures prevented oxidation during processing and storage of egg powder. Vacuum packing and dark conditions were highly effective in preventing oxidation during storage. Propyl gallate seemed to be slightly effective in preventing polyunsaturated fatty acid loss, oxysterol formation, and color loss during processing and storage, whereas synergistic combination of ascorbyl palmitate plus dl-a-tocopherol seemed to show a slight prooxidant effect in terms of fatty acid and cholesterol oxidation. Propyl gallate concentrations of 100 and 200 ppm seemed to be optimal to prevent, respectively, polyunsaturated fatty acid loss and oxysterol formation and color loss. Propyl gallate seemed to be more effective under highly oxidative conditions.