Effect of rosemary extracts on the stabilization of frying oil during deep fat frying

Rapeseed oil and a mixture of rapeseed oil with palmolein containing silicone oil were used for preparation of french fries. The intermittent frying was continued for 5 days in a household fryer with replenishment of used oil, The decomposition of polyunsaturated triacylglycerols, formation of polar substances, polymers, colored products and conjugated dienes, but also of several sensory attributes, correlated with frying time. Polymers, dienes and coloration were closely intercorrelated and correlated with sensory characteristics of oil and fries, particularly when multiple regression was applied for prediction. Rosemary extracts inhibited the formation of polar substances, polymers and decomposition of polyunsaturated triacylglycerols, especially in the case of rapeseed oil and improved the sensory attributes of french fries.