[Effect of the qualitative characteristics of food products undergoing heat treatment in soybean oil on its tocopherol content].

Non-refined soybean oil was heated for 4 hours at 180 degrees C together with moistened starch or casein. The total tocopherol and individual isomers were determined. Under experimental conditions described there was a considerable loss of tocopherols (49% of the initial amount). The loss of alpha-isomer is regarded to be the most essential from the physiological standpoint. Introduction of carbohydrates (e.g. starch) to the heated oil maked the tocopherol content descend 39.4%, whereas that of proteins (e.g. casein) resulted in a 34.6%-decrease. The product heated in the oil had a selective action on the isomeric composition of tocopherols. Starch heating resulted in a decrease of gamma-isomer losses, casein heating produced the same effect. However, alpha-isomer losses increased. The data obtained indicate the necessity of discounting tocopherol losses on thermal treatment while appraising different culinary dishes and products as vitamin E source in nutrition.