EFFECT OF HEAT-TREATMENT ON THE BIOLOGICAL VALUE OF BETA-CAROTENE ADDED TO SOYBEAN COOKING OIL IN RATS

Vitamin A deficiency is one of the major nutritional problems in the w orld, most common in developing countries. Food fortification is a rec ognised approach to supply vitamins and minerals to needed populations . Vegetable cooking oils were previously suggested by us as a carrier for vitamin A fortification. Fortification of cooking oil with beta-ca rotene could also be a strategy to prevent vitamin A deficiency. The o bjective of this article is to start studies on the use of cooking soy a oil as a vehicle for synthetic carotene, to evaluate its stability t o heat treatment, and to test its bioavailability and bioconversion to vitamin A in rats. Batches of carotene-fortified soybean oil were pre pared, containing 2, 4 and 8 RE/g of diet. Some of them were heated to test its stability. At 100 degrees C there was no loss of carotene, a t higher temperature carotene retention was 65%. The bioavailability a nd bioconversion of beta-carotene added to soybean oil was measured th rough feeding nursing rats and their pups method. Weight gain was good and plasma vitamin A increased significantly in all groups. Liver vit amin A values of rats fed diets with fortified soybean oil heated at 1 00 degrees C was similar to the 4 RE non-heated fortified oil group (0 .72 +/- 0.06 and 0.64 +/- 0.08 mu mol/g, respectively). Heated at 170 degrees C the liver total vitamin A value was reduced (0.45 +/- 0.04 m u mol/g), but kept bioavailable vitamin A equivalent to 2 RE (0.47 +/- 0.09 mu mol/g). Bioconversion of beta-carotene to vitamin A was valid ated by the plasma and liver findings. beta-carotene added to soybean oil showed good stability to heat and its bioconversion to vitamin A w as shown in rat assays, beta-carotene mixed well with edible soybean o il and the fortified cooking oil showed potential as a carrier to be u sed for the prevention of vitamin A deficiency.