Effect of heat treatment on the biological value of beta-carotene added to soybean cooking oil in rats

Int J Food Sci Nutr. 1998 May;49(3):205-10. doi: 10.3109/09637489809086413.


Vitamin A deficiency is one of the major nutritional problems in the world, most common in developing countries. Food fortification is a recognised 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-carotene could also be a strategy to prevent vitamin A deficiency. The objective of this article is to start studies on the use of cooking soya oil as a vehicle for synthetic carotene, to evaluate its stability to heat treatment, and to test its bioavailability and bioconversion to vitamin A in rats. Batches of carotene-fortified soybean oil were prepared, 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, at higher temperature carotene retention was 65%. The bioavailability and bioconversion of beta-carotene added to soybean oil was measured through feeding nursing rats and their pups method. Weight gain was good and plasma vitamin A increased significantly in all groups. Liver vitamin A values of rats fed diets with fortified soybean oil heated at 100 degrees C was similar to the 4 RE non-heated fortified oil group (0.72 +/- 0.06 and 0.64 +/- 0.08 mumol/g, respectively). Heated at 170 degrees C the liver total vitamin A value was reduced (0.45 +/- 0.04 mumol/g), but kept bioavailable vitamin A equivalent to 2 RE (0.47 +/- 0.09 mumol/g). Bioconversion of beta-carotene to vitamin A was validated by the plasma and liver findings. beta-carotene added to soybean oil showed good stability to heat and its bioconversion to vitamin A was shown in rat assays. beta-carotene mixed well with edible soybean oil and the fortified cooking oil showed potential as a carrier to be used for the prevention of vitamin A deficiency.

MeSH terms

  • Analysis of Variance
  • Animals
  • Biological Availability
  • Dietary Fats, Unsaturated*
  • Female
  • Food, Fortified*
  • Hot Temperature*
  • Liver / chemistry
  • Nutritive Value
  • Rats
  • Rats, Wistar
  • Soybean Oil*
  • Vitamin A / analysis
  • Vitamin A / blood
  • Vitamin A Deficiency / diet therapy*
  • beta Carotene / metabolism
  • beta Carotene / pharmacokinetics*


  • Dietary Fats, Unsaturated
  • beta Carotene
  • Vitamin A
  • Soybean Oil