OIL CONTENT AND FATTY ACID VARIATION IN SEED OF COMMERCIAL CACTUS PEAR (OPUNTIA FICUS - INDICA) IN SOUTH AFRICA - Maryke T. Labuschagne1, A. Hugo2 & B. I. Choane1

1Department of Plant Sciences and 2Department of Microbial, Biochemical & Food Biotechnology, University of the Free State, Bloemfontein 9300, South Africa

Cactus pear (Opuntia spp.) is a drought tolerant crop with low agronomic requirements and high water-use efficiency. Cladodes are used as animal feed, and fruits are sold on the fresh market. The fruits contain a large number of seeds, which sparked interest in possible uses of the seed. The seed of 10 commercial cactus pear cultivars were analysed for oil content and fatty acid composition. The oil content of the seeds was relatively low, with a maximum of 5.7% in Meyers. The oil had a very low palmitic acid content of between 10.9 and 15.0%, much lower than that of cotton oil (about 25%), which is very positive, since palmitic acid is a saturated fatty acid which has recently been found to be less hypercholesterolemic than saturated fatty acids in the range of C12 - C14. Linoleic acid content varied between 57.9 - 65.6 %, which is higher than in cotton oil. Linolenic acids are essential fatty acids, however, less than 3% is preferred for oil stability. The linolenic acid of the cactus pear was less than 1% for all cultivars. The oleiec acid content varied between 11.6 to 15.6%, which is much the same as cotton oil. Oleic acid has the same low-density lipoprotein (LDL) lowering effect as linolenic acid, but is not as susceptible to oxidation as linolenic acid. Unsaturated fatty acids were the major components (on average about 80%), while the saturated fatty acids made up between 14.7 and 18.8%. Other fatty acids that occurred in relatively large amounts (2 - 6%) were stearic acid and vaccenic acid. Cultivars varied for fatty acid composition, which indicates that selection can be made in the desired direction. Therefore, although the oil content of the seeds was relatively low, the fatty acid composition indicates that cactus pear has the potential of producing an oil for the health market.