Antioxidant content and potential of fresh and processed cladodes and fruit from different coloured cactus pear (Opuntia ficus-indica and Opuntia robusta) cultivars

English: Different coloured cactus fruit, peel, seeds and cladodes were studied for antioxidant content and -capacity in fresh products. Fruit and cladodes from seven different cultivars from the O.ficus-indica spp. and one of O. robusta spp. were collected representing the four colours of fruit available namely, green, pink, orange and purple. It was found that fresh cactus pear fruit and cladodes contained exceptionally high levels of Ascorbic acid, Total Phenolics and Betalains and modest amounts of Carotene. Antioxidant potential remained at very high levels regardless of the specific antioxidant content. The highest antioxidant content and -capacity were found in purple (O.robusta Robusta) fruit and cladodes, attributed to the high levels of Betalains. Ascorbic acid, working synergistically with Phenolics, was found to provide almost as much antioxidant capacity to orange fruit coloured cultivars. It was thus found that cultivars with purple and orange fruit and cladodes were the best in regards to antioxidant content as well as -potential. Five cultivars, representing the four colours were further investigated by processing into different products in order to determine the influence that preservation techniques had on the antioxidant content and potential in the fruit, peel and cladodes. Juice, dried products, chutneys, whole preserves and pickles were prepared from the fruit (pulp), peel and cladodes of the five different coloured cultivars that attained the highest values in the fresh study. Betalains were retained in processed products; Ascorbic acid was mostly preserved in the processed products that involved minimal heat treatments, while Carotene and Phenolics increased after processing. Processed cladodes, more than fresh cladodes, from all the cultivars, were concluded to provide an excellent source of antioxidants and could be suggested for products such as cladode flour and pickles. The peel in general was found to contain very similar antioxidant content and potential as the fruit and should be included in products when possible. In fruit, the purple fruit is highly recommended for processing, as it displayed the highest antioxidant potential in its fresh form and maintained these levels in processed product. Dried fruit is the product with the highest source of antioxidants to the consumer. Juice and chutney from pink or orange fruit would also provide products that the South African consumer is accustomed to with exceptionally high antioxidant potential. The study brings to light the potential that cactus pear products have for the food industry. It could be developed into a profitable industry if the public could be made aware of the health benefits that they provide.