Betalain profile and antioxidant phytochemicals of Opuntia fruits from Santiago del Estero, Argentina.

CORIA CAYUPÁN, Y. S.; NAZARENO M. A.

Palermo

Congreso; VIII International Congress on Cactus pear and cochineal; 2013

Universitá de Palermo

Cactus pear fruits of the Opuntia genus from Santiago del Estero, Argentina, were collected in order to determine the profile of betalains of these fruits in order to find the best sources for obtaining betaxanthins and betacyanins that can be used to obtain food colorants. Secondly, compounds responsible for the beneficial health properties such as pigments, polyphenols and vitamins were characterized as well as the free radical scavenging activity of different mature Opuntia fruits. Opuntia megacantha (orange and yellow pulp) and Opuntia ficus-indica (yellow, purple and pink) fruits were brought to the laboratory, cleaned and analyzed immediately after harvest. Analyses were performed in triplicate using at least 5 fruits. Results showed highly variable values among the different species studied and even within the same species among different colored fruits. Total Soluble Solids varied between 7.5-12.6°Brix. Ascorbic acid and DHA as vitamers vitamin C was determined by HPLC (0.22-0.71 mg/g). The total phenolic contents were measured by Folin-Ciocalteu method (0.19-0.47 mg GA/g). The ascorbic acid interference was significant. Total betalain contents was determined by UV-Vis spectrophotometry (30-166 ug/g). Betacyanin and betaxanthin profiles were analyzed by HPLC-DAD. The betacarotene content was determined by HPLC to avoid interference from betaxanthins (0.60-1.70 ug/g) and provitamin A value was calculated. Free radical scavenging activities of the fruit extracts were measured using two methods: DPPH and ABTS radicals and results were expressed as ascorbic acid (VCEAC) and Trolox (TEAC) equivalents, respectively. The analyzed fruits are good sources of vitamins and antioxidants and they can be considered excellent alternatives to be incorporated into the diet. The fruits with the highest pigment levels were identified as the best sources to obtain the red and yellow pigments for food colouring and other purposes.