Betalains and antioxidant activity in fruits of cactaceae from Brazilian semiarid

Several cacti species produce fruits of high nutritional value being source of compounds such as betalains and phenolics that are related to human health. The genus Opuntia has been highly cultivated in Northeastern Brazil due to its high adaptability to water scarcity, although the greater emphasis has being given to the Opuntia ficus-indica, more for its forage potential than for its fruit production. In turn, Tacinga inamoena is an endemic species of the Brazilian Semiarid. Therefore, fruits of these species are still underexploited. Based on that, this study aimed to evaluate the content of betalain and antioxidant activity of different portion of fruits of Opuntia stricta, Tacinga inamoena, and Opuntia ficus-indica. Fully ripen fruits were harvested from plants of different locations of Semiarid. Fruits of O. ficus-indica were evaluated in different portions (mesocarp, pulp, and mesocarp+pulp). Whole fruits of O. strica and T. inamoena were evaluated. The betalain for these cactus fruits presented high variation, being the content for Opuntia stricta far superior. The betaxanthin contents ranged from 1.39 to 46.90 mg/100 g FW, for the whole fruit of T. inamoena and O. stricta, respectively. The different portions of O. ficus-indica fruit presented contents of 13.09, 14.85 and 17.36 mg/100 g FW (mesocarp, endocarp, and whole fruit, respectively). On the other hand, the content of betacyanin varied from 0.64 to 1.94 mg/L for T. inamoena and O. ficus-indica pulp respectively, and O. stricta showed the highest content of 182.27 mg/100 g FW. The total extractable polyphenols content was of 74 mg GAE/100 g for O. stricta, ranged from 14.1 to 32.0 mg GAE/100 g for fruits of other species. The antioxidant activity was higher for O. stricta fruits, with 1730.44 g pulp/g DPPH.. However, biological assays are needed to prove the biological activity of these fruits, providing higher added value to these underexploited fruits.