Biothiols, taurine, and lipid-soluble antioxidants in the edible pulp of Sicilian cactus pear (Opuntia ficus-indica) fruits and changes of bioactive juice components upon industrial processing

Biothiols, taurine, and flavonols, as well as tocopherols and carotenoids have been assessed in theedible pulp of Sicilian red (Sanguigna), yellow (Surfarina), and white (Muscaredda) cultivars of cactuspear. The yellow cultivar has the highest level of reduced glutathione (GSH, 8.1 ( 0.78 mg/100 gpulp), whereas the white cultivar showed the highest amount of cysteine (1.21 ( 0.12 mg/100 gpulp). Taurine accounted for 11.7 ( 1.0 mg/100 g in the yellow pulp, while lower levels were measuredin the others. With the exception of kaempferol in the yellow cultivar (2.7 ( 0.2 íg/100 g pulp), theedible pulp of cactus pear was not a source of flavonols. Very low amounts of lipid-soluble antioxidantvitamins such as vitamin E and carotenoids were measured in all cultivars. As a consequence ofindustrial processing, a total loss of GSH and â-carotene and a net decrease of vitamin C and cysteinewere revealed in the fruit juice, whereas betalains, taurine, and vitamin E appeared to be lesssusceptible to degradation.