Abstract

Cactus pear (Opuntia ficus-indica) is a crop cultivated in the central and north regions of Chile, in arid and semiarid zones and until now have a low industrial use. The objective of this study was the characterization of two colored cactus pear pulp (purple and orange) and the preparation of two toppings. Cactus pear toppings were elaborated in the laboratory, according to a selected formulation and then were concentrated close to 67°Brix. Analytical assays were done, total phenolics were measured according to the Folin-Ciocalteau reagent method; betalains were quantified using a photometric method and identified by HPLC analyses. The most important carotenoid pigments were identified by HPLC analyses. Also the stability of the bioactive compounds in the toppings was evaluated. Total phenolics compounds, betalains and the major carotenoid pigments were determined in Cactus pear toppings by Folin-Ciocalteau, spectrophotometric and HPLC methods, respectively. The stability of the bioactive compounds in the toppings was evaluated too. Results shown that the major pigment presents in the cactus pear pulps were betalains. The highest level of betanin was identified in the purple cactus pear pulp (111.0 mg kg -1), whereas the orange pulp showed the highest amount of betaxanthins (89.4 mg kg -1). The total phenolics were 777.4 and 371.9 mg L -1 for purple and orange pulp, respectively. Lower amount of carotenoids such as lutein, lycopene and ß-carotene were found in both pulps. The bioactive compounds, carotenoids, polyphenols and betalains showed degradation close to 90, 50 and 30%, respectively, due to the thermal processing used to prepare the toppings, being the betalains the most stable compounds against the thermal treatment. In conclusion, the purple pulp shows the highest concentration of bioactive compounds; those were susceptible to degradation in the sauce depending on the type of compound. Grant: Universidad de Chile-VID: MULT Project No 06/26-2.