Effect of the cactus cladodes peeling in the functional, technological and chemical characteristics and bioactive compounds in cactus cladodes powders

The objective of this research is to study the functional, technological and chemical characteristics of 2 types of cactus cladodes powder (with and without epidermis). Cladodes from 2-3 years from a Garden variety of the University of Chile were used. The cladodes previously washed and sliced (0.5 cm), were dried in an air forced tunnel (80°C by 6 hours). Two grindings were realized until a particle size was reached close to 200 µm using blades mills. Apparent density (g ml-1), moisture (g 100 g-1), water retention capacity (WRC), swelling capacity (SWC) (g ml-1), fat absorption capacity (FAC), and dietary fiber (SDF and IDF) were determined in the powders. The antioxidant capacity was measured using the DPPH method (TEAC and EC50). The polyphenols content was determined using the Folin-Ciocalteu reagent (mg GAE 100 g-1). The data were analyzed by ANOVA using Stat Graphics plus 5.1 program. The results showed that there was no differences (p<0.05) in the technological characteristics of the powders for moisture, WRC, SWC, FAC and for insoluble fiber (IDF) content. Nevertheless, there were significant differences for the soluble dietary fiber (SDF) and for the bioactive composition; where the powder from cladodes with epidermis have a greater SDF content (14.33+/-0.27 g 100 g-1) and phenolic concentration (4.32+/-0.06 mg EAG g-1) and antioxidant capacity (1.86+/-0.02 TEAC), compared to powders obtained from cladodes without epidermis (9.15+/-0.19 g 100 g-1, 2.96+/-0.07 mg EAG g-1; 1.03+/- 0.05 TEAC, respectively). The unexpected difference in the soluble fiber content can be attributed to the peeling that it could eliminate part of the epidermis layers containing mucilage, which are part of the soluble fiber. In conclusion the use of whole cladodes, besides avoiding the peeling, provides powders with greater dietary fiber and bioactive compounds content.