Nopal cladode (Opuntia ficus-indica) flour: Production, characterization, and evaluation for producing bioactive film

Abstract Nopal cladode flour (NC) was prepared by milling and sieving, and its use in edible film production was evaluated. NCs with different granulometry were produced (NC-45, NC-80, and NC-120), and their chemical composition, physical properties (analyzed by SEM, XRD, and FT-IR), phenolic compounds content, and antioxidant activity were characterized. The FTIR spectra of NCs showed bands related to proteins, fibers, lipids, sugars, and pectin. The XRD pattern of NCs showed the presence of crystallites related to calcium salts and peaks due to cellulose type I and hemicellulose. NC-120 presented the smallest average particle size (166 μm), the lowest carbohydrate content (72%), and the highest lipid content (2.9%) and antioxidant activity, so it was chosen to prepare starch/NC120 composite films by casting; glycerol was used as plasticizer. NC120 addition to the starch matrix did not improve the mechanical resistance of the film, but it decreased the permeability to water vapor and enhanced the phenolics compound content (13.67 ± 0.5 mg of GAE/g of film) and the antioxidant activity measured by DPPH• and ABTS•+ radicals. Thus, NC has potential application as bioactive compound for the development of starch-based composite films with antioxidant activity.