Development and Characterization of Edible Films Based on Mucilage of Opuntia ficus‐indica (L.)

Abstract

Mucilage of Opuntia ficus-indica (OFI) was extracted and characterized by its composition and molecular weight distribution. Mucilage film-forming dispersions were prepared under different pHs (3, 4, 5.6, 7, and 8) and calcium concentration (0% and 30% of CaCl(2), with respect to mucilage's weight), and their particle size determined. Mucilage films with and without calcium (MFCa and MF, respectively) were prepared. The effect of calcium and pH on mucilage films was evaluated determining thickness, color, water vapor permeability (WVP), tensile strength (TS), and percentage of elongation (%E). The average molecular weight of the different fractions of mucilage was: 3.4 x 10(6) (0.73%), 1 x 10(5) (1.46%), 1.1 x 10(3) (45.79%), and 2.4 x 10(2) Da (52.03%). Aqueous mucilage dispersions with no calcium presented particles with an average size d(0.5) of 15.4 microm, greater than the dispersions with calcium, 13.2 microm. MFCa films showed more thickness (0.13 mm) than the MF films (0.10 mm). The addition of calcium increased the WVP of the films from 109.94 to 130.45 gmm/m(2)dkPa. Calcium and pH affected the mechanical properties of the films; the largest TS was observed on MF films, whereas the highest %E was observed on MFCa films. The highest differences among MF and MFCa films were observed at pHs 5.6 and 7 for TS and at pHs 4 and 8 for %E. No effect of pH and calcium was observed on luminosity and hue angle. Chroma values were higher for MF when compared with MFCa, and increased as pH of the films increased. Practical Application: In this study mucilage from nopal was extracted and characterized by its ability to form edible films under different pHs, and with or without the addition of calcium. Opuntia ficus-indica mucilage had the ability to form edible films. In general, it can be considered that mucilage films without modification of pH and without the addition of calcium have the best water vapor barrier properties and tensile strength. Mucilage from nopal could represent a good option for the development of edible films in countries where nopal is highly produced at low cost, constituting a processing alternative for nopal.

Towards Drylands Biorefineries: Valorisation of Forage Opuntia for the Production of Edible Coatings

“…The ash content in the mucilage was 13.14%, which is similar to the values reported by Rodríguez-González et al [28] and Rodríguez-González [27] for the mucilage of O. atropes and O. ficus-indica, i.e., 11.91% and 14.01%, respectively. The protein content in the mucilage was 1.11%, which is quite similar to the value measured by Espino-Díaz et al [9] in O. ficus-indica (1.04%) using the same analytical method. Finally, the crude fibre content was 55.92%, which is also similar to the values (57.71% and 57.23%) measured in the mucilage of O. atropes and O. ficus-indica, respectively, by Rodríguez-González et al [28] and Rodríguez-González [27].…”

“…The average moisture content in the mucilage was 7.75%, which is lower than that reported by Espino-Díaz et al [9] and Rodríguez-González [27], who obtained mean values of 12.43% and 9.31%, respectively, in the mucilage of O. ficus-indica. These differences may be due to the storage temperature and drying time, since the mucilage is highly hygroscopic.…”

“…It generates gels that retain large amounts of water and have good emulsifying characteristics. Among other applications, the mucilage of O. ficus-indica has been employed to produce edible films with good mechanical properties [9,10]. Edible films and coatings are defined as any material used for encapsulating food to extend the shelf-life of the product, that may be eaten with the food with or without removal of the material [11].…”

Effect of edible coatings on bioactive compounds and antioxidant capacity of tomatoes at different maturity stages

“…The used of edible coating has received more attention in recent years, due to the growing interest for reducing environmental pollution caused by plastics, the need to extend the shelf life of foods, and the increasing demand for healthier and ecological foods (Espino-Díaz et al 2010). Edible coatings are composed of hydrocolloids (polysaccharides or proteins), hydrophobic compounds (lipids or waxes) or a combination of both (composite coatings) that may enhance the coating properties for optimal handling (Espino-Díaz et al 2010).…”

“…Edible coatings are composed of hydrocolloids (polysaccharides or proteins), hydrophobic compounds (lipids or waxes) or a combination of both (composite coatings) that may enhance the coating properties for optimal handling (Espino-Díaz et al 2010).…”