Mucilage extraction from opuntia spp for production of biofilms

Crops like Opuntia spp grows essentially in the tropical and subtropical regions, under arid climate conditions, preventing soil degradation and being helpful in the control of desertification processes. The fruits are widely used for human consumption and the cladodes are essentially used as feed. The cladodes have in its composition mucilage, a complex polymeric carbohydrate structure with the ability to retard water loss and being able to form viscous or gelatinous colloids. Its gelling, thickening and emulsifying properties turn cactus mucilage useful to be applied in different areas such as cosmetics, pharmaceutical, and some other industries. In the food industry, it could find application in food packaging as edible films and coatings because of its elastic flow characteristic and its ability in forming a molecular network. Therefore, the aim of this work is to develop an efficient and sustainable method to extract the mucilage from the cladodes with characteristics suitable to be used as a biofilm material. The methodologies tested comprised the same general steps: 1) Removal of the outer layers from cladodes; 2) Washing and cutting step; 3) Mix with a solvent (water or ethanol); 4) Pressing or centrifugation; 5) Precipitation with ethanol; 6) Drying step to obtain mucilage powder (drying and lyophilization). Based on preliminary results, a yield (in dry basis) of 0.72 and 15.29%, was obtained for pulp and peel, respectively. A critical assessment of the methods tested indicate that there are still options for improvement (e.g. use of different solvents and solvents mixtures) and that higher yield can be obtained.