Quality by design approach to optimize cladodes soluble fiber processing extraction in Opuntia ficus indica (L.) Miller.

Opuntia ficus indica by-products can be exploited as sources of high-value components for applications in food and other industries. The aim of the present work is to elucidate and optimize the mucilage extraction process from cladodes. The effect of five water-to-biomass ratios (1:1, 1:3, 1:5, 1:7, 1:9 w/v), pH range (2.0, 4.5, 7.0, 9.5, 12.0) and ionic strength (water supplemented with NaCl or CaCl2 at the concentration of 0.1, 1.0, 10.0 and 100.0 mM) were evaluated on mucilage yield. The analysis of the critical factors was done by the response surface methodology. Ultrasound and microwave assisted extractions were evaluated to improve the mucilage recovery and quality. In this work: (1) the development of a multivariate model to predict mucilage recovery on the basis of biomass/water ratio and time of extraction; (2) pH, ionic strength and temperature were found critical process variables by the application of Plackett-Burman design; (3) the optimal operating conditions obtained were found to be: 1:9 biomass/water ratio, pH 12.0, ionic strength 1.0 mM NaCl; (4) ultrasonic or microwave treatments are efficient tools to enhance the recovery of mucilage depending on its final uses. Within a multi-disciplinary approach, this work provides achievements for a more efficient extraction process of soluble polymers from cladodes. Further studies on green assisted extraction tools and their effects in terms of quality of extracts are required in order to obtain high added value bio-products.