Rosa Beatriz Cabrera

• Carminic acid (E 120) is a natural colorant extracted from cochineal e.g., the desiccated bodies of Dactylopius coccus Costa female insects. The major usage of Natural Red lies in the food, cosmetic and pharmaceutical industries. The recovery and purification of carminic acid from raw cochineal is regarded as a difficult and complicated process. Current industrial technology suffers from low and irreproducible yields while generating a low quality final product. An improved strategy for the downstream processing of carminic acid was developed. Beaded adsorbents were screened and subsequently tested in packed-bed and finite bath contactors. Efficient adsorption and desorption conditions were found for two resin types. Different mass transfer resistance mechanisms were identified. Fluid side effects and intraparticle resistance mechanisms were dominating. This was quantitatively described in terms of film mass transport coefficients and particle diffusivities. Employing batch adsorption in an agitated vessel in combination with a macroporous beaded adsorbent showed a dramatic increase in sorption performance as a function of the fluid regime in the vessel. A hybrid mechanism including a perfusion like component can be hypothesized in order to explain these experimental findings. Quantitative evaluation of these events required the definition of a modified pore mass transfer coefficient or hyperdiffusivity, which is able to account the influence of mixing on sorption kinetics. The knowledge generated served as the basis for the design of an adsorption process at the pilot scale. The process yielded a high quality carminic acid preparation. The final product complied with food industry regulations and it was free of toxic metal ions and allergenic components. Process productivities compared favorably with current manufacturing schemes. General criteria for further scale-up are provided.