Extraction pathways and purification strategies towards carminic acid as natural-based food colorant: A comprehensive review.

As a current trend of fabricating healthier products, food manufacturing companies seek for natural-based food colorant aiming to replace the synthetic ones, which apart from meeting sensorial and organoleptic aspects, they can also act as health promoters offering additional added value. Carminic acid is a natural based food colorant typically found in several insect taxa. However, there are current approaches which pursue the production of this natural pigment via biotechnological synthesis. To date, this colorant has been intensively applied in the manufacture of several food items. Unfortunately, one of the main limitations deals with the establishment of the right protocol of extraction and purification of this component since there is no report analyzing the main extraction techniques for obtaining carminic acid. Therefore, this review, for the first time, comprehensively analyzes the ongoing strategies and protocols proposed by scientists towards either extraction or purification of carminic acid from its origin source, and from biotechnological systems. Emphasis has been focused on the main findings dealing with extraction techniques and the relevant insights in the field. A detailed discussion is provided on the advantages and drawbacks of the reported extraction and purification methods, main solvents used and their key interactions with target molecules.

Laccase induction by synthetic dyes in Pycnoporus sanguineus and their possible use for sugar cane bagasse delignification.

The use of synthetic dyes for laccase induction in vivo has been scarcely explored. We characterized the effect of adding different synthetic dyes to liquid cultures of Pycnoporus sanguineus on laccase production. We found that carminic acid (CA) can induce 722 % and alizarin yellow 317 % more laccase than control does, and they promoted better fungal biomass development in liquid cultures. Aniline blue and crystal violet did not show such positive effect. CA and alizarin yellow were degraded up to 95 % during P. sanguineus culturing (12 days). With this basis, CA was selected as the best inducer and used to evaluate the induction of laccase on solid-state fermentation (SSF), using sugarcane bagasse (SCB) as substrate, in an attempt to reach selective delignification. We found that laccase induction occurred in SSF, and a slight inhibition of cellulase production was observed when CA was added to the substrate; also, a transformation of SCB under SSF was followed by the 13C cross polarization magic angle spinning (CPMAS) solid-state nuclear magnetic resonance (NMR). Results showed that P. sanguineus can selectively delignify SCB, decreasing aromatic C compounds by 32.67 % in 16 days; O-alkyl C region (polysaccharides) was degraded less than 2 %; delignification values were not correlated with laccase activities. Cellulose-crystallinity index was increased by 27.24 % in absence of CA and 15.94 % when 0.01 mM of CA was added to SCB; this dye also inhibits the production of fungal biomass in SSF (measured as alkyl C gain). We conclude that CA is a good inducer of laccase in liquid media, and that P. sanguineus is a fungus with high potential for biomass delignification.