Carminic acid quantification and protein content determination,
in the extracts obtained, were performed in a Varian UV–vis spectrophotometer.
Solid precipitated and lakes obtained were analysed
in a Thermo Nicolet FTIR spectrophotometer. Colourimetric
measurements were performed in an Ocean Optics spectrophotometer
with a CIE1931 standard system. Carminic acid standard,
from Sigma–Aldrich, was used and all solvents and salts were of
analytical grade.