and characterisation
and generally involves the use of an acidified extragent.
Common extraction procedures are non-selective and yield pigment
solutions with large amounts of by-products, such as sugars,
sugar alcohols, pectin, organic acids, amino acids and proteins.
Some of these impurities may accelerate anthocyanin degradation
or cause problems in further processing steps, such as freeze drying
or spray drying. Furthermore, the low content of anthocyanins
in raw materials hinders the commercial large scale production of
these pigments. Purification by solid-phase extraction (SPE) is a
relatively simple method allowing the elimination of non-phenolic
impurities. Currently SPE gains wider application as a rapid and
economical process and because different cartridges with a great
variety of sorbents can be used. In addition, it can also be automated
reducing the processing time. Different SPE conditions have