Chlorella vulgaris biomass used as colouring source in traditional butter cookies

A study was undertaken to determine the effects of Chlorella vulgaris biomass as a colouring ingredient in traditional butter cookies. The cookies were manufactured at a pilot scale and stored for 3 months at room temperature, protected from light and air. The effects of C. vulgaris incorporation on the biscuits' colour were tested weekly during the first month, and monthly afterwards, for a total period of 3 months. C. vulgaris cookies presented an accentuated green tonality, which increased with the quantity of added biomass. The colour parameters of the cookies remained very stable along the storage period. The texture of the cookies was also evaluated, and a significant increase of their firmness was evidenced with an increase of added microalgal biomass. This work is set out as an example of the possibility of imparting a green colour relatively non-perishable food product, using a naturally occurring product. Green colouring is relatively difficult to impart, especially when using only natural products. Chlorella sp. has been and is used as a food supplement, and the authors found that the stable non-perishable tonalities obtained were agreeable to the consumer. It is therefore concluded that a possibility of developing similar products exists.