Recovery of Natural Colour from Flaxseed Hulls and Evaluation of its Bioactivities.

Colour is an important attribute that plays a critical role in the quality of a food
product. It not only affects the appearance but also acceptance of the product. The
current study focuses on the extraction of colour from flaxseed hulls which have
various applications in food, pharmaceutical and cosmetic industries. Colour from the
hulls of flaxseed was extracted using 1% sodium hydroxide (NaOH) solution. The
powdered extract obtained after drying, was soluble in alkali, dilute acid and DMSO.
The powdered form of the extract yielded 26.6 mg/g hull. Physico-chemical
characteristics of the extract revealed the pigment to be similar to melanin. Stability of
the flaxseed colour was checked to determine its potential to be used as a natural
colourant. The extract possessed significant antioxidant activity, when compared to
BHT (known synthetic antioxidant), by DPPH radical scavenging activity, FRAP
assay and β-carotene linoleate model. Antiinflammatory activity was studied by
inhibition of Lipoxygenase (LOX) activity which increased with increase in dose
(IC50 is 0.39 mg). The colour extract had slight antimicrobial activity only against
Listeria sp among the food pathogens studied. Our results reveal that the extracted
colour from flaxseed hulls which is similar to melanin could find applications in food,
cosmetic and textile industry.