Flaxseed has gained attention lately due to its content of functional ingredients. This work deals with the preparation of refined protein products from flaxseed flour.
Three protein isolates namely , flaxseed protein isolate I ,prepared by the alkali-
extraction isoelectric precipitation of the protein, isolate II, prepared by alkali
extraction of the protein then spray drying. Isolate III same as isolate II, but freeze
dried. Two flaxseed protein concentrates were also prepared. Concentrate I, prepared
by acid washing at the IEP of the protein and concentrate II, prepared by 80% ethanol
washing. Results revealed that flaxseed protein isolate I was superior to isolate II and
III, regarding its protein content, protein digestibility and functional properties.
Concentrate I was better than concentrate II. Amino acid analysis of the flaxseed
protein products revealed that lysine was the first limiting amino acid followed by
threonine. Chemical score of individual amino acids also confirm the amino acid
content (resulting from analysis) of flaxseed protein products. Essential amino acid
index and biological value were higher for all flaxseed protein products than that fIX
soybean flour. All protein product were rich sources of sulphur amino acids. Protein
products exhibited poor nitrogen solubility as indicated by the nitrogen solubility index,
but had favorable water absorption capacity, oil absorption capacity and emulsifying
capacity.