Extraction and functional properties of barley proteins

Barley proteins may possess unique properties that could be utilized in value-added products. Proteins were extracted from Candle (waxy) and Condor (regular) barley grains, quantified and their functional properties were determined. Starch and beta-glucan were concentrated in the pearled grain flour (19% PGF) while protein, lipid and ash were concentrated in the pearling flour (19% PF) with the proteins having a favorable amino acid profile. The NaOH extraction at pH 11/23°C resulted in the highest (P ≤ 0.05) protein recovery and purity whereas beta-glucan and starch could be isolated with NaOH or Na2CO3 at pH 11/50°C. The hordein content (42-45%) was highest in 19% PGF while 19% PF of Condor contained 64% of globulins. Barley protein concentrates have high hydration capacity (4-7 g water/g protein), foaming capacity (200-437%) and stability (72-88%) and can form stable emulsions. Alkali-extracted barley proteins show potential as functional and nutritional ingredients in various foods products.