Abstract:

The optimal process conditions for alkaline extraction, ultrasonic-assisted alkaline extraction and ultrasonic waveassisted alkaline extraction combined with enzymatic hydrolysis of proteins from oat bran were explored by single factor and orthogonal array design methods. The optimized alkaline extraction, ultrasonic-assisted alkaline extraction and ultrasonic waveassisted alkaline extraction combined with enzymatic hydrolysis presented oat protein yields of 31.96%, 39.31% and 61.43%, respectively, and the isoelectric points of the resultant products were 4.6, 3.6 and 3.8, respectively, according to the solubility and precipitation ratios at varying pH conditions and the corresponding precipitation ratios 57.92%, 63.24% and 72.24% at these isoelectric points, respectively. Moreover, the amino acid composition analysis and nutritional evaluation demonstrated that all of the resultant products displayed essential amino acid composition in good agreement with the FAO/WHO pattern. The product resulting from ultrasonic wave-assisted alkaline extraction combined with enzymatic hydrolysis exhibited a higher EAAI when compared to the products resulting from alkaline extraction and ultrasonic-assisted alkaline extraction, indicating a higher nutritional value.

Key words: oat protein, alkaline extraction, ultrasonic wave-assisted alkaline extraction, ultrasonic wave-assisted alkaline extraction combined with enzymatic hydrolysis, amino acid, nutrition evaluation