Extraction of phytic acid and preparation of protein isolates from rapeseed meal

Phytic acid and protein are two kinds of valuable components in rapeseed meal. To improve comprehensive utilization in this research, phytic acid was extracted with acetum from double-low coldpressed rapeseed meal, and protein was recovered from the crude extract of phytic acid by membrane separating technology. The meal residue was dried to extract protein, which was then purified by ultrafiltration to obtain high purity product. Extraction conditions of phytic acid were optimized by response surface methodology (RSM) as follows: mass fraction of acetic acid 0.7%, extraction temperature 48℃, liquid-to-solid ratio 10 mL/g, extraction time 1.6 h. Under this condition, extraction yield was 1.865%. Protein recovered and phytic acid loss accounting for rapeseed meal were 3.63% and 0.395% respectively in crude extract of phytic acid. Purity of the protein refined by ultrafiltration was between 70% and 90%, in which the content of polyphenols was significantly reduced and no phytic acid and glucosinolates could be detected.