Recovery of sinapic acid from mustard bran enzymatic hydrolysate combining membrane filtration and adsorption chromatography

The purification of sinapic acid (SA) from mustard bran hydrolysate through a membrane filtration-adsorption chromatography combined process was developed in this work. Ultrafiltration (UF) treatment (UH030, 30 kDa, 1.4 bar) successfully removed 98 % proteins without influencing SA content. Nanofiltration (NF) treatment (NP010, 1 kDa, 10 bar) removed most solutes larger than 300 Da while allowing 85 % of SA to pass into the permeate. UF or NF alone resulted in 2–3 times increase in SA purity, yet neither process significantly increased the antioxidant activity of the hydrolysate. UF coupled with XAD16 adsorption concentrated SA by 13-fold and increased its purity 40-fold to 20 % w/w (74 % recovery). NF combined with adsorption concentrated SA by 17-fold and increased its purity 110-fold to 55 % w/w (60 % recovery). The purified fraction exhibited strong antioxidant activity. This work has demonstrated that the combined process of membrane filtration and adsorption chromatography is promising for the purification of SA from agro-industrial by-product streams. • Ultrafiltration with 30 kDa cut-off separates proteins from sinapic acid. • Nanofiltration removes solutes larger than ∼ 300 Da. • Combining nanofiltration with adsorption achieves a sinapic acid purity of 55 %. • The purified product shows strong antioxidant potential.