Fractionation of antioxidants from autohydrolysis of barley husks.
The liquid phase from nonisothermal autohydrolysis of barley husks was extracted with ethyl acetate and redissolved in ethanol to yield a crude extract (denoted BHEAE), which was subjected to further processing to enhance the antioxidant activity. A fractionation method, carried out for characterization purposes, consisted of the extraction of BHEAE with organic solvents of increasing polarity and further fractionation in Sephadex LH-20. Among the tested solvents, ethyl acetate allowed the highest yield, phenolic content, and antioxidant activity. Upon elution with methanol, products with high DPPH radical scavenging capacity (IC50 = 0.22 g/L) were obtained. The major compounds in the isolate were benzoic and cinnamic acids. Adsorption-desorption in commercial polymeric resins was carried out as an alternative strategy for BHEAE refining. This method is more suited for possible scale-up and provided a concentrate with a Trolox equivalent antioxidant capacity of 9 mM, which was obtained at a yield of 18 g/kg of barley husks.
Conde
Enma
E
Departament of Chemical Engineering, University of Vigo, Edificio Politécnico, Ourense, Spain.
Moure
Andrés
A
Domínguez
Herminia
H
Parajó
Juan Carlos
JC
D000085:Acetates; D000327:Adsorption; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology; D019817:Benzoic Acid / Q000302:isolation & purification; D005591:Chemical Fractionation; D002934:Cinnamates / Q000302:isolation & purification; D001467:Hordeum / Q000737:chemistry*; D006868:Hydrolysis; D010936:Plant Extracts / Q000737:chemistry; D012117:Resins, Synthetic; D012639:Seeds / Q000737:chemistry*; D012997:Solvents
D000085:Acetates; D000975:Antioxidants; D002934:Cinnamates; D010936:Plant Extracts; D012117:Resins, Synthetic; D012997:Solvents; C029010:cinnamic acid; C007650:ethyl acetate; D019817:Benzoic Acid