Evaluation of deodorization techniques using cyclodextrins on the headspace volatiles and antioxidant properties of onion

Sulphur-containing volatiles in onion produce unpleasant odors and this limit their usage in foods. To expand its application, several additives including α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), and chitosan were added to onion solution and evaluated for their effect on sulphur-containing volatiles. Also, antioxidant property using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and oxidative stabilities in an oil-in-water (O/W) emulsion were carried out. The total volatile contents were decreased in the order of α-CD (50.1%), β-CD (49.3%), HP-β-CD (46.2%), and chitosan (7%). Meanwhile, HP-β-CD showed the highest DPPH radical scavenging ability followed by β-CD, α-CD, and chitosan with decreasing order. The β-CD significantly enhanced the oxidative stability of the O/W emulsion, whereas α-CD and β-HP-CD showed prooxidative behavior. Overall, β-CD might be used as a sulphur-containing volatile decreasing agent, which could keep the antioxidant properties of onion in the O/W emulsion.