The ability of chlorine and chlorine-related oxidants to induce oxidative gelation in wheat flour pentosans

Aqueous solutions of water-soluble non-starch polysaccharides (WSNP) were extracted from untreated wheat flours and subjected to various oxidant systems (H 2 O 2 ,-peroxidase, sodium chlorite, gaseous chlorine, chlorine dioxide, chlorine dioxide/peroxidase and ferric chloride). The increase in viscosity of the solutions, as a result of the oxidative gelation of the WSNP, was dependent on both the type of WSNP (cake, cookie and bread flour WSNP) and on the oxidising agent. Bread flour WSNP underwent more extensive gelation with the H 2 O 2 , and ferric chloride systems than did the other WSNP. Bread flour WSNP were the only ones which responded with an increased viscosity to chlorine dioxide in the absence of exogenous peroxidase. With cake and cookie flour WSNP, the presence of the enzyme was necessary to induce gelation. Treatment of cake flour WSNP with gaseous chlorine resulted in the largest increase in flow time recorded for the tested WSNP solutions. The increase in viscosity of the cookie and bread flour WSNP solutions was less pronounced. Treatment of the WSNP solutions with H 2 O 2 /peroxidase or C1O 2 /peroxidase lowered their ferulic acid content. However, no such decrease in ferulic acid content was observed when WSNP solutions were treated with gaseous chlorine.