Starch characterization after ozone treatment of wheat grains

• Wheat grains were ozonated in a semi-industrial reactor.
• Ozone treatment does not lead to physicochemical modifications of starch.
• Ozone treatment does not affect starch molecular structure

Soft wheat grains were subjected to oxidation by ozone treatment. A Box Benhken design with three variables (humidification rate, ozone inlet concentration and reaction time) was used for the experiment. Two wheat cultivars differing on their technological properties were used. The products were characterized by determining rheological, thermal and other physicochemical properties such as RVA (Rapid Visco Analyzer), DSC (Differential Scanning Calorimetry), molecular weight distribution and amylopectin branched chain length distribution. Contrary to previous works, results clearly show no significant effect of ozone treatment on wheat starch in our experimental conditions (i.e. starch extracted from ozonated whole wheat grain) whatever the cultivar studied. Only slight increases of carboxyl groups have been noticed with increasing ozonation. Modifications observed on rheological properties in flour samples (i.e. alveographic and RVA measurements) in previous works (Gozé et al., 2015) could mainly be explained by the oxidation of others molecules such as proteins and non-starch polysaccharides.