Structure, Physico-chemical and Microbiological Properties of Ozone-oxidized Wheat, Corn, Potato and Rice Starches

Abstract

A limited number of studies have been conducted on the effects of ozone use on cereal and its components. Starch, an important natural macromolecule, is an essential component of cereals. In present study, the effects of ozone on the structure, physico-chemical and microbiological properties of wheat, corn, potato and rice starches were investigated. Wheat starch, corn starch, potato starch and rice starch water mixtures were prepared in the ratio of 1:9 (dry sample to water ratio) and treated with ozone at a rate of 60 g/h for 1 hour, while unozonated samples were used as controls. Light microscopy represented that the structures of corn and potato starch samples were affected by 1 hr ozonation rather than the structures of wheat and rice starch samples. Colour of ozone-oxidized wheat, corn and potato starch samples could meet the consumer preference due to the higher lightness, higher whiteness and lower chroma value. However, high chroma, high yellownes and low whiteness values of ozonated rice starch is not adequate for consumer desire. Microbiological analysis showed that 1 hr ozonation reduced the total bacteria and mould/yeast counts significantly for all wheat, corn, potato and rice starch samples (P ＜ 0.05) due to most probably the reduced pH of samples. Ozonation can be an alternative modification technique, but further research is needed to understand the certain benefits and limitations of ozone applications on starch oxidation for human safety and health.