In this work, effects of ozone treatment on the inactivation of microorganisms and physicochemical changes
in wheat flour during the storage were evaluated. Total plate count (TPC) in wheat flour was found to be
slightly reduced immediately after ozone treatment, but then significantly (P b 0.05) decreased in the first
few days' of storage. Ozone had more impact on pH value and aw than fatty acid value and water content
of wheat flour. PPO activity in ozone treated flour was significantly inhibited and got slightly lower during
storage. Ozone treated flour presented reduced pasting temperature and increased peak viscosity during
storage, and no obvious changes were detected in the major volatile compounds as shown by the results of
GC–MS. In addition, fresh noodles were made to evaluate the shelf-life extending effect as induced by ozone
and noodles made from treated flour with 4 days' storage presented a better microbial and color stability.
Industrial relevance: This paper presents a new discovery of the non-immediately lethal effect of moderate
ozone treatment on the microorganisms in wheat flour, which also indicates a potential for ozone as the alternative
to chemical oxidants in flour and eliminates the potential residue of hazardous chemicals. Some physicochemical
properties and the sensory qualities can be also improved. The discovery of this phenomenon
would provide a new concept for “low-bacteria wheat flour” production and have important consequences
for the application of ozone in food industry.