To develop a new functional food using koji as a component, we
focused on the heat process for accelerating the physiological effects
of koji. In this study, we showed that heating is an effective way of
enhancing the antioxidant activity of koji and determined appropriate
heating conditions for koji. Furthermore, we measured an increase in
free phenolic and 5-hydroxymethylfurfural food content levels as an
indicator of antioxidant properties attributed to optimal koji
processing.