Table 2. Correlation coefficient between the contents of antioxidant, antioxidant effects by DPPH-ABTS⁺ radical scavenging activities and reducing power from rice muffins prepared with chestnut powder

	Polyphenol	Flavonoid	DPPH	ABTS+	Reducing power
Polyphenol	1
Flavonoid	0.940**1)	1
DPPH	0.971**	0.946**	1
ABTS+	0.987**	0.949**	0.993**	1
Reducing power	0.987**	0.898**	0.968**	0.980**	1

Significant differences among groups by linear regression analysis and correlation coefficient at ^**p<0.01.