有色米のクッキーにおける脂質過酸化抑制効果および有色米色素のラジカル消去活性に対する各種処理の影響  [in Japanese] Effect of Colored Rice on the Lipid Peroxidation in Cookies and Effect of Treatments on the Radical-Scavenging Activity of Colored Rice Pigment  [in Japanese]

有色米の加工食品への利用を目的とし, 有色米色素のラジカル消去活性, 耐熱性, 耐紫外線性, 耐塩性, および有色米のクッキーにおける脂質過酸化抑制効果などについて調べた. 1) 紫黒米色素は, アスコルビン酸, α-トコフェロールと同等の高いラジカル消去活性を有していた.赤米色素のラジカル消去活性は紫黒米色素の約1/4であった. 2) 紫黒米, 赤米色素ともに, 90℃, 60分間の加熱においてはラジカル消去活性にほとんど変化がなかった.180℃, 15分間の加熱では, 紫黒米, 赤米色素のラジカル消去活性の残存率はそれぞれ80%, 92%であり, このとき紫黒米色素の残存率は約50%であった. 3) 24時間の紫外線照射により, 紫黒米, 赤米色素のラジカル消去活性の残存率はそれぞれ46%, 39%であり, このとき紫黒米色素の残存率は約50%であった. 4) 有色米色素は塩化ナトリウムに対して安定であった. 5) クッキーの小麦粉を50%有色米に代替した試料において, 50℃, 39日間の保存でPOVの上昇が90%以上抑制された. 6) 官能検査においては, 総合評価で有色米無添加試料と赤米50%添加試料の間には有意差がみられなかった.

The effects of heat treatment, radiation with UV light, and addition of sodium chloride on the radical-scavenging activity of the pigments separated from purple-black and red rice were investigated. The activity of the purple-black rice pigment was as strong as the activity of ascorbic acid and α-tocopherol. The activity of the purple-black and red rice pigment remained at almost the same level during heat treatment at 90℃ for 60min, and more than 80% was retained after 15min of heating at 180℃. Radiation with UV light for 24h resulted in about 50% of the radical-scavenging activity and color intensity of the purple-black rice pigment being retained. The radical-scavenging activity of the colored rice pigment was stable to the addition of sodium chloride. The effect of colored rice on the lipid peroxidation in cookies was also investigated. After 39 days of storage at 50℃, the cookies in which 50% of wheat flour had been substituted by colored rice showed inhibition of the peroxide value by more than 90% relative to the control sample without any colored rice.