炊飯過程における米の糊化変化の非破壊・連続計測 <技術論文>

A Non-destructive and Continuous Measurement of Gelatinization of Rice in Rice Cooking Process

羽倉 義雄

鈴木 寛一

日本食品科学工学会誌

A non-destructive and continuous method to measure gelatinization of rice samples in a rice-water system during rice cooking process was examined. An aluminum pot and a lid of a rice cooker were used as two electrode plates, and changes in dielectric properties (capacitance : C, and dielectric dissipation factor : tan δ) of the samples in the rice cooking process were measured by a capacitance meter. Differential scanning calorimetry (DSC) was used to measure gelatinization enthalpy and to determine the degree of gelatinization. Dielectric loss was calculated from the dielectric properties, which changed as the rice cooking process proceeded. Thus, we defined the degree of gelatinization as the value obtained by integrating the dielectric loss with respect to time. The degree of gelatinization based on the dielectric properties was consistent with that based on the DSC. We concluded that the degree of gelatinization in the rice cooking process can be non-destructively and continuously determined by measuring the dielectric properties.

アルミニウム製の鍋と蓋に2枚の電極板としての機能を持たせ, 炊飯過程における米-水系試料の誘電特性の変化を低周波領域で測定し, 以下の結果を得た.

(1) 炊飯過程における電気容量の変化は, 加熱開始5分後から急激に増加し, 沸騰が始まる7分付近でピークを示し, 11分以降は加熱前の水準に戻った. 電気容量の増加が始まった時点の試料温度は米デンプンの糊化開始温度とほぼ一致していた.

(2) DSCによる米の糊化度の変化は, 沸騰直前から急激に糊化が始まり, 加熱開始7分後に50%のデンプンが糊化し, その後糊化速度が緩やかに減少して行く傾向を示した.

(3) 実測した電気容量と誘電正接から誘電体損を求め, これを時間で積分し新たな糊化度を定義したところ, DSC測定により得られた糊化度と良好に一致した.

(4) 以上の結果より, 誘電特性を利用した炊飯過程の米の糊化度の非破壊・連続測定の可能性が示唆された.

家政学・生活科学 [ 590 ]

日本語

日本食品科学工学会

[ISSN] 1341-027X

[NCID] AN10467499

[URI] http://www.journalarchive.jst.go.jp/japanese/jnlabstract_ja.php?cdjournal=nskkk1995&cdvol=49&noissue=6&startpage=416