加熱によるダイコンの軟化およびペクチンの分解に関する速度論的解析 <報文>

Kinetic Studies on Softening of Japanese Radish and β-Elimination of Citrus Pectin during Thermal Processes

岡崎 尚

前重 静彦

鈴木 寛一

日本食品科学工学会誌

In order to clarify thermal softening mechanism of vegetables, the softening rate of vegetable during a thermal process was investigated, comparing with the kinetics for a-elimination of pectin. A Japanese radish and a citrus pectin were used as samples. The cylindrical samples (7mmφ × 30mm in length) were cooked in water in a temperature range from 90°C to 110°C using a pressure-vessel. The softening behavior obeyed a first order equation. The softening rate constants and the activation energy were 0.17 × 10-3 s-1 ~ 2.30 × 10-3 s-1 and 146 kJ • mol-1 from 90°C to 110°C, respectively. The pectin solution (0.5% in M/10 phosphate buffer, pH 6.5), which was sealed in a glass tube, was heated in the same temperature range as the Japanese radish. The β-elimination rate of the pectin was also analyzed by using a first order equation. The rate constants of β-elimination and the activation energy were 0.33 × 10-4 s-1 ~ 3.73 × 10-4 s-1 and 143 kJ • mol-1, respectively. Though the rate constants for softening of Japanese radish were approximately 10 times larger than those for β-elimination of the pectin, both activation energies were almost the same values. This result suggests that the softening mechanism of Japanese radish might be closely related with the #-elimination of the pectic substance in the radish.

ダイコンの加熱による軟化速度と柑橘ペクチンの加熱による分解速度を90℃～110℃の温度範囲で測定し, 両者の関係を速度論的に比較した.

(1) 加熱によるダイコンの軟化は, 90℃～110℃の温度範囲で一次の速度式に近似した.

(2) 加熱による柑橘ペクチンの分解は, 90℃～110℃の温度範囲で一次の速度式に近似した.

(3) 加熱によるダイコンの軟化速度と柑橘ペクチンの分解速度は, 90℃～110℃の温度範囲でアレニウス式に従い, みかけの活性化エネルギーは, それぞれ146kJ・mol-1と144kJ・mol-1でほとんど等しかった. このことから, ダイコンの軟化はペクチンの分解によって支されている可能性が高い.

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=44&noissue=9&startpage=647