Kinetic Studies on the Thermal Degradation of Pantothenic Acid

Pantothenic Acid의 열분해(熱分解)에 관한 속도론적(速度論的) 연구(硏究)

Thermal degradation of pantothenic acid in potassium biphthalate buffer and in food samples such as rice, mushroom and beef was studied as functions of temperature and pH. Thermal degradation of pantothenic acid in buffer and food systems followed first order reaction at temperature between $60{\sim}104^{\circ}C$. Activation energy calculated from the Arrhenius equation ranged from 15,700 cal/mole 17,300 cal/mole for both systems. D values at $120^{\circ}C$ were approximately 18 hours for food samples and 15.4 hours at pH 5.65 for buffer sample. Z values of food samples were about $37^{\circ}C$, which were similar to those of buffer sample. The decomposition rate constant of pantothenic acid in buffer sample decreased when the pH increased from 4.0 to 6.46, but activation energy increased. In the range of $pH\;6.46{\sim}8.0$, decomposition rate constant increased but activation energy decreased as pH increased. The kinetic model of pantothenic acid decomposition in buffer system was proposed on the basis of empirical relationship.

Potassium biphthalate buffer와 쌀, 버섯, 쇠고기에서의 pantothenic acid 열분해속도(熱分解速度)에 미치는 온도(溫度)와 pH의 영향(影響)을 검토하였다. 완충액시료와 식품시료에서의 pantothenic acid 열분해반응(熱分解反應)은 $60{\sim}140^{\circ}C$에서 1차(次) 반응(反應)을 나타내었다. 또한 Arrhenius식(式)으로부터 구한 활성화에너지(Ea)는 $15,700{\sim}17,300\;cal/mole$이었다. 식품시료와 완충액시료의 $D_{120}$을 비교해 본 결과 식품시료가 약 18시간(時間)으로 완충액시료의 15.4시간(時間)보다 높은 것으로 식품시료가 열(熱)에 보다 안정함을 나타내었다. 식품시료와 완충액시료가 모두 $p{\geq}6.46$인 경우에 pH가 증가함에 따라 반응속도상수(反應速度常數)는 증가하였으며 Ea는 감소하였다. 이 실험 결과를 바탕으로 두 pH 범위에서 반응속도상수(反應速度常數)의 온도(溫度) 및 pH 변화에 따론 예측(豫測)모형(模型)을 설정하였다.