Kinetics of pH Changes during Thermal Degradation of MSG under Model System

Model System 하에서 MSG 열분해 중 pH 변화의 속도론적 연구

  • Cha, Bo-Sook (Department of Food and Nutrition, Su Won Women's Junior College) ;
  • Han, Min-Soo (Miwon Research and Development Center) ;
  • Kim, Woo-Jung (Department of Food Science and Technology, King Sejong University)
  • 차보숙 (수원여자전문대학 식품영양과) ;
  • 한민수 (미원기술연구소) ;
  • 김우정 (세종대학교 식품공학과)
  • Published : 1992.06.01

Abstract

Effect of temperature and initial pH were studied on the pH change of MSG solution during heating. The heating temperature and initial pH of 2% MSG solution were in the range of $100{\sim}120^{\circ}C$ and $pH\;2{\sim}9$, respectively. The results showed that the pH of MSG solution was more rapidly decreased as the temperature increased and the initial pH decreased due to pyroglutamic acid formation from MSG thermal degradation. A linear relationship was obtained between pH decreased and logarithmic value of heating time and the decreasing rate constant of pH were calculated from the slope. The pH decreased$({\Delta}pH)$ after 3 hrs of heating was 1.2 at the initial pH 4 and $120^{\circ}C$ and 0.33 at pH 5 and $120^{\circ}C$ while little pH change measured at the range of $pH\;6{\sim}9$. Activation energy calculated for pH decrease during heating was 11.77 and 22.26 kcal/mole at pH 4 and pH 5, respectively.