Effect of Freezing, Thawing and Blanching on the Pigment of Purple Sweet Potato

동결, 해동 및 Blanching이 자색고구마 색소에 미치는 영향

  • Kim, Seon-Jae (Department of Food Engineering, Mokpo National University) ;
  • Rhim, Jong-Whan (Department of Food Engineering, Mokpo National University)
  • 김선재 (목포대학교 식품공학과) ;
  • 임종환 (목포대학교 식품공학과)
  • Published : 1997.02.01


The effect of freezing, thawing and blanching on the change of extractable pigment content of purple sweet potato (PSP) was investigated. Freezing at $-5^{\circ}C$ was more effective than freezing at $-20^{\circ}C\;or\;-40^{\circ}C$, and rapid thawing methods such as microwave heating or hat air blast heating were effective than slow thawing methods such as thawing at $4^{\circ}C\;or\;20^{\circ}C$. Inactivation of enzymes, which cause pigment destruction during thawing, by blanching before freezing was necessary to obtain the highest possible amount of extractable pigment from PSP. Microwave blanching for $3{\sim}4$ min or hot air blanching for $10{\sim}15$ min were effective in extracting pigment from PSP.