Abstract
Water adsorption characteristics and lipid rancidity of fresh and roasted Peanuts were investigated at $25{\sim}60^{\circ)C$ and $11{\sim}85%$ relative humidity. peanuts of 50g were reached to the equilibrium water content in 14 days at $40^{\circ}C$, in 30 days at $25^{\circ}C$, respectively, in all of the relative humidity. BET monolayer water contents were $2.19{\sim}2.69%$ in fresh peanuts and $2.47{\sim}2.67%$ in roasted ones as dry basis at $25{\sim}40^{\circ)C$. Zero order reaction rate of peroxide value(POV) were $8{\sim}21times$ lower as $0.032day^{-1}$ and $0.142day^{-1}$in fresh peanuts than those of $0.663day^{-1}$ and $1.120day^{-1}$ in roasted peanuts at water activity of 0.51, but those were showed the relatively smaller differences according to the water activity and temperature. The critical peroxide value(POV) and carbonyl value(CV) were determined as 15.0meq/kg and 4.7meq/kg at $60^{\circ}C$ $0.51a_w$ by the regression analysis between chemical and sensory evaluation.
생 및 볶은 땅콩의 흡습특성 및 산패를 온도 $25-60^{\circ}C$와 습도 11-85%RH조건에서 조사하였다. 모든 습도 조건에서 땅콩 50g이 평형수분함량에 도달하는 시간은 온도 $40^{\circ}C$에서 14일, 온도 $25^{\circ}C$에서 30일이 소요되었다. 건물기준 단분자층 수분함량은 생땅콩이 $2.19{\sim}2.69%$이었으며, 볶은 땅콩이 $2.47{\sim}2.67%$이었다. 땅콩의 산패속도는 온도나 습도보다 땅콩의 상태에 따라 크게 차이가 나서, 생땅콩은 볶은땅콩에 비해 $a_W\;0.51$의 경우 과산화물가(POV)의 0차반응상수 K값은 $25^{\circ}C$ 및 $40^{\circ}C$에서 $0.032day^{-1}$ 및 $0.142day^{-1}$ 로 매우 낮은 상태이나, 볶은 땅콩은 같은 조건에서 $0.663day^{-1}$ 및 $1.120day^{-1}$로 $8{\sim}21$배 높게 나타났다. 산패와 기호도향과의 직선회귀식을 이용하여 볶은 땅콩의 저장 한계 POV 및 카아보닐가(CV)를 조사한 결과 $60^{\circ}C$, $0.51a_w$에서 15.0meq/kg 및 4.7meq/kg 으로 나타났다.