Abstract
The diffusion phenomena of water, solid and reducing sugar in Chinese cabbage during salting (5$0^{\circ}C$, 25% salt solution) and desalting (5$0^{\circ}C$, distilled water) were investigated. Water loss and solid gain during salting were rapid in the first 6hrs and then almost leveled off. After 24hrs of salting, water loss and solid gain in 100g of initial wet Chinese cabbage were 33.35g and 6.26g respectively. Moisture content was changed from 94.29% to 83.11% during 24hrs of salting. The reducing sugar concentration was also changed from 29.2 mg/$m\ell$ to 6.5mg/$m\ell$, which was linearized as a function of the square root of salting time and showing that Y=30.1841-5.0269√t. After 24hrs salting, water gain and solid loss during desalting were rapid in the first 4hrs and then increased linearly. After 12hrs of desalting, the water gain and solid loss in 100g of initial wet Chinese cabbage were 20.82g and 9.14g respectively. The amount of solid loss after 12hrs desalting was higher than that of solid gain after 24hrs salting due to the diffusion of solute presented initially in the Chinese cabbage during salting and desalting. The concentration of salt in Chinese cabbage after 12hrs desalting was 2.98% which was a suitable salt concentration for the preparation of Kimchi. At this time, the concentration of reducing sugar was only 1.6mg/$m\ell$. The linear regression equation of reducing sugar concentration during desalting was Y=6.7854-1.5992√t.
배추의 염절임(5$0^{\circ}C$, 25% 소금용액)및 탈염(5$0^{\circ}C$, 증류수)과정중 침지시간에 따른 물질이동을 수분흡수 또는 유출, 소금유출 또는 흡수 및 환원당유출로써 조사하였다. 염절임 과정중 수분유출과 소금흡수는 초기 6시간 침지과정에서 빠르게 이루어진 후 증가현상이 둔화되었다. 24시간 염절임 과정 후 초기 100g 배추무게당 수분유출과 소금흡수는 각각 33.35g과 6.26g이었다. 염절임과정중 수분함량은 94.29%에서 83.11%로 줄어들었다. 환원당농도 역시 29.2mg/$m\ell$에서 6.5mg/$m\ell$로 낮아졌으며, 침지시간(hr) 의 평방근을 이용한 직선식은 Y=30.1841-5.0269√t이었다. 24시간 염절임 한후 탈염과정에서의 수분흡수와 소금유출은 초기 4시간 침지과정에서 빠르게 이루어진 후 직선적으로 계속적인 증가현상을 나타내었다. 12시간 탈염과정 후 초기 100g배추 무게당 수분흡수는 20.82g이 었으며, 소금유출은 9.14g이었다. 탈염과정에서의 소금유출이 염절임과정의 소금흡수보다 높은 이유는 염절임 및 탈염과정에서 배추의 고형분 유출에 기인된 것이었다. 12시간의 탈염공정으로 김치 제조시 배추의 적정 소금농도인 3%로 낮출수 있었다. 이때의 환원당농도는 1.6mg/$m\ell$로 낮아졌으며, 침지시간의 평방근을 이용한 직선식은 Y=6.7854-1.5992√t로써 염절임 공정의 기울기값 (-5.0269)과 비교할때 탈염공정에서의 환원당 겉보기 유출속도는 낮았다.
(Dept. of Food Engineering, Dankook University)
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