• Korean Journal of Food Science and Technology
• /
• v.22 no.6
• /
• pp.690-695
• /
• 1990

The adsorption characteristics of coffee were mvestigated at $5, 15, 25, and 35^{\circ}C$ under various water activities such as 11, 32, 57, 75 and 90% and prediction models were developed by optimization program. The moisture adsorption isotherm curves were similar to the typical sigmoid type. The values of equilibrium moisture content and the monolayer moisture content were highest in the Freeze Dried, which was due to porous structure by the drying method. In the result of adjusting the isotherm models in this paper, Halsey model generally gave the best fit for isotherms of coffee. Prediction model for equilibrium moisture content was established with water activity and temperature. Adsorption prediction models were also developed with water activity, with water activity and time, and with water activity, time and temperature, respectively.

• Korean Chemical Engineering Research
• /
• v.54 no.1
• /
• pp.81-88
• /
• 2016

Limonene is orange flavored natural material that is mainly contained in mandarine and lemon peels. D-limonene was extracted from cold-storaged mandarine peel by using Soxhlet extractor at $120^{\circ}C$ for 2 hours with ethanol as solvent. Henry constants of d-limonene and impurity were calculated as $H_{Lim}=8.55$ and $H_{imp}=0.223$ from the result of HPLC analysis. 4-bed SMB of limonene simulation with $0.46{\times}25cm$ columns was conducted by using Aspen chromatography program. Then effective condition for purity was found by changing $m_2$ and $m_3$ values in triangle diagram. The highest purity was 98.59% at $m_2=2.57$, $m_3=9.55$. For this case, feed, desorbent, extract, and raffinate flow rates were 1 mL/min, 1.19 mL/min, 0.857 mL/min and 1.34 mL/min, respectively. Scale-up simulation was also conducted by increasing column diameter from 0.46 cm to 1.6 cm for getting the same efficiency. The increased flow rates were 12 mL/min, 14 mL/min, 10 mL/min, and 16 mL/min for feed, desorbent, extract, and raffinate. It was possible to scale-up with maintaining same limonene purity because linear isotherms of limonene and impurity were assumed.