• Food Science and Preservation
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• v.1 no.2
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• pp.99-105
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• 1994

To convert the analog signal from the drying process into the digital signal, the interface circuit was designed and built. To measure the weight and temperature during drying process, strain gauge type load cell and temperature transducer composed of pt 100 $\Omega$ thermometers and wheatstone bridge circuits were built and used. The temperature control device was composed of photocoupler and triac. Microcomputer aided experimental convective drying system was built with above cricuits and devices. Drying characteristics of onions can be estimated using this system.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.78-82
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• 1995

A microcomputer drying system, which could be designed to be operated easily and economically, was developed. The optimum drying conditions with this system for onion and ginger were obtained. The temperature, relative humidity, and weight of material were measured and controlled successfully, and the better quality of products was obtained. Optimum drying condition for onion was $65^{\circ}C$ and 25% RH, and for ginger was $50^{\circ}C$ and 25%, respectively.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.72-76
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• 1996

Hot air drying of Lentinus edodes was studied using the microcomputer drying system that can control the drying parameters such as air temperature, relative humidity and a weight-loss of water. The physico-chemical properties of dried products were measured in order to investigate the drying characteristics. The mechanism of water movement during air drying of Lentinus edodes closely followed the Page model. That was $M-M_c/M_0-M_c\;=\;\exp\;(-0.275t^{1.154})$ at $50^{\circ}C$ and 20% RH. The free amino acids increased with increased relative humidity. The color and browning degree increased with increased air temperature and relative humidity. The rehydration rate was low when the air temperature and relative humidity were high.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.65-70
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• 1987

In Girder to measure the pressure and weight decrease of drying sample during the vacuum drying process of food, sensing devices were designed and constructed with strain gauge. Microcomputer based vacuum drying system was made up of these devices interfaced to apple II microcomputer. The electrical output signal from vacuum sensor which constituted with Bourdon tube whereon strain gauge attached were digitalized and input to microcomputer through the MC 6821 interface I.C. chip. The relationship between read-out digital value (D) from microcomputer and readings of vacuum gauge (P, mmHg) was P=-146.136+3.620D'(r=0.9994) The pressure control of vacuum dryer was successfully conducted in the range of $400{\sim}600\;mmHg$ accuracy. The digitalized load cell output (D) could be correlated with the real weight (W, g) as W=-14,000+0.585D (r=0.9998) Drying curves of green red pepper under $64^{\circ}C$, $400{\sim}600\;mmHg$ was similar to those of red pepper and differently affected by the degree of vacuum pressure but was varied according to their shape (cut or whole). Moisture movement of green red pepper during the vacuum drying process was fitted to Page model. The empirical equations obtained were $M-M_e/M_o-M_e={\exp}\;(-0.0673{\theta}^{1.177})$ and $M-M_e/M_o-M_e={\exp}\;(-0.0655\;{\theta}^{1.477})$ for whole and cut green red pepper, respectively.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.200-205
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• 1987

A microcomputer-based on-line monitoring and controlling system was built and applied to the dehycration operation. Drying conditions-drying temperatures and air velocities-were successfully controlled by the control deveices incorporated on/off realy and thyristor, and with the high language program. Drying variables-temperature in drier and weight loss of radish slice were accurately measured and acquisited. The computer-based drying system effectively saved the man power required to measure and record data during the drying period and also made possible to conduct the process undisturbed for long period. The drying rate curves of radish at various drying conditions were obtained from automatic data analyzing program. And also the computer programmed control made possible to investigate the effect of air velocity change during the drying period. The dynamic change of air velocity of from one to another level could be performed and affected markedly the drying rate at first stages of drying, but no significant effect were found in falling rate period.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.550-555
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• 1987

Strain gauges attached on the Bourdon tube and load cell were used as the sensors for measuring the vacuum pressure in drying chamber and the weight loss of Shiitake mushrooms respectively. The vacuum drying system was interfaced further with the Bear II microcomputer. The interface devices used were built with such IC chips as MC 6821, ADC 0809, SN 74244 and SN 7424. The relationship between readings of vacuum gauge (P, mmHg) and digital outputs (D) from the microcomputer was represented by P =3.08 D-13.4875(r=0.9999). The weights of drying sample (W) were also related with the digital outputs (D) by W=0.4076 D-6.4762 (r=0.9999). During the vacuum drying of Shiitake mushrooms. the data on pressure and weight were recorded at regular intervals using an acquisition program on the microcomputer system. The Page model was fitted well to the drying data of Shiitake mushrooms. resulting in the following empirical equations : $(M-M_e)/(M_o-M_e)=\exp(-0.1569t^{1.0048})$ at 400 mm Hg up to 14 hours and $(M-M_e)/(M_o-M_e)=\exp(-0.1385_t^{1.2688})$ at 600 mm Hg up to 8 hours.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.1
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• pp.29-33
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• 1989

As one of the application of microcomputer for data acquisition and temperature control of food drying process, these studies designed and built 'the interface system, measuring sensors of weight and temperature, temperature control system'. The basic and assembly language was used to operating these system. These system measured successfully the variables such as weight and temperature during food drying, and controlled Automatically the drying temperature.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.764-768
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• 1993

This study was developed a computer-controlled automatic drying system. In order to control automatically the temperature, relative humidity weight of the sample, drying system with computer and connecting parts such as microcomputer, PC-Lab card, Op. Amp., and relay system were developed for controlling the heater, fan, humidifier and dehumidifier. Using this system, drying characteristic mechanism of ginseng were investigated. The increase of drying temperature decreased Hunter L value and increased a and b value. The hardness and shrinkage rate of white ginseng had a increasing tendency with the increase of drying temperature. Crude saponin content was not affected by drying temperature and relative humidity.