• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1086-1092
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• 2003

This study was carried out to investigate the effectiveness of blanching on the different drying methods and to examine the quality properties of carrots dried by freeze., vacuum- or hot air-drying during storage. Blanched carrots (BC) dried faster than raw carrots (RC), while RC showed more effective rehydration than BC by hot air- and vacuum-drying methods. There was more stability for BC on carotene retention and browning degree than RC in all drying methods during storage. Moreover, firmness of RC and BC by vacuum-drying was slightly lower than that of hot air-drying, but higher than freeze-drying. In firmness, BC and RC showed similar trends with different drying methods (decreasing with increased storage periods), while BC showed about 3 time firmer texture than RC in all cases during storage. The dried carrots prepared with blanching treatment showed more fine structures than those not treated. These results showed that the blanching treatment of carrots was good for maintaining quality by various drying methods.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.799-804
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• 2002

Optimum conditions of freeze-dried carrots were determined using response surface methodology. Physicochemical and sensory properties of freeze-dried carrot prepared at different plate temperatures and chamber pressures were evaluated. Drying time increased with decreasing plate temperature and chamber pressure. Rehydration ratio decreased inversely with chamber pressure at low plate temperature, but increased proportionally with chamber pressure at high temperature. Density, color, and sensory off-flavor were not affected by the plate temperature and chamber pressure. Sensory color, tenderness, and carrot flavor increased with decreasing plate temperature, but were not affected by chamber pressure. Based on the drying time, rehydration ratio, and sensory attributes, optimum plate temperature and chamber pressure for the preparation of freeze-dried carrot were determined as $43^{\circ}C$ and 700 micronHg, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.111-115
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• 2009

Carrots were dried using 30, 50, and 80% polyethylene glycol (PEG) or maltodextrin as a dehydrating agent, and the dried carrots were compared with the freeze dried and hot-air dried in terms of rehydration ratio, color, carotene content, and sensory evaluation. The amount of moisture loss during drying of carrots using PEG or maltodextrin increased with increasing concentration of dehydrating agent. Rehydration ratio as well as carotene content of the PEG-treated carrots were greater than those of freeze-dried or hot-air dried carrots. Regarding color and sensory evaluation of the dried carrots, the PEG-treated and maltodextrin-treated carrots were better than freeze-dried or hot-air dried carrots. These results suggest that drying of carrots using PEG or maltodextrin is a very efficient method because of its good rehydration capacity and minimal destruction of nutrients and cell structure.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.214.1-214
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• 2003

본 연구는 4~6개월의 유아들을 위하여 재수화시킨 후 숟가락으로 떠먹일 수 있도록 쌀을 기본으로 하고 당근, 쇠고기 및 계란을 각각 주재료로 한 냉동건조 이유식 제조의 최적조건을 결정하기 위하여 수행되었다. 본 연구에서 얻어진 결과를 요약하면 다음과 같다. 당근, 쇠고기 및 계란이유식에서 모두 냉동건조시간은 수분함량이 높고 가열판 온도가 낮을수록 증가하였다. 파쇄성은 수분함량이 감소하고 가열판온도가 증가함에 따라 증가하였다. 관능적 특성 중 수화속도, 균질성 및 매끄러운 정도는 수분함량이 증가하고 가열판 온도가 감소할수록 증가였고, 뜨기 쉬운 정도는 수분함량이 증가할수록 증가하였으나, 가열판온도의 영향은 거의 받지 않았다. 또한 피막형성성은 수분함량과 가열판온도가 증가할수록 증가하였다. 이유식 제조치 최적조건은 당근이유식의 경우 수분함량 88.5%와 가열한 온도 34$^{\circ}C$로, 쇠고기이유식에서는 수된함량 88.5% 와 가열판온도 28$^{\circ}C$로, 그리고 계란이유식에서는 수분함량 87.5%와 가열판 온도 39$^{\circ}C$로 결정되었다.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.209-215
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• 2009

This study was performed to produce the processing factors of pesticides in dried carrot. It is essential data for establishing the maximum residue limits (MRLs) of pesticides in dried carrot. The target pesticides were azinphos-methyl, chlorpyrifos, captan, endosulfan and triclorfon. These pesticides are included Korea's MRL list in carrot and USA's MRL list in dried foods. To infiltrate these pesticides up to each MRL level in carrot, the dipping test was performed in laboratory. Also, the supervised residue trial of the pesticide for carrot was conducted in the green house to recognize the field trial's tendency. In the dipping test in laboratory (including drying examination), the processing factors of the carrot at various concentrations and temperatures could be evaluated. In field test, the processing factors were 5.9 for azinphos-methyl, 1.7 for captan, 7.6 for chlorpyrifos, 6 for endosulfan, 0 for trichlorfon, respectively. The dipping test in laboratory on various kinds of conditions showed more precise processing factors than field trial. The processing factors obtained from the dipping test of carrot were 0~4.7 at the various concentration of the pesticides, and 0~6.7 at various drying temperature. The lower level processing factors were 0~0.6 for trichlorfon and the higher level were 3.0~5.8 for chlorpyrifos. The highest processing factor was 9.1 for captan.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.241-247
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• 1991

The objective of this experiment was to study the effect of dextrin on vacuum frying dried carrots. The concentrations of dextrin solution were 0%, 10%, 20%, 30% and the criteria for quality evaluation were sorption characteristics, rehydration power, color and crispness differences. The sorption characteristics were evaluated by Peleg's equation. Rehydration, color and crispness were determined by rehydration percentage, colorimetry and sensory evaluation, respectively. The dextrin pretreatment of carrot resulted in the reduction of adsorption rate and the equilibrium moisture content of dried carrot at various range of relative humidities, and the adsorption rate of samples pretreated with aqueous dextrin solution at different temperatures($4^{\circ}C,\;20^{\circ}C,\;30^{\circ}C$) were in the following decreasing order : control>10% dextrin>20% dextrin>30% dextrin. As the concentration of dextrin solution and ambient temperature increased, BET monomolecular layer moisture content decreased significantly. In addition, as the concentration of dextrin solution increased, the crispness intensity increased and the color of sample treated with 20% dextrin solution was similar to that of raw carrot.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.313-320
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• 1993

A sublimation model of the freeze drying process, which accounted for the removal of free water, was presented and used to study the operation conditions of freeze driers for carrot juice. It was found that the shortest drying time was obtained when the condenser temperature and chamber pressure were kept at heir lowest values and the plate temperature was controlled independently so that the scorch and melting constraints were both held throughout the drying period. The effect of sample thickness on the drying time was significant. Optimal policies were investigated experimentally in laboratory freeze dryer.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1126-1134
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• 1996

The physical characteristics changes of carrots during drying were studied to minimize the quality degradation by applying improved drying process and pretreatment method. Physico-chemical properties of the product were analyzed, and then, drying mechanisms were explained by diffusion coefficients and drying models. In hot air drying process, the drying and rehydration efficiencies were high at low relative humidity and high temperature. Browning degree and specific volume also showed similar trend to drying efficiency. Diffusion coefficient, which describes moisture transfer, was also high at low relative humidity and at high temperature. It was verified using. Arrhenius equation that drying process was influenced by temperature. It was also observed during experiment that temperature changes were more effective in drying than relative humidity changes. Quadratic model was the most fittable in explaining the process. As a result of analyzing the experimental data with respect to the drying time, the contents of carotene and moisture could be modeled as a polynomial. As the air velocity increased, drying performance and rehydration efficiency increased.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.188-196
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• 2006

Changes in physicochemical characteristics and functional components content of saengsik, uncooked food, were investigated to find efficient drying methods, one of important manufacturing process of saengsik. No changes in proximate compositions of all samples were observed during hot-air drying at 50, 55, and $60^{\circ}C$ and freeze-drying. Colors of carrot, Lentinus edodes, and sea mustard did not change, while a value of cabbage, L, a, and b values of Agaricus bisporos, and a value of laver changed slightly by hot-air drying at all temperatures and freeze-drying. Dietary fiber content increased by hot-air drying but not by freeze-drying. Reductions in vitamin C and ${\beta}-carotene$ contents of carrot, cabbage, sea mustard, and laver were higher by hot-air drying than by freeze-drying. Contents of total phenolics and lectin of L. edodes and A. bisporos were not affected by hot-air drying and freeze-drying. Contents of pectin, alginic acid, and porphyran in sea mustard and laver increased by hot-air drying.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.430-434
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• 1989

The effect on pretreatments with sugar and blanching on the quality of dried carrot flake were investigated. The color of carrot flakes soaking in sugar solution for 2 mins $(60^{\circ}C,\;30 Brix)$ after water blanching $(100^{\circ}C,\;10 min)$ was similar to fresh carrots and the carrot flakes contained relatively high carotene and $Cu^{++}$ values. The osmotic dehydration with sugar solution $(80^{\circ}C,\;40\;Brix)$ prior to air drying reduced browning reaction and shrinkage. According to sensory test, no significant difference occured, after osmotic dehydration, among air drying. But there was a significant difference occured air drying after water blanching.