• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.422-427
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• 1994

The quality of salted and semi-dried mackerel prepared by cold osmotic dehydration using a high osmotic pressure resin during storage at $5{\pm}1^{\circ}C$ was evaluated. The moisture contents in salted and semi-dried mackerel decreased in. range of 4 during storage. The brown pigment formation content and peroxide value of salted and semi-dried mackerel prepared by osmotic dehydration were more lower than those of salted and semi-dried mackerel prepared by traditional drying methods such as sun-drying, hot-air drying and cold air drying. The viable cell count and histamine contents of cold osmotic dried products were much lower and revealed a tendency to increase during storage, but even these values after storage of 15 days showed that the salted and semi-dried mackerel was safety in respect of food sanitation. The ratio of saline soluble nitrogen to total nitrogen in cold osmotic dried products were higher than that of traditional dried products during storage. Judging from the results of chemical and sensory evaluation, shelf-life of salted and semi-dried mackerel by cold osmotic drying were more longer than that of salted and semi-dried mackerel prepared by traditional drying.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.135-142
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• 2004

The objective of this study was carried out to determine which method is effective for improving seed germination in carrot and onion among osmotic or solid matrix priming. Seeds were osmotic primed with -0.5 MPa polyethylene glycol 8000 (PEG) solution and solid matrix primed with Micro Cel E (seed, Micro Cel E, and water mixed with the ratio of 4.0：2.0：8.0 by weight for carrot, and the ratio of 4.0：1.2：5.0 for onion at $20^{\circ}C$ for 4 days). Seeds were rapidly absorbed water after osmotic priming and solid matrix priming treatment. The moisture content of solid matrix primed seeds was lower than that of osmotic primed seeds in carrot and onion. Osmotic priming and solid matrix priming did not influenced on increasing of percent germination, but $T_{50}$ of treated seeds was shorter than those of untreated seeds at four temperature regimes. The effects of osmotic or solid matrix priming in reducing the $T_{50}$ was greater when the seeds were germinated at $15^{\circ}C$ than at $25^{\circ}C$ and $30^{\circ}C$ temperature. Solid matrix primed seeds germinated faster than osmotic primed seeds at all temperature in both carrot and onion. After priming, surface-dried seeds germinated faster than dried-back seeds in carrot and onion. Emergence speed of carrot and onion seeds was faster than untreated seeds by osmotic priming or SMP treatment although the final emergence percentage was not significantly influenced. On the other hand, early growth was not significantly influenced by osmotic priming or SMP treatment of carrot and onion seeds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1283-1287
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• 1999

This study was carried out to develop new processed food from cherry tomatoes. The dried cherry tomatoes were prepared by using a sequence of osmotic dehydration, air drying, vacuum drying and freeze drying. The moisture contents of dried cherry tomato products by nontreatment and osmosis treatment were about 11~13% and 7.5~ 10%, respectively. The vitamin C contents of the dried product after osmotic dehydration were higher than those of the dried products by nontreatment. The vitamin C content of the freezing dried product was the highest of the others. The vacuum dried product by nontreatment was retained color of fresh fruit in the change of color. The ΔE value of the air dried product was lower than those of the others. As a result to microscopic analysis, fresh cherry tomato was observed regular tissue, while cherry tomato treated by osmosis was observed a cell collapse following the loss of water. The dried product had cell shrinkage and dense tissue. And the cell wall of dried products after osmotic dehydration were much more damage than those of nontreatment dried product. The palatability of the air dried product was the best of three drying methods. The dried cherry tomatoes treated by osmosis were superior to the dried cherry tomatoes by nontreatment.

• Food Science and Preservation
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• v.5 no.3
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• pp.305-314
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• 1998

In the drying process, many undesirable physicochemical changes occur that influence dried food product qualities. Pretreatments method is used to reduce the deterioration of dried food product qualities such as color, flavor, texture, rehydration ability and retention of nutrients. The methods of pretreatments are blanching, chemical treatment and osmotic dehydration. Osmotic dehydration is a water removal process which is based on placing foods in a concentrated osmotic solution or in a dry osmotic material. A large number of process variables have a significant effect on process and final product quality. In order to improve final product quality it is necessary to know the role of each process variable and understand the mecanisms throughout the process. Osmotic dehydration is a valuable processing tool with great future in minimal processing of fruits and vegetables.

• Food Science and Preservation
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• v.24 no.4
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• pp.497-504
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• 2017

The aim of this study was to investigate the characteristics of paprika dried by various methods. Moisture content of dried paprika was higher in vacuum freeze-dried red paprika (DRP) (11.85%) than in vacuum freeze-drying of osmotic dried red paprika in sugar (RPS), vacuum freeze-drying of osmotic dried red paprika in fructose (RPF) and vacuum freeze-drying of osmotic dried red paprika in corn syrup (RPCS). Carbohydrate content of DRP was the lowest among the dried groups, but fat, protein, and ash contents were the highest in DRP. The pH of paprika was the highest in RPF (5.34), while it was the lowest in DRP (5.05). Reducing sugar and sugar contents of RPF were 28.59 g/100 g and $5.03^{\circ}Brix$, respectively, which are the highest level among the groups. All color values in inside of paprika were the highest in RPCS, while in outside of paprika, L value is the highest in RPCS, and the value of a, b were the highest in RPS. Regarding the texture characteristics of paprika, strongness, hardness, adhesiveness, chewiness and brittleness were the highest in RPS (p<0.05).

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.36-41
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• 2008

This study was conducted to investigate the effects of combined osmotic dehydration and hot-air drying on the quality of dried apple products. Apple cylinders were steeped in 30% and 50% sucrose solutions at different steeping times. During the osmotic dehydration, as the concentration of the sucrose solution and steeping time increased, weight reduction and water loss increased, and the solid gain showed similar results. Osmotic dehydration in the sucrose solutions was followed by hot-air drying at 50 and $70^{\circ}C$. The experimental data were fitted successfully using the modified Page model. At the drying temperature of $50^{\circ}C$, the drying time increased from 4.15 hr for the control to 5.78 hr and 6.42 hr for the 30 and 50% sucrose solution treatments, respectively. Similar results were shown at the $70^{\circ}C$ drying temperature. The k and n values of the apple cylinders decreased by osmotic dehydration, and the k and n of the apple cylinders steeped in the 50% sucrose solution were lower than those of the samples steeped in the 30% sucrose solution. The qualities of the dried apple products were compared to samples that did not undergo osmotic dehydration. The shrinkage and rehydration capacity of the apple products decreased via osmotic dehydration, and decreased as the concentration of the sucrose solution increased. The compressibility ratios of the apple products to raw apple cylinders increased by osmotic dehydration, and increased as the concentration of sucrose solution increased. The sensory evaluation results for the apple products rehydrated in yoghurt indicate that osmotic dehydration greatly enhances the palatability of apple products in terms of appearance, taste, and texture.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.497-502
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• 1990

The effect of sugar concentration, immersion time and temperature on water loss, solid gain or loss, and sugar molality of potatoes during osmotic concentration was analyzed by a response surface methodology (RSM), and those values were predicted by using a second degree polynomial regression model. Effect of osmotic concentration and blanching on vitamin C retention of air dried potatoes (6% MC: wet basis) was also evaluated. The most significant factor was sugar concentration for water loss, solid gain or loss, sugar molality, rate parameter and retention of vitamin C. Second and third factors were immersion time and temperature respectively. Water loss and solid gain were rapid in the first 10 min and then levelled off. A 44.6% of water loss was observed during osmotic concentration using a sugar solution $(60\;Brix,\;80^{\circ}C$) with 20 min of immersion time. Dried potatoes after osmotic concentration had higher vitamin C content than dried potatoes after blanching. Optimum regions for osmotic concentration process of potatoes were $60-70^{\circ}C$ of immersion temperature, 60 Brix of sugar solution and 16-20 min of immersion time based on above 30% of water loss and 50% of vitamin C retention.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.903-907
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• 1998

Mass transfer characteristics during osmotic dehydration of mushrooms(Agaricus bisporus) in sugar solution were studied as a function of sugar concentration, immersion time and temperature, and the effect of osmotic dehydration on browning inhibition of air-dried mushrooms was also evaluated. Increasing the sugar concentration, immersion time and temperature increased moisture loss, sugar gain, molality and rate parameter. The changes of sugar gain and rate parameter were more significantly affected by concentration than by temperature of sugar solutions, while 1$0^{\circ}C$ increase in temperature or 10 Brix increase in concentration had the same effect on water loss. Water loss, sugar gain, molality were rapid in the first period of osmotic dehydration especially in the case of higher concentration and temperature of sugar solutions. Effects of osmotic dehydration in sugar solution(60 Brix, 8$0^{\circ}C$) with 18 min of immersion time(O.D.=0.099) rior to air dehydration on browning inhibition of dried mushrooms were more significant than blanching in water(8$0^{\circ}C$) with the same immersion time(O.D.=0.330) and the control (O.D.=0.559).

• Food Science and Preservation
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• v.6 no.3
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• pp.319-323
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• 1999

This study was conducted to minimize the deterioration of dried kiwifruit quality. Osmotic dehydration was carried out as pretreatment before drying. After the kiwifruits were pretreated under optimized osmotic dehydration conditions, they were dried by three drying methods(hot air drying, vacuum drying, freeze drying). Hot air drying and vacuum drying were superior to freeze drying in the drying speed. But vacuum and freeze drying preserved more vitamin C than hot air drying. Also, osmotic dehydrated kiwifruit kept better quality than nontreated kiwifruit. Diffusion coefficient which describes moisture transfer, was high in drying process pretreated with osmosis. The changes of vitamin-C followed the second-order reaction rate equation with high RE, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1573-1579
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• 2004

This study was conducted to develop intermediate material for new processed food from sweet pumpkin. Osmotic dehydration was carried out as pretreatment before drying. After the sweet pumpkins were pretreated under optimized osmotic dehydration conditions, they were dried by three drying methods (hot air drying, vacuum drying and cold air drying). The moisture contents of dried sweet pumpkin products by osmosis treatment (sucrose) and hot air drying, vacuum drying, and cold air drying were 14.48, 14.09 and 13.87%, respectively. Cold air drying preserved more vitamin C content and showed lower color difference than hot air drying and vacuum drying. As a result of microscopic analysis, cold air dried sweet pumpkin was observed regular tissue, while hot air and vacuum dried sweet pumpkins were observed a cell collapse following the loss of water.