• Journal of Sericultural and Entomological Science
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• v.53 no.1
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• pp.50-54
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• 2015

Mulberry fruit is common to keep a frozen storage because of the very high water content. Because freezing-storing cost is generated before the processing or sales, farmers of mulberry fruit production are weighted in financial burden. In addition, mulberry fruit has difficulty in expanding consumption by made in the simple processed products like the mulberry jam, mulberry juice, mulberry enzyme, alcohol, etc. Recent, frozen fruits including frozen blueberries, frozen strawberries, frozen mango, frozen rich, frozen mulberry fruit has been started to sell in the large discount stores and convenience stores. However, there is restricted sales in only special place that have the frozen distribution facilities. So, for the income improvement and consumption promotion of mulberry farmers facing these difficult situations, we developed the processing method of semi-dried mulberry fruit using the vacuum freezing dryer. The frozen mulberry fruit which was stored below $-40^{\circ}C$ is to dry in a vacuum freeze dryer, at $30{\sim}35^{\circ}C$, 23 ~ 24 hours. Semi-dried mulberry fruit seperated respectively. It had soft texture, and maintained shape, size and flavor. In particular, semi-dried mulberry fruit can be stored at room temperature.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.350-356
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• 1988

A pilot plant scale freeze dryer was designed and manufactured and its performance was tested. Freezing capacity of water vapor in the developed freeze dryer was 8㎏/batch and heating and defrosting methods were conduction and hot gas types, respectively. And exhausting time of vacuum pump was 7-8 minutes and temperature of cold trap was kept below $-50^{\circ}C$. In the freeze drying of fruits and vegetables, its optimum and maximum drying capacities were 2 and 4㎏/batch, respectively. Performance of the new freeze dryer was compared quite well with a foreign made freeze dryer.

• Food Science of Animal Resources
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• v.18 no.2
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• pp.164-175
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• 1998

The objective of this study was to investigate the effects of freezing rate on ice crystal size and freeze-drying rate. Our experiments were carried out with self-manufactured freeze-dryer. Gelatin gels (2% w / w, 80$\times$20mm) were frozen unidirectionally (Neumann's model) from the bottom at -45, -30, -20, and -15$^{\circ}C$ and followed with freeze-drying. Under the upper conditions we measured freezing rate and the change of temperature and pressure during freeze drying. Freeze-dried gelatins were cut horizontally into 5 mm thickness from the bottom and measured their pore sizes. Also freeze-drying rate(primary drying) is estimated by measuring the temperature of sample and pressure of vacuum chamber. During freeze-drying, profiles of pressure and temperature were shown constant tendency regardless of freezing temperature and we could expect the end-point of freeze drying by considering pressure and temperature together. In temperature profiles, the point which temperature increased significantly was observed during freeze-drying. There is no relationship between freeze temperature and drying rate of primary drying in our model system. As freezing temperature increased, ice crystal size(X*) which correspond to 63.2% of cumulative frequency was increased and at the same freezing temperature ice crystal size(X*) was decreased with distance from the bottom of the sample. Freezing conditions have a strong influence on the quality of the final freeze-dried products in freeze-drying system.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.85-99
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• 2022

Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.