• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.207-210
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• 1982

For the removal of initial water content in cuttlefish, the effects of fixed-bed drying condition on the drying rate were investigated, with following results. 1. The drying rate of cuttlefish dried at fixed-bed condition was also faster than that at natural convection type or hot air dryer.2. By controlling air temperature and its direction to cut-and-peeled sample the drying time can be reduced to 2 hrs. 3. Shirai's equation and Arrhenius' law were applicable to fixed-bed dried cuttlefish. Drying rate constant (k) by Shirai's equation, and Arrhenius' plot were as shown in Table 3, 4 and Fig.3, respectively.

• Journal of Biosystems Engineering
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• v.29 no.1
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• pp.59-64
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• 2004

This study was performed to determine drying equations of sarcodon aspratus. Drying tests for sarcodon aspratus were conducted in an experimental dryer equiped with an air conditioning unit. The drying tests were performed at three air temperatures of 30$^{\circ}C$, 40$^{\circ}C$ and 50$^{\circ}C$, and two relative humidities of 30% and 50%. Measured moisture ratio data were fitted with the selected four drying models(Page, Thompson, Lewis and simplified diffusion models) using stepwise multiple regression analysis. When the coefficients of determination and root mean square errors of moisture ratio were evaluated for four drying models, the Page model was found to fit adequately to all the drying test data with coefficient of determination of 0.9996 and RMSE of 0.00523.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.216-220
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• 2002

The microbiological examinations of food service operations were conducted for the hygienic evaluation at four elementary schools in Busan, Korea. Total one hundred and seventy two swabbed samples using sponge were collected from the surface of environments, utensils and equipments of food service facilities and analyzed by measuring the total, coliform and psychrotrophic count. Sampling sites were the surfaces of floors, drains, walls, knives, cutting boards, rubber gloves, vinyl aprons, plastic containers, carriers, shelves, trays, dry shelves, electric tray dryer, food containers, soup containers, rice cookers, frying pans, boiling cookers, refrigerators, dumb waiters and dishwashers. The swabbed samples kept in an ice-parked box were transported to a laboratory and analyzed. The results demonstrated that the degree of contamination depended on the sampling sites. Averages of total counts of surface swab samples were ranged from 0.62 to 7.79 Log CFU/200 cm$^2$. The level of coliforms were ranged from not detectable to 5.26 Log CFU/200 cm$^2$, and those of psychrotrophs from not detectable to 6.15 Log CFU/200 cm$^2$. The severely contaminated sites were dumb waiters, drains, rice cookers, knives, plastic containers and floors. Also cutting boards, rubber gloves, carriers, drying shelves, vinyl aprons, boiling cookers, soup containers, frying pans and refrigerators were highly contaminated with the level of abode 3.5 Log CFU/200 cm$^2$. Therefore, those sites should be focused and controlled according to control points of sanitation standard operating procedures (SSOP). Also, periodic microbiological examination in addition to visual examination is recommended on these highly contaminated sites indicated above results at food service operations in elementary school.

• Food Science and Preservation
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• v.23 no.5
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• pp.689-695
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• 2016

In this study, the drying characteristics of medicinal (Ganoderma lucidum, Phellinus linteus) and edible (Pleurotus eryngii, Lentinus edodes) mushrooms were investigated. Their shrinkage ratios, Hunter's color values, and rehydration ratios were evaluated. Mushrooms were cut with rectangular (1 cm) and square ($1{\times}1cm$) shapes, and dried in the room temperature and at $50^{\circ}C$ and $70^{\circ}C$ using hot-air dryer. Initial moisture contents of edible mushrooms were higher than those of medicinal mushrooms, whereas final moisture contents were vice versa. Drying rate was the highest when drying at $70^{\circ}C$ (p<0.05). Moreover the drying rate of square slices was higher than that of rectangular slices (p<0.05). The shrinkage ratios of both medicinal mushrooms and edible mushrooms were the least when drying at $50^{\circ}C$ and $70^{\circ}C$, respectively (p<0.05). The changes of color values were less in the medicinal mushrooms dried in the room temperature than in the hot-air dried medicinal mushrooms (p<0.05). However, in case of edible mushrooms, the changes of color values were less in the hot-air dried mushrooms (p<0.05). Rehydration ratios of medicinal mushrooms dried at $50^{\circ}C$ was the highest (p<0.05). In contrast, rehydration ratios of edible mushrooms was the highest when drying in the room temperature (p<0.05). Thus, the hot-air drying at $50^{\circ}C$ would be suggested as the efficient drying method for both medicinal mushrooms and edible mushrooms.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.272-279
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• 1988

Kinetics of ascorbic acid destruction and browning were evaluated by the dynamic test using actual drying data in order to apply in the optimization of food dehydration. Radish was chosen as a test material because it has many typical quality characteristics during drying. Radish was dried in the cabinet dryer with being measured in moisture, food temperature, ascorbic acid and browning. Using moisture and temperature history, proposed kinetic model was integrated and parameters of the model were searched by the iteration scheme to show minimum discrepancy between predicted and experimental data. Ascorbic acid destruction and browning were represented by first and zero order reaction respectively. Arrhenius equation was used to describe temperature dependence. Several mathematical functions of moisture dependence were compared in the model simplicity and residual sum of square. Attained kinetic models were analyzed as functions of temperature and moisture. Rate of ascorbic acid destruction was low at high moisture content, increased with moisture decrease to show a maximum at the moisture of $9{\sim}12g/g$ dry solid, and then decreased up to full dryness. Browning rate increased with moisture decrease to show a sharp maximum at $4{\sim}6g/g$ dry solid and decreased with further moisture decrease.

• Food Engineering Progress
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• v.13 no.3
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• pp.190-194
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• 2009

The aim of this study was to investigate the change of volatile aroma compounds in kimchi during fermentation, before and after drying process. Also, the encapsulation effect of cyclodextrin on volatiles during the drying process was examined. GC-MS was used for detection and identification of volatile compounds. During kimchi fermentation, in the early stage, dimethyl sulfide, carbon disulfide were detected as major compounds and after 7 days several sulfur compounds, dimethyl disulfide, methyl 2-propenyl disulfide, allyl methyl sulfide, and di-2-propenyl disulfide bacame the major volatiles. After vacuum-drying, the kimchi powder lost 11 compounds but still retained 13 volatiles of which major compounds were dimethyl sulfide, acetaldehyde and methanethiol. In order to keep volatiles in kimchi powder along with the drying process, 0.25-1.0% cyclodextrin was added in kimchi and dried-kimchi was prepared by using vacuum dryer. Cyclodextrin acted as an encapsulation agent for aroma compounds and it resulted in less loss of volatiles during drying process. Addition of cyclodextrin will permit industry-scale production of dried-kimchi powder with less loss of aroma compounds.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.195-199
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• 2011

This study investigated the antioxidant effects and physiological activities of extract from various parts of pumpkin (Cucurbita moschata Duch.) such as leaf, flesh, skin and seed. Different dried parts of C. moschata were boiled in ethanol for three hours, evaporated, and lyophilized with a freeze-dryer. Total polyphenol contents were the highest in leaf ($29.62{\pm}0.88mg$ GAE/g DM). The same result was observed in the measurement of the flavonoid content. The leaf extract of C. moschata had stronger DPPH radical-scavenging activities and ABTS-radical scavenging activities than any other part. Leaf extract of C. moschata was found to have the highest ferric-reducing antioxidant power (FRAP) value. Meanwhile, at 0.1 mg/mL of all extracts higher degree of tyrosinase inhibitory effects than kojic acid was observed (leaf; 49.58%, flesh; 40.20%, skin; 41.30%, seed; 36.79% and kojic acid; 20.70%). The glycation inhibitory activity decreased in the order leaf>skin>flesh>seed. The ${\alpha}$-glucosidase inhibitory activity of seed extract was the highest with a value of 63.58% at the concentration of 1 mg/mL.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.633-638
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• 2015

Lactobacillus is a probiotic that suppresses the growth of pathogens while preventing constipation, diarrhea, and intestinal inflammation. However, various environmental conditions such as pH and temperature affect the growth of Lactobacillus. In this study, Lactobacillus plantarum was encapsulated with starch using a spray dryer to protect the viability of the organism during storage and to increase its acid tolerance. The lower water activity and storage temperature resulting from this method influenced the survival of L. plantarum. In encapsulated Lactobacillus powders, viability of Lactobacillus was increased during storage at $20^{\circ}C$ relative to that of L. plantarum stored at $35^{\circ}C$ in the same water activity conditions. Furthermore, L. plantarum encapsulated in starch with ginger showed increased viability when compared to non-encapsulated L. plantarum stored without treatment. Finally, based on a simulated digestion test, encapsulated L. plantarum survived at a pH of 2, whereas the non-encapsulated L. plantarum did not. Thus, coating the encapsulated powder with these materials was effective in maintaining Lactobacillus viability.

• The Korean Journal of Food And Nutrition
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• v.32 no.6
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• pp.620-629
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• 2019

To examine the possibility of ear mushroom (EM) as a source of natural vitamin D, the UVB (ultraviolet B) was treated according to sample drying status, drying methods before UVB treatment and harvest time. And then, vitamin D₂ and ergosterol contents were investigated. According to the sample drying status, the vitamin D₂ contents of fresh and freeze-dried EM (whole) increased to 4,634.4~4,780.9 ㎍/100 g D.W. (dry weight) under UVB dose 52.5~70.0 kJ/㎡ and above 18,693.1 ㎍/100 g D.W. under above 105 kJ/㎡, respectively. By drying methods before UVB treatment, vitamin D₂ contents of EM powder (below 500 ㎛) that dried in the vinyl house and freeze-dryer increased to 4,886.2~5,132.9 ㎍/100 g D.W. under above 105 kJ/㎡ and 17,103.7 ㎍/100 g D.W. under 70 kJ/㎡, respectively. Ergosterol content decreased with increasing UVB dose in all experiments. According to the harvest time, vitamin D₂ content under UVB dose 210 kJ/㎡ showed marked difference and in order of June, July, August, October and April. As for the results, the optimum harvest time, drying method before UVB treatment, sample size, UVB dose for the EM contained high vitamin D₂ content were June, freeze-drying, whole, and 105 kJ/㎡, respectively.

• Journal of Biosystems Engineering
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• v.42 no.3
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• pp.190-198
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• 2017

Purpose: A thin-layer drying equation was developed to analyze the drying processes of soybeans (white and black beans) and investigate drying conditions by verifying the suitability of existing grain drying equations. Methods: The drying rates of domestic soybeans were measured in a drying experiment using air at a constant temperature and humidity. The drying rate of soybeans was measured at two temperatures, 50 and $60^{\circ}C$, and three relative humidities, 30, 40 and 50%. Experimental constants were determined for the selected thin layer drying models (Lewis, Page, Thompson, and moisture diffusion models), which are widely used for predicting the moisture contents of grains, and the suitability of these models was compared. The suitability of each of the four drying equations was verified using their predicted values for white beans as well as the determination coefficient ($R^2$) and the root mean square error (RMSE) of the experiment results. Results: It was found that the Thompson model was the most suitable for white beans with a $R^2$ of 0.97 or greater and RMSE of 0.0508 or less. The Thompson model was also found to be the most suitable for black beans, with a $R^2$ of 0.97 or greater and an RMSE of 0.0308 or less. Conclusions: The Thompson model was the most appropriate prediction drying model for white and black beans. Empirical constants for the Thompson model were developed in accordance with the conditions of drying temperature and relative humidity.