• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.5
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• pp.635-640
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• 2006

This study was conducted to determine the effect of far infrared ray drying on the microbial and quality changes of vacuum packaged waxy corns, such as microbial growth, rehydration, color differences, weight loss and hardness during the storage at $4^{\circ}C$ and $25^{\circ}C$ for 7 months. After far infrared ray drying for 6 hours at $60^{\circ}C$, 2.32 log CFU/g of total microbial counts in raw waxy corns was enumerated, but no microorganism was detected in steamed or sugar-treated waxy corns. However, no microorganism was observed in all treatments except for control samples until 3 month storage at $4^{\circ}C$, whereas steamed and sugar-treated waxy corns showed 2 and 2.7 log reduction compared to that of control after 3 month storage. Yeasts and molds were more resistant than bacteria against far infrared ray drying at the same conditions. Similar results were observed in $25^{\circ}C$ storage. The degree of gelatinization in raw waxy corns far infrared ray drying changed from 98% to 96.2% after 7 month storage at $4^{\circ}C$, whereas steamed waxy corns with far infrared ray drying changed from 81.14% to 58.73%. Water contents in sugar-treated waxy corns with far infrared ray drying gradually reduced compared to steamed waxy corns as drying time increased. The L values in raw waxy corns far infrared ray drying increased as drying time increased, but L values in steamed or sugar-treated waxy corns significantly reduced after 12 hour far infrared ray drying. Hardness in raw waxy corns was higher than in steamed or sugar-treated waxy corns before storage, but similar hardness was observed between raw- and sugar-treated waxy corns after 9 hour drying. This results showed that the microbial reduction, the enhancement of shelf life and quality establishment of steamed or sugar-treated waxy corns could be maximized by using far infrared ray drying.

• Korean journal of food and cookery science
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• v.24 no.5
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• pp.706-712
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• 2008

This study was conducted to evaluate the sanitation level and use of dish cloths, chopping board, and drawer in the refrigerator in 50 university students' houses located in Seoul and Kyonggido. The survey questionnaire evaluated general information, frequency of the washing, cleaning method, drying method and the associated factors. The highest percentage of the cleaning and drying methods of dish cloths were “boiling(76.0%)”, and “dry in the kitchen or on the sink(78.0%)”, respectively. For the chopping board and drawer in the refrigerator, the highest percentage of cleaning method was “use detergent” and drying method was “dry in the kitchen”. The mean of coliforms for dish cloths, chopping board, and drawer in the refrigerator was 4.46${\pm}$1.95 log CFU/100 $cm^2$, 3.92${\pm}$1.64 log CFU/100 $cm^2$, 3.48${\pm}$2.01 log CFU/ 100 $cm^2$, respectively. Salmonella spp. were not detected from all samples. But E. coli were detected from dish cloths(4.0%) and S. aureus were detected from dish cloths(16.0%), chopping board(12.0%), and drawer in the refrigerator(8.0%). The results of microbiological test of kitchen utensils indicated that the sanitary conditions of dish cloths, chopping board, drawer in the refrigerator should be improve promptly.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.51-60
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• 1997

We investigated the characteristics of air-and vacuum-drying heated by hot plates for 8~14cm-diameter logs or 6~12cm-thick pillars of Pinus koraiensis. And we evaluated the effects of longitudinal kerf and vacuum drying heated by hot plates. The vacuum drying times from green to 10.9~18.6% MC were 15 days, and these times were one-fifth compared to the air-drying times. The longitudinal kerfing had no significant, effect on drying rates during both air-drying and vacuum drying. But drying defects such as surface checks and V-shaped cracks were effectively prevented during air-drying and vacuum drying by longitudinal kerfing. The vacuum drying was more advantageous than air-drying for preventing of surface checks, end checks and V-shaped cracks, and especially, the vacuum dried pillars with longitudinal kerf were almost free from drying defects. In accelerated weathering conditions the resin did not exude for all specimens.

• KSBB Journal
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• v.23 no.5
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• pp.375-380
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• 2008

We made an experiment of keeping extension of raw and semi-dried flounder (Pleuronectes herzensteini). Effect of with(WG) or without gill (OG), drying degree (20% drying：20D, 40% drying：40D) and storage temperature (5 and $10^{\circ}C$) and 0.1% chitosan-ascorbate (CA) treatment of vacuum packaging flounder on growth of contaminated microorganism during storage for 10 days were investigated. Total aerobacter (TA) in the OG-treated raw flounder was $0.3{\sim}0.5$ log cycle lower than that of WG-treated flounder and also, number of coliform (CF) and E. coli (CO) in OG were lower compared with WG. Number of TA,. Especially, the TA was $0.42{\sim}1.20$ log cycle lower compared with raw flounder. The TA of the raw flounder stored at $5^{\circ}C$ compared to $10^{\circ}C$ was $0.6{\sim}1.3$ log cycle lower. The growth of total aerobacter, coliform (and E. coli separated from raw flounder in tryptic soy broth were completely inhibited by 0.1% CA. But the growth of TA in the raw and 20% dried flounder was 1.5 log cycle inhibited by 0.1% CA, and the growth of CF and CO were also slightly inhibited. We did value raw sample that treated CA 0D and 20D, and did vaccum packaging at the $10^{\circ}C$ for 10 days, Sensory quality such as appearance, freshness, and texture and overall acceptability after cooking of the 0.1% CA-treated raw and 20% dried flounder were evaluated from good to very good, while CA non-treated products were evaluated to moderate.

• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.466-469
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• 2008

This study examined the effect of drying temperature on the qualitative properties of Chrysanthemum boreale M. flowers. The flower samples were dried in a hot air dryer at $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively, to attain a $23{\pm}1%$ moisture content. The time required to reach the target moisture content was 8.5-69 hr, and there was a very high negative correlation between log (spending time) and temperature. The Hunter color L- and b-values of the flowers were decreased with increasing drying temperature, whereas the a-value was increased. The volatile compounds contained in the dried flowers were determined by a solid-phase microextraction method. Twelve primary volatile compounds were detected and then quantified based on the GC chromatograms of the samples. The total contents of volatile compounds were increased with increasing drying temperature, and germacrene D and camphor were the main compounds in all samples.

• Korean Journal of Food Science and Technology
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• v.18 no.1
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• pp.61-65
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• 1986

This study was performed to examine the drying characteristics of apples at various drying conditions. Air velocity has no effect on the drying rate except the constant rate period. In this experiment the diffusion coefficients of moisture in the apple tissue were in the range of $1.1470-2.2148{\times}10cm^2/sec$. As a result of balance of heat and mass transfer during the falling rate period. an empirical equation based on Fick's law was obtained as follows; $log{\Delta}t\;=\;log\;t_o\;-\;D{\frac{{\pi}^2{\theta}}{4d.}}$ This equation can be used to calculate the temperature of apples during the falling rate period, provided the diffusion coefficients of apple are known. The experimental values of the internal moisture distribution during apple dehydration were nearly in accord with the theoretical values.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.346-355
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• 2021

Ngoc Linh ginseng is one of the most valuable endemic medicinal herbs in Vietnam. In this study, Ngoc Linh ginseng callus was fermented by Lactobacillus plantarum ATCC 8014 (at 6, 7, and 8 log CFU/ml) to evaluate the extraction efficiency of bioactive compounds. The post-fermentation solution was spray-dried using maltodextrin with or without Stevia rebaudiana (3% and 6% v/v) as the wall material. Bioactive compounds such as polyphenols, polysaccharides, and total saponins, and L. plantarum viability during fermentation and after spray-drying, as well as under simulated gastric digestion, were evaluated in this study. The results showed that probiotic density had a significant effect on bioactive compounds, and L. plantarum at 8 log CFU/ml showed the best results with a short fermentation time compared to other tests. The total content of polyphenols, polysaccharides, and saponins reached 5.16 ± 0.18 mg GAE/g sample, 277.2 ± 6.12 mg Glu/g sample, and 4.17 ± 0.15 mg/g sample, respectively after 20 h of fermentation at the initial density of L. plantarum (8 log CFU/ml). Although there was no difference in the particle structure of the preparation, the microencapsulation efficiency of the bioactive compound in the samples containing S. rebaudiana was higher than that with only maltodextrin. The study also indicated that adding S. rebaudiana improved the viability of L. plantarum in gastric digestion. These results showed that S. rebaudiana, a component stimulating probiotic growth, combined with maltodextrin as a co-prebiotic, improved the survival rate of L. plantarum in simulated gastric digestion.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.295-298
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• 2007

In order to sterilize Bacillus cereus and Enterobacter sakazakii in rice flour, hot-air drying ($65^{\circ}C$/15 min, HT) and microwave drying (700 watt/30 sec, MT) treatments were evaluated and a storage study performed. Color changes (${\Delta}E$) appeared to be less in the MT rice flour than in HT treated rice flour. The effectiveness of the MT treatment showed reduced growth rates for B. cereus (0.54 log CFU/g) and E. sakazakii (1.45 log CFU/g). The populations of B. cereus in the control (NT) rice flour greatly increased during storage at 4, 10 and $20^{\circ}C$ as storage times increased. However, the growth of B. cereus was minimized in the MT rice flour. In conclusion, MT treatment is considered to be a good drying method when substituted for HT treatment to assure microbial safety in rice flour.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.3
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• pp.392-400
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• 2011

The objectives of this study were to analyze environmental microbial contamination levels by sampling the surfaces of processing lines and equipment and to verify CCPs of the HACCP plan in a fresh-cut produce processing plant The level of airborne microorganisms in the processing plant was $10^1$ log CFU/plate/15min. Total plate counts and coliform groups of the processing facilities were 1~2 log CFU/100 $cm^2$. No E. coli or S. aureus were detected in the processing plant. However, total plate counts on the cutting board for raw materials and on the spin-dryer were $4.20{\pm}2.12$ log CFU/$cm^2$ and $4.57{\pm}0.92$ log CFU/$cm^2$, respectively. These levels were higher than the safe microbial level, and therefore, the chance of cross-contamination during processing was increased. According to the results of microbiological analyses, total aerobic bacteria and coliform groups of the samples were increased after the second washing and spin-drying steps, due to cross-contamination from the spin-dryer. Thus, an effective method that can be used for microbial control during the washing and drying steps is needed for microbial control in fresh-cut produce processing plants. The results of a verification study also suggest that modification of the HACCP plan is needed along with additional CPs, which were identified as a second washing, spin drying, and the cold storage of final products.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.25-32
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• 2001

A microwave vacuum (MW/V) dryer was developed for drying short roundwoods, from which woodcraft souvenirs in Korean market are mostly made, and which were hardly dried without defects in a conventional kiln. It consisted of three 1.5 kW magnetrons of 2,450 MHz, a vacuum pump, a load cell of 100 kg and a cavity of $580{\times}580{\times}1,360\;mm^3$. A computer program was developed to switch on or off the magnetrons according to drying schedules, those were based on microwave injection time or the average of wood temperatures. To evaluate the new MW/V dryer the roundwood specimens of rigida pine, poplar and birch were dried. Their log diameters and lengths ranged from 125 to 25 em and from 25 to 50 cm, respectively. In spite of the presence of minor drying defects, the MW/V drying is found to be an effective method for drying short roundwoods. Wooden turneries made of red alder and ash logs were also MW/V dried from green to 4%MC without any degradation. The rates of the MW/V drying were examined for three different lengths of poplar logs.