Ki-Hyun Kwon

Characteristics Evaluation and Development of Peach Washing System

This study was conducted to find condition of improving the quality of peach by using surfacing washing system. The rate of weight loss of A,B groups were showed slower decreasing trend than CT group and the value of soluble solid degree was not different significantly among all groups from the results of stored peach treat with surface washing system of peach in the first experiment. The colory value of surface were increased with increasing storage period in all treatments. Browning pace of A,B groups were slower than control. Emission of carbon dioxide was increased from the results of respiration rate, 6-10 mL/kg/hr and 32-41 mL/kg/hr . In second experiment with surface washing system of peach, the value of soluble solid was showed with similar value from 10 to 13 . The pace of soft rot of EW groups were lower than CT groups from the results of hardness during storage period. The results of colory value was not showed with significant difference in and storage temperature but changed to browning in EW groups. The moisture contents was from 85% to 90% in all groups. And the count of total microorganism of EW groups were lower than control. Also total coliform of EW groups were negative. In sensory evaluation, washing peach was showed higher value with significant difference in all acceptability.

Analysis of Aroma Patterns in Muskmelon at Different Storage Temperatures Using a Mass Spectrometry-based Electronic Nose

Changes in the flavor of muskmelons stored at different temperatures were examined to judge aroma patterns during storage. A mass-spectrometry based electric nose was used to distinguish the subtle differences in the muskmelons volatile compounds. The data were used for a discriminant function analysis (DFA), and then the partial least square algorithm was used for a quantitative analysis. Volatile components in the muskmelons increased with storage, and the first discriminant function score (DF1: r 2 =99.88%, F=3072.5) moved from a positive position to a negative position as the storage period increased. The proper point of maturity was anticipated as the 28 th day at 0 o C, 21 st day at 4 and 7 o C, and 14 th day at 10 o C. Also, using the DF1 score we could predict the general tendency (vitamin C, stem moisture, acidity) of the muskmelons. The electronic nose revealed that the major volatile compounds that changed during storage of the melons were ethyl ethyl acetate, butyl acetate, nonanol, dodecanoic acid, hexadecanoic acid and tricosane. The amount of volatile compounds detected increased during storage.

Effects of malic acid or/and grapefruit seed extract for the inactivation of common food pathogens on fresh-cut lettuce

This study investigated the antimicrobial activity of malic acid (MA), grapefruit seed extract (GSE), and combined (MA+GSE) treatment against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on fresh-cut lettuce. The antimicrobial effects of 1% MA and 0.5% GSE alone and in combination (1% MA+0.5% GSE) were tested on artificially inoculated lettuce during storage at 5°C for 14 days. The maximum reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes were 4.96, 4.80, and 3.95 log CFU/g observed with MA+GSE during storage for 14 days, respectively. MA+GSE showed the greatest reduction against in E. coli O157:H7 and L. monocytogenes. These results indicate that the combined treatment was more effective than MA and GSE alone treatment. Therefore, it suggests that MA + GSE could be used as an effective intervention method for improving microbiological safety of fresh-cut lettuce.

Choosing Quality Indicators for Quality Prediction of Frozen Green Pumpkin in Distribution

We aimed to determine the quality indicators for quality prediction of frozen green pumpkin in distribution. Freshly harvested green pumpkin slices were blanched under optimal conditions (confirmed in a preliminary experiment), quick-frozen at for 24 h, and stored at 0, -5, -15, and . The correlation between each quality characteristic and the sensory preference rate was analyzed. There was a significant correlation between storage temperature-related drip rate and preference rate across all temperatures, except at. Hunter values, a and b, showed relatively high correlation coefficient values at -5, -15, and . Therefore, a change in the Hunter values should be considered when storing green pumpkin, because of their significant correlation with changes in the sensory preference and drip rates. Furthermore, they should be applied as quality indicators for the quality prediction of frozen green pumpkin in distribution.

Physicochemical Properties and Respiration Rate of Four Different Varieties Muskmelons (Cucumis melo L.) Cultivated in Korea

We evaluated the physicochemical properties of four varieties of muskmelons (Thankyou, Beauty, Picnic, Sympony) during storage at . We stored Thankyou, Sympony, and Beauty varieties for 28 days at , while the Picnic variety was stored for 21 days. After the storage period, the mineral content of the Thankyou variety changed the least, by 2.36%, while that of the Sympony and Picnic varieties changed the most. The Thankyou variety also lost the least amount of free sugar content during storage. The Sympony variety had the highest vitamin C content at the beginning of the storage (26.0 mg%/100 g). After 14 days of storage, there was little difference in the vitamin C content of the varieties, which ranged from 11.5 to 12.5 mg%/100 g. The Picnic variety, which had the highest respiratory quotient, indicated lower storability than the other varieties. In a sensory evaluation, the Thankyou variety was considered to be the best in terms of consumer preference. However, the stem water loss seen in this variety tends to be the first thing that consumers see and may determine its merchantable quality.

Study on Process Development of Ginseng's Surface Washing System

This study was attempted to develop surface washing-system of ginseng. The effect of sterilization, washing and keeping freshness of ginseng through analyzing unit process were examined to establish optimal condition for washing system. Surface washing method of fresh ginseng used two way and full cone spray type. Sterilization was used at water with electrolysis water of 50 and 80 ppm. Ginseng was sterilized with electrolysis water during 30 and 60 s, dehydrated during 1 min and dried during 1min at 30 and . Hardness of surface-washed ginseng showed good result on 1 min spraying time with 80 ppm electrolysis water at storage. Ginseng with 80 ppm electrolysis water was sterilized better with . There are no changes with 0% on appearance quality at 80 ppm electrolysis.