This study compared the quality and antioxidant characteristics of commercial and traditional Doenjangs from various regions of Korea. The pH, salinity, and brix degree of the samples tested ranged from 4.61～6.36, 0.90～1.00% and 0.97～1.10 °Bx, respectively. The pH was highest for Doenjang made in the Jeonnam region. No significant differences in the salinity or brix degree of Doenjang from different regions of Korea were found(p>0.05). The L, a, and b-values for color of the Doenjang samples ranged from 52.92～55.00, 0.03～0.62 and －0.74～2.70, respectively. The total polyphenol content(TPC) ranged from 18.71～25.78 ㎎ GAE/㎖, and the 1, 1-diphenyl-2-picrylhydrazyl(DPPH) and 2, 2-azinobis(3-ethyl benzothiazoline)-6-sulfonic acid(ABTS) radical scavenging activities ranged from 6.43～14.38 and 2.46～7.08 ㎎ AE/㎖, respectively. The TPC was highest for Doenjang from Gyeongnam, while that from Gyeongbuk had the lowest content. The DPPH radical scavenging activity was highest for Doenjang from Jeonnam and lowest for Doenjang from Gangwon. The ABTS radical scavenging activities for Doenjang from Gyeonggi and Gyeongbuk were lower in comparison to samples from other regions. Consequently these results should provide better information for standardizing and improving the quality and functional activity of commercial Doenjang in Korea.

This study was carried out to analyse the microbiological contamination and biogenic amines(BA) content in Korea traditional soybean paste and commercial soybean paste. The results of microbiological anaylsis through Korean traditional soybean pastes(L1~L4) were 7.8 ± 0.1 log CFU/g ~ 7.9 ± 0.1 log CFU/g, commercial soybean pastes(H1~H6) were 6.2 ± 0.1 log CFU/g ~ 7.4 ± 0.1 log CFU/g for APC (Aerobic Plate Count), and L1~L4, H5, H6 soybean pastes were 2.3 ± 0.4 log CFU/g ~ 2.6 ± 0.1 log CFU/g for Bacillus cereus. But other microorganism was not dectected. Among biogenic amines, PUT(putrescine), TYR(tyramine), HIS(histamine), PHE(2-Phenylethylamine) were dectected high level and CAD(cadaverine), TRY(tryptamine), AGM(agmatine) were dectected medium level and SPD(spermidine), SPM(spermine), NOR(noradrenaline), SER(serotonin) were dectected low level. Dectected contents of biogenic amines were higher in commercial soybean paste compared to the traditional soybean paste.

The study results regarding the ingredient differences, sensory characteristics, purchasing type, usage and improvement direction for home-made traditional doenjang and factory produced commercial doenjang are as follows. The L-value indicates that home-made traditional doenjang has a higher value in average than the factory produce done, and the a-value indicates the opposite. Home-made traditional doenjang had higher water content than commercial doenjang ; however the pH values of commercial doenjang and home-made were 5.34 and 5.32 respectively, which was very similar. Factory produced commercial doenjang showed higher protein content than the home-made traditional doenjang. Regarding the correlation between ingredients, there was a significantly negative relationship between the L-value and a-value but a significantly positive relationship between the L-value and b-value. There were no significant relationship with water content, pH and protein content. For the color and taste, which are the sensory characteristics, commercial doenjang showed higher value than the traditional doenjang, but for smell, the values were similar. Regarding grittiness, the factory produced commercial doenjang had bigger particles than the traditional doenjang. Preference was a bit higher in the traditional doenjang. Of the 380 study subjects, most were from 40 to 49 years old (65.5%), and the most family type were nuclear families which was a total of 400 people (69%). Moreover, the most residential type was apartment which was 355people (61.2%), and for the monthly income, more than 2,510,000won was 48.3%. For the educational background, college education was 304 people (52.4%), and high school education was 199 people, 34.3%. In the usage, most of the people eat doenjang more than once a week, and usually their parents make the doenjang. People used both commercial doenjang and home-made traditional doenjang >home-made only >factory produced commercial doenjang only in that order. The reasons for using the home-made traditional doenjang aredelicate taste and flavor>more nutritious> anti-cancer ingredients in that order. The reason they use the factory produced commercial doenjang is because they don't know how to make it at home. The things that needed to be improved in the home-made traditional doenjang are bad smell> entire quality> flavor> color in order, indicating that studies for reducing bad smell are required. The things that needed to be improved in the factory produced commercial doenjang are taste & flavor> entire quality>bad smell> color in that order, indicating that people are more concern about it tasting like home-made than the smell. From the above results, we can see that better functional doenjang should be developed for family health and to increase the consumption of the doenjang, which has good functional psychological activities, also more various types of foods that use doenjang and scientific studies to reduce the home-made doenjang smell should be continuously studied. Moreover, studies on how to make the factory produced commercial doenjang taste more like traditional doenjang should be performed.