The official analytical method for the analysis of harmful heavy metals in Meju, distributed in Korea, employs a strong acid to decompose the organic components. This analysis is time consuming and harmful to the users and/or the environment. This study aimed to develop a new pre-treatment technology using laser ablation, to rapidly analyze harmful heavy metals without using strong acids. The results obtained from this method were validated by the National Institute of Food and Drug Safety Evaluation guideline (NIFDS, 2016). Moreover, a comparison of the two methods showed that the analytical time for 55 Meju samples was shortened by 96% or more in the new method. The results showed no significant difference in the recovery ranging from 90–120%. The proposed method proved suitable for detecting harmful heavy metals in Meju.
The purpose of this study was to evaluate the quality properties of Meju prepared by inoculating two strains of Bacillus amyloliquefaciens HJ5-2, and Aspergillus oryzae PS03. The three soybean varieties that include Daewonkong, Daechan, and Saedanbaek were used in this experiment. The fermentation temperature during the Meju aging varied at 20℃, 30℃, and 40℃, respectively. The physicochemical analysis of the soybeans, showed that the cured protein and fat contents were 34.83~43.49% and 12.91~18.90%, respectively. The pH and total acidity were 6.47~6.93 and 0.11~1.22%, respectively. The change in appearance of the Meju was that the yellow-green mold was well formed on seven days at fermentation temperature of 20℃ and 30℃, but at 40℃, there was minimal mold formation and cracking of the surface. The amino nitrogen content was highest on the Daechan Meju at 621.83 mg% for seven days. The amylase increased as the fermentation period increased in all samples, and the protease increased rapidly until the first day of the fermentation, and then gradually increased thereafter. The total number of bacteria increased or decreased as the fermentation proceeded to 6.66~10.07 log CFU/g. The mold counts increased with increasing fermentation period in the range of 6.38~8.79 log CFU/g.
This study was conducted to investigate quality characteristics of red bean gochujang prepared with different ratios of meju for eight weeks. We determined quality characteristics such as pH, moisture content, total microbial flora counts, amino-type nitrogen content, total polypenol content, and antioxidant activity. The pH decreased by fermentation period, whereas total acidity was 0.36~0.39% in the early stage of fermentation, 0.63~1.16% at four weeks of fermentation, and decreased to 0.43~0.65% after the eighth week of fermentation. Moisture content of the control (no red bean, no rice) decreased 62.13% to 50.93%, but in case of the treatment, it slightly decreased. Total cell counts revealed similar tendency at the beginning of fermentation, and at eight weeks of fermentation. In case of lactic acid bacteria, all samples except RB-1.5 (gochujang added meju made of mixing ratio of rice:soybean:red bean (1:2:1.5) slightly increased. Amino nitrogen and total polyphenol of all samples increased in the fermentation period, especially RB-1.5 sample had the highest levels than other samples. By increasing the amount of red bean, DPPH radical scavenging activities increased. In taste sensing analysis, all treat samples except RB-1.5 revealed lower sourness than the control. Also, in case of bitterness, all samples revealed low content than the control. So, by adding red bean, it can enhance taste and function of gochujang.
본 연구에서는 우리나라의 전통메주의 품질관리 및 표준화를 위한 기초자료로 제시하고자 전국적으로 수집한 전통메주 18종(TM1~TM18)의 이화학적 및 미생물 분포의 특성을 조사하였다. 메주의 외관은 시료에 따라 색, 곰팡이 생성 양상 등이 다르게 나타났으며, 형태는 사각형으로 무게는 약 0.84~2.04 kg 정도로 나타났다. 이화학적 특성으로 pH, 적정산도, 수분함량 및 조단백질 함량을 측정한 결과, pH는 5.31~ 8.21, 적정산도는 0.91~2.74% 수준으로 시료 간의 차이를 보였다. 수분함량은 4.79~42.16%로 시료에 따라 약 8.8배, 조단백질 함량은 41.37~23.48% 수준으로 1.7배의 차이를 나타내었다. 색도를 측정한 결과, L값의 경우 39.07~67.92, b값 및 a값은 각각 3.57~8.87, 7.48~20.67 수준으로 조사되었다. 메주의 발효정도를 알 수 있는 아미노태 질소 함량은 시료에 따라 257.29~839.58 mg%로 유의적으로 큰 차이를 보였고(p<0.05), TM13이 839.58 mg%로 가장 높았으며, TM3가 257.29 mg%로 가장 낮은 함량을 나타내었다. 미생물의 분포 특성으로 총균수, 효모 및 곰팡이수를 측정한 결과, 총균수는 8.43~ 5.91 log cfu/g 수준이었고, 효모는 2.48~5.19 log cfu/g, 곰팡이수는 3.42~7.48 log cfu/g 수준으로 시료에 따라 미생물의 분포가 다양하게 나타났다. 이와 같은 결과로 부터 메주를 생산하는 지역 및 산업체의 메주 제조방법, 메주의 발효기간 및 온도 등의 발효조건, 사용되는 원료 콩의 품종 등에 대한 품질기준 및 관리가 마련되어야 할 것이다.
In this study, we analyzed the utensils, covers and mats that were used for making meju, the shape of meju, and the heating method used for making meju from the 225 ways of preparing jang mentioned in the 32 volumes of the ancient cook books from 530 AD to 1950. The heating method of traditional meju bean and starch included 57 kinds of steaming, 59 of boiling, 21 of roasting + boiling, and 2 of cooking. The shape of meju included 41 kinds of egg, 27 of ball, 22 of lump, a kind of doughnut, 8 kinds of hilt, 6 of flat, 4 of chip, and a kind of square. Among the 72 gochoojang meju, the heating method of bean included 9 kinds of boiling, and 6 kinds of steaming; whereas the heating method of starch included 19 kinds of steaming of dough, 11 of rice cooking, and 5 of boiling of dough. The utensils for molding of bean meju were 49 kinds of straw sack, 14 of round straw container, 11 of heating bed, 7 of large straw bowl or Japanesesnailseed, 5 of jar, 4 of ditch, 3 of straw bowls, 2 of pottery steamer of dough, 2 of gourd, and a kind of long round bamboo bowl and sack of straw. The cover and the mat used for molding of meju included 36 kinds of straw, 17 kinds of paper mulberry leaf, 15 of wide straw seat, 14 of mugwort, 11 of pine tree leaf, 10 of soybean leaf, 6 of cocklebur leaf, 6 of sumac leaf, 6 of barley straw, 6 of mulberry leaf, 5 of fallen leaf, 5 of cogon grass, 4 of reed seat, 3 of scrap of cloth, 2 of Indian bean tree leaf, a kind of reed. There were only 5 kinds of hanging.
This study evaluated the quality characteristics of rice-doenjang prepared with Aspergillus oryzae MD05 and Bacillus subtilis HJ18-4. The physicochemical characteristics of rice-doenjang prepared with three types of meju, such as grain type(Rice 1), disc shape(Rice 2), and brick shape(Rice 3), were compared. We determined amino and ammonia nitrogen contents, protease and amylase activities, reducing sugar content, and total aerobic counts and lactic acid bacteria counts. The amino nitrogen and reducing sugar contents in all meju types gradually increased during fermentation. The amino nitrogen contents reached 151.5~200.0 ㎎%. Rice 3 were had the highest levels among the 4 types of rice-doenjang. After 42 days of fermentation, amylase and protease activity of Rice 3 were 366.57 and 94.26 unit/g, respectively, which were the highest levels among the 4 types of rice-doenjang. The total aerobic bacteria counts were not changed during 42-day fermentation. This results suggest that high quality characteristics of brick-shaped meju(Rice 3) were better than those of the other meju preparations.
Generally, non-aflatoxigenic fungi, such as Aspergillus oryzae, and Aspergillus niger are main microflora in Korean traditional fermented foods including Meju and soybean paste, but sometimes, Aspergillus flavus and Aspergillus parasiticus can be contaminated and accumulated aflatoxins during fermentation and storage. So the screening of aflatoxigenic strains in fermented traditional food is very important to improve the sanitary quality of those foods. In this work, we screened aflatoxin producing fungi from commercial Meju and soybean paste in Western Gyeongnam by immunoassay. Samples were randomly purchased from market of the commercial Meju(10 EA) and soybean paste(20 EA) in nine areas of Western Gyeongnam. Of the samples collected, 24 strains and 22 strains of Aspergillus sp. were isolated from Meju and soybean paste, respectively. The isolated strains were cultured on SLS media at 25℃ for 15 days. The cultured broth were extracted with ethyl acetate and were analysed to determine aflatoxin B₁(AFB₁) by direct competitive ELISA(DC-ELISA). Six strains(25%) isolated from Meju, and 2 strains(9%) isolated from saybean paste, were confirmed as aflatoxin producing strains. The average range of aflatoxin productivity of isolates from Meju was 54.6 ± 38.7 ng/ml and that from soybean paste was 11.1 ± 8.6 ng/ml, respectively. Among them, isolated strain No. M-5-4 produced a high level of AFB₁ and showed 98.26 ng/ml of AFB₁. Every isolates were also re-confirmed their AFB₁ productivity by thin layer chromatography(TLC). The TLC results also showed same trend as DC-ELISA results. As the above results, the screening of hazard mycotoxigenic fungi from traditional fermented foods should be necessary for the safety and the application of HACCP system in the food manufactory in Korea.
대두의 품종별 백립중은 12.1∼27.1 범위로 새알이 가장 무거웠고 광안이 가장 가벼운 것으로 조사되었다. 대두 무게에 대한 종피의 무게비율은 신팔달콩 2호가 9.40%로 가장 높았고, 장엽이 6.13%로 가장 낮은 것으로 나타났으나 품종간에 차이를 보였다. 조단백질은 평균 41.7%로 39.0∼48.5% 범위의 품종간 차이를 보였으며 단백이 48.5%로 가장 높은 함량을, 장엽이 39%로 가장 낮았다. 지질은 평균 19.7%로 17∼22% 범위였으며, 무한, 태광 등이 22%로 가장 높았고 단백, 광안이 17%로 가장 낮았다. 특히 단백질 함량이 높은 단백콩과 광안콩이 높은 지질함량을 보였는데, 전반적으로 단백질 함량이 높은 품종들이 낮은 지질함량을 나타내고 단백질함량이 낮은 품종들이 높은 지질함량을 보였다. 수분흡수율은 235.9∼202.82%범위로 평균 218.4%였으며, 보광이 235.9%로 가장 높았고 단경이 202.8%로 가장 적었다. 수침 후 경도는 평균 1.404kg/3.14mm^2로 0.890∼2.593kg/3.14mm^2의 범위였는데 새알이 0.890kg/3.14mm^2로 가장 높은 경도를, 진품이 2.593kg/3.14mm^2로 가장 낮은 경도를 보였다. 한편 수분흡수율과 수침시간과의 상관관계를 검토한 결과, 보광, 광안, 황금 등 전 품종에서 R_2=0.94∼0.99의 범의로 고도의 유의적인 상관관계를 나타내어 수분흡수율이 높을수록 수침경도는 작아지는 것으로 조사되었으며 진품의 수침경도는 2.593kg/3.14mm^2로 가장 높았다. 한편 대두의 가열 후 경도는 0.066∼0.475kg/3.14mm^2의 범위로 평균 경도는 0.153kg/3.14mm^2였고, 단원이 0.066kg/3.14mm^2로 가장 낮았다.
고추장의 품질향상과 전통고추장과 유사한 관능적 요인을 갖는 고추장을 제조하는데 가장 중요한 역할을 할 것으로 기대되는 메주를 찹쌀 고추장으로 유명한 전라북도 순창에서 메주를 제조 0, 20, 40, 60일 숙성하여 숙성기간별로 구분된 메주의 화학적 특성 변화를 조사하였다. 환원당 및 유리당의 함량은 메주 숙성이 진행됨에 따라 감소하였으나 glucose의 함량은 숙성 40일 메주에서 0.119%로 가장 높았으며 비휘발성 유기산의 총함량도 속성 40일 메주에서 459.25㎎%로 가장 높았다. Lactic acid를 포함한 5가지의 유기산이 모두 40일 속성 메주에서 가장 높은 함량을 보였으며 속성기간에 따른 유기산의 변화는 모든 유기산이 속성40일까지 증가하다가 그 이후에 감소하는 것으로 나타났으며, 질소화합물 및 유리아미노산의 함량 역시 숙성 40일 메주에서 가장 높은 함량을 보여 숙성 40일 메주에서 미생물의 대사가 가장 활발한 것으로 사료되었다.