Abstract ▼

Ⅳ. Results of Research
1. Secure the microorganism resources for improving quality of kimchi
∙ Among the isolates from kimchi, Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus sakei are selected as indicator bacteria in sour kimchi, which are lower the pH of culture medium
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Ⅳ. Results of Research
1. Secure the microorganism resources for improving quality of kimchi
∙ Among the isolates from kimchi, Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus sakei are selected as indicator bacteria in sour kimchi, which are lower the pH of culture medium
∙ Lactococcus lactis WK11, Lactobacillus brevis WK12 are selected, which exhibits inhibitory activity against the bacteria associated with acidification of kimchi

2. The development of microbial additives for kimch
∙ Lc. lactis cultured in MRS broth were mixed with an equal volume of 2% alginate solution, the final concentrations were 1% alginate. This lactic acid bacteria and alginate 1% mixed solution was coated with 0.2 mm beads, soaked with 10% bean flour and lyophilized to 48 hours

3. Control of the fermentation rate using microbial additives
∙ Kimchi treated with Lc. lactis 1×107 CFU/g and 10% Lc. lactis culture medium(% of kimchi) prolonged optimal fermentation period (pH 4.2, acidity 0.6–0.8%) up to more than 2 times
∙ Microbial additives prepared in the form of beads, exhibited a similar effect to that of the addition of viable cells, may facilitate the formulated manufacture of kimchi with a longer shelf life
∙ Heat treated at 65℃-30 minutes with kimchi sauce or addition of lactic acid, have a slightly effect on extending shelf life

4. Improvement of hygienic safety for low-salted kimchi
∙ The initial counts of coliform bacteria in non-starter kimchi and starter kimchi were showed similar counts. However, depending on the fermentation progresses, it declined rapidly in starter kimchi due to the inoculated starter bacteria

5. The development of optimal fermentation processes for traditional fermented food using microbial additives
∙ Considering commercial antiseptic solution (100 ppm sodium hypochlorite solution) and the case of pasteurized result, antiseptic solution has microbial reduction effect more than 2 minutes treatment and 5 minutes treatment was better. In case of pasteurization condition of kimchi sauce, at 65℃ for 30 minites showed microbial reduction effect
∙ The initial number of Lc. lactis inoculated differently, 1×103 CFU/g, 1×105 CFU/g, 1×107 CFU/g each, the kimchi adapted 1×107 CFU/g as initial inoculum level prolonged shelf life. Futher, improve efficiency with inoculation method, mixed gently with culture medium, starter and kimchi sauce without additional aging periods at process for preparing kimchi

6. Identification of the dominant bacteria in jeotgal fermentation
∙ Jeotgal or jeot, a traditional Korean salted and fermented food, is made by adding 20–30% (w/w) salt to various types of seafood. To develop a more complete overview of the bacterial community present in jeotgal, 610 pure colonies were isolated from Myeolchi-jeotgal and Saeu-jeotgal , the most commonly consumed varieties of jeotgal, which are made with anchovy (Engraulis japonicas) and tiny shrimp (Acetes japonicas), respectively. The bacterial isolates were identified by 16S rDNA sequence analysis. A total of 104 species comprising 47 genera and 31 previously unknown species were identified. Eleven genera were isolated from both jeotgal samples, including species in the genera Staphylococcus, Bacillus, Halomonas, and Kocuria, with Staphylococcus spp. constituting the highest number. The most populous genus detected in Myeolchi-jeotgal was Bacillus and its relatives, while the most populous in Saeu-jeotgal was Staphylococcus mainly identified as S. equorum. They may be the major organisms involved in jeotgal fermentation and the future starter candidates.
∙ The bacterial community present in Ojingeo-jeotgal, which is made with squid. One hundred twenty one bacteria were isolated and identified by 16S rRNA gene sequence analysis. Among the 121 total isolates, the most populous genus was Bacillus and then followed by coagulase-negative staphylococci.

7. Selection of the starter candidates for Ojingeo-jeotgal fermentation which inhibit the growths of Staphylococcus aureus and Vibrio parahaemolyticus
∙ Six strains of Bacillus species inhibiting the growth of food pathogens, Staphylococcus aureus and Vibrio parahaemolyticus, were selected from the 121 isolates from Ojingeo-jeotgal. They inhibited the growths of both pathogens and showed proteolytic activities on the media containing 6% NaCl and 2% skim milk.

8. Selection of the safe starter candidates for jeotgal fermentation
∙ To select starters for jeotgal, the safety and technological properties of its predominant bacteria isolates, which were identified as Staphylococcus equorum, were assessed. As the result of safety assessments of S. equorum (antibiotic susceptibility test, hemolysis gene identification, biofilm formation test, and enterotoxin gene identification), 39 S. equorum strains cleared all of the tested safety hazards and were adopted for technological property assessments.
∙ Among the 39 strains, five strains (C4X11, C6037, KS1035, KS1039. KS2036) exhibited protease, lipase, nitrate reductase activities and they did not produce four kinds of biogenic amines.
∙ Most of the strains could grow on the agar with 20% NaCl, therefore the selected five strains covers the safety and technological requirements for jeotgal starters.

9. Development of starter culture application methods
∙ Development of food-grade medium made with shrimp for the culture of starters
∙ Evaluation of freeze-drying efficiency for the long-term storage of starter candidates

10. Evaluation of starter culture effectiveness in jeotgal fermentation
∙ Culturable bacterial community analysis of Saeu-jeotgal was performed during ripening for 135 days to prove that a wild-type strain can be used to accelerate and standardize jeotgal. Thirty nine species detected at the day 1 were decreased to 13 species at day 135. The order of dominance in genus level is Staphylococcus, Salimicrobium, Kocuria, and Psychrobacter . The proportions of Staphylococcus and Salimicrobium began 2% and then became 39% and 36% of all isolates at the day 135, respectively. Both strains may be the dominant of Saeu-jeotgal and were shown to grow at 24% salt condition. We confirmed the effectiveness of Staphylococcus species for Saeu-jeotgal fermentation.
∙ Proteolytic bacteria were isolated from Myeolchi-jeotgal and Saeu-jeotgal using high-salt-content media and their growths in high-salt-content media were checked to draw the role of bacteria during the ripening of jeotgal. Among the isolates, Virgibacillus halodenitrificans from Myeolchi-jeotgal and Halobacillus trueperi from Saeu-jeotgal showed proteinase activities. Vb. halodenitrificans and Staphylococcus equorum, the dominant species from Myeolchi-jeotgal and Saeu-jeotgal , showed growths at the nutrient broth containing 25% NaCl. They may play a significant role in the ripening of jeotgal and have a high possibility to be used as the starter.

11. Establishment of microbial safety assessment system
∙ Through this research study, we reconfirmed the necessity of characterization in the functionality and safety of S. equorum for starter development because all of the tested phenotypic characteristics were expressed in strain-specific manners. The methods applied for the safety assessments of S. equorum will be a good example for the safety assessment of starter candidates.

12. Development of Medium composition for microbial additive formulation
∙ Pickled cabbage juice solution by utilizing basic medium components, carbon source and nitrogen source, adjust the trace elements
∙ Box-behnken experimental design and screening of nitrogen through the reaction surface conducted experiments
∙ Nitrogen sources include peptone 4%(w/v) was added to determine the best formulation

13. Formulation Development of microbiological additives
∙ LAB starter can be liquid form, frozen form and powder form, liquid form is difficult to keep it and to maintain quality in the process of distribution but powder form is easy. Consequently in this study, in order to develop a formulation of the LAB starter,
∙ LAB starter(liquid form, freezed form, powder form) was evaluated during storage period

14. Screening of cryoprotectants to increase survivability of lactic acid bacteria
∙ Improvement of ciability of freeze-dried lactic acid bacteria using good-grade protective agents
∙ The viability of freeze-dried lactic acid bacteria (LAB), including Weissella cibaria SW1-1, Lactobacillus plantarum A-1, Lb. sakei 2-12 24 and Leuconostoc citreum 3526 was evaluated with food grade protective agents (e. g., skim milk, yeast extract, soy powder and trehalose)
∙ Soy powder showed a strong protective effect upon the viability of both LAB species, followed by skim milk and yeast extract.
∙ The viability of LAB species was not dose-dependent with soy powder, showing the highest rate of 92.7% for Lb. brevis A101 and 94.7% for Lc. lactis CHJ10 when 10% soy solution was used as a protective agent.
∙ Soy powder was best among protective agents, showing approximately 90%

15. Development of microbial additive mass culture technology
∙ Improvement of viability of freeze-dried lactic acid bacteria using food-grade protective agents
∙ Correlation on pH and microbial growth characteristics of the culture
∙ Glucose and yeast extract medium contrast selected _MRS broth MRS medium compared to ensure afford ability

16. Survivability of powder type starter during storage period
∙ According to the study, in case of Keeping the lactobacillus in -20℃ for 28 days, the survival rate was best. Results suggest the possibility of producing freeze dried powders of LAB starter with high viability for the food industry
∙ During storage of freeze-dried lactic acid bacteria, those survival rate decrease rapidly, reaching 0∼19.1% in room temperature.
∙ There was synergetic effect of soy powder to improve viability of LAB when Ca-alginate beads were soaked in 10% of soy powder solution before freeze-drying. No significant -rate was observed for both LAB
∙The highest survival rate was observed with 1% alginate solution, 10% soy powder solution showing 95.1%, 96.6% of survival rate right after freeze drying

17. Distribution system construction and supply management manual written by the online and offline

목차 Contents

• 표 지 ... 1
• 제 출 문 ... 2
• 요 약 문 ... 3
• SUMMARY ... 11
• CONTENTS ... 17
• 목 차 ... 18
• 제 1 장 연구개발과제의 개요 ... 19
• 제 1 절 연구개발의 목적 ... 19
• 제 2 절 연구개발의 필요성 ... 19
• 제 3 절 연구개발의 범위 ... 24
• 제 2 장 국내외 기술개발 현황 ... 25
• 제 3 장 연구개발 수행 내용 및 결과 ... 33
• 1세부: 김치발효용 미생물첨가제 개발 및 발효조절기술 개발 ... 33
• 2세부: 김치발효용 미생물첨가제 개발 및 발효조절기술 개발 ... 72
• 협동: 젓갈용 우수미생물 선발 및 미생물 첨가제를 이용한 젓갈발효 조절 기술 개발 ... 143
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 187
• 제 1 절 목표달성도 ... 187
• 제 2 절 관련분야에의 기여도 ... 192
• 제 5 장 연구개발 성과 및 성과활용 계획 ... 193
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 197
• 제 7 장 참고문헌 ... 200
• 끝페이지 ... 242