• Title/Summary/Keyword: starters

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Fungal Distribution in Traditional Meju and Characterization of Isolated Strains

  • Ye-Eun Son;Ye-Jin Kang;Sun-Young Choi;Yoon-Kyung Choi;Ju-Eun Lee;Junyoung Kim;Hee-Soo Park
    • The Korean Journal of Mycology
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    • v.51 no.3
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    • pp.219-227
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    • 2023
  • This study was conducted to analyze the distribution and characteristics of fungal species in meju using the traditional method. Fungal distribution in meju was investigated using metagenomic and morphological analyses, based on which Aspergillus flavus/oryzae strains were identified as the dominant fungi in all meju samples, followed by Pichia, Rhizopus and Lichtheimia spp. As A. flavus/oryzae was dominant, we further evaluated the aflatoxin production ability and enzymatic activity of the isolates. Thin-layer chromatography and polymerase chain reaction revealed that the A. flavus/oryzae strains isolated from meju are non-aflatoxigenic fungi. Based on the analyses of amylase and protease activities, strains with high activities of amylase or protease were identified, which are proposed to be used as starters for meju fermentation.

Sourdough and Bread Properties Utilizing Different Ratios of Probiotics and Yeast as Starters (스타터로 사용한 Probiotics-효모 비율을 달리하여 제조한 Sourdough 제빵특성)

  • Chae, Dong-Jin;Lee, Kwang-Suck;Jang, Ki-Hyo
    • Korean Journal of Food Science and Technology
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    • v.43 no.1
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    • pp.45-50
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    • 2011
  • In this study, the influence of mixed starter compositions using Saccharomyces cerevisiae and three mixed probiotics, including Bifidobacterium longum, Enterococcus faecium, and Lactobacillus acidophilus on sourdough and bread preparation was examined. The following probiotic and yeast mixing ratios were used: Exp. 1, probiotics:yeast=2.0:0.1; Exp. 2, 1.5:0.1; Exp. 3, 1.0:0.1 (g/g). Starters for the sourdough preparation were incubated separately for 15 hr, combined, then further incubated for 10 hr. Exp 2 resulted in an increase in the numbers of probiotics and yeast in sourdough by 100 times but reduced pH. This is also reflected by the extent of the acidity increase in sourdough produced in Exp. 2. Among the three groups, bread volume and crumb elongation increased in Exp. 2, but crumb fineness and aroma compounds were not significantly different. In a sensory evaluation, flavor, taste, and overall acceptance for the sourdough produced in Exp. 2 improved markedly.

IN-LINE NIR SPECTROSCOPY AS A TOOL FOR THE CONTROL OF FERMENTATION PROCESSES IN THE FERMENTED MEATS INDUSTRY

  • Tamburini, Elena;Vaccari, Giuseppe;Tosi, Simona;Trilli, Antonio
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.3104-3104
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    • 2001
  • The research described here was undertaken with the aim of monitoring, optimizing and ultimately controlling the production of heterofermentative microbes used as starters in the salami industry. The use of starter cultures in the fermented meats industry is a well-established technique used to shorten and standardize the ripening process, and to improve and control the organoleptic quality of the final product. Starter cultures are obtained by the submerged cultivation of suitable microorganisms in stirred, and sometimes aerated, fermenters where monitoring of key physiological parameters such as the concentration of biomass, substrates and metabolites suffers from the general lack of real-time measurement techniques applicable to aseptic processes. In this respect, the results of the present work are relevant to all submerged fermentation processes. Previous work on the application of on-line NIR spectroscopy to the lactic acid fermentation (Dosi et al. - Monreal NIR1995) had successfully used a system based on a measuring cell included in a circulation loop external to the fermenter. The fluid handling and sterility problems inherent in an external circulation system prompted us to explore the use of an in-line system where the NIR probe is immersed in the culture and is thus exposed to the hydrodynamic conditions of the stirred and aerated fluid. Aeration was expected to be a potential source of problems in view of the possible interference of air bubbles with the measurement device. The experimental set-up was based on an in-situ sterilizable NIR probe connected to the instrument by means of an optical fiber bundle. Preliminary work was carried out to identify and control potential interferences with the measurement, in particular the varying hydrodynamic conditions prevailing at the probe tip. We were successful in defining the operating conditions of the fermenter and the geometrical parameters of the probe (flow path, positioning, etc.) were the NIR readings were reliable and reproducible. The system thus defined was then used to construct and validate calibration curves for tile concentration of biomass, carbon source and major metabolites of two different microorganisms used as salami starters. Real-time measurement of such parameters coupled with the direct interfacing of the NIR instrument with the PC-based measurement and control system of the fermenter enabled the development of automated strategies for the interactive optimization of the starter production process.

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Improvement of Kimchi Fermentation by Using Acid-Tolerant Mutant of Leuconostoc mesenteroides and Aromatic Yeast Saccharomyces fermentati as Starters

  • Kim, Young-Chan;Jung, Eun-Youg;Kim, Hyung-Joo;Jung, Dai-Hyun;Hong, Seong-Gil;Kwon, Tae-Jong;Kang, Sang-Mo
    • Journal of Microbiology and Biotechnology
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    • v.9 no.1
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    • pp.22-31
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    • 1999
  • Saccharomyces fermentati and Leuconostoc mesenteroides were isolated from a traditional kimchi, and then the Leu. mesenteroides was mutated to the acid-tolerant mutant Leu. mesenteroides M-l00. In the result of growth properties in MRS broth with various pHs adjusted with HCl and acid solution (latic acid:acetic acid=1:2), an acid-tolerant mutant Leu. mesenteroides M-100 showed more increased ability for growth than its wild strain at various temperatures. The strains were used as starters for the fermentation of kimchi. The experiments were performed with classified experimental groups (Group I, control kimchi; Group II, addition of YK-19 only; Group III, addition of M-100 only; Group IV, addition of mixture of M-100 and YK-19), and their pH, total acidity, reducing sugars content, organic acid productivity, organoleptic tests, and microfloral changes were compared. As a result, in pH and acidity, the optimal ripening period of Group IV was about 13.5 days (i.e. from the 8.5 to 22 days of fermentation). This result indicates that the optimal ripening period of Group IV was about 1.5 times longer than that of Group I. Furthermore, Group IV was edible to 28 days of fermentation. In addition, high contents of succinc acid was observed in Group IV. Group IV was also highly ranked on the organoleptic test. During the fermentation of kimchi, the number of Leuconostoc sp. in group I reduced after 7 days; however, the number of Leuconostoc sp. in Group II, III, and IV decresed after 14 days of fermentation. An especially high number of Leu. sp. was observed in Group IV, and this gave better flavor of kimchi than any other during the whole fermentation period. Citric acid, tartaric acid, succinic acid, fumaric acid, and lactic acid were detected in the kimchi, and a significant increase in the concentration of lactic acid during fermentation was observed in the all experimental groups.

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Effects of Psychrotrophic Lactic Acid Bacterial Starter on Kimchi Fermentation (저온성 젖산균 스타터가 김치발효에 미치는 영향)

  • So, Myung-Hwan;Shin, Mi-Yee;Kim, Young-Bae
    • Korean Journal of Food Science and Technology
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    • v.28 no.5
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    • pp.806-813
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    • 1996
  • Five strains of psychrotrophic lactic acid bacteria which had been isolated from kimchi were inoculated as kimchi starters, and then their effects were investigated during fermentation at $8^{\circ}C$. The initial numbers of Gram negatives and coliforms in no-starter-inoculated kimchi were $4.0{\times}10^{6}CFU/ml\;and\;3.2{\times}10^4CFU/ml$ respectively, while these of lactic acid bacteria were only $1.6{\times}10^3CFU/ml$. Starter-inoculated kimchi showed sharp decreases in Gram negatives and coliforms from initial stage, but no-starter-inoculated kimchi showed slow increases in those bacteria in the early stage, and sharp decreases after 10 days. It took 10 days in no-starter-inoculated kimchi, $4{\sim}6$ days in Leuconostoc-inoculated kimchi and 2 days in Lactobacillus-inoculated kimchi for lactic acid bacteria to reach stationary phase of growth. No-starter-inoculated kimchi required 10 days to reach optimum ripened state, while all starter-inoculated kimchi samples required 4 days. The inoculations of all these starters did not cause over acidifications. Remarkable softening occurred in Leu. dextranicum-inoculated kimchi in 6 days, but did not in the rest. Except the Leu. paramesenteroides-inoculated kimchi, the qualities of Leuconostoc-inoculated kimchi were as good as those of no-starter-inoculated kimchi, but those of Lactobacillus-inoculated kimchi were not so good.

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Fermentation Characteristics of Low-Salt Kimchi with Starters on Fermentation Temperature and Salt Concentration (종균이 첨가된 저염김치의 발효온도 및 소금 농도에 따른 발효 특성)

  • Moon, Sung-Won;Park, Sun-Hyun;Kang, Byung-Sun;Lee, Myung-Ki
    • The Korean Journal of Food And Nutrition
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    • v.27 no.5
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    • pp.785-795
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    • 2014
  • This study was conducted to develop low-salinity Kimchi with acetic acid, starters and fruits added for health and taste. The quality characteristics of the developed Kimchi by storage period and salt concentrations were investigated herein. The effects of salinity and fermentation temperature ($0^{\circ}C$, $5^{\circ}C$) on the quality characteristics of low-salinity Kimchi were investigated through physicochemical and microbiological analysis. The sensory characteristics are shown in the results below. The pH and acidity were quickly changed by higher temperature over longer storage periods, with gradual decrease in the pH accompanied with an increase in acidity. The microbiological analysis revealed increase in the total cell number regardless of the concentration and strain added during the storage period. Finally, test of the overall acceptability with regard to sensory characteristics according to the different strain sets in low-salinity Kimchi showed the average score for smell, salty taste and overall acceptability were highest in the hetero-fermentation strain group.

Antibacterial activity of lactic acid bacteria isolated from traditional fermented foods and development of a starter for fermented milk (전통발효식품에서 분리한 유산균의 항균 활성 및 발효유 스타터 개발)

  • Park, Jong-Hyuk;Moon, Hye-Jung;Oh, Jeon-Hui;Lee, Joo-Hee;Choi, Kyung-Min;Cha, Jeong-Dan;Lee, Tae-Bum;Lee, Min-Jeong;Jung, Hoo-Kil
    • Food Science and Preservation
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    • v.20 no.5
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    • pp.712-719
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    • 2013
  • This study was conducted to investigate the antibacterial activity of lactic acid bacteria isolated from traditional fermented foods and to develop a new starter for fermented milk. The isolates were identified using 16S rDNA sequencing and named Lactobacillus plantarum A, Leuconostoc lactis B and L. acidophilus C. The activity of these strains to inhibit the growth of food-borne human pathogens (Escherichia coli NCTC 12923, Salmonella Typhimurium NCTC 12023, Listeria monocytogenes NCTC 11994) was measured using the paper disc method. All these strains showed strong antibacterial activity against Li. monocytogenes NCTC 11994. The experiment groups were the fermented milks with these strains, and the control group was the fermented milk with the commercial starter (ABT 5). The change of pH, acidity and viable cell counts were measured during their aging time. All the experiment groups showed a significant difference in their aging times compared to the control group. However, the sensory test showed that the experiment groups can be used as useful starters for fermented milk. This result suggests that L. plantarum A, Leu. lactis B and L. acidophilus C have the potential to be developed as new starters for fermented milk.

Synbiotic Potential of Yoghurt Manufactured with Probiotic Lactic Acid Bacteria Isolated from Mustard Leaf Kimchi and Prebiotic Fructooligosaccharide (갓김치로부터 분리한 Probiotic 유산균과 Prebiotic Fructooligosaccharide로 제조한 요구르트의 Synbiotic 가능성)

  • Lim, Sung-Mee
    • Microbiology and Biotechnology Letters
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    • v.40 no.3
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    • pp.226-236
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    • 2012
  • In the present work, the influence of prebiotic fructooligosaccharide (FOS) on adhesion to Caco-2 cells, viability, acid and bile tolerance, antibacterial, antioxidant, enzymatic, and metabolic activities of the probiotic starters Lactobacillus acidophilus GK20 and Lactobacillus paracasei GK74, has been explored. Experiments were conducted with fermented yoghurt over a period of 7 days at $4^{\circ}C$. When compared to control fermentations without prebiotic, the addition of FOS was seen to significantly (p<0.05) increase the viable cell counts of the probiotics, overall viscosity, and concurrently reduce the pH of the fermented yoghurts. Both Escherichia coli ATCC 11229 and Salmonella enteritidis ATCC 13076 were inhibited by the probiotics' antibacterial activities, while the synbiotic yoghurt containing mixed probiotics and FOS was noted to highly improve antagonistic action. When fermented with mixed starters, the addition of FOS (1.0%) resulted in the highest proteolytic ($1.06{\pm}0.06$ unit) and ${\beta}$-galactosidase activities ($20.14{\pm}0.31$ unit). However, FOS did not affect acid and bile tolerance, adhesion to Caco-2 cells or the antioxidant activity of the probiotics, although both L. acidophilus GK20 and L. paracasei GK74 had functionality as probiotic strains. Hence, a significant synbiotic effect was observed in fermented yoghurt after 7 days of storage at $4^{\circ}C$, and as a result, such synbiotic yoghurt can be said to possess synergistic actions which improve the gastrointestinal environment and promote of health.

Safety Assessment of Starters for Traditional Korean Fermented Foods (전통발효식품용 종균의 안전성 평가 필요성)

  • Jeong, Do-Won;Lee, Jong-Hoon
    • Microbiology and Biotechnology Letters
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    • v.42 no.1
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    • pp.1-10
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    • 2014
  • Most microorganisms have been used for foods for such a long period of time with no question posed for their safety. However, the progress of food processing technology has activated international food trades, and the consumers and authorities of import countries have come to question the safety of microorganisms used in foods. At present, the most widely known safety standards are Generally Recognized as Safe (GRAS) status from the US Food and Drug Administration (FDA) and Qualified Presumption of Safety (QPS) status by the European Food Safety Authority (EFSA). GRAS status is not for the safety of microorganisms themselves but for the permissibility of strains or cultures in specific food uses. QPS provides a qualified generic approval to a defined taxonomic unit. The increase of commercialized traditional fermented foods in Korea has spurred the starter development for traditional food fermentations. However, starter development in Korea has been carried out based on the technological properties of microorganisms with no research on developing a standardized tool for safety assessment. In the globalization of traditional Korean fermented foods, technological properties as well as safety of future starters should be guaranteed, and establishment of the safety assessment regulation for microorganisms used for foods is necessary.

A Comparative Study of the Assay Methods Used to Quantify Fermentable Sugar in Makgeolli Sul-dut (막걸리 술덧의 발효성 당 분석방법 비교 연구)

  • Kim, Byong-Soo;Kim, Gye-Won;Shim, Jae-Yong
    • Korean Journal of Food Science and Technology
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    • v.48 no.1
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    • pp.48-53
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    • 2016
  • The objective of this study was to evaluate the accuracy and efficiency of different methods used for the fermentable sugar assay in the production of Makgeolli sul-dut. In the initial stage of fermentation, Ipguk treatment produced a higher alcohol content compared to the Nuruk treatment. However, the alcohol content was not significantly different between the two starters at the final stage of fermentation. Acidity in the Ipguk treatment was higher than that of Nuruk throughout the fermentation period. After analyzing the fermentable sugars using dinitrosalicylic acid (DNS), Fehling's method, refractometer, glucose kit, and high performance liquid chromatography (HPLC), it was confirmed that the HPLC method was the most accurate for fermentable sugar quantification. In both types of starters, DNS and Fehling's methods showed results comparable to HPLC in terms of fermentable sugar content, while the glucose kit and refractometer analyses showed relatively large discrepancies, indicating that the Fehling's method could also be effective for the analysis of fermentable sugars in the manufacture of Makgeolli.