• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.60-63
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• 1992

Individual starter culture were inoculated into liquid medium and incubated at $40^{\circ}C$ for 16 hours. Whole cell were obtained and evaluated for ${\beta}-galactosidase$ activity using orthonitrophenyl-${\beta}-D-galactopyranoside$ (ONPG) as substrate. S. thermophilus had more ${\beta}-galactosidase$ activity than other Lactobacilli did. To study the effect of storage temprature on enzyme activity of yoghurt, some samples of cultured yoghurt were stored under refrigeration $(4^{\circ}C)$, and the others under room temperature $(23^{\circ}C)$. At $4^{\circ}C$, yoghurt had ${\beta}-galactosidase$ activity and many viable bacteria in 1 month. After 20 days, yoghurt had maximum ${\beta}-galactosidase$ activity. At $23^{\circ}C$, yoghurt had ${\beta}-galactosidase$ activity by 5 days. As this experiment shown ${\beta}-galactosidase$ activity was ascribed to viable bacteria, especially S. thermophillus. Commercial yoghurt had lower ${\beta}-galactosidase$ activity. There were considerable variations with regard to the lactose hydrolyzing capabilities of commercial yoghurt samples.

• Journal of Dairy Science and Biotechnology
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• v.34 no.1
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• pp.9-20
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• 2016

Various microflora, including lactic acid bacteria, are important and necessary components of various cheeses and have significant roles in cheese manufacturing and ripening. In general, the starter culture and secondary microflora could affect the physicochemical properties of various cheeses and could contribute to modifications during manufacturing and ripening. Therefore, during cheese manufacturing and ripening, microbial diversity may depend on continuous interactions among microflora and various environmental conditions. The microbial diversity of cheese is very complex and difficult to control using the classical microbiological techniques. However, recent culture-independent methods have been rapidly developed for microflora in cheese, which could be directly detected using DNA (and/or RNA) in combination with culture-dependent methods. Therefore, this review summarizes state-of-the-art molecular methods to analyze microbial communities in order to understand the properties that affect quality and ripening as well as the complex microbial diversity of various raw-milk, long-ripened cheeses.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.928-934
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• 2011

The objective of this study was to characterize the lactate metabolism and lipolysis in Emmental cheese made of Korean raw milk throughout the ripening periods; 14 d at $10^{\circ}C$, 42 d at $23^{\circ}C$, and 30 d at $4^{\circ}C$. Emmental cheese was made using a commercial starter culture with propionic acid bacteria (PAB) and without PAB as a control on the pilot plant scale. Changes in the contents of five organic acids (citric, lactic, formic, acetic, and propionic acid) and individual free fatty acids (FFAs) were measured using HPLC/PDA and GC/FID. As a result of propionic fermentation by PAB, the concentration of acetic acid and propionic acid increased up to 1.5 and 6.1 g/kg, respectively and the most dramatic increased occurred when incubated in the hot room ($23^{\circ}C$). Lactic, citric, and formic acid contents were 2.6, 2.5 and 0.8 g/kg at the end of ripening, respectively. As a result of lipolysis, the amount of total FFAs was 6,628.2 mg/kg. Compared to the control, levels of individual FFAs from butyric (C6:0) to linoleic (C18:2) acids increased significantly (p<0.05) during the ripening period. Especially, 65.1% of total FFAs was released in the $23^{\circ}C$ room and the most abundant FFAs were palmitic (C16:0), stearic (C18:0) and oleic acid (C18:1). These results demonstrated that the lipolysis of Emmental cheese was strongly affected by bacterial lipase from PAB.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.912-926
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• 2018

We investigated the quality properties and bacteria diversity of pork salami containing homemade kimchi powder (KP). Pork salamis were manufactured with commercial starter culture (control), and 1% KP (KP1), 3% KP (KP3), and 5% KP (KP5). The salami was fermented and aged for 2 days and 56 days, respectively. The pH and $A_W$ values of salamis with KP were significantly lower than that of the control (p<0.05). The 2-thiobarbituric acid reactive substance values of all salamis with KP increased but were below 0.2 mg MDA/kg. Salamis with KP, decreased the $L^*$ value, but increased the $a^*$ and $b^*$ values (p<0.05). The Lactobacillus count was significantly higher in the salamis with KP than in the control by day 14 (p<0.05). The number of Leuconostoc was higher in salamis with KP than in the control and was the highest in salamis in KP1. The KP1 protected lipid oxidation and showed low TBARS value of pork salami compared to the control. This study demonstrates that KP can improve pork salami properties and can serve as a potential natural compounds for fermented meat prodcuts like Metzgerei.

• Food Science of Animal Resources
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• v.42 no.1
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• pp.46-60
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• 2022

In this study, angiotensin-I-converting enzyme inhibitory (ACEI) activity was evaluated in fermented goat milk fermented by lactic acid bacteria (LAB) from fermented foods and breast milk. Furthermore, the potential for ACEI peptides was identified in fermented goat milk with the highest ACEI activity. The proteolytic specificity of LAB was also evaluated. The 2% isolate was inoculated into reconstituted goat milk (11%, w/v), then incubated at 37℃ until pH 4.6 was reached. The supernatant produced by centrifugation was analyzed for ACEI activity and total peptide. Viable cell counts of LAB and titratable acidity were also evaluated after fermentation. Peptide identification was carried out using nano liquid chromatography mass spectrometry (LC-MS/MS), and potential as an ACEI peptide was carried out based on a literature review. The result revealed that ACEI activity was produced in all samples (20.44%-60.33%). Fermented goat milk of Lc. lactis ssp. lactis BD17 produced the highest ACEI activity (60.33%; IC₅₀ 0.297±0.10 mg/mL) after 48 h incubation, viable cell counts >8 Log CFU/mL, and peptide content of 4.037±0.27/mL. A total of 261 peptides were released, predominantly derived from casein (93%). The proteolytic specificity of Lc. lactis ssp. lactis BD17 through cleavage on the amino acid tyrosine, leucine, glutamic acid, and proline. A total of 21 peptides were identified as ACEI peptides. This study showed that one of the isolates from fermented food, namely Lc. lactis ssp. lactis BD17, has the potential as a starter culture for the production of fermented goat milk which has functional properties as a source of antihypertensive peptides.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.5
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• pp.661-668
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• 2011

This study was conducted in order to determine the optimum conditions for the production of fermented grapefruit extract showing high cell growth, antioxidant activity and total flavonoid content. Five lactic acid bacterial strains - Lactobacillus plantarum KCTC3104, Lactobacillus brevis KCTC3102, Weisella cibaria KCTC3746, Leuconostoc citreum KCTC3526 and Leuconostoc mesenteroides KCTC3505 - were evaluated first in order to determine the optimum strain able to grow with high efficiency on grapefruit as a substrate and possesses higher antioxidant activity and flavonoids content. Among these strains, L. mesenteroides KCTC3505 was selected as a starter culture. To estimate the available or effective content of grapefruit in basal medium, the effects of 30%, 50%, and 70% grapefruit contents on the performance of fermentation were tested, and it was found that grapefruit can be added at 70% levels to medium. In this study, three factors of fermentation conditions - incubation time, sucrose, and glucose contents - were evaluated for their effects on fermentation performance. Taguchi experiment design was employed and the responses of experiments were calculated using signal and noise ratio calculation with larger-the-best characteristics. Finally, the optimum conditions for the manufacture of fermented grapefruit extract were as follows: grapefruit 70%, sucrose 10 g/L, glucose 10 g/L, sodium acetate 1 g/L, NaCl 1 g/L, dipotassium phosphate 0.1 g/L, magnesium sulfate 0.01 g/L and 16 hr of incubation.

• Food Science of Animal Resources
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• v.43 no.5
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• pp.877-888
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• 2023

We studied the proteolysis and conducted a sensory evaluation of fermented sausages using strains derived from Kimchi [Pediococcus pentosaceus-SMFM2021-GK1 (GK1); P. pentosaceus-SMFM2021-NK3 (NK3)], Doenjang [Debaryomyces hansenii-SMFM2021-D1 (D1)], and spontaneous fermented sausage [Penicillium nalgiovense-SMFM2021-S6 (S6)]. Fermented sausages were classified as commercial starter culture (CST), mixed with GK1, D1, and S6 (GKDS), and mixed with NK3, D1, and S6 (NKDS). The protein content and pH of GKDS and NKDS were significantly higher than those of CST on days 3 and 31, respectively (p<0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the NKDS had higher molecular weight proteins than the GKDS and CST. The myofibrillar protein solubility of the GKDS and NKDS was significantly higher than that of the CST on day 31 (p<0.05). The GKDS displayed significantly higher pepsin and trypsin digestion than the NKDS on day 31 (p<0.05). The hardness, chewiness, gumminess, and cohesiveness of the GKDS were not significantly different from those of the CST. The GKDS exhibited the highest values for flavor, tenderness, texture, and overall acceptability. According to this study, sausages fermented using lactic acid bacteria (GK1), yeast (D1), and mold (S6) derived from Korean fermented foods displayed high proteolysis and excellent sensory evaluation results.

• Food Science and Preservation
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• v.6 no.4
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• pp.456-462
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• 1999

The radish juice inoculated with mixed culture of Leuconostoc mesenteroides and Lactobacillus brevis was fermented and stored. Radish juice was heat-treated for 30 min at 65$^{\circ}C$ and 15 min at 80$^{\circ}C$, and stored for 8 weeks at 25$^{\circ}C$, 15$^{\circ}C$, and 5$^{\circ}C$, respectively. When the radish juice was heat-treated, any bacteria were not detected and any quality changes were not occured. On the other hand non-heated radish Juice, pH was decreased and acidity was increased during storage. The turbidity of the heat-treated radish juice was higher than that of the non-heated juice when it stored at 5'E. From the sensory evaluation, the pasteurization condition of 15 min at 80$^{\circ}C$ was not appropriate because the fresh smell of Dongchimi was decreased and the cooked smell was increased. The radish juice stored at 5$^{\circ}C$ without heat-treatment was evaluated to have the best quality. The storage period of the non-heated radish juice was shown to be extended over 8 weeks at 5$^{\circ}C$.

• Journal of Dairy Science and Biotechnology
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• v.38 no.3
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• pp.154-160
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• 2020

Physical and sensory characteristics of commercial yogurts are important aspects for consumer acceptability. In addition, beneficial functions of commercial yogurts are also emphasized for the probiotic dairy products. The aim of this study was to investigate the functional properties of yogurts with the combination of bacteriocin-producing Pediococcus acidilactici. Yogurts fermented with commercial starter culture (control yogurt) and control yogurt together with P. acidilactici HW01 (yogurt+HW01), P. acidilactici JM01 (yogurt+JM01), or P. acidilactici K10 (yogurt+K10) were prepared. During 28 days after fermentation, the viability of lactic acid bacteria, pH, and brix, in the yogurt samples were assessed with standard methods. Moreover, to investigate the antilisterial activity of the yogurt samples, Listeria monocytogenes was simultaneously inoculated when the yogurts were prepared with lactic acid bacteria, and the viability of L. monocytogenes was determined. Although yogurt+K10 did not completely remove L. monocytogenes, control yogurt, yogurt+HW01, and yogurt+JM01 eradicated L. monocytogenes at day 2 after fermentation. However, yogurt+K10 also removed L. monocytogenes at day 3 after fermentation. Taken together, these findings suggest that the combination of yogurt with P. acidilactici does not affect its quality and they may consequently aid in the development of new probiotic yogurt.

• Korean Journal of Agricultural Science
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• v.30 no.1
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• pp.66-75
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• 2003

This experiment was carried out to examine the fermentation properties of yogurt added fresh mulberry, freeze dried-mulberry and heated air dried-mulberry at concentrations of 0%, 0.3%, 0.6% and 0.9%. Lactic acid bacteria was used mixed starter culture(Str.salivarius ssp. thermophilus and Lac. delbrueckii ssp. bulgaricus). We obtained excellent results from the yogurt added fresh mulberry. In yogurt added 0.9% fresh-mulberry, lactic acid contents and titratable acidity were higher than those of 0%, 0.3%, 0.6% fresh-mulberry added. Also, sensory scores of color, taste and overall acceptability of the yogurt with 0.9% fresh mulberry was higher than those of any other groups.