• 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.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.6
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• pp.1041-1048
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• 2015

This study was performed to produce quality vinegar using different types of nuruk, which is the most effective in making traditional brown rice vinegar. The vinegar was produced with 20% vinegar starter, and pears were added to reduce the nuruk aroma. Three different types of Nuruk that were prepared were rice, wheat, and a rice+wheat (1:1) combination. The total acidities of brown rice pear vinegar made from rice-nuruk, wheat-nunuk, and rice+wheat-nuruk were 8.1%, 7.5%, and 6.4%, respectively. Free sugars, including glucose, galactose, and fructose, were highly detected from all three vinegar samples. Acetic acid and lactic acid were the major organic acids in all three vinegar samples. For free amino acids, alanine, glutamic acid, and arginine were mainly detected in all three vinegar samples. Total phenolic compounds were higher in brown rice pear vinegar made of rice-nuruk than in that made of wheat-nuruk, whereas total flavonoids showed the opposite pattern. DPPH-radical scavenging activity was higher in brown rice pear vinegar made of wheat-nuruk than in that made of rice-nuruk.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.46-52
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• 1992

The optimum condition for the developement of a whey beverage from the concentrated whey was studied. Reverse osmosis system was used to obtain concentrated lactose from cheese whey. The hydrolysis degree of lactose by $\beta$-D-galactosidase was determined using HPLC (high performance liquid chromatography). The order of hydrolysis degree was 1:1, 2:l and 3:l concentrated lactose. It resulted from the concentrated salt which slightly inhibited $\beta$-D-galactosidase with constant enzyme dosage. The optimum condition for enzyme dosage was 2% in non-concentrated lactose, 3% in 2:l and 3% in 3:l concentrated lactose after 4 hours of reaction. When the 3:l concentrated lactose was used, more than 70% was hydrolyzed by 3% enzyme dosage. Furthermore the change of fermented whey by lactic acid bacteria was investigated. Based on the result of sensory test, the most favorable response was obtained at pH 4.2 and titratable acidity of 0.7% about 6 hours of fermentation at $37^{\circ}C$ with 2%: thermophilic starter.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.902-907
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• 2006

Freeze dried crude bacteriocin was encapsulated within an acid-soluble coating material, Eudragit EPO, using a surface modification technique through a hybridization system. The pH and titratable acidity of control yoghurt were 3.92 and 1.56%, respectively, after 24 hr of fermentation at $42^{\circ}C$, whereas yoghurt containing 500 AU/mL encapsulated bacteriocin exhibited a higher pH (4.37) and lower titratable acidity (1.2%). Yoghurt containing encapsulated bacteriocin had significantly lower titratable acidity when the duration of fermentation (to pH 4.5) and subsequent refrigerated storage ($4^{\circ}C$) was longer than 20 days. There were no significant differences in the viability of lactic acid bacteria after 15 hr of fermentation. This suggests that microencapsulated bacteriocin has the potential to control the excessive growth of yoghurt starters caused by temperature abuse or post-acidification.

• Food Science of Animal Resources
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• v.30 no.4
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• pp.649-654
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• 2010

In order to develop new functional yogurts using mulberries and mulberry leaves, which were cultivated in Hwasun-gun, Jeonnam Province, Korea, the nutritional compositions, fermentation conditions, sensory properties, and storage stabilities of the yogurts were analyzed. The mulberry powder yogurt contained 87.96% moisture, 3.21% carbohydrate, 4.52% protein, 3.63% lipid, and 0.68% ash, and the mulberry leaf yogurt contained 86.36% moisture, 4.13% carbohydrate, 4.87% protein, 3.79% lipid, and 0.85% ash. A yogurt base was fermented for 13 h with 0.01% ABT-5 starter inoculum at $40^{\circ}C$. To prepare the mulberry jam and mulberry leaf yogurts, a variety of mulberry jam and mulberry leaf samples were added to the yogurt base. The sensory evaluation results of the yogurts containing the mulberry jam and mulberry leaves indicated that a product made with 15% mulberry jam was more strongly preferred than other samples. When the mulberry jam and mulberry leaf yogurts were stored at $4^{\circ}C$ for 15 d, there were no significant changes in pH, titratable acidity, or viable cell numbers of lactic acid bacteria and Bifidobacterium bifidum.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.461-471
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• 1995

The heterofermentative Leuconostoc mesenteroides, which is propagated from the initial to the intermediate stage of Kimchi fermentation, produces organic acids and carbon dioxide to impart refreshment, weak acid taste to Kimchi. But owing to lactic acid production by the homofermentative Lactobacillus Plantarum, Kimchi finally reaches its acidified state. So, Leu. mesenteroides was isolated from Kimchi and identified and was improved by mutation for carbon dioxide production at low pH, and for the high total acceptability. We tested with a wild-type strain K-1 and its improved mutant strain M-10 of Leu. mesenteroides. The wild-type strain K-1 could grow in pH 4.2 at 30$\circ$C or 20$\circ$C, and in pH 5.0 at 10$\circ$C. But the mutant strain M-10 could grow in pH 3.3 at 10$\circ$C. In the respect of total acceptability, mutant strain M-10 inoculated Kimchi was ever better than any others. Mutant M-10 inoculated Kimchi prolonged the optimum ripening period of Kimchi up to two times as compared with the control group.

• The Korean Journal of Food And Nutrition
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• v.7 no.2
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• pp.151-158
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• 1994

This study was carried out to clear up the cause of low-acid producing phenomenon occurred In non-fat dry milk during liquid-yoghurt fermentation by Lactobacillus case, and to present its improving methods. All samples of non-fat dry milks which were low in TCA-soluble peptides showed low-acid production, but those high in TCA-soluble peptides showed high-acid production. The addition of trypsin-hydrolysate of Na-caseinate to non-fat dry milk showed some improving effect on acid production but that of papain-hydrolysate did not show any improving effect and that of bacterical neutral protease-hydrolysate showed some inhibitory effect. The improving effects on growth and acid production of lactic acid bacteria were more prominent when the trypsin-hydrolysate of Na-caseinate was added. to such fermenting system in which the levels of TCA-soluble peptides and the proteolytic ability of starter bacteria were abnormally low. The liquid-yoghurt made with non-hydrolysed Na-caseinate and defective non-fat dry milk showed precipitate occurrence but that with trypsin-hydrolysate of Na-caseinate and defective non-fat dry milk did not make any precipitate during storage as with normal non-fat dry milk.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1077-1085
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• 1997

This study was carried out to elucidate the utilization of the fusant for shortening the ripening time by making an observation of the microstructure and the profile of component change. In ripening cheese, moisture content of the sample treated with tested strain is not a remarkable difference among the test samples. With an increase of the ripening time, L. helveticus showed the highest increase in protein content, followed by fusant, and then L. bulgaricus. The fat content of all starters was gradually decreased while it was it was rapidly decreased after 7 days. The pH of all starters was gradually decreased when the ripening time increased. The titratable acidity was greatly increased between a 9th day and a 15th day ripening. In investigating the light microscopic microstructure of ripened cheese samples, the sample treated with fusant indicated little difference from the other starters in decomposition of protein and fat components by microbial enzymes. In SEM observation, the structure of all cheese samples was uniform and the rough texture was converted into smooth texture by the interaction of cheese components and the abscission of single bond in casein matrix when the ripening time is increased. The fusant showed similar results in the examination of component change and its microstructure compared with the other starters. Therefore, it was revealed that the fusant can be partially used as a cheese starter instead of conventional starters by replacing them or combining them together with the other starters for shortening the ripening time.

• Food Science of Animal Resources
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• v.43 no.1
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• pp.170-183
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• 2023

This study evaluated the effects of milk fermented with Pediococcus acidilactici strain BE and Pediococcus pentosaceus strain M103 on diabetes in rats (Rattus norvegicus). The bacteria were separately used as starter cultures for milk fermentation, and the products were then fed to diabetic rats for 15 days. Blood glucose levels, immunohistochemical and histological indicators, lipid profiles, and total lactic acid bacterium counts were evaluated before and after treatment. The administration of milk fermented with P. acidilactici strain BE reduced blood glucose levels from 410.27±51.60 to 304.07±9.88 mg/dL (p<0.05), similar to the effects of metformin (from 382.30±13.39 mg/dL to 253.33±40.66 mg/dL, p<0.05). Increased insulin production was observed in diabetic rats fed milk fermented with P. acidilactici strain BE concomitant with an increased number and percentage area of immunoreactive beta-cells. The structure of insulin-producing beta-cells was improved in diabetic rats fed milk fermented with P. acidilactici strain BE or metformin (insulin receptor substrate scores of 5.33±0.94 and 3.5±0.5, respectively). This suggests that the administration of milk fermented with P. acidilactici BE potentially reduces blood glucose levels and improves pancreatic beta-cell function in diabetic rats.

• 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.