• The Korean Journal of Food And Nutrition
• /
• v.17 no.1
• /
• pp.8-17
• /
• 2004

The effect of chlorella extract on the growth and acid production of yoghurt starter was investigated in order to prepare the yoghurt added with chlorella extract. The various levels of chlorella extract powder were added to skim milk medium and the medium was fermented by single or mixed culture of 4 types of lactic acid bacteria such as Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus bulgaricus. The changes in acid production(pH, titratable acidity) and number of viable cells of the medium during fermentation in skim milk added with chlorella extract powder have determined. When chlorella extract powder was added to skim milk medium at the levels of 0.5%, 1.0%, 2.0%, and 3.0%, the addition of 0.5% chlorella extract powder with the single culture of Str. thermophilus, Lac. casei, and Lac. bulgaricus showed the highest number of viable cell counts after 9 hours incubation. And also all single cultures of the yoghurt starter produced the higher amounts of acid with the addition of 0.5% chlorella extract powder. When chlorella extract powder was added to the medium at the levels of 0.25%, 0.5%, 1.0%, and 2.0%, the addition of lower lever(0.25∼0.5%) of chlorella extract powder with the mixed culture of the lactic acid bacteria showed more the acidity of pH and the number of viable cell counts. Among the treatments tested, the addition of 0.25% chlorella extract powder with the mixed culture of Str. thermophilus and Lac. casei produced the highest number of viable cell counts after 12 hours incubation. Therefore it was suggested to manufacture the yoghurt with the addition of 0.25% chlorella extract powder and the inoculation of mixed culture of Str. thermophilus and Lac. casei for on the stimulation of growth of the yoghurt starter.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.27 no.9_10
• /
• pp.1134-1143
• /
• 2003

The purpose of this study is to investigate surface color change and effects of mordants on the K/S values of silk and wool fabrics dyed with Lac extract, according to the mordanting methods and conditions such as temperature, concentration and time of the mordanting bath. The results were as follow; 1 K/S values of the silk and wool fabrics according to the temperature of the mordanting bath were shown a slight decline beyond 40$^{\circ}C$. 2. Surface color of the silk changed from red to reddish purple and that of the wool showed red tone when mordanted with Aluminum postassium sulfate, Copper acetate and Copper (II) sulfate regardless of the mordanting conditions. 3. The light and dry cleaning fastness of silk and wool fabrics dyed with Lac extract according to the mordanting methods were very good.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.8
• /
• pp.1248-1253
• /
• 2002

Coocus laccae(Laccifer lacca Kerr), usually known as Lac, is a kind of cocoon which is parasitic on the tree around India and China. It contains the laconic acid of red colored dyes and has been used for cosmetic or natural dyeing prior to the introduction of New World cochineal. Nevertheless, the characterization of lac has not been studied, very little informed. The purpose of this study is to examine the effects of dyeing conditions fur Lac extract, such as pH of dye bath, concentration of Lac exact dyeing temperature and time, to find out the optimum conditions. The results were as follow. 1. The highest K/S values of the silk and wool was shown at PH 3 and PH 4. 2. K/S values of the silk came to nearly the adsorption equilibrium state at 40$^{\circ}C$ and the curve of wool showed a dramatic increase with the increase of temperature. 3. Dyed silk and wool fabrics showed good light fastness without using mordants.

• Journal of Food Hygiene and Safety
• /
• v.14 no.4
• /
• pp.352-357
• /
• 1999

Changes in titratable acidity, viable cells and sensory properties of curd yogurt during lactic fermentation in milk added with mugwort extract have been studied. Milk added with 5%, 10％, 15％ or 20% of mugwort extract was fermented with single or mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus for 24 hours. Addition of mugwort extract markedly stimulated the acid production and propagation of lactic acid bacteria. Among the organism tested, the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus produced the highest amount of acid, and Lactobacillus bulgaricus showed the highest number of viable cell counts. Sensory property of curd yogurt added with mugwort extract was evaluated as better than reference sample(milk yogurt). The sample prepared by fermenting milk containing mugwort extract at 5% level with Lactobacillus bulgaricus showed the most favorite characteristics.

• Food Science of Animal Resources
• /
• v.24 no.4
• /
• pp.416-423
• /
• 2004

This experiment was carried out to investigate the effect of loquat (Eriobotrya japonica Lindley) extract on the acid production and growth of lactic culture in reconstituted skim milk. The supplementation level of loquat extract to reconstituted skim milk was 10％, 15％ and 20％. Reconstitued skim milk containing loquat extract was fermented by single of mixed culture of Streptococcus thermophilus, Lactobacillus acidophilus and Lactobacillus casei. General compositions of loquat extract, changes of viable cell count, pH and titratable acidity during fermentation were determined. Chemical compositions of loquat extract were 91.5％ moisture, 0.2％ crude ash, 8.6$^{\circ}$ Brix soluble sugar, 0.34％ total acid, and 4.11 in pH. Supplementation of loquat extract stimulated acid roduction and growth of lactic acid bacteria. Among supplementation levels, a group that was fermented by a single culture of Str. thermophilus with 10％ loquat extract was shown the highest viable cell count (2.10${\times}$10$\^$9/ CFU/mL) at 12 hours after inoculation. When loquat extract was added to reconstituted skim milk at the level of 10％, all mixed cultures of lactic acid bacteria showed higher acid production and the number of viable cell count than 3 kinds of single cultures. Especially, the growth of mixed culture of Str. thermophilus and Lac. acidophilus was promoted by the addition of 10％ loquat extract. Therefore, it was suggested to manufacture the yoghurt with the addition of 10％ loquat extract and the inoculation of mixed culture of Str. thermophilus and Lac. acidophilus for on the stimulation of growth of the lactic culture.

• Korean journal of food and cookery science
• /
• v.10 no.1
• /
• pp.35-38
• /
• 1994

The growth extent of Leu. mesenteroides and Lac. plantarum in the medium which contain sterilized extract of each of garlic, red pepper powder, and onion was examined. Garlic and onion decreased the growth of Leu. mesenteroides and Lac. Plantarum, and garlic represented more negative effect on the growth of Lac. plantarum than that of onion. Red pepper powder had negative effect on the growth of Lac. plantarum, and positive effect on the growth of Leu. mesenteroides in accordance with incubation processing.

• Food Science of Animal Resources
• /
• v.23 no.4
• /
• pp.333-341
• /
• 2003

The effect of water extract of Schizandra chinensis on the growth of yoghurt starter was investigated in order to manufacture the drink type yoghurt added with water extract of Schizandra chinensis. It was the most desirable extraction conditions for Schizandra chinensis to soak in 50 times of water for 15 hours at 20$^{\circ}C$. The water extract of Schizandra chinensis showed pH 3.07, 2.39％ acidity, 1.10％ total sugars, and 0.15 optical density for color. The water extract of Schizandra chinensis was added to MRS broth medium from 0.1％ to 1.0％ and the medium was fermented by 4 types of lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus bulgaricus, and Streptococcus thermophilus. The addition of water extract of Schizandra chinensis inhibited the growth of the lactic acid bacteria. The maximum addition amounts of water extract of Schizandra chinensis was 0.9％ for Lac. acidophilus, 0.8％ for Lac. casei, 0.2％ for Lac. bulgaricus and 0.1％ for Str. thermophilus in order to maintain the propagation of the lactic acid bacteria. When the drink type yoghurts added with 0.4％, 0.6％, 0.8％ and 1.0％ water extract of Schizandra chinensis were kept at 4$^{\circ}C$ for 15 days, it was showed that the number of lactic acid bacteria was not significantly changed during the storage. The viable cell counts of the drink type yoghurts by addition of 0.4∼l.0％ of water extract of Schizandra chinensis were 1.13${\times}$10$\^$9/∼2.29${\times}$10$\^$9/ CFU/mL, and these bacterial counts were still more than the legal standard(1.0${\times}$10$\^$8/ CFU/mL) even at 15 days of storage.

• Korean Journal of Food Science and Technology
• /
• v.53 no.3
• /
• pp.348-355
• /
• 2021

Bacteriophages (phages) are known determinants of kimchi microbial ecology. Lactobacillus plantarum is related to kimchi over-acidification during the late stages of kimchi fermentation. A phage infecting Lac. plantarum was isolated from kimchi and characterized. The phage population for kimchi in a market was 2.3 log particles/mL, which corresponded to 32% of the bacterial population on a log scale. The isolated phage was designated as ΦLP12116. ΦLP12116 which belonged to the Siphoviridae family and has a very narrow host range, infecting only Lac. plantarum. The phage was stable at a lactic acid concentration of 1.0% and pH 4.0 at 4℃, indicating that it could survive in kimchi. In the kimchi extract broth treated by the phage, the growth of Lac. plantarum KCCM 12116 was inhibited by 2.2 log CFU/mL compared to the growth in non-phage-treated broth. Therefore, this study suggests that the growth of Lac. plantarum, which is known as an acid-producing strain during late fermentation in kimchi, may be controlled using the phage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.2
• /
• pp.420-426
• /
• 2004

In this study, among 10 medicinal plants extracted with 50%-ethanol, antimicrobial activities measured by paper disc method were showed in Scutellaria baicalensis (Sb) on Leu mesenteroides and in Phellodendron amurene (Pa) on Lac. plantarum and Leu. mesenteroides. While 0.05∼0.2% of Pa extracts showed also relatively strong growth inhibition of both strains of lactic acid bacteria cultured in MRS broth for 24 hours at 3$0^{\circ}C$, Sb extract at concentration of 0.1% showed similar inhibitory effect on Leu mesenteroides to that of 0.05% of Pa extract. Addition of 0.02∼0.04% of Pa extracts to kimchi lowered effectively extents of pH decrease and acidity increase, and numbers of lactic acid bacteria and total bacteria compared to those of control during fermentation at 4$^{\circ}C$. This extending effect on fermentation period was obtained by adding 0.04% in case of Sb. Mixed extracts of Pa and Sb (Pa-Sb) by ratio 1 : 1 delayed also fermentation of kimchi at 0.03∼0.04%. In sensory evaluation kimchi containing 0.04% of Pa extract were less sour than kimchi containing 0.02% of Sb extract and/or control at late stage of fermentation.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.5
• /
• pp.509-516
• /
• 1998

A plasmid vector, pXGPRMATG-lac-Tgx, was developed for overproduction of $\beta$-galactosidase in Escherichia coli using the genetic components of groEx, a heat-shock gene cloned from symbiotic X-bacteria in Amoeba proteus. The vector is composed of intragenic promoters P3 and P4 of groEx, the structural gene of lac operon, transcription tenninator signals of lac and groEx, and ColEl and amp'of pBluescript SKII. The optimized host, E. coli DH5$\alpha$, transfonned with the vector constitutively produced 117,310-171,961 Miller units of $\beta$-galactosidase per mg protein in crude extract. The amount of enzyme in crude extract was 53% of total water-soluble proteins. About 43% of the enzyme could be purified to a specific activity of 322,249 Miller units/mg protein after two-fold purification, using two cycles of precipitation with ammonium sulfate and one step of gel filtration. Thus, the expression system developed in this study presents a low-cost and simple method for purifying overproduced $\beta$-galactosidase in E. coli.