• Food Science of Animal Resources
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• v.35 no.1
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• pp.143-148
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• 2015

Yogurt powder is fermented milk processed in the form of dry yogurt, and has advantages such as stability, storability, convenience, and portability. China and Vietnam are important export target countries because of the increased demand for dairy products. Therefore, we surveyed dairy product standardization in order to establish an export strategy. Lactic acid bacteria counts are unregulated in Korea and Vietnam. In China, lactic acid bacteria counts are regulated at $1{\times}10^6$ colonyforming units (CFU)/mL and detected at $6.24{\pm}0.33\;Log\;CFU/mL$. All three countries have regulated standards for total bacterial counts. In China, total bacterial counts of milk powder are regulated to n=5, c=2, m=50,000, M=200,000 and detected at $6.02{\pm}0.12\;Log\;CFU/mL$, exceeding the acceptable level. Lactic acid bacterial counts appeared to exceed total bacterial counts. Coliform group counts, Staphylococcus aureus, Listeria monocytogenes, and Salmonella species were not detected. Acidity is not regulated in Korea and Vietnam. In China, acidity was regulated to over $70^{\circ}T$ and detected $352.38{\pm}10.24^{\circ}T$. pH is unregulated in all three countries. pH was compared to that of general fermented milk, which is 4.2, and that of the sample was $4.28{\pm}0.01$. Aflatoxin levels are not regulated in Korea and China. In Vietnam, aflatoxin level is regulated at 0.05 ppb. Therefore, all ingredients of the yogurt powder met the safety standards. This data obtained in this study can be used as the basic data in assessing the export quality of yogurt powder.

• The Korean Journal of Food And Nutrition
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• v.17 no.1
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• pp.53-59
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• 2004

To increase the nutritional and economic value of commercial peanut yogurt, a peanut yogurt was prepared by 12% skim milk added defatted peanut powder(DPP). The proximate compositions of DPP were moisture 2.3%, crude protein 31.39%, crude lipid 38.84, ash 2.89% and carbohydrate 24.58, respectively. The yogurt product were evaluated for acid production(pH, titratable acidity), number of viable cell, viscosity, color, quality-keeping property and sensory property. By addition of 5% and 10% DPP, the titratable acidity of yogurt was higher than that of yogurt not added DPP. The propagation of lactic acid bacteria was stimulated by adding 5% DPP, and the number of viable cells were about 8.9 log cfu/ml. On the other hand, the number of viable cells in control were 8.3 log cfu/ml. Viscosity of yogurt made from adding 5% and 10% DPP was higher than that of yogurt with only skim milk. When yogurt added with DPP was kept for 15 days at 5$^{\circ}C$ its quality-keeping was relatively good. As the DPP increased, L value(lightness) decreased and a value(redness) increased obviously but the b value(yellowness) of 5% peanut yogurt increased and 10% and 15% again decreased. The overall sensory scores of yogurts added with DPP showed lower than that of yogurt with only skim milk.

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

• Food Science of Animal Resources
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• v.22 no.3
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• pp.247-251
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• 2002

This study was carried out to investigate the keeping quality of market milks collected from several dairy processing companies. Microbiological, chemical, and sensory properties of Intra-high temperature(UHT) treated milks stored at 5, 10, 15t were evaluated during the storage of 154days. No significant difference during the storage was shown in bacterial counts, pH and titratable acidity. Standard plate count(SPC) was remained less than 20,000 cfu/ml after 15 day storage at 5, 10, 15$^{\circ}C$. Also, Psychrotrophic bacterial count and Coliform count were not detected or detected at low level. The pH ranged from 6.55 to 6.83 and the titratable acidity ranged from 0.13% to 0.16%. In sensory evaluation, UHT milks showed normal flavor until 10days, but thereafter off-flavor was slightly developed. Consequently, UHT milks remained in good quality when stored at 5$^{\circ}C$,10$^{\circ}C$t until 15days except sensory properties. According to this experiment, the shelf-life of UHT milk can be extended to 10 days, even though maintaining the storage temperature strictly below 10 t in milk market is not easy.

• The Korean Journal of Food And Nutrition
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• v.16 no.1
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• pp.66-71
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• 2003

For the purpose of making a functional and stable yogurt, new type yogurt were prepared from 12% whole milk and 2% skim milk added hot-water extracted from sea tangle. The yogurt product were evaluated for acid production(pH, titratable acidity), number of viable cell, viscosity, degree of curd sedimentation, quality-keeping property and sensory property. By addition of hot-water extracted from 0.5% sea tangle, the titratable acidity of yogurt(1.89%) was higher than that of yogurt not added hot-water extract of sea tangle(1.53%). The propagation of lactic acid bacteria was stimulated by adding hot-water extracted from 0.5% sea tangle, and the number of viable cells were about 1.4${\times}$10$\^$9/CFU/$m\ell$. On the other hand, the number of viable cells in control were 4.4${\times}$10$\^$8/CFU/$m\ell$. Viscosity of yogurt made from adding hot-water extracted from 0.5% sea tangle(25 CPS) was higher than that of yogurt with only milk(22 CPS). When yogurt made from adding hot-water extracted from sea tangle was kept at 7$^{\circ}C$ for 15 days, its quality-keeping was relatively good. The sedimentation of curd was repressed a little by adding hot-water extracted from 0.5% and 0.1% sea tangle. The overall sensory score of yogurt made from adding hot-water extracted from 1% sea tangle was the best of tested yogurt.

• Food Science and Preservation
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• v.6 no.4
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• pp.442-447
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• 1999

A curd yogurt was prepared by fermenting milk added with skim milk powder and purple sweet potato by culture of 5 types of lactic acid bacteria(Lactobacillus delbruekii sub. sp. lactis, Streptococcus lactis, acidity, number of viable cell, stability of purple sweet potato's pigment and keeping qualify. Among the organisms tested, the acid production and number of viable cell by the culture of L bulgaricus remarkably increased for the first 12 hem which showed 1.04${\times}$10$\^$9/ CFU/mL in number of viable cell and 4.22 In pH where as fermentation by the culture of B. bifidum was slow. After 36 hours of incubation which showed 3.3 ${\times}$ l0$\^$8/ CFU/mL in number of viable cell and 5.1 in pH. In stabilities of purple sweet potato anthocyanin pigment n fermentation, yogurt by B. bifidum was found to be most stable followed by Leuc. lactis, L. delbruekii sub. sp. lactis, L bulgaricus, but yogurt by St. lactis was not stable. When curd yogurt added with Purple sweet Potato was kept at 2∼3$^{\circ}C$ for 14 day, its keeping quality(pH, titratable acidity, number of viable cell) was relative good except product by L. bulgaricus was found to be decreased most of viable cell. After 2 weeks of keeping, pigment of yogurt was decreased by B. bifidum, stable by L. delbruekii sub. sp. lactis.

• Journal of Korean society of Dental Hygiene
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• v.21 no.5
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• pp.517-526
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• 2021

Objectives: This study was conducted to analyze the sugar content, acidity, and viscosity of the Korean frozen desert. Methods: A total of 60 types of frozen desserts marketed in Korea were randomly selected and classified into frozen desserts, milk-fat ice cream group, and non-fat ice cream group according to the classification criteria for frozen desserts. Each product was treated under the same conditions to investigate the component of each product, and sugar content, acidity, and viscosity were measured. Frequency analysis and one-way ANOVA were performed. Results: As a result of analyzing the characteristics related to dental caries activity by group, the frozen dessert had the lowest average pH of 3.67, and the sugar content was significantly higher in the milk-fat group (33.22) and non-fat group (32.89) than in the frozen dessert. The viscosity was also the highest in the milk-fat group at 32.62, and the frozen dessert was significantly lower at 9.42. Conclusions: Due to the abnormal temperature and spread of the coronavirus, consumption of frozen desserts at home is on the rise. To prevent dental caries in children, education is needed for children and their guardians for proper oral care after eating frozen desserts.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.258-263
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• 1993

New type yoghurts were prepared by fermenting milk containing puffed rice flour(PRF) with some commercial lactic acid bacterial starters. The yoghurts were evaluated for pH, tillable acidity, viscosity and color with sensory evaluation for final quality. The optimum moisture content of rice for puffing was over or less 14%. Increasing addition level of PRF, lightness decreased and, redness and yellowness increased with increasing viscosity greatly. There was no quality difference among commercial starters but pH, acidity and viscosity of yoghurt were affected. During the storage at $5^{\circ}C$, pH dropped, acidity and viscosity increased gradually. The number of lactic acid bacteria was increased until 6 days storage to $3{\times}10^8$ and dropped after on. The yoghurt containing PRF was inferior in flavor texture and taste comparing with commercial yoghurt.

• Korean Journal of Agricultural Science
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• v.23 no.2
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• pp.219-226
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• 1996

Liquid yoghurts were made with ginseng extract, white ginseng powder and tail ginseng powder, which have pharmacological effects and are palatable by Korean. The acidity, number of lactic acid bacteria and viscosity of yoghurts were examined and taste, flavor and characteristics of preservation of yoghurts were also tested. The results obtained were summarized as follows; l. The acidity of yoghurt was high for ginseng yoghurts, especially tail ginseng yoghurt(1.15%) was higher than that of control yoghurt(0.76%). 2. The number of lactic acid bacteria in yoghurt was higher for ginseng yoghurt than that of control yoghurt($1.5{\times}10^8/m{\ell}$), especially tail ginseng yoghurt($4.3{\times}10^8/m{\ell}$) showed the highest number of lactic acid bacteria. 3. The viscosity of yoghurt was high for ginseng yoghurt, especially white ginseng powder yoghurt was higher than that of control. 4. The score of yoghurts for tastes, flavor and overall acceptability were higher for tail ginseng yoghurt than those of control yoghurt. 5. When yoghurts were stored at $5^{\circ}C$ for 10 days, the pH, acidity, number of lactic acid bacteria of all yoghurt were not changed significantly.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.17-25
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• 2015

The present study was carried out to evaluate the preparation of the fermented milks with rice bran and to prove that the bacteria used are necessary for providing amino acids in this process. The rice bran on fermented milk with Streptococcus thermophilus (ST-body1) and Lactobacillus casei (LC-10). The fermentation limit was set until acidimetry score reaches 1. There are reports of titratable acidity, pH, viable cell count and amounts of organic acids affecting amino acid production about physical and chemical analysis measured using HPLC. Finally, sensory test was surveyed. In this study, the rate of acidification was higher in the fermented milk with rice bran than in the common fermented milk. In case of the number of cells was $1.0{\times}10^8CFU/mL$ in group. The lactic acid and citric acid content in yogurts prepared with rice bran using Streptococcus thermophilus (ST-body1) and Lactobacillus casei (LC-10) was higher than that in the control yogurt. Amino acids derived by rice bran were effected in fermentation for each bacteria's necessary amino acid production, and it made bacteria growth larger. From the physical test of the fermented milk with rice bran, flavor, texture, sweetness, overall taste of the fermented milk of Streptococcus thermophilus (ST-body1) were found to be much better than those of the other groups. The results obtained for the fermented milk prepared with rice bran using Streptococcus thermophilus (ST-body1) are significant.