• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.458-463
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• 1995

A curd yogurt was prepared from milk added with skim milk powder or egg white powder(EWP). The effects of EWP addition on growth and acid production by lactic acid bacteria in milk were studied. The effects of EWP addition on quality of curd yogurt in point of apparent viscosity, sensory property and volatile aroma compounds were also investigated. Addition of PAT markedly stimulated acid production by lactic acid bacteria and stimulating effect of EWP on acid production was proportional to the amount of addition. Apparent viscosity of curd yogurt added with EWP was generally higher than that of control. Curd yogurt fermented with L. acidophilus showed thixotropic characteristics. Sensory property of curd yogurt added with EWP was evaluated as better than reference sample and sample added with EWP at 2% level was evaluated as better than other samples. Acetone, ethanol, diacetyl, butanol and acetoin were detected by gas chromatographic analysis.

• Food Science of Animal Resources
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• v.39 no.5
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• pp.792-803
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• 2019

The supplementation with natural ingredients that are rich in polyphenols could improve the quality and functionality of yogurt. Lotus leaf (LL) are abundant in phenolic compounds. We aimed to investigate the effects of LL powder on the quality properties, total phenolic content (TPC), and antioxidant activity of yogurt. Yogurt was supplemented with four different concentrations (0%, 0.2%, 0.5%, and 1%) of LL powder and evaluated for 14 d refrigerated storage. During storage, the titratable acidity (TA) of all LL yogurt groups was higher than that of the control (p<0.05). The $L^*$ and $a^*$ values decreased by LL addition to the yogurts, while the $b^*$ values increased. All LL yogurt groups indicated better viscosity than that of control, and among them, 0.2% LL yogurts had the highest viscosity without significant decrease until the end of the storage duration. The addition of LL into yogurt enhanced the water-holding capacity (WHC) by at least 1.5-fold than that of control for the entire storage duration. The TPC of yogurts gradually increased with the addition of LL (p<0.05) and continued to increase during storage; the 1% LL yogurt at 14 d showed the highest value of $61.94{\pm}1.68{\mu}g$ GAE/g. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and reducing power of the yogurts were also significantly enhanced with increasing LL concentrations (p<0.05). These results suggest that lotus leaf may be useful as a natural ingredient for improving the quality and antioxidant activity of yogurt.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.315-320
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• 2018

This study was carried out to determine the effect of enzymatically saccharified Korean rice wine lees powder (eKRWLP) on the quality characteristics and storage stability of curd yogurt. Yogurt with different contents [0.5-2.0% (w/w)] of eKRWLP was incubated with commercially available mixed lactic acid bacteria (Lactobacillus acidophilus, Streptococcus thermophilus, Bifidobacterium longum) at $40^{\circ}C$ for 18 h. The production of acid measured at pH and titratable acidity of yogurts increased with increasing eKRWLP content. After 12 h fermentation, titratable acidity of eKRWLP yogurt was 0.77-0.90% and was higher than that (0.72%) of yogurt made without eKRWLP. The viable cell counts of lactic acid bacteria in eKRWLP yogurts were increased in proportion to the addition of eKRWLP, and increased up to 8.01-8.13 log CFU/g after 12 h incubation. The repressive effect of whey separation in eKRWLP yogurt curd significantly decreased than that in Korean rice wine lees powder (KRWLP) yogurt. With sensory evaluation, yogurt with 0.5% eKRWLP obtained the highest scores among all eKRWLP yogurts. When eKRWLP yogurts and the control preparations fermented for 12 h were incubated at $4^{\circ}C$, their pHs and titratable acidities were slightly changed and the number of viable lactic acid bacteria were well maintained above $10^7CFU/g$ for 16 days.

• Journal of the Korean Society of Food Culture
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• v.28 no.4
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• pp.392-400
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• 2013

The purpose of this study was to determine the optimal amounts and mixing condition of skim milk powder (A), and roselle (B) for the production of yogurt prepared with roselle. The experiment was designed according to the central composite design for estimating the response surface method, which yielded ten experimental points, including two replicates for the skim milk powder and roselle. The physicochemical and mechanical analysis of each sample, including pH (P<0.001), titratable acidity (P<0.001), color (P<0.05), viscosity (P<0.001), showed significant differences. Antioxidant properties (total phenolic content, DPPH free radical scavenging activity) and viable cell counts of lactic acid were significantly different (P<0.05). The sensory measurements were significantly different in color, flavor, sourness, texture, and overall quality (P<0.05). The optimal formulation, calculated by numerical and graphical methods, was 7.82 g of skim milk powder and 2.09 g of roselle. From findings of this study, the roselle may be used in yogurt and can be applied for other food industries.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.83-92
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• 2012

This study was performed for analyzing the general composition and the change in the quality of soymilk-derived yogurts manufactured by adding skim milk and whey powder to soymilk heat-treated at $95^{\circ}C$/5 min and $120^{\circ}C$/10 min, respectively. 1. During the storage of soymilk yogurt, the concentrations of total solids, protein, fat, and lactose slightly decreased, whereas viscosity, content of ash and NPN, and the number of lactic acid bacteria remained unchanged. 2. The pH and titratable acidity changed rapidly in all soymilk yogurts after 3 h of incubation. 3. We found $7.8{\times}10^8$ lactic acid bacteria in the control sample, $4.7{\times}10^8$ and $5.02{\times}10^8$ in soymilk yogurt with skim milk, respectively, and $5.9{\times}10^8$ and $5.5{\times}10^8$, respectively in soymilk yogurt with whey powder according to degree of heat treatment with $95^{\circ}C$/5 min and $120^{\circ}C$/10 min. 4. The viscosity of yogurt samples became lower as the heat treatment increased in temperature and in the length of time. 5. The value of sensory evaluation was relatively high in soymilk yogurt with the added skim milk, which was heat-treated $95^{\circ}C$/5 min; however, the value was significantly lower than that of the control sample. 6. Lactose, glucose, and galactose were detected in all samples because lactose is degraded into glucose and galactose within 3 h of inoculation.

• Korean Journal of Medicinal Crop Science
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• v.6 no.4
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• pp.265-270
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• 1998

The curd yogurt was prepared from skim milk powder added with the juice, puree and powder, respectively, of the roots of Platycodon grandiflorum (Jacq.) A.DC. Twelve hours were proved to be best for fermentation of the curd yogurt, which showed 4.1 in pH and 1.15% in titratable acidity. Quality of the curd yogurt in sensory evaluation was best when 2 % of juice, 1 % of puree and 1 % of powder were added to the skim milk powder, respectively. When curd yogurt was kept at $5^{\circ}C$ for 9 days, pH decreased, while titratable acidity increased. The viscosity was highest with addition of puree 1%. After fermentation, number of viable cell was $6.2{\times}10^8/ml$ in control. $4.4{\times}10^8/ml$ in juice 2%, $3.7{\times}10^8/ml$ in puree 1% and $4.2{\times}10^8/ml$ in powder 1%. When curd yogurt was kept at $5^{\circ}C$ for 9 days, its keeping quality (pH, titratable acidity, viscosity and number of viable cells) were good.

• Korean journal of food and cookery science
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• v.23 no.4 s.100
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• pp.537-550
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• 2007

In a previous study, isoflavones showed prominent physiological effects on diabetes, hyperlipemia, and alcoholic hepatotoxicity. The purpose of this study was to develop isoflavone-rich bean sprout- and isoflavone extract-containing foods, to improve symptoms of diabetes and hyperlipemia. The foods employed were yogurt, bread, and cookies. Through sensory evaluations, the ingredient amounts were determined. In the sensory evaluations of the yogurt and bread, overall taste scores decreased with increasing amounts of bean sprout powder. However, for the cookies, the overall taste score increased with an increasing amount of bean sprout powder, and the addition of isoflavones had no influence on flavor. The results indicated the following ingredient levels for ultimate product development. For the yogurt, 100 mL of low fat milk was fermented at $50^{\circ}C$ for 36 hr, and mixed with 0.5 g of roasted bean sprout powder and 31 mg of isoflavone extract. For the bread, bean sprout powder was added to wheat flour at a replacement level of 10%, which was mixed with 12 g of butter and 124 mg of isoflavone extract for 200 g of dough. For the cookies, the bean sprout powder was added to wheat flour at a replacement level of 60%, and then mixed with 15 g of butter and 124 mg of isoflavone extract for 100 g of dough. The total isoflavone contents of the yogurt, bread, and cookies were 14.35 mg/100 mL, 38.24 mg/100 g, and 190.00 mg/100 g, respectively.

• 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.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.905-917
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• 2022

It is well known that the fruit of the vitamin tree (Hippophae rhamnoides L.) provides excellent anti-diabetic, antibacterial, immune regulation, anti-inflammatory, and anti-aging effects. In some countries including Europe the fruit has been added to certain foods to develop functional foods. The present research was carried out to elucidate the biological function of vitamin tree fruit powder added to fermented milk. It was found that there was an antioxidant effect of yoghurt made with vitamin tree fruit powder, and this effect was greater with increased incubation time and amount of vitamin powder, as shown by 1,1-diphenyl2-picrylhydrazyl (DPPH) and 2,2-anziobis (3-ehtylbenzothiazoline-6-sulfonic aicd) (ABTS) radical scavenging activities. The antibacterial effect of yoghurt containing vitamin tree fruit powder was shown to be effective against four pathogenic microorganisms, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonela Typhimurium. In particular, yoghurt supplemented with 5% of vitamin tree fruit powder showed the best antibacterial effect. The yogurt containing the vitamin tree fruit powder significantly inhibited the expression of the anti-inflammatory cytokines interleukin (IL)-6 (yogurt [Y] + Hippophae rhamnoides L. powder [HP] and yogurt containing 5% Hippophae rhamnoides L. powder [HPY]) and IL-1β (HP, Y + HP and HPY) in a concentration-dependent manner among tumor necrosis factor (TNF)-α, IL-6, IL-1, and induced nitric oxide synthase (iNOS). Our results clearly demonstrated that vitamin tree fruit powder could be a good functional ingredient for improving health through yoghurt manufactured with vitamin tree.

• Korean Journal of Agricultural Science
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• v.48 no.2
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• pp.273-281
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• 2021

These days, different types of yogurt are being manufactured by adding various starters and functional ingredients for health. The purpose of this study was to prepare yogurt added with rice followed by fermentation with two types of starters and to examine its attributes. Ten percent of skim milk powder and 0, 2.5, 5.0, 7.5, or 10% rice were mixed in water (w/v) and then inoculated with two types of starter: 1) Type A, Streptococcus thermophiles and Lactobacillus delbrueckii ssp. bulgaricus as starter; and 2) Type B, Streptococcus thermophiles, Lactobacillus acidophilus, and Bifidobacteium animalis ssp. lactis as starter. The pH of B type yogurt was lower (p < 0.05) than that of A type yogurt from 6 hours to 14 hours after fermentation. The number of microorganisms in all fermented milk showed maximum increases at 2 and 6 hours of fermentation (p < 0.05). The number of microorganisms in fermented milk peaked at 6 hours after fermentation and maintained this level thereafter. There was no effect of rice addition on microbial growth or acidity of the fermented milk. Sensory attributes of yogurt samples with and without added rice were not significantly different. This experiment showed that the production efficiency of yogurt with added rice was not different when two different types of starters were used to manufacture yogurt.