• Journal of Dairy Science and Biotechnology
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• v.33 no.3
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• pp.203-207
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• 2015

The majority of food drying processes are based on the use of thermal energy. However, such methods may deteriorate the quality of the final product. Freeze-drying is one of the most useful processes for drying thermosensitive substances. Food that contains beneficial bacteria, for example, is susceptible to heat treatment, but during freeze-drying beneficial bacteria are preserved in these food items. The primary goals of this study were to develop yogurt snacks and to compare the viability of lactic acid bacteria (LAB) in yogurt snacks under different freeze-drying temperatures. In addition, the survival of LAB during storage was investigated. Survival of LAB in freeze-dried yogurt snacks gradually decreased over 16 weeks of storage. LAB had a residual viability of 25.5% after 16 weeks of storage at room temperature. LAB survived better in freeze-dried plain yogurt snacks than in freeze-dried strawberry yogurt snacks during storage. Freeze-dried yogurt snacks contained 11.9% fat, 57.1% carbohydrate, and 18.7% protein. In conclusion, the viability of LAB in freeze-dried yogurt snacks depends on the temperature during freeze-drying: the higher the freeze-drying temperature, the lower the viability of LAB in yogurt snacks. The viability of LAB in yogurt snacks was also dependent on the moisture content and nutritional value.

• Journal of Dairy Science and Biotechnology
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• v.37 no.4
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• pp.237-246
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• 2019

In this study, quality characteristics of yogurt supplemented with Angelica gigas Nakai leaf extract were examined. The pH of the yogurt ranged from 4.40 to 4.45 and the titratable acidity ranged from 0.96% to 0.98%. The viscosity tended to decrease with the addition of the Angelica gigas Nakai leaf extract, but did not affect stability during storage. In the range of 0.1% to 0.3%, lactic acid bacteria were present in the range of 1.9×10⁹ to 3.2×10⁹ CFU/mL. The decursin content in yogurt was quantitatively analyzed, depending on the addition of 0.1% to 0.3% of Angelica gigas Nakai leaf extract and was found to be 0.26 ㎍/g, 15.23 ㎍/g, and 23.57 ㎍/g respectively. Organic acid showed the highest generation of lactic acid. The antioxidant properties of yogurt were shown to increase with the addition of the Angelica gigas Nakai leaf extract. The sensory score of yogurt supplemented with 0.1% of the Angelica gigas Nakai leaf extract was highly valued, at a level similar to that of plain yogurt. Yogurt supplemented with 0.2% of the extract was rated above the normal score of 6.31 to 6.50. As shown by the results, the optimal concentration of Angelica gigas Nakai leaf extract for addition to yogurt was within 0.2%.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.113-118
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• 2020

We investigated the quality characteristics and antioxidant capacities of Korean commercial yogurt. Twenty commercial yogurt samples exhibited a pH of 4.05-4.51, titratable acidity of 0.80-1.45%, viable counts of 6.65-9.39 log CFU/g, and total phenolic content of 0.71-2.92 mg gallic acid equivalent/g dry weight (dw). Lactic acid was the major organic acid detected by HPLC with UV detection, and its content was 5.4 times and 46.5 times higher than that of malic acid and citric acid, respectively. The tested commercial yogurt samples exhibited antioxidant potential (1.62-8.95 mM trolox equivalent/g, dw) measured based on scavenging activities of DPPH and ABTS radicals. The average antioxidant potentials of commercial set yogurt containing fruit syrup were significantly (p<0.05) higher than that of cream and plain yogurt. A positive linear correlation was observed between the total phenolic content and the antioxidant capacities, suggesting that phenolic components are likely to contribute significantly to the antioxidant potential of commercial yogurt.

• Food Science of Animal Resources
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• v.35 no.4
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• pp.479-485
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• 2015

This experiment investigated whether yogurt containing fermented pepper juice (FPJY) affects cholesterol level in high fat and high cholesterol diet (HFCD) fed rat. Twenty five Sprague-Dawley male rats of 7 wk were divided into 5 groups, and fed following diets for 9 wk; CON (control diet), HFCD (HFCD), PY (HFCD supplemented with 2% of plain yogurt), LFY (HFCD supplemented with 2% of FPJY), and HFY (HFCD supplemented with 5% of FPJY). In the LFY group, hepatic total lipid level decreased significantly compared to the HFCD group (p<0.05). Serum HDL cholesterol level tended to increase and hepatic total cholesterol level decreased and were comparable to the CON group (p>0.05). In HFY group, body weight and hepatic total lipid level significantly decreased over the HFCD group (p<0.05). Serum and hepatic total cholesterol level, kidney, and body fat weights decreased, and were compared to the CON group (p>0.05). Liver weight decreased as FPJY content was increased. Results suggested FPJY would inhibit organ hypertrophy and accumulation of body fat, hepatic lipid, and cholesterol in HFCD fed rat.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.249-254
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• 2011

Applying ginger to processed foods to improve health is limited due to its pungent odor. In this study, fermented gingers were prepared using lactic acid bacteria from dairy products or kimchi and their chemical and sensory properties were examined. Adding dried ginger or fermented gingers (GSt, GLa, GLm) to plain yogurt made them less tasty and lowered the overall acceptability of yogurt except GLp. For all fermented gingers including GLp, the characteristic flavors of the ginger decreased by fermentation so adding fermented ginger into yogurt did not affect its flavor significantly. Thus GLp would be expected to be a food ingredient instead of dried ginger without lowering organoleptic qualities. The content of 6-gingerol, a bioactive component in ginger, decreased in all fermented gingers. However, 6-shogaol, which increased in GSt, GLa, and GLm, was not detected in GLp.

• The Korean Journal of Community Living Science
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• v.14 no.2
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• pp.71-81
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• 2003

This study was carried out in order to facilitate the consumption of milk which tend to decrease in recent years and to improve the school milk program. The survey by means of prepared questionnaire was conducted to investigate a perception and satisfaction of school milk program, and milk intake at home and school with elementary, middle, and high school students. Most of the subjects thought drinking milk is important for their health but only 50.2% of them were actually drinking milk everyday. In particular, the frequency of consuming milk at home was significantly lower in students being provided with school milk program than the students without school milk program. Most of the students commonly drunk plain milk rather than flavored milk, however actually they preferred flavored milk to plain milk. The frequency of consuming milk and the degree of satisfaction for milk being served in the school milk program was lowered. The major reason of disliking milk being served in school milk program was ‘poor taste’. And to promote milk consumption in school milk program, the subjects anticipated the serving of various milk and dairy products, flavored milk and yogurt etc. Thus, it was suggested that to improve the school milk program and promote milk consumption among the students, serving various products that can satisfy their preferences and demands and the proper food guide and education on nutrition are called for.

• Applied Biological Chemistry
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• v.37 no.3
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• pp.143-147
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• 1994

Four samples of commercially manufactured yogurts (plain, drinking type) were purchased and evaluated their physico-chemical properties, buffering capacity. And the survival rate of lactic acid bacteria and their ${\beta}-galactosidase$ activity under the acidic conditions (in vitro) were investigated. The values of pH, titratable acidity, viscosity and viable cell counts of yogurts were $3.71{\sim}4.08$, $0.990{\sim}1.045%$, $256{\sim}3164\;cps.$ and $10^8{\sim}10^9\;cfu/ml$, respectively. The volume of 1.0 M-HCl required to reduce the pH of yogurt (50 ml) to minus 2 value was $3.58{\sim}4.33\;ml$. When commercial yogurts were incubated at $37^{\circ}C$ for 120 minutes under the acidic conditions (pH 3.5, 2.5, 1.5), the survival rates of lactic acid bacteria in yogurt were $3.5{\times}10^{-2}{\sim}3.6{\times}10^{-1}%$ at pH 2.5, $8.3{\times}10^{-5}{\sim}4.2{\times}10^{-3}%$ at pH 1.5, respectively, but there was no significant difference at pH 3.5. The remaining activities of ${\beta}-galactosidase$ were $9.4{\sim}36.2%$ at pH 2.5, $4.2{\sim}19.0%$ at pH 1.5, respectively. These results suggested that a significant number of lactic acid bacteria in yogurt might be destroyed in the hostile environment of the stomach, but ${\beta}-galactosidase$ activity from yogurt might be somewhat maintained probably due to the protecting effect by its cell wall and membrane.

• Journal of the Korean Society of Food Culture
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• v.17 no.5
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• pp.551-559
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• 2002

This study was undertaken to investigate intake and consumption behavior of dairy products in college students in order to identify a better way to increase milk consumption. This survey was carried out through questionnaires. The subjects were 307 college students in ChungJu. A total of 98.3% students thought milk as good for health but only 21.5% of them drank it everyday. Most students reported drinking milk two to three times a week. Male students reported drinking milk for drinking, whereas females students for nutrition. College students preferred flavored milk rather than plain milk. Students preferred the drink-type yogurt among the dairy products. The major reason for drinking fermented milk was taste. After drinking the fermented milk, 39.1% of female students thought that fermented milk could prevent constipation. Most students thought that better taste and quality of milk and milk product would increase their consumption.

• Culinary science and hospitality research
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• v.17 no.4
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• pp.251-262
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• 2011

The preference for maesengee sauce was investigated by developing 3 types of maesengee sauces. Through the comparative analysis of the developed maesangee sauces, the study aimed to develop maesangee sauce as a health functional food and to activate the local economy by the development of maesangee sauce as the processed food in the future. For the composition analysis of maesangee, the maesangee that was purchased from Gangjin-gun in July, 2009 was used as a base material. Based on the investigation results of preference for maesangee sauces, the following 3 types of maesangee sauces including maesangee red vinegar sauce, maesangee plain yogurt sauce and maesangee wrapping sauce were developed. By performing the comparative analysis of preference for the developed maesangee sauce types, this study aimed to put perfection in the research. The sample product of the developed maesangee sauce was used for the questionnaire survey for 42 students attending culinary colleges located in Gwangju from November 9, 2009 to November 16, 2009. For the statistical analysis, frequency analysis was used. The composition analysis result of maesangee revealed the presence of p(227.98mg/100g), Ca(58.32mg/100g) and Fe(7.8mg/100g), No detection of Vitamin A($0{\mu}gRE$/100g), Vitamin $B_1$(0.0837mg/100g), Vitamin $B_2$(0.0641mg/100g), Vitamin B6(0.0261mg/100g), Vitamin C(19.9877mg/100g), Vitamin E(0.3677mgaTF/100g), Vitamin K($7.2079{\mu}g$/100g), and Niacin(1.5057mgaNF/100g). Based upon the questionnaire survey results, the sample product development of maesangee red vinegar sauce, maesangee plain yogurt sauce and maesangee wrapping sauce was achieved along with their preparation methods.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.267-273
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• 2013

We aimed to improve the flavor quality of plain yogurt, which is known to be sour and less desirable in flavor, varying concentrations of a buckwheat saccharification solution (BSS) were added to milk, followed by fermentation with commercially available mixed strains of lactic acid bacteria. Volatile compounds were analyzed using the gas chromatography-headspace-solid phase microextraction (GC-HS-SPME) method. Fermentation properties, including pH, titratable acidity, viable cells, viscosity, and color value were also measured. Eleven volatile compounds were identified with GC-MS. Of which, diacetyl, butanoic acid, and 2-heptanone proportionally increased as the levels of BSS increased. Undesirable compounds such as acetic acid and 2-butanone, decreased as BSS concentration increased. Fermentation properties were significantly altered with the addition of BSS. Our findings indicate that the flavor quality of plain yogurt can be improved by adding BSS for fermentation, with an additional health benefit from buckwheat.