• Food Science of Animal Resources
• /
• v.41 no.1
• /
• pp.122-134
• /
• 2021

Recently, yogurt has been extensively studied to further enhance its functions using edible plant extracts. This study was conducted to investigate whether safflower petal (SP) as a natural food additive can be used to develop functional yogurt with improved health benefits. SPs were extracted with ethanol (SPE) and hot water (SPW), and then safflower yogurt was prepared by adding 0%-1.0% of those extracts to plain yogurt. With an increase in the fermentation duration, the pH of SPE and SPW yogurt samples was decreased, whereas titratable acidity and microbial counts were increased. The concentration of total polyphenols and total flavonoids, the activity of antioxidants, and the inhibitory effect on reactive oxygen species (ROS) were higher in SPW yogurt than SPE yogurt. Furthermore, α-glucosidase and lipase activity inhibitory effects of SPW yogurt were higher than those of SPE yogurt. In particular, free radical-scavenging activities, ROS inhibitory effect, and α-glucosidase activity inhibitory effects were significantly increased in SPW yogurt in a dose-dependent manner. Overall, these results suggest that SP extract possesses antioxidant activities and that it can downregulate α-glucosidase and lipase activities. The SP extract may have potential benefits as a natural food additive for the development of functional yogurt.

• Journal of Dairy Science and Biotechnology
• /
• v.24 no.1
• /
• pp.29-42
• /
• 2006

Recent trend of consumers' for health give rise to the interest in health and functional foods. Functional yogurt is a primary item in USA, EU, and Japan that are leaders in health and functional food industry and its market is going to be enlarged. Also in Korea, functional yogurt has been recognized as health food by consumers. Concept of functional yogurt is various by health of intestine, stomach, and liver, and lowering blood pressure in Korean market. However, functional yogurt is not registered as health and functional foods in Health/Functional Food Act of Korea. Under these circumstances, the results of trustable and scientific research on the efficacy of functional yogurt should be accumulated to obtain the consumers' solid recognition of functional yogurt as health and functional food.

• Journal of Dairy Science and Biotechnology
• /
• v.38 no.3
• /
• pp.154-160
• /
• 2020

Physical and sensory characteristics of commercial yogurts are important aspects for consumer acceptability. In addition, beneficial functions of commercial yogurts are also emphasized for the probiotic dairy products. The aim of this study was to investigate the functional properties of yogurts with the combination of bacteriocin-producing Pediococcus acidilactici. Yogurts fermented with commercial starter culture (control yogurt) and control yogurt together with P. acidilactici HW01 (yogurt+HW01), P. acidilactici JM01 (yogurt+JM01), or P. acidilactici K10 (yogurt+K10) were prepared. During 28 days after fermentation, the viability of lactic acid bacteria, pH, and brix, in the yogurt samples were assessed with standard methods. Moreover, to investigate the antilisterial activity of the yogurt samples, Listeria monocytogenes was simultaneously inoculated when the yogurts were prepared with lactic acid bacteria, and the viability of L. monocytogenes was determined. Although yogurt+K10 did not completely remove L. monocytogenes, control yogurt, yogurt+HW01, and yogurt+JM01 eradicated L. monocytogenes at day 2 after fermentation. However, yogurt+K10 also removed L. monocytogenes at day 3 after fermentation. Taken together, these findings suggest that the combination of yogurt with P. acidilactici does not affect its quality and they may consequently aid in the development of new probiotic yogurt.

• Preventive Nutrition and Food Science
• /
• v.18 no.1
• /
• pp.45-49
• /
• 2013

This study was carried out to determine a possibility of adding Corni fructus extract (CFE) into yogurt for improving the neutraceutical properties of yogurt and the effects of adding CFE (2~6%, v/v) on the physicochemical and sensory properties of the products during a 15-day storage period at $4^{\circ}C$. Incorporation of CFE into the yogurt samples resulted in a significant pH reduction and a significant increase in titratable acidity. When evaluating the color of the yogurt, the $L^*$-values were not significantly influenced by CFE supplementation; however, the $a^*$- and $b^*$-values significantly increased with the addition of CFE during storage. The power law and Casson models were applied to assess the flow behavior of CFE-added yogurt samples. The magnitudes of apparent viscosity (${\eta}_{a,100}$), consistency index (K), and yield stress (${\sigma}_{oc}$) for 4~6% CFE yogurt samples were significantly greater than those for the control, indicating that CFE can be used as a thickening agent for yogurt. The sensory test revealed that addition of CFE (2~4%) to yogurt did not significantly affect the overall scores, but the overall preference score for 6% CFE yogurt was significantly decreased. Based on the data obtained from the present study, we concluded that the concentrations (2~4%) of CFE could be used to produce a CFE-added yogurt without the significantly adverse effects on the physicochemical and sensory properties.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.2
• /
• pp.254-260
• /
• 1995

Yogurt base were prepared from milk added with skim milk powder or Aloe vera powder and femented with lactic acid bacteria(the single or mixed strain of Lactobacillus bulgaricus and Streptococcus thermophilus). The yogurt product were evaluated for acid production(pH, titratable acidity), number of viable cell, viscosity, sensory property and quality-keeping property. The composition of organic acid were also analyzed by HPLC. Addition of Aloe vera remarkably accelerated acid production, and titratable acidity of Aloe vera yogurts(1.293∼1.407%) after 24 hours incubation was higher than that of yogurts added with only skim milk powder(9.98∼1.110%). Yogurt fermented with the mixed strain of L. bulgaricus and Sc. thermophilus was more acidic than that of single strains. The propagation of lactic acid bacteria was stimulated by Aloe vera and the number of viable cell after 24 hours incubation were above 9.87log CFU/ml. Viscosity of Aloe vera yogurt(3,860∼4,300CPS) was higher than that of yogurt with only skim milk powder(2,402∼2,604CPS). The overall sensory score of Aloe vera yogurt femented by mixed strain was the best of tested yogurt. When yogurt with Aloe vera was kept at 5℃ for 15 day, it's quality-keeping property was relatively good. The major organic acid of Aloe vera yogurt was lactic acid and lactic acid content of yogurt increased by addition of Aloe vera powder. The citric acid content decreased wtih fermentation and malonic acid, pyroglutaric acid and α-ketoglutaric acid were analyzed out a little.

• Food Science of Animal Resources
• /
• v.39 no.1
• /
• pp.162-176
• /
• 2019

This study was performed to evaluate the antioxidant activity of yogurt fermented at low temperature and the anti-inflammatory effect it has on induced colitis with 2.5% dextran sodium sulfate (DSS) in Balb/c mice. Yogurt premix were fermented with a commercial starter culture containing Lactobacillus acidophilus, Bifidobacterium lactis, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. bulgaricus at different temperatures: $22^{\circ}C$ (low fermentation temperature) for 27 h and $37^{\circ}C$ (general fermentation temperature) for 12 h. To measure antioxidant activity of yogurt samples, DPPH, $ABTS^+$ and ferric reducing antioxidant potential (FRAP) assays were conducted. For animal experiments, inflammation was induced with 2.5% DSS in Balb/c mice. Yogurt fermented at low temperature showed higher antioxidant activity than that of the yogurt fermented at general temperature. In the inflammatory study, IL-6 (interleukin 6) was decreased and IL-4 and IL-10 increased significantly in DSS group with yogurt fermented at general temperature (DYG) and that with yogurt fermented at low temperature (DYL) compared to that in DSS-induced colitic mice (DC), especially DYL had higher concentration of cytokines IL-4, and IL-10 than DYG. MPO (myeloperoxidase) tended to decrease more in treatments with yogurt than DC. Additionally, yogurt fermented at low temperature had anti-inflammatory activity, although there was no significant difference with general temperature-fermented yogurt (p>0.05).

• Journal of Animal Science and Technology
• /
• v.47 no.6
• /
• pp.1051-1058
• /
• 2005

This experiment was carried out to investigate the biological function of Lycium chinence Miller yogurt. Antioxidant activity was higher in methanol extract yogurt than in water extract yogurt. The antioxidant activity was shown at 83.9% in Lycii folium extract yogurt, 47.0% in Lycii fructus extract yogurt and 54.0% in Lycii cortex extract yogurt. Angiotensin converting enzyme inhibitor activity was shown highly both in water extract and methanol extracts from the Lycii folium. The $\alpha$-glucosidase inhibitor activity was shown at the 4.0% concentration of Lycii folium extract yogurt, Lycii fructus extract yogurt and Lycii cortex extract. In an orally administrated rat, normal yogurt, Lycii fructus extract yogurt and Lycii cortex extract yogurt have no effect on blood cholesterol content. IgG production in blood is more increased in Lycii cortex extract yogurt than in normal yogurt and Lycii fructus extract yogurt.

• The Korean Journal of Community Living Science
• /
• v.25 no.4
• /
• pp.601-608
• /
• 2014

This study evaluates changes in yogurt with Ulmus davidiana var. japonica (U. davidiana) in terms of its physicochemical, microbial, and sensory properties during storage. The pH value and mean microbial counts of this yogurt with 0.2 to 0.8% of U. davidiana added ranged from 4.1 to 4.3 and from $1.4{\times}10^8$ to $2.3{\times}10^8cfu/mL$, respectively, during storage at $7^{\circ}C$ for 16 d. In terms of its color, the L value was significantly higher in the control and U. davidiana yogurt 0.2 to 0.4% up to 4 d, than other yogurt samples, and the b value was influenced by the addition of U. davidiana over 0.6% throughout the storage. According to a sensory test, there was a significant difference in the yellowness score between U. davidiana yogurt and the control, but earthy, and bitterness, and viscosity scores were similar. Overall acceptability was not significantly influenced after 8 d of storage in all yogurt samples, including the control. According to these results, concentrations (0.2 and 0.4%) of U. davidiana yogurt had no significantly adverse effects on its physicochemical, microbial, and sensory properties.

• Food Science of Animal Resources
• /
• v.40 no.4
• /
• pp.613-627
• /
• 2020

Paprika is known to contain polyphenolic compounds that have good antioxidant properties. This study was conducted to investigate the benefits of adding paprika juice of different colors to yogurt and to determine how paprika affects the quality characteristics of yogurt. Stirred yogurt samples supplemented with different levels of red, orange, or yellow paprika juice were inoculated with mixes of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. Paprika addition decreased the pH but increased titratable acidity, lactic acid bacteria (LAB) counts, total polyphenol content (TPC), levels of vitamin A and C, and antioxidant activity. Proteolysis and viscosity of paprika-containing yogurts were significantly higher than those of the control yogurt without paprika juice (p<0.05). In particular, the viscosity of red paprika yogurt was significantly higher than that of yogurts containing 5% orange and yellow paprika juices (each p<0.05). The antioxidant activity of the methanol extract of the yogurt containing 2.5% orange paprika juice was the highest. Storage at 4℃ for 15 days only slightly altered LAB counts, antioxidant activity, and TPC of paprika yogurt. These results indicate that paprika could be used as a natural food additive for the development of functional yogurts.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.2
• /
• pp.323-331
• /
• 2020

Objective: The present work was undertaken to determine the possibility of using xanthan and guar gums as stabilizers to enhance the yogurt quality. Methods: Yogurt was manufactured from standardized milk (3.5% fat, 8.5% solid-not-fat contents) with the addition of 2% to 3% starter culture. Enzyme-hydrolyzed xanthan gum (0.1%, 0.5%, 1.0%) and guar gum (0.1%, 0.5%, 1.0%) were added to the yogurt as stabilizers. Prepared yogurt samples were kept at refrigeration temperature (4℃±2℃) for 21 days and various quality and sensory parameters were studied at regular intervals (7 days). Results: Results showed that yogurt with 0.5% xanthan gum (T5) was best in terms of preventing syneresis and improving the viscosity, water holding capacity and texture of the product. Additionally, adding gums did not adversely affect the sensorial attributes of the product. Conclusion: Modified gums were found useful in augmenting yogurt quality and therefore addition of gums is highly recommended for manufacturing yogurt.