Commercial yogurt can be classified as fermented milk (FM) and condensed fermented milk (CFM). A selection of commercial yogurt was collected from domestic markets and the quality characteristics were compared by analyzing total acidity, viscosity, organic acids, sugars, conjugated linoleic acid (CLA), and aroma pattern. Total acidity and viscosity in FM were significantly lower than those in CFM (p<0.05). The major organic acid of commercial yogurt was lactic acid, the content of which was 8.15-4.72 times and 26.83-47.20 times higher than that of citric acid and acetic acid, respectively. CFM contained 1.47 times more lactic acid and 2.53 times more citric acid than FM. The total sugar content in FM was two times higher than that in CFM and the major sugars measured were sucrose, lactose, glucose, and maltose. The sucrose content was the highest in FM. CFM contained 23.65 times more CLA and 10.81 times more lipid than FM. The aroma patterns of yogurt analyzed with an electronic nose were clustered into Therefore, among commercial yogurt, CFM had higher viscosity, organic acid and CLA content, but lower sugar content than FM, which resulted in a relatively strong sour and weak sweet taste.

This study was carried out to investigate the quality characteristics and antioxidant activity of yogurt dressing prepared with different amounts (0, 5, 10, 15, and 20%) of black currant (Ribes nigrum L) extract. All samples were evaluated for chemical composition, pH, viscosity, sugar content, color, organic acid content and antioxidant activity. Our findings revealed that with increasing amounts of black currant extract in yogurt dressing, the moisture, crude protein and crude lipid contents decreased. The pH and viscosity gradually decreased, whereas the sugar increased with increase in black currant extract. Further, the lightness (L) value decreased, while the redness (a) and yellowness (b) values increased with increase in added black currant extract. Among the organic acids, the contents of citric acid, malic acid, succinic acid and acetic acid increased, while that of tartaric acid and lactic acid decreased with increasing levels of added black currant extract. The total polyphenol and total anthocyanin contents were 5.90-245.97 mg/100 g and 0.62-190.09 mg/100 g, respectively. In addition, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-thylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities significantly increased with increase in added black currant extract.

Yogurt is produced by fermentation of milk using bacteria known as “yogurt cultures”. Most of these bacteria are probiotics such as Lactobacillus delbrueckii subsp. bulgaricus, Lb. rhamnosus, Streptococcus thermophilus, and Bifidobacterium. The domestic fermented milk market is increasing, and about 30 companies are producing yogurt. The purpose of this study was to analyze the quality characteristics of domestic commercial liquid yogurt. Total 30types of commercial yogurts were sampled and their physicochemicial properties, including pH, sugar content, acidity, viscosity, and microbial characteristics of lactic acid bacteria counts, were measured. Commercial liquid type yogurt showed a pH of 4.5, sugar content of 7.4-21.2%, total acid content of 0.4-0.9%, and viscosity of 0.1-250 cP. In terms of microbial populations, lactic acid bacteria counts were 7.2-11.3 log CFU/mL and anaerobic lactic acid bacteria counts were 8.0-11.5 log CFU/mL. The quality characteristics differed depending on the constituents of the sample and the microorganisms used. These results are related to the quality characteristics of yogurts and are useful for identifying new trends in the domestic fermented milk industry.

The objective of this study was to select yogurt starter from Korean traditional fermented foods. The 2 strains (KM24, KM32) among 50 strains of isolated lactic acid bacteria selected as starter based on milk clotting ability, antimicrobial activity against various pathogens, tolerance in artificial gastric and bile juice and growth in 10 % skimmed milk. The strains were identified as Lacobacillus plantarum (KM32) and Pediococcus pentosacesus (KM24) by 16S rRNA gene sequencing. Viable cell number of yogurt fermented with mixed strains (KM24 and KM32) was 9.66 log CFU/mL after fermentation for 48 h and maintained 109 CFU/mL during fermentation for 72 h at 37℃. The pH and titratable acidity of mixed cultured yogurt were 4.25% and 0.83% after fermentation for 48 h at 37℃, respectively. The physico-chemical characteristics of mixed cultured yogurt after fermentation for 48 h were 38.45 μg/mL (polyphenol content), 48.57% (DPPH radical scavenging activity) and 465.40 cp (viscosity), respectively. The mixed cultured yogurt maintained 109 CFU/mL of lactic acid bacteria during storage 10 days at 4℃. The viable cell number of yogurt prepared with mixed culture(KM32+KM24) maintained higher and than that of control (L. casei) during storage. These results indicated the potential use of selected strains (KM32+KM24) isolated from kimchi as a yogurt starter with strong acid tolerance and probiotics properties.

Yogurt contains many microorganisms that are beneficial to human health, and is a probiotic that supplies many nutrients such as calcium and protein. It is difficult to safety preserve for a long time because it possesses a high content of water. To address this problem, powdered “instant” yogurt has been developed, but it has flaws low flowability and solubility. Therefore, yogurt was granulated using a fluidized bed granulator to increase flowability and solubility. The fluidized bed granulator was designed by using response surface methodology (RSM), whose variables were feeding rate (FR), atomization air pressure (AP) and product temperature (PT). After being granulated, the yogurt was analyzed for yield and lactic acid bacteria count. The maximum yield of yogurt granules was 79.42%, at FR of 0.54 mL/min, AP of 2.64 kPa, and PT of 58.18℃, and the colony count for lactic acid bacteria was more than 6 log10 CFU/g. Therefore, spherical granulation of yogurt using a fluidized bed granulator could be used for making convenient probiotic products with improved flowability and solubility.

The objective of this study was to investigate the effect of hot water extract of Welsh onion root (HEWO) on growth of lactic acid bacteria and fermentative characteristics of yogurt. The physiochemical characteristics of HEWO such as pH, soluble solid, reducing sugar, total polyphenol content and DPPH radical scavenging activity were studied. The lactic bacterial count in brain heart infusion (BHI) broth with HEWO was about 1 log cycle higher than in control for 24 h at 37℃. The pH of yogurt prepared with HEWO (WY100) and 50% HEWO (WY50) was gradually decreased significantly but increased the viscosity of yogurt with increasing HEWO concentration during fermentation. The viable cells of lactic acid bacteria after fermentation for 24 h were 8.03 (control), 8.77 (WY50), 8.84 (WY100) log CFU/mL, respectively. The DPPH radical scavenging activity of yogurt increased with increasing HEWO concentration. Sensory quality of yogurt prepared with HEWO was higher than that of control. The pH and lactic acid bacteria of all tested yogurts decreased during storage for 10 days at 4℃ but lactic bacterial count of yogurt prepared with HEWO maintained 108 CFU/mL during storage. These results indicated the potential use of HEWO as a valuable resource to improve fermentation and functionality of yogurt.

Quality characteristics of yogurt with added colored barely flour was investigated during fermentation by lactic acid bacteria. Chemical properties such as moisture, crude protein, starch, ash and β-glucan contents was measured. pH, acidity, brix, Hunter color value and growth of lactic acid bacteria in yogurt was investigated during fermentation by L. acidophilus, L. bulgaricus, and S. thermophilus mixed culture. Crude protein contents of Daeanchal and Boseokchal was 16.16 and 12.17%, respectively. Starch contents of daeanchal were shown lower score. The pH of yogurt by addition of barley flour (Daeanchal) addition 0 and 20% were 6.66 and 6.40, respectively. The pH of yogurt supplemented with barley flour tended to be lower than before control which was not added barely flours and oligosaccharide in yogurt. Titratable acidity of yogurt added barley flour was higher compared with that of control. Brix of yogurt was decreased during fermentation by lactic acid bacteria. Lightness of yogurt added barley flour (Daeanchal) addition 0 and 20% were 83.25 and 69.83, respectively. The original microbial population of the yogurt during 0, 5, 8, and 15 hr fermentation were 7.48, 7.79, 8.15, and 8.71 Log CFU/g, respectively. Moreover, the addition of colored barley flour was to promote the proliferation of lactic acid bacteria in yogurt. In our research, addition of colored barley flours added into the yogurt may also have contributed to growth of lactic acid bacteria.

To evaluate peanut sprouts as a functional food material, the quality characteristics and antioxidant activities of soybean yoghurt with different percentages (0.5, 1.0, 2.0, and 3.0%) of peanut sprout powder (PSP) contents were investigated. The pH of soybean yogurt with PSP decreased in a time- and dose-dependent manner during fermentation, whereas the titratable acidity increased under the same conditions. The Hunter L value (lightness) decreased while the b value (yellowness) and a value (redness) increased as the PSP concentration in soybean yogurt increased. Prior to fermentation, the sugar content of the soybean yogurt increased as the PSP level increased, but the contents decreased as fermentation progressed. Meanwhile, the viscosity of the soybean yogurt increased during fermentation, and the lactic acid bacteria population was higher than that of the control. The sensory properties, including the flavor, color, taste, and overall acceptability, of the soybean yogurt containing 0.5 and 1% PSP, respectively, were higher than those of other tested yoghurts (with 0, 2.0, and 3.0% PSP contents). The antioxidant activity of the soybean yogurt significantly increased at the PSP concentrations of over 1.0%. These results suggest that the addition of PSP has beneficial effects on the quality and functionality of soybean yogurt, and that the addition of 1.0% PSP is the most suitable for manufacturing soybean yogurt.

Baechu kimchi without cuttlefish (control), baechu kimchi with cuttlefish (CK), cuttlefish baechu kimchi with yogurt (CK+Y), and cuttlefish baechu kimchi with vitamin C (CK+VC) were prepared, and the fermentation characteristics of the prepared kimchi samples were investigated during 28 days of fermentation at 4℃. The levels of moisture, crude lipid, and crude ash did not differ much among the samples, but the crude protein levels of CK, CK+Y, and CK+VC were greater than that of the control. The pH values of CK+Y and CK+VC slowly decreased compared with those of the control and CK during fermentation. The acidity increased sharply until 21 days then gradually increased thereafter. The total microbial counts achieved maximum levels at 21 days, and the kimchi to which yogurt and vitamin C were added showed values lower than that of the control. The number of Leuconostoc sp. in CK+Y and CK+VC was higher than that in the control. In our sensory evaluations, cuttlefish kimchi with yogurt or vitamin C scored highest in terms of texture, sour taste, ripened taste, and overall acceptability.

단호박 가루 첨가량을 달리한 호상 요구르트를 개발하여 요구르트의 품질특성을 비교하였다. 단호박 가루의 첨가량 0%, 0.5%, 1%, 2%, 3%로 첨가하여 요구르트를 제조해 색도(명도, 적색도, 황색도), 점도, pH, 산도, 관능검사(색, 향, 맛, 전반적 기호도)를 측정하고 1일, 5일, 10일, 15일등 5일차 간격으로 저장성 실험을 하였다. 색도에서는 저장기간별 단호박 첨가량이 증가할수록 L값은 감소하였으나 a,b값은 증가하였다(p2%>

단감분말을 첨가한 호상 발효유를 제조하기 위하여 탈지분유에 단감분말을 4% 및 7% 첨가하여 Lactobacillus acidophillus 균주를 접종하여 유산균의 생육에 미치는 영향과 관능적 특성 및 품질 특성을 검토하였다. 단감분말은 단백질 2.2%, 지질 30.5%, 탄수화물 56.6% 및 회분 2.5%를 함유하였다. 단감분말을 첨가하여 24시간 발효시킨 발효유의 유기산중 lactic acid 농도가 1.12%∼1.21%로 탈지분유만을 사

진품콩에 작두콩의 종실을 첨가하여 맛과 영양이 우수한 요구르트를 제조하기 위하여 진품콩에 작두콩의 혼합 비율별로 두유를 착즙하고 유산발효 시킨 제품의 가공특성을 검토하였다. 원료콩의 단백질 함량은 진품콩이 38.0%로 작두콩 27.5f%보다 높았다. 유산발효 중 PH와 당도는 발효개시 후 4시간까지는 급격히 저하했다가 8시간 이후에는 완만하게 감소하였으며 유기산 함량과 유산균 수는 증가하였고, 20시간 발효시 진품콩 100%에 비하여 진품콩 95

섬유질이 풍부하고 enthocyanin색소가 풍부한 자색 고구마를 이용하기 위하여 탈지유와 설탕이 들어있는 기본배지에 증자, 박피한 고구마를 첨가한 후 5종(Lactebacillus bulgaricis, Lactobacillus delbruchii sub. sp. lactis, Streptococcus lactis, Bifidobacterium bifidum, Leuconostoc lactis) 의 젖산균주를 배양, 접종하여 호상 요쿠르트를 만들

진해(鎭咳), 거담(祛痰)의 약리작용으로 기관지 질병 치료에 효과가 있는 길경을 건강보조 식품으로 널리 애용하기 위해 탈지유와 설탕이 들어있는 기본배지에 길경을 즙, 퓨레 및 분말을 각각 첨가하고 4종의 흔합유산균주를 접종하여 호상 요구르트를 제조하여 시 험한 결과는 다음과 같다. 1. 즙, 퓨레 및 분말 상태를 각각 첨가한 호상요구르트의 최적 발효시간은 12시간 이었으며 이때 pH는 4.1, 산도는 1.15%였다. 2. 길경 첨가 상태별 관능검사에 의한 최적 첨가량은 즙은 2% , 퓨레 및 분말은 각각 1% 첨가시에 좋았으며 즙 2% 첨가가 가장 좋았다. 3. 저장기간에 따른 요구르트의 pH는 저장기간의 경과에 따라 약간 감소하였고, 산도는 약간 증가하였으며 점도는 퓨레 첨가시에 가당 높았다. 4. 생균수는 발효완료 후 대조구가 6.2×108/ml, 즙 2% 첨가는 4.4×108/ml, 퓨레 및 분말 1% 첨가에서 각각 3.7×108/ml, 4.2×108/ml이었으며, 저장 9일동안 모든 시료에서 기준생균수 1억 마리 이상으로 좋은 저장성을 나타내었다.