Effects of dynamic high-pressure (DHP) treatments with and without integration with heating on microbial stability, vitamin C concentration, color, sugar content, and pH of orange juice were studied and compared with those of the conventional thermal treatment. Freshly squeezed orange juice was heated at 90oC for 1 min or DHP-treated at 205 MPa and 20, 50, 60, or 70oC. The DHP treatment at 20oC without heating and the treatment at 50oC inactivated indigenous mesophilic aerobic microorganisms in orange juice by 4.2 and >7 log CFU/mL, respectively. The DHPtreated juice exhibited brighter color and higher vitamin C concentration and sugar content than the thermally treated juice, regardless of integration with heating. The DHP-treated juice demonstrated brighter color and higher sugar contents than untreated juice and thermally treated juice during storage at 4oC for 63 days. The results have demonstrated the potential of applying DHP treatments to pasteurize orange juice with increasing brightness and sugar content of the juice.
취나물의 보존과 유통 시에 미생물 품질을 높이기 위하여 hurdle technology를 이용한 데침, 위생처리제와 감압포장 처리에 따른 분석을 하였다. 데침 열처리 후 위생처리제로는 20% 에탄올과 10% NaCl에서 6일 후에 총 세균수가 2 log CFU/g으로 효과적으로 제어되었다. 데침 시의 물온도는 100℃ 온도가 균의 제어에 더 유리하였으며, 보관온도는 4℃ 온도가 균 증식을 적게 하였다. 2회 반복적인 데침과 NaCl 첨가 80℃ 데침 물온도의 처리에서도 현저한 증식 억제 효과를 확인하였다. 데침 시에 접촉되었던 물이 없는 감압포장 상태에서의 데침도 10일간 2 log CFU/g 총세균수를 보여 주어 세균 억제에 효과적임을 알았다. 그리므로 80~100℃에서 10% NaCl 물로 2회 반복 데침이 취나물의 미생물적인 품질을 높여 주었고, 물 접촉이 없는 반복 데침도 취나물의 보관 유통에 도움이 됨을 알 수가 있었다.
Bamboo leaf powder was added to Chiffon cake to increase its neutraceutical effects and storage periods. Specifically, 0, 7, 10 and 13% leaf powder was added to the cakes. The content of total dietary fiber in the bamboo leaf powder was 65.57%. The moisture content did not differ significantly among groups. The cake containing 10% bamboo leaf powder had the greatest volume, whereas the control group (0% bamboo leaf powder) had the lowest volume (p〈0.05). The Hunter's L and a values decreased significantly as the amount of bamboo leaf powder increased. The b value of the control was lowest among the groups (p〈0.05). Evaluation of the consumer acceptance of flavor revealed that the cakes containing the added bamboo leaf had greater consumer acceptance than the control. However, when the color was evaluated, the 13% group showed the lowest acceptance (p〈0.05). Other factors such as texture, taste and overall acceptance did not differ significantly among groups. Additionally, the elasticity did not differ among groups, while the air cells were most uniform in the control. The strength of bamboo leaf aroma, bitter taste and aftertaste increased as the amount of bamboo leaf powder added increased. Cakes containing 10% and 13% added powder had the greatest moisture content, while the control had the lowest content (p〈0.05). As in previous studies, the results of this study indicated that 10% bamboo leaf powder was the optimal level for the preparation of Chiffon cake. To evaluate the storage of cakes, the 10% group and the control were inoculated with Aspergillus oryzae and then incubated at 30℃ for 6 days. The microbial colony counts in the control group were dramatically increased after 48 hrs; however, the fungal concentration of the 10% group did not increase for 4 days. In conclusion, the addition of 10% bamboo leaf powder to Chiffon cake increased the storage time while maintaining adequate consumer acceptance.
This study was carried out to investigate the general characteristics, such as volume, pH, sperm motility and sperm concentration of the semen collected from Beagle dogs (age 24~48 months, weight 10~15 kg) by using the method of digital manipulation of the penis, and the effect of preservation temperature and time on motility of fresh semen. Multiple ejaculates were collected from 4 male Beagles. The average volume, pH, motility and sperm concentration of the second fraction (contained with small volume of the third fraction) per ejaculation were 2.94±0.24(SD) ml, 6.43±0.42(SD), 97.04±3.50(SD)% and 1.67±0.23(SD)×108 cells/ml, respectively. Average semen volume per ejaculate, semen pH, sperm motility and sperm concentration of the first fraction from the ejaculate were 1.24±0.20(SD) ml, 6.03±0.26(SD), 11.30±4.02(SD)% and 7.25±1.02(SD)×105 cells/ml. Those of second fraction were 2.52± 0.32(SD) ml, 6.32±0.31(SD), 96.25±3.52(SD)% and 2.35±0.35(SD)×108 cells/ml. Those of third fraction were 2.71±0.27 (SD) ml, 6.52±0.20(SD), 95.65±2.78(SD)% and 5.72±0.29(SD)×107 cells/ml. Motility of semen was higher at 17℃ preservation temperature than 5℃ or 36℃ during preservation period. When preservation temperature was 17℃, motility was 96.54±2.05(SD)% at 1 h, 90.20±3.90(SD)% at 6 h, 89.05±2.01(SD)% at 12 h, 78.21±3.50(SD)% at 18 h, 45.24±6.25 (SD)% at 24 h and 30.75±17.24(SD)% at 30 h, respectively.
In this study, ohmic heating was applied for pasteurization of red pepper powder, and investigated its pasteurization effect. After pasteurization, seasoned squid jeotkal was manufactured by using red pepper powder, and its quality changes were investigated. On comparing sensory evaluation in squid jeotkal by pasteurized and conventional red pepper powder during storage at 5, 15 and 25℃, quality changes in squid jeotkal by the pasteurized red pepper powder. But quality change difference between two products were decrease with increasing storage temperature. Viable cell counts in two products stored at 5℃ were increased slowly until 60 days. Viable cell counts in squid jeotkal by conventional red pepper powder were increased up to ca. 10^6 CFU/g at 15, 25℃ after 30, 15 days, respectively, but that by pasteurized were ca. 10^8 CFU/g at 25℃ after 30 days. Changes in pH, VBN and NH₂-N in two products were shown difference significantly, but were decreased by increasing storage temperature. In squid jeotkal by conventional red pepper powder, the main free amino acids were glutamic acid, leucine, glycine, aspartic acid and alanine, and these amino acids held 47.95% of the total free amino acid. But in squid jeotkal by pasteurized red pepper powder, glutamic acid, glycine, aspartic acid, leucine and lysine, and these amino acids held 57.58% of the total free amino acids.
제조 조건을 달리한 4가지 chitin으로부터 제조된 chitosan의 물리화학적 특성인 점도와 탈아세틸화도를 측정하였으며, 4종류의 chitosan이 첨가된 깍두기를 제조하여 chitosan을 첨가하지 않은 깍두기를 대조군으로 하여 20℃에서 2일, 4일, 6일, 8일간 저장하면서 저장기간에 따른 pH, 적정산도, 깍두기 국물의 점도 및 미생물 수의 변화를 측정한 결과는 다음과 같다. Chitosan 용액의 정도는 313.1~98.8 cps로 나타났으며, chitin 추출시 염산의 농도가 낮은 것이 점도가 높았으며, 반응 온도가 낮을 때 더 높은 점도를 나타냈다. 그리고 chitosan 용액의 유동학적 특성은 의가소성 유체(pseudoplastic fluid)의 특성을 나타내었다. IR 분석 결과 chitosan의 탈아세틸화도는 92~96%로 높게 나타나, 점도와는 달리 chitosan의 원료가 되는 chitin의 제조조건에 의해서는 크게 영향받지 않았다. 모든 시료군에서 저장기간이 길어짐에 따라 pH는 감소하고 적정산도는 증가하는 경향을 나타냈으며, 대조군에 비해 chitosan 첨가군이 pH는 높고 적정산도는 낮은 값을 계속 유지하였다. 깍두기 국물의 점도는 저장기간이 길어짐에 따라 감소하는 경향을 나타냈고, 저장 8일째에는 대조군이 chitosan 첨가군에 비해 점도가 높게 나타났다. 총균수는 저장기간 전반에 걸쳐 chitosan 첨가군의 경우가 대조군에 비해 약간 많았고, Leuconostoc 속 미생물 수는 약간 적은 경향을 나타냈다. 또한 김치의 부패균으로 알려진 Lac. plantarum의 수에 있어서는 제조시 HCl의 농도가 낮고, 반응 온도가 높은 chitosan C를 첨가한 군이 대조군이나 다른 chitosan 첨가군에 비해 저장시 증가 속도가 약간 느렸다.
한국산업규격(KS)에서 오징어젓은 오징어 배합비율이 75% 이상으로 정하고 있다. 본 연구는 저염 젓갈을 제조하기 위한 기초연구로 유산균 첨가에 따른 영향을 실험한 결과이다. 면역활성이 있는 기능성 유산균을 오징어젓 및 어리굴젓에 각각 첨가한 후, 냉장 또는 실온에서 45일간 보존하면서 미생물학적, 관능적 품질을 평가하였다. 오징어젓은 실온에서 보관한 경우, 보존기간이 경과하면서 유산균 수는 대체로 증가하였다. 어리굴젓의 경우에도 유산균 첨가 시료에서 실온에 2주간 노출한 경우, 생균수가 약 100배 증가하였다. 한편, 일반세균의 경우에는 유산균 첨가 및 비첨가 대조구 모두 현저한 변화가 없이 일정수준으로 유지되는 것으로 나타났다. 미생물 학적 변화를 바탕으로 판단할 경우 본 시험에 공시된 오징어젓 및 어리굴젓은 유산균 첨가에 의한 현저한 미생물의 증식이나 감소는 수반되지 않으며, 소비자가 통상적으로 섭취하는 기간동안 유산균의 빠른 증식은 물론, 일반세균의 증식억제효과는 기대하기 어려울 것으로 판단된다. 그러나 저염화와 더불어 관능적 품질 향상이 뚜렷하게 나타났으며, 기호성이 우수한 제품의 개발이 가능하다고 판단된다.
The effects of microwave treatment on the perservation of foods, such as a seaweed soup and sea stoned radish shreds, were studied. Microwave treatment of microbial cell suspensions revealed that viable cells decreased dramatically when heated to 6. However, it was unlikely that microwave treatment to 60 is enough to decrease the viable cell counts efficiently in a seaweed soup and radish shreds. It was thought that microwave heating to at least 7 as a final temperature was an important factor to reduce microbial cell counts in foods. When foods were heated to 7 with a repetitive 15 sec "on" followed by 30 sec "off", no big differences were observed in viable counts during storage at 2 for 3 days, as compared to those treated with a full power. The microwave treatment with three stages was designed to solve problems associated with variations depending on food volumes and difficulties of heat diffusion in a solid food to be irradiated with a microwave oven. The three stage method was found to have a similar efficiency in the reduction of viable cell counts in foods to microwave treatment at a full power and to conventional methods, such as water bath heating or boiling for 3 min with a gas range.in with a gas range.