• 생명과학회지
• /
• 제16권4호
• /
• pp.653-658
• /
• 2006

사과 겹무늬썩음병균이(Botryosphaeria dothidea) 생성하는 세포벽 분해효소인 endopolygalaturonase를 억제하는 polygalacturonase-inhibiting protein (PGIP)를 사과 과실로부터 분리하였다. 분리되어진 사과 PGIP는 사과 겹무늬썩음병균이 생성하는 PG에 대하여 혼합형의 저해를 나타내었다. PGIP의 반응 최적온도는 $40^{\circ}C$이며 최적 pH는 5.0이었다. 이 효소는 $60^{\circ}C$까지는 비교적 안정하였으나 $70^{\circ}C$에서는 효소의 활성이 완전히 억제되었으며 pH 4.0에서 8.0까지는 안정하였다. PGIP는 $K^+$, $Cu^{2+}$, $Mg^{2+}$, $Ca^{2+}$ 과 $Zn^{2+}$ 등의 금속이온과 SDS 그리고 CDTA에 의해 효소의 활성이 저해되었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제19권10호
• /
• pp.1437-1449
• /
• 2006

Thirty six pre-weaned Barbari kids at 4 months age were reared on four rations computed using coarse cereal grains and by-products of pulses and oil seeds with Crude Protein (CP) and Total Digestible Nutrients (TDN) of 12 and 55% (Low protein Low energy); 12 and 60% (Low protein High energy); 14 and 55% (High protein Low energy); and 14 and 60% (High protein High energy), respectively. After 180 days on feed, male animals ($4{\times}5=20$) were slaughtered to study the effect of diet on carcass characteristics and meat quality. To asses the effect, if any, of such diet on product quality, meat balls were prepared and evaluated for quality changes when fresh as well as during storage ($-20{\pm}1^{\circ}C$). Feeding a ration with CP12 and TDN 60% (LH) to kids produced animals with highest slaughter weight (20.3 kg) yielding higher carcass weight and dressing percentage, lean (65.6%) and fat (6.6%) contents with low bone and trim losses. Although total variety meat yield was markedly higher in HL, the non-carcass fat deposition was relatively higher in LH carcasses. The water activity ($a_w$) of fresh goat meat ranged from 0.994-0.995 and total cholesterol 72.8-90.5 mg/100 g meat. The pH was high in HL and HH meat resulting in decreased ($p{\leq}0.05$) extract release volume (ERV). Meat balls were prepared using meat obtained from goats fed different rations (treatments) and stored at $-20{\pm}1^{\circ}C$. They were evaluated on day 0 and months 1, 2, 3, 4 for physicochemical, microbiological and organoleptic changes. Overall moisture (%), $a_w$, TBA number and pH value were 67.9, 0.987, 0.17, 6.6 respectively and were not affected by treatments except pH that was significantly ($p{\leq}0.01$) lower on LH. As the storage period advanced moisture, pH, $a_w$ and TBA number increased irrespective of treatments. Feeding various diets had no marked effect on microbial load of meat balls but with increasing storage period Standard Plate Count (SPC) and psychrotrophs declined ($p{\leq}0.01$). Treatment LL and LH produced meat balls with better flavour.

• Fisheries and Aquatic Sciences
• /
• 제17권3호
• /
• pp.319-324
• /
• 2014

An 8 weeks feeding trial was carried out to evaluate the effects of dietary microbial phytase (P) supplementation on nutrient digestibility, and body composition in juvenile olive flounder Paralichthys olivaceus fed soybean meal-based diets. Seven experimental diets were formulated to be isonitrogenous and isocaloric to contain 50.0% crude protein (CP) and 16.7 kJ of available energy/g with or without dietary phytase supplementation. White fish meal (FM) provided 92.4% of the total protein in the basal diet ($S_0$), in the other 6 diets, 30% or 40% FM protein was replaced by soybean meal: 70% FM + 30% soybean meal ($S_{30}$); 70% FM + 30% SM + 1000 U phytase/kg diet ($S_{30}P_{1000}$); 70% FM + 30% SM + 2000 U phytase/kg diet ($S_{30}P_{2000}$); 60% FM + 40% SM ($S_{40}$); 60% FM + 40% SM + 1000 U phytase/kg diet ($S_{40}P_{1000}$); and 60% FM + 40% SM + 2000 U phytase/kg diet ($S_{40}P_{2000}$). After two weeks of the conditioning period, triplicate groups of 25 fish initially averaging $6.15{\pm}0.04g$ ($mean{\pm}S.D.$) were randomly distributed into the aquarium and were fed one of the experimental diets for 8 weeks. After feeding trial, supplementation of phytase significantly improved the apparent digestibility coefficients of phosphorus in flounder diets (P<0.05) containing 30% and 40% soybean meal regardless the levels. However, phytase had no significant influence on growth performance and whole body composition of fish. Based on the experimental results, we conclude that dietary supplementation of phytase could improve the apparent digestibility coefficient of phosphorus in olive flounder.

• 한국축산식품학회지
• /
• 제18권3호
• /
• pp.209-215
• /
• 1998

Effects of protein concentration, ionic strength, pH, and temperature range on the heat-induced denaturation of salt soluble protein extracted from spent layer meat were investigated. Viscosity of salt soluble protein heated at 65$^{\circ}C$ for 30 min began to increase sharply above 7 mg/ml of breast protein concentration, and above 21 mg/ml of leg protein concentration, respectively. Both turbidity and viscosity showed the highest value in cooked protein solution with pH 6.0 and 1% NaCl. The turbidity of salt soluble protein started to increase continuously from 40$^{\circ}C$ to 80$^{\circ}C$. The viscosity increased rapidly from 45$^{\circ}C$ to 60$^{\circ}C$ in breast protein, and increased from 50$^{\circ}C$ to 55$^{\circ}C$ in leg protein, respectively, and then kept relatively constant. Breast protein had higher viscosity than leg protein during heat-induced gelation. Therefore, salt soluble protein from spent layer meat was associated with denatured protein (turbidity change) prior to gelation (viscosity change) during heating. Breast protein showed lower thermal transition temperature, and better gel formation than leg protein during heating.

• Applied Biological Chemistry
• /
• 제36권5호
• /
• pp.370-375
• /
• 1993

벼잎의 산성 buffer(pH 2.8) 추출 조효소는 5개의 전기영동 band들이 PR protein으로 알려진 chitinase와 ${\beta}-1,3-glucanase$의 효소활성을 보유하고 있는 것으로 나타났다. 조효소는 DEAE-cellulose 및 chitin affinity chromatography로 염기성 및 산성 효소군으로 분획되었으며, 이들은 두 효소활성이외에도 lysozyme 활성을 보유하고 있었다. 분자량이 $14.3{\sim}66.0\;kd$ 범위인 이 두 효소군이 보유한 각 효소활성의 최적 pH와 온도를 조사해본 결과,${\beta}-1,3-glucanase$는 각각 pH 5와 $60^{\circ}C$로 동일하였으나, chitinase는 염기성 효소군에서 pH 4와 $50^{\circ}C$, 산성 효소군에서는 pH 3와 $60^{\circ}C$으로 다르게 나타나서, 전기영동 양상과 더불어 서로 상이한 효소분획인 것으로 추정되었다.

• 한국식품조리과학회지
• /
• 제6권3호통권12호
• /
• pp.9-15
• /
• 1990

Peanut prptein isolate was tested for the purpose of finding out the effect of pH, Sodium Chloride concentration and heat treatment on the solubility, surface hydrophobicity, foam expansion and foam stability. The solubility of peanut protein isolate was affected by pH and showed the lowest value at pH 4.5. When the peanut protein isolate was heated, the solubility decreased at pH 3 and pH 7 but at pH 9 solubility increased. At all pH range, solubility decreased as NaCl was added. The surface hydrophobicity of peanut protein isolate showed the highest value at pH 1.5. Generally, at acidic pH range the surface hydrophobicity was high, but at alkaline region, the surface hydrophobicity increased as the temperature increased. And when NaCl was added, the surface hydrophobicity was also increased. Foam expansion of peanut protein isolate was no significant difference among the values about pH. When the peanut protein was heated and NaCl was added, foam expansion was increased at pH 7. Foam stability was significantly low at pH 4.5 and foam stability was increased at acidic pH region below pH 4.5. At pH 7 and pH 9, heat treatment above $60^{\circ}C$ increased foam stability. When NaCl was added, foam stability was significantly increased at pH 3 and pH 7.

• Journal of Nutrition and Health
• /
• 제27권5호
• /
• pp.451-459
• /
• 1994

This study was performed to investigate the effect of sources of protein on iron bioavailability in 10 healthy young Korean women. The 18-day metabolic study consisted of a 6-day adaptation period, 6-day moderate protein(60g protein/day, 18mg Fe/day) and 6-day high protein period(90g protein/day, 18mg Fe/day). During the moderate and high protein period, 5 subjects were fed the high plant protein meals(80% plant protein). Fecal excretion of dietary iron was significantly higher(p<0.05) in high protein high plant diet group(HPP, 9.48$\pm$1.61mg/day) than in high protein high animal diet group (HPA, 14.40$\pm$0.89mg/day). Apparent absorption and bioavailability of iron was also significantly higher(p<0.10) in HPA(40.7$\pm$5.3%, 6.46$\pm$1.61mg/day) than in HPP(14.4$\pm$5.3%, 2.39$\pm$0.89mg/day). But there was no significant difference between the high animal protein group and high plant protein group in moderate protein period. Serum iron concentration and transferrin saturation increased as animal protein intake increased, from 106.0$\pm$5.1ug/이 and 30.6$\pm$1.5% for MPA to 129.1$\pm$6.7ug/이 and 37.1$\pm$1.3% for HPA. Statistically positive correlations were shown not only between the level of dietary heme iron and apparent absorption(r=0.95, p<0.05), but also between serum iron concentration and apparent absorption(r=0.64, p<0.05). Negative iron balance was shown in two subjects fed the moderate protein meals. These results suggest that recommanded dietary allowances of iron may be under the need to maintain the positive balance, and iron bioavaliability increase by only high level of animal protein intake.

• Asian-Australasian Journal of Animal Sciences
• /
• 제12권7호
• /
• pp.1096-1103
• /
• 1999

A study was conducted to clarify the impact of recombinant porcine somatotropin (pST) on the efficiency of absorbed nitrogen use for protein deposition in growing pigs. Three levels of dietary crude protein (9.0, 11.5, 14.0% CP) were used. Each had either a sub-optimum or near optimum lysine: CP concentration (Low-lysine, 3.8 g/100 g CP and High-lysine, 5.5 g/100g CP) in order to achieve different metabolic efficiencies for nitrogen deposition (ca. 45 vs. 60%). Twelve crossbred female pigs $(59{\pm}4kg\;BW)$ were placed in metabolism cages and fitted with bladder catheters. Each pig received an excipient injection daily for the first 10-d, a pST (5 mg/d) injection for the second 10-d, and then excipient for the last 10-d. Pigs were randomly assigned to one of six dietary treatments (2 pigs/diet) and fed 4 times per d at $92g/kg\;BW^{0.75}$ $(3{\times}maintenance)$. Means for the excipient period were compared to means for the pST period. Urinary nitrogen (N) output declined in pST-treated pigs (p<0.01) irrespective of dietary protein content or lysine level. Nitrogen retention increased by an average of 11% (p<0.01) with pST treatment (726 vs. $803mg\;N/kg^{0.75}\;BW/d$). Forty-eight percent of the absorbed N was retained with Low-lysine diets, but this increased to 53% with pST injection (+11%, p<0.01). Pigs fed High-lysine diets retained 62% of absorbed N which increased to 69% with pST (+11% p<0.01). the addition of lysine improved N use by 27% (High vs. Low, p<0.01), but the effect of lysine and pST was additive (+40%). Therefore, pST improves N retention and the efficiency of apparently absorbed N use in growing pigs (>60kg). It does so with diets having the potential for either low or high efficiencies of N use (48% and 62%). More work is needed to determine if the partial efficiency of N use improves in direct proportion to pST dose since the improvement in protein deposition is a function of pST dose.

• Nutrition Research and Practice
• /
• 제4권5호
• /
• pp.375-382
• /
• 2010

The precise effects of protein intake on fractional synthesis rate (FSR) of muscle protein are still under debate. The sample size of these studies was small and the conclusions in young and elderly subjects were inconsistent. To assess the effect of dietary protein intake on the FSR level, we conducted a meta-analysis of controlled protein intake trials. Random-effects models were used to calculate the weighted mean differences (WMDs). Ten studies were included and effects of short-term protein intake were evaluated. In an overall pooled estimate, protein intake significantly increased the FSR (20 trials, 368 participants; WMD: 0.025%/h; 95%CI: 0.019-0.031; P < 0.0001). Meta-regression analysis suggested that the protein dose was positively related to the effect size (regression coefficient = 0.108%/h; 95%CI: 0.035, 0.182; P = 0.009). A subgroup analysis indicated that protein intake significantly increased FSR when the protein dose was ${\leq}$ 0.80 g/kg BW (16 trials, 308 participants; WMD: 0.027%/h; 95%CI: 0.019-0.031; P < 0.0001), but did not affect FSR when the protein dose was > 0.80 g/kg BW (4 trials, 60 participants; WMD: 0.016%/h; 95%CI: 0.004-0.029; P = 0.98). In conclusion, this study is the first integrated results showing that a short-term protein intake is effective at improving the FSR of muscle protein in the healthy elderly as well as young subjects. This beneficial effect seems to be dose-dependent when the dose levels of protein range from 0.08 to 0.80 g/kg BW.

• 한국식품영양과학회지
• /
• 제32권4호
• /
• pp.608-613
• /
• 2003

본 연구는 채식을 하는 폐경 후 여성의 단백질 영양상태와 골밀도 및 골대사의 관련성을 알아보기 위하여 연령, 체질량지수 등의 요인이 차이가 없도록 채식군 38명, 일반식군 38명 총 76명의 대상자를 선정하고 영양소 섭취량, 골밀도, 골대사관련 지표를 분석하였다. 채식군과 일반식군의 평균 연령은 각각 60.7세와 60.5세였으며, 두 군간의 연령, 체중과 체질량지수는 유의적인 차이가 없었다. 영양소섭취상태 분석결과 열량 섭취량은 채식군이 1518.4㎉(권장량의 82.7%)로 일반식군 1355.4 ㎉(72.6%)보다 높았다. 1일 평균 단백질의 섭취량은 채식군 52.6 g(권장량의 95.6%)과 일반식군 51.8 g(권장량의 94.2%)으로 유사한 수준이었으나, 이중 동물성 단백질의 섭취비율은 채식군이 15.3%, 일반식군이 34.9%로 유의적인 차이를 보였다(p＜0.001). 칼슘의 섭취량은 채식군이 492.6 mg(권장량의 70.3%), 일반식군이 436.5 mg(권장량의 62.3%)으로 두 군 모두 낮은 섭취수준을 보였다. 혈액성상 분석 결과 총 단백질의 함량은 두 군간에 유의적인 차이가 없었으나, 혈청 알부민은 채식군이 일반식군에 비하여 유의적으로 낮았다(p＜0.001). 요추와 대퇴경부의 평균 골밀도는 두군간에 유의적인 차이가 없었다. 골대사 지표인 소변 중 디옥시피리디놀린(DPD) 함량은 채식군이 6.7 nM/mM Cr, 일반식군이 6.9 nM/mM Cr로 군간에 유의적인 차이가 없었다. 소변의 pH는 채식군 6.60, 일반식군 6.23으로 일반식군의 소변의 산도가 유의적으로 높았다(p＜0.05). 단백질 영양상태와 골밀도 및 골대사지표와의 상관관계를 분석한 결과 연령과 체질량지수 보정 후 채식군의 소변 디옥시피리디놀린 배설량은 단백질(p＜0.05), 식물성 단백질(p＜0.05)의 섭취량과 유의적인 음의 상관관계를 나타내었다. 일반군의 경우 혈청 총 단백질(p＜0.05)과 알부민 함량(p＜0.05)은 소변중 디옥시피리디놀린 배설량과 유의적인 양의 상관관계를 나타내었다. 이상의 연구 결과를 종합하여 볼 때 채식을 하는 폐경 후 여성은 단백질의 섭취량 및 혈청 함량이 정상 수준으로 나타났으며, 칼슘의 섭취량은 일반 폐경 후 여성에서와 같이 권장량의 70%수준의 낮은 섭취상태를 보여 채식인의 경우도 칼슘의 섭취부족이 영양상의 문제점으로 나타났다. 골밀도와 골대사 지표 측정결과 채식군과 일반식군 간에 유의적인 차이를 나타내지 않아 채식이 골대사에 미치는 직접적인 영향을 확인할 수 없었다. 그러나 채식인의 경우 총 단백질 및 식물성 단백질의 섭취량이 골용해를 감소시키는 것으로 나타나 일반식군에서보다 채식군에서 적절한 단백질의 섭취가 골격 건강 유지에 중요한 인자로 제시 되었다. 따라서 채식을 하는 폐경 후 여성의 경우 골격건강을 위하여 단백질의 급원이 되는 식품의 섭취에 더욱 관심이 필요한 것으로 보여 진다. 그러나 본 연구의 경우 대상자의 수가 적은 제한점이 있기 때문에 보다 많은 연구가 계속적으로 수행되어야 할 것으로 생각된다.