Park YW
Georgia Small Ruminant Research and Extension Center, College of Agriculture, Home Economics and Allied Programs, Fort Valley State University, 31030-4313, Fort Valley, GA, USA
Small Rumin Res. 2000 Jul 1;37(1-2):115-124. doi: 10.1016/s0921-4488(99)00144-3.
Concentrations of 12 major and trace minerals and cholesterol in commercial goat fluid milk, evaporated, powdered, yogurt, and cheese products manufactured in the US were evaluated for compositional differences. Minerals were determined by an Inductively Coupled Argon Plasma Emission Spectroscopy (ICAP), while cholesterol was analyzed using colorimetric and gas chromatographic (GC) methods. Mean total solids content (%) of fluid milk, evaporated milk, powdered milk, yogurt, plain soft and Monterey Jack cheeses were: 11.3, 20.9, 94.1, 11.5, 32.5, and 57.7, respectively. Mean calcium and phosphorus contents (ppm, dry basis) of the corresponding products were: 103, 125; 440, 393; 7715, 7471; 161, 144; 691, 1105; 3492, 3067, respectively. The respective iron and zinc contents (ppm) of the corresponding products were: 0.062, 0.349; 1.518, 1.635; 3.33, 30.21, 0.117, 0.338; 7.16, 3.64; 8.86, 3.81. The levels of potassium (K) in cheeses were lowest among all the products including fluid goat milk, suggesting that a significant amount of K was lost during cheese manufacturing processes. Levels of all trace minerals were higher in yogurt and cheeses than in fluid milk. The levels of trace minerals in cheeses were greater than those in yogurt products. Iron and aluminum contents of certain goat milk products were considerably higher than normal, possibly due to contamination of minerals from manufacturing utensils and product metal cans. Sulphur contents of fermented products were significantly greater than those of fluid milk, which may be accountable for the microbial synthesis of sulfur containing proteins during the manufacturing processes of the products. Cholesterol contents (mg/100g, wet basis) of fluid, evaporated, powdered goat milk and Monterey Jack cheese determined by GC method were: 11.0, 24.9, 119.5 and 91.7, respectively. Cholesterol contents of the goat milk products analyzed by colorimetric method were substantially greater than those by GC method.
对美国生产的市售山羊液态奶、炼乳、奶粉、酸奶和奶酪产品中12种主要和微量元素以及胆固醇的含量进行了评估,以分析其成分差异。矿物质通过电感耦合氩等离子体发射光谱法(ICAP)测定,而胆固醇则采用比色法和气相色谱法(GC)进行分析。液态奶、炼乳、奶粉、酸奶、原味软奶酪和蒙特里杰克奶酪的平均总固体含量(%)分别为:11.3、20.9、94.1、11.5、32.5和57.7。相应产品的平均钙和磷含量(ppm,干基)分别为:103、125;440、393;7715、7471;161、144;691、1105;3492、3067。相应产品的铁和锌含量(ppm)分别为:0.062、0.349;1.518、1.635;3.33、30.21;0.117、0.338;7.16、3.64;8.86、3.81。在包括山羊液态奶在内的所有产品中,奶酪中的钾(K)含量最低,这表明在奶酪制造过程中大量的钾流失了。酸奶和奶酪中所有微量元素的含量均高于液态奶。奶酪中微量元素的含量高于酸奶产品。某些山羊奶制品的铁和铝含量明显高于正常水平,这可能是由于生产器具和产品金属罐中的矿物质污染所致。发酵产品中的硫含量明显高于液态奶,这可能是产品制造过程中含硫蛋白质微生物合成的原因。通过气相色谱法测定的液态、炼乳、山羊奶粉和蒙特里杰克奶酪的胆固醇含量(mg/100g,湿基)分别为:11.0、24.9、119.5和91.7。通过比色法分析的山羊奶制品的胆固醇含量明显高于气相色谱法测定的结果。