A high performance liquid chromatographic method for the simultaneous determination of four fat soluble vitamins: retinol (vitamin A), cholecalciferol(vitamin D), tocopherol(vitamin E) and phylloquinone(vitamin K_1) i...A high performance liquid chromatographic method for the simultaneous determination of four fat soluble vitamins: retinol (vitamin A), cholecalciferol(vitamin D), tocopherol(vitamin E) and phylloquinone(vitamin K_1) in fortified milk powders and egg yolk has been developed. The method requires enzymatic hydrolysis of lipid component of the sample as a pretreatment. Several factors which influence the enzymatic hydrolysis were studied-Separation was achieved using μ-Bondapak C-18 column(3.9×300mm), 98% methanol as mobile phase, a double channel detection was selected; vitamins D_3 E_1 K_1 were detected by UV spectrophotometry (265 nm) first, then vitamin A by fluorometry (EX 325nm, EM 480mm). The retention times of vitamin A_1 D_3, E and K_1 4.87, 9.00, 10.58 and 15.45 min respectively. Detection limit were 0.64, 0.25, 0.50 and 0.07 ng; and the recoveries were 90.5%～103.6% 90.0%～95.6%, 91.7%～98.8%, 91.5%～98.6%, respectively. The vitamins A, D_0, E, K_1 contents in foods were determined satisfactorily.展开更多
Human milk is the ideal nutritional support for premature neonates. Considering the need for aggregating nutritional value to human milk provided to such vulnerable group of infants, human milk was concentrated by the...Human milk is the ideal nutritional support for premature neonates. Considering the need for aggregating nutritional value to human milk provided to such vulnerable group of infants, human milk was concentrated by the block freeze concentration technique. The effects of freeze concentration on the physicochemical properties, the efficiency of the process, color parameters, and the density and dynamic viscosity of human milk were assessed. The freeze concentration technology was used to successfully concentrate human milk to a factor equal to 180.48% and 72% of total solid retention in the second stage of freeze concentration. The values observed in the concentrates for the biochemical properties showed that the fraction of concentrated fluid human milk of the second stage (C2) presented elevated amounts of carbohydrates, protein and energy. The elevated caloric value observed in the ice fraction of the first stage (I1) refers to the retention of lipids in it. When added to human milk, C2 and I1 may satisfy the special requisites of nutrients and energy to guarantee the growth and development of preterm neonates.展开更多
文摘A high performance liquid chromatographic method for the simultaneous determination of four fat soluble vitamins: retinol (vitamin A), cholecalciferol(vitamin D), tocopherol(vitamin E) and phylloquinone(vitamin K_1) in fortified milk powders and egg yolk has been developed. The method requires enzymatic hydrolysis of lipid component of the sample as a pretreatment. Several factors which influence the enzymatic hydrolysis were studied-Separation was achieved using μ-Bondapak C-18 column(3.9×300mm), 98% methanol as mobile phase, a double channel detection was selected; vitamins D_3 E_1 K_1 were detected by UV spectrophotometry (265 nm) first, then vitamin A by fluorometry (EX 325nm, EM 480mm). The retention times of vitamin A_1 D_3, E and K_1 4.87, 9.00, 10.58 and 15.45 min respectively. Detection limit were 0.64, 0.25, 0.50 and 0.07 ng; and the recoveries were 90.5%～103.6% 90.0%～95.6%, 91.7%～98.8%, 91.5%～98.6%, respectively. The vitamins A, D_0, E, K_1 contents in foods were determined satisfactorily.
文摘Human milk is the ideal nutritional support for premature neonates. Considering the need for aggregating nutritional value to human milk provided to such vulnerable group of infants, human milk was concentrated by the block freeze concentration technique. The effects of freeze concentration on the physicochemical properties, the efficiency of the process, color parameters, and the density and dynamic viscosity of human milk were assessed. The freeze concentration technology was used to successfully concentrate human milk to a factor equal to 180.48% and 72% of total solid retention in the second stage of freeze concentration. The values observed in the concentrates for the biochemical properties showed that the fraction of concentrated fluid human milk of the second stage (C2) presented elevated amounts of carbohydrates, protein and energy. The elevated caloric value observed in the ice fraction of the first stage (I1) refers to the retention of lipids in it. When added to human milk, C2 and I1 may satisfy the special requisites of nutrients and energy to guarantee the growth and development of preterm neonates.
