Scuola di Bioscienze e Medicina Veterinaria, Università degli Studi di Camerino, 62032 Camerino, Italy.
Scuola di Scienze e Tecnologie, Università degli Studi di Camerino, 62032 Camerino, Italy.
J Dairy Sci. 2022 Aug;105(8):6422-6430. doi: 10.3168/jds.2022-21901. Epub 2022 Jun 9.
The aim of this study was to evaluate the concentrations of Zn, Cu, Mn, Se, Mo, Co, Li, B, Ti, Cr, Rb, Sr, Cd, and Pb in donkey milk and their distribution in major milk fractions (i.e., fat, casein, whey proteins, and aqueous phase). Individual milk samples were provided by 16 clinically healthy lactating donkeys. Subsequent centrifugation, ultracentrifugation, and ultrafiltration were carried out to remove fat, casein, and whey proteins to obtain skim milk, a supernatant whey fraction, and the aqueous phase of milk, respectively. Concentrations of the elements were measured in whole milk and fractions by inductively coupled plasma-mass spectrometry, and the concentrations associated with fat, casein, and whey proteins were then calculated. The effect of removal of fat, casein, and whey proteins was determined by repeated-measures ANOVA. The fat fraction of donkey milk carried a small (∼4.5% to 13.5%) but significant proportion of Mo, Co, Ti, Cr, and Sr. The casein fraction in donkey milk carried almost all milk Zn, a majority of Cu and Mn, and most of Mo, Ti, and Sr. Relevant proportions, between 20% and 36%, of Se, Co, and Cr were also associated with caseins. The majority of Se, Co, Li, B, Cr, and Rb, and relevant proportions of Mn, Mo, Ti, and Sr were found in soluble form (ultracentrifuged samples) and distributed between whey proteins and the aqueous phase of milk (ultrafiltered samples). Whey proteins in donkey milk carried the majority of milk Se and Co. All Li and B was present in the aqueous phase of milk, which also contained most Rb and Cr, and 17% to 42% of Mn, Se, Mo, Co, Ti, and Sr.
本研究旨在评估驴奶中 Zn、Cu、Mn、Se、Mo、Co、Li、B、Ti、Cr、Rb、Sr、Cd 和 Pb 的浓度及其在主要乳成分（即脂肪、酪蛋白、乳清蛋白和水相）中的分布。16 头临床健康泌乳驴提供了个体奶样。随后通过离心、超速离心和超滤将脂肪、酪蛋白和乳清蛋白去除，分别获得脱脂奶、上清乳清部分和奶的水相。通过电感耦合等离子体质谱法在全奶和各部分中测量元素浓度，然后计算与脂肪、酪蛋白和乳清蛋白相关的浓度。通过重复测量方差分析确定去除脂肪、酪蛋白和乳清蛋白的效果。驴奶的脂肪部分携带少量（约 4.5%至 13.5%）但显著的 Mo、Co、Ti、Cr 和 Sr。驴奶的酪蛋白部分携带了大部分的 Zn、大部分的 Cu 和 Mn，以及大部分的 Mo、Ti 和 Sr。相关比例在 20%至 36%之间的 Se、Co 和 Cr 也与酪蛋白有关。大部分的 Se、Co、Li、B、Cr 和 Rb，以及相关比例的 Mn、Mo、Ti 和 Sr 以可溶形式（超速离心样品）存在，并分布在乳清蛋白和奶的水相之间（超滤样品）。驴奶中的乳清蛋白携带了大部分的 Se 和 Co。所有的 Li 和 B 都存在于奶的水相中，其中还含有大部分的 Rb 和 Cr，以及 17%至 42%的 Mn、Se、Mo、Co、Ti 和 Sr。
