Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland, P61 C996; School of Food and Nutritional Sciences, University College Cork, Cork, Co. Cork, Ireland, T12 YN60.
Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland, P61 C996.
J Dairy Sci. 2019 Nov;102(11):9611-9621. doi: 10.3168/jds.2019-16415. Epub 2019 Aug 22.
This study examined the effect of dietary factors on compositional and functional properties of whole milk powder (WMP) produced from bovine milk. Raw milk samples were obtained from 3 groups of 18 Holstein Friesian spring-calving cows randomly assigned to diets based on perennial ryegrass (GRS), perennial ryegrass/white clover sward (CLV), and total mixed ration (TMR). Raw milks obtained in late lactation were subsequently standardized for fat, heat-treated (90°C for 30 s), evaporated, and homogenized before spray drying. The WMP produced from each diet were analyzed to determine differences in color, particle size distribution, heat coagulation time, yogurt gelation, texture profile, and protein profile due to each diet. Significant differences in heat coagulation time were observed between the CLV and TMR samples, whereas color values were significantly different between GRS and TMR samples. No significant differences in gross composition, protein profile, or whey protein nitrogen index were found between the 3 WMP samples. Average D values (the particle size at which 90% of the particles were smaller than the specified size) for fat globules were significantly lower in the TMR sample compared with the GRS and CLV samples. Yogurts produced from GRS- and CLV-derived WMP had significantly higher elastic moduli (G') than those produced from TMR-derived WMP. Similarly, texture profile analysis revealed significantly higher firmness values in yogurt samples derived from CLV compared with TMR samples. Our data characterize the effect of these diets on the composition and functional properties of fat-standardized WMP, suggesting better yogurt functionality and thermal stability in WMP derived from pasture-based bovine diets.
本研究考察了饮食因素对牛乳全脂奶粉（WMP）组成和功能特性的影响。从 3 组 18 头荷斯坦弗里生春季产奶牛中随机获得原料奶，这些奶牛分别被分配到基于多年生黑麦草（GRS）、多年生黑麦草/白三叶草草地（CLV）和全混合日粮（TMR）的日粮中。在泌乳后期获得的原料奶随后进行标准化，以调整脂肪含量，进行热处理（90°C 30s）、蒸发和均质，然后进行喷雾干燥。对每种日粮生产的 WMP 进行分析，以确定由于每种日粮导致的颜色、粒度分布、热凝固时间、酸奶凝胶、质构特性和蛋白质谱的差异。CLV 和 TMR 样品之间的热凝固时间存在显著差异，而 GRS 和 TMR 样品之间的颜色值存在显著差异。3 种 WMP 样品之间的总组成、蛋白质谱或乳清蛋白氮指数没有显著差异。与 GRS 和 CLV 样品相比，TMR 样品中脂肪球的平均 D 值（90%的颗粒小于指定尺寸的粒径）显著降低。由 GRS 和 CLV 衍生的 WMP 制成的酸奶的弹性模量（G'）显著高于由 TMR 衍生的 WMP 制成的酸奶。同样，质构特性分析表明，与 TMR 样品相比，CLV 衍生的酸奶样品具有显著更高的硬度值。我们的数据描述了这些饮食对标准化脂肪 WMP 组成和功能特性的影响，表明来自基于牧场的牛日粮的 WMP 具有更好的酸奶功能和热稳定性。
