Faculty of BioScience and Technology for Food, Agriculture and Environment, University of Teramo, Via Renato Balzarini 1, 64100 Teramo, Italy.
Department of Veterinary Medicine, University of Perugia, Via S. Costanzo 4, 06126 Perugia, Italy.
J Dairy Sci. 2019 Apr;102(4):2918-2927. doi: 10.3168/jds.2018-15868. Epub 2019 Feb 14.
Zinc represents an essential microelement for several biochemical mechanisms. The body's inability to store zinc necessarily requires a constant dietary supply to avoid alteration of physiological functions. The aim of the present study was to investigate the effect of dietary enrichment with zinc on chemical-nutritional and aromatic properties of milk and cheese. Thirty commercial dairy cows, balanced for parity, milk production, and days in milk, were randomly assigned to 2 groups. The control group was fed with a conventional complete diet (22 kg of dry matter/animal per day), whereas the experimental group received a daily zinc supplementation of 60 mg per kg of dry complete feed. During the experimental period, the milk yield was monitored and samples of milk and caciotta cheese were collected to obtain information about the chemical-nutritional composition and aromatic profile. Dietary zinc integration did not influence milk yield and composition, but induced a marked reduction of somatic cell count and improved the oxidative stability of ripened caciotta cheese. In both milk and cheese, the experimental group samples were characterized by a lower concentration of saturated fatty acids and an increase in oleic acid, vaccenic acid, and rumenic acid. The aromatic profile of dairy products was also positively affected by dietary zinc intake, with an increase in concentration of carboxylic acids, aldehydes, and esters. The present results suggest a positive role of zinc in improving animal health and nutraceutical properties of milk and corresponding cheese. Taking into account the analysis of volatile compounds, zinc dietary supplementation of dairy cows should contribute to the production of cheeses with interesting organoleptic properties, although more studies are necessary to confirm the consumer acceptability of these changes.
锌是几种生化机制所必需的微量元素。由于人体无法储存锌，因此必须从饮食中不断补充，以避免生理功能发生变化。本研究旨在探讨饮食中锌的富集对牛奶和奶酪的化学-营养和芳香特性的影响。将 30 头商业奶牛按胎次、产奶量和泌乳天数进行平衡，随机分为 2 组。对照组饲喂常规全价日粮（每天 22 公斤干物质/动物），而实验组每天接受 60 毫克/公斤干全价饲料的锌补充。在实验期间，监测牛奶产量，并采集牛奶和卡伊奥塔奶酪样品，以获得有关化学-营养成分和芳香特征的信息。日粮锌的添加并未影响牛奶的产量和组成，但显著降低了体细胞计数，提高了成熟卡伊奥塔奶酪的氧化稳定性。在牛奶和奶酪中，实验组样品的特征是饱和脂肪酸浓度降低，油酸、葵酸和反油酸增加。膳食锌的摄入还对乳制品的芳香特征产生了积极影响，羧酸、醛和酯的浓度增加。这些结果表明，锌在改善动物健康和牛奶及其相应奶酪的营养特性方面发挥了积极作用。考虑到挥发性化合物的分析，奶牛日粮中添加锌应该有助于生产具有有趣感官特性的奶酪，尽管需要更多的研究来证实消费者对这些变化的接受程度。
