Zacometti Carmela, Tata Alessandra, Massaro Andrea, Riuzzi Giorgia, Bragolusi Marco, Cozzi Giulio, Piro Roberto, Khazzar Sara, Gerardi Gabriele, Gottardo Flaviana, Segato Severino
Experimental Chemistry Laboratory, Istituto Zooprofilattico Sperimentale delle Venezie, 36100 Vicenza, Italy.
Department of Animal Medicine, Production and Health, University of Padova, 35020 Legnaro, Italy.
Foods. 2023 Apr 30;12(9):1871. doi: 10.3390/foods12091871.
The study aimed to assess the seasonal variation in raw milk volatile organic compounds (VOCs) from three indoor feeding systems based on maize silage ( = 31), silages/hay ( = 19) or hay ( = 16). After headspace solid-phase microextraction (HS-SPME), VOC profiles were determined by gas chromatography (GC). Chemical and VOC (log transformations of the peak areas) data were submitted to a two-way ANOVA to assess the feeding system (FS) and season (S) effects; an interactive principal component analysis (iPCA) was also performed. The interaction FS × S was never significant. The FS showed the highest ( < 0.05) protein and casein content for hay-milk samples, while it did not affect any VOCs. Winter milk had higher ( < 0.05) proportions of protein, casein, fat and some carboxylic acids, while summer milk was higher ( < 0.05) in urea and 2-pentanol and methyl aldehydes. The iPCA confirmed a seasonal spatial separation. Carboxylic acids might generate from incomplete esterification in the mammary gland and/or milk lipolytic activity, while aldehydes seemed to be correlated with endogenous lipid or amino acid oxidation and/or feed transfer. The outcomes suggested that VOCs could be an operative support to trace raw milk for further mild processing.
该研究旨在评估来自三种室内饲养系统的原料乳挥发性有机化合物（VOCs）的季节性变化，这三种饲养系统分别基于玉米青贮饲料（n = 31）、青贮饲料/干草（n = 19）或干草（n = 16）。经过顶空固相微萃取（HS-SPME）后，通过气相色谱法（GC）测定VOCs谱图。将化学数据和VOC数据（峰面积的对数转换）进行双向方差分析，以评估饲养系统（FS）和季节（S）的影响；还进行了交互式主成分分析（iPCA）。FS×S的交互作用从未显著。FS显示干草奶样品的蛋白质和酪蛋白含量最高（P < 0.05），而它不影响任何VOCs。冬季乳的蛋白质、酪蛋白、脂肪和一些羧酸的比例较高（P < 0.05），而夏季乳的尿素、2-戊醇和甲基醛含量较高（P < 0.05）。iPCA证实了季节性空间分离。羧酸可能由乳腺中的不完全酯化和/或乳脂肪分解活性产生，而醛似乎与内源性脂质或氨基酸氧化和/或饲料转移相关。结果表明，VOCs可作为一种有效的支持手段，用于追踪原料乳以便进行进一步的温和加工。
