Bellassi Paolo, Rocchetti Gabriele, Maldarizzi Gianluca, Braceschi Gian Paolo, Morelli Lorenzo, Lucini Luigi, Cappa Fabrizio
Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
Centro Studi Assaggiatori Società Cooperativa, Galleria V. Veneto, 9, 25128 Brescia, Italy.
Foods. 2021 Nov 7;10(11):2722. doi: 10.3390/foods10112722.
This work investigated the microbiological quality and chemical profiles of two different dairy creams obtained by centrifugation vs. natural creaming separation systems. To this aim, an untargeted metabolomics approach based on UHPLC-QTOF mass spectrometry was used in combination with multivariate statistical tools to find potential marker compounds of the two different types of two dairy creams. Thereafter, we evaluated the chemical, microbiological and sensorial changes of a ricotta cheese made with a 30% milk cream (i.e., made by combining dairy creams from centrifugation and natural creaming separation) during its shelf-life period (12 days). Overall, microbiological analysis revealed no significant differences between the two types of dairy creams. On the contrary, the trend observed in the growth of degradative bacteria in ricotta during shelf-life was significant. Metabolomics revealed that triacylglycerols and phospholipids showed significant strong down-accumulation trends when comparing samples from the centrifugation and natural creaming separation methods. Additionally, 2,3-Pentanedione was among the best discriminant compounds characterising the shelf-life period of ricotta cheese (VIP score = 1.02), mainly related to sensorial descriptors, such as buttery and cheesy. Multivariate statistics showed a clear impact of the shelf-life period on the ricotta cheese, revealing 139 potential marker compounds (mainly included in amino acids and lipids). Therefore, the approach used showed the potential of a combined metabolomic, microbiological and sensory approach to discriminate ricotta cheese during the shelf-life period.
本研究调查了通过离心分离与自然乳脂分离系统获得的两种不同乳脂的微生物质量和化学特征。为此，采用了基于超高效液相色谱-四极杆飞行时间质谱的非靶向代谢组学方法，并结合多变量统计工具来寻找这两种不同类型乳脂的潜在标志物化合物。此后，我们评估了用30%乳脂制成的乳清奶酪（即通过将离心分离和自然乳脂分离得到的乳脂混合制成）在保质期（12天）内的化学、微生物和感官变化。总体而言，微生物分析表明两种类型的乳脂之间没有显著差异。相反，在保质期内乳清奶酪中降解细菌生长的观察趋势是显著的。代谢组学研究表明，在比较离心分离法和自然乳脂分离法的样品时，三酰甘油和磷脂呈现出显著的强烈下降积累趋势。此外，2,3-戊二酮是表征乳清奶酪保质期的最佳判别化合物之一（VIP分数=1.02），主要与感官描述符有关，如黄油味和奶酪味。多变量统计显示保质期对乳清奶酪有明显影响，揭示了139种潜在的标志物化合物（主要包括氨基酸和脂质）。因此，所采用的方法显示了代谢组学、微生物学和感官方法相结合在区分乳清奶酪保质期方面的潜力。
