Bettera Luca, Alinovi Marcello, D'Incecco Paolo, Gatti Monica, Carini Eleonora, Pellegrino Luisa, Bancalari Elena
Department of Food and Drug, University of Parma, 43124 Parma, Italy.
Department of Food, Environmental and Nutritional Sciences, University of Milan, 20133 Milan, Italy.
Foods. 2023 Sep 2;12(17):3302. doi: 10.3390/foods12173302.
The present study investigated some physico-chemical and microbiological traits of 20-month ripened hard cheeses produced from low-temperature high-speed centrifuged raw milk that developed a structural defect consisting of eyes or slits in the paste. Cheeses obtained using the same process and that did not develop the defect were used as controls. The colour, texture, moisture, water activity, proton molecular mobility, microstructure, extent of proteolysis, and viable microorganisms have been evaluated in all the cheese samples, and the significant differences between the defective and non-defective cheeses have been critically discussed. At a microstructural level, the defects caused fat coalescence and an unevenly organised protein matrix with small cracks in the proximity of the openings. The different fat organisation was correlated to a different transverse relaxation time of H population relaxing at higher times. The textural and colour features were not different from those of the control cheeses and were comparable with those reported in the literature for other long-ripened hard cheeses. On the other hand, the defective cheeses showed a higher moisture level and lower lactobacilli and total mesophilic bacteria concentrations, but the microbial origin of the defect remains an open hypothesis that deserves further investigation.
本研究调查了用低温高速离心的原料乳生产的、经过20个月成熟的硬质干酪的一些物理化学和微生物特性，这些干酪在凝乳中出现了由气孔或裂缝组成的结构缺陷。使用相同工艺且未出现缺陷的干酪用作对照。对所有干酪样品的颜色、质地、水分、水分活度、质子分子迁移率、微观结构、蛋白水解程度和活菌进行了评估，并对有缺陷和无缺陷干酪之间的显著差异进行了批判性讨论。在微观结构层面，这些缺陷导致了脂肪聚结以及蛋白质基质组织不均匀，在气孔附近有小裂缝。不同的脂肪组织与在较长时间弛豫的氢质子群的不同横向弛豫时间相关。有缺陷干酪的质地和颜色特征与对照干酪并无差异，且与文献中报道的其他长时间成熟硬质干酪的特征相当。另一方面，有缺陷的干酪显示出较高的水分含量以及较低的乳酸菌和嗜温菌总数，但缺陷的微生物来源仍是一个有待进一步研究的开放性假设。
