USDA Agricultural Research Service, Eastern Regional Research Center, Dairy and Functional Foods Research Unit, Wyndmoor, PA 19038, USA.
J Dairy Sci. 2011 Sep;94(9):4292-9. doi: 10.3168/jds.2010-3884.
Queso Chihuahua, a semi-hard cheese manufactured from raw milk (RM) in northern Mexico, is being replaced by pasteurized milk (PM) versions because of food safety concerns and the desire for longer shelf life. In this study, the functional traits of authentic Mexican Queso Chihuahua made from RM or PM were characterized to identify sources of variation and to determine if pasteurization of the cheese milk resulted in changes to the functional properties. Two brands of RM cheese and 2 brands of PM cheese obtained in 3 seasons of the year from 4 manufacturers in Chihuahua, Mexico, were analyzed after 0, 4, 8, 12, and 16 wk of storage at 4°C. A color measurement spectrophotometer was used to collect color data before and after heating at 232°C for 5 min or 130°C for 75 min. Meltability was measured using the Schreiber Melt Test on samples heated to 232°C for 5 min. Sliceability (the force required to cut through a sample) was measured using a texture analyzer fitted with a wire cutter attachment. Proteolysis was tracked using sodium dodecyl sulfate-PAGE. Compared with PM cheeses, RM cheeses showed less browning upon heating, melted more at 232°C, and initially required a greater cutting force. With aging, cheeses increased in meltability, decreased in whiteness when measured before heating, and required less cutting force to slice. Seasonal variations in the cheesemilk had minimal or no effect on the functional properties. The differences in the functional properties can be attributed, in part, to the mixed microflora present in the RM cheeses compared with the more homogeneous microflora added during the manufacture of PM cheeses. The degree of proteolysis and subsequent integrity of the cheese matrix contribute to melt, slice, and color properties of the RM and PM cheeses. Understanding the functional properties of the authentic RM cheeses will help researchers and cheesemakers develop pasteurized versions that maintain the traditional traits desired in the cheeses.
奇瓦瓦干酪是一种由产自墨西哥北部的生奶（RM）制成的半硬奶酪，由于食品安全问题和对更长保质期的需求，正在被巴氏杀菌奶（PM）版本所取代。在这项研究中，对使用 RM 或 PM 生产的正宗墨西哥奇瓦瓦干酪的功能特性进行了表征，以确定变异来源，并确定奶酪牛奶的巴氏杀菌是否导致功能特性发生变化。在墨西哥奇瓦瓦州的 4 家制造商处，在一年中的 3 个季节中，从 2 个 RM 奶酪品牌和 2 个 PM 奶酪品牌中获取了奶酪样品，在 4°C 下储存 0、4、8、12 和 16 周后进行了分析。使用分光光度计在 232°C 加热 5 分钟或 130°C 加热 75 分钟前后收集颜色数据。在将样品加热至 232°C 5 分钟后，使用 Schreiber 熔融试验测量熔融性。使用配备金属丝切割附件的质地分析仪测量切片性（切割样品所需的力）。使用 SDS-PAGE 跟踪蛋白质水解。与 PM 奶酪相比，RM 奶酪在加热时褐变较少，在 232°C 时更易融化，并且最初需要更大的切割力。随着老化，奶酪的熔融性增加，加热前的白度降低，切割所需的力减小。奶酪乳季节性变化对功能特性的影响最小或没有。RM 奶酪与 PM 奶酪相比，功能特性的差异部分归因于 RM 奶酪中存在的混合微生物群，而 PM 奶酪在制造过程中添加了更均匀的微生物群。蛋白质水解的程度以及随后奶酪基质的完整性有助于 RM 和 PM 奶酪的熔融、切片和颜色特性。了解正宗 RM 奶酪的功能特性将有助于研究人员和奶酪制造商开发出保持奶酪传统特性的巴氏杀菌版本。
