McCarthy M J, McCarthy K L
Department of Food Science and Technology, University of California, Davis 95616-8598, USA.
Magn Reson Imaging. 1996;14(7-8):799-802. doi: 10.1016/s0730-725x(96)00166-x.
Global food markets are changing in response to consumer demands for more processed foods and higher quality foods. Consumers find processed foods convenient, less prone to spoilage, more portable, nutritionally efficient, and more consistent in quality level than fresh foods. These demands have resulted in food producers working to develop new types of foods and reformulate standard types of foods. A typical type of reformulation would be a reduced-calorie food or an all-natural food product. The characterization of food processes and products is most often accomplished through the use of averaged measurements. An averaged measurement provides a characterization of the process or product with a single value of one variable measured at a specific time. For example, the average moisture content of a food during drying or the shear viscosity of an emulsion at one temperature and one shear rate. Averaged measurements are useful in characterizing a given process and are in many cases sufficient for process design or product development. However, these single point measurements do not provide significant information on the phenomena responsible for controlling product properties during processing or storage. More information on the physical and chemical processes controlling or influencing process performance and product quality should result in both improved production efficiency, improved product quality, and novel products. Magnetic resonance imaging provides new methods and approaches to investigate and quantify the attributes of products as they vary in time and location within the product. The attributes that can be quantified range from the composition of a material (moisture content, fat content), to physical structure and to derived characterizations like the shear-stress shear-rate relationship in fluids.
全球食品市场正在发生变化，以响应消费者对更多加工食品和更高品质食品的需求。消费者发现加工食品方便、不易变质、更便于携带、营养高效，且在质量水平上比新鲜食品更稳定。这些需求促使食品生产商努力开发新型食品并重新配方标准食品类型。典型的重新配方类型可能是低热量食品或全天然食品。食品加工过程和产品的特性描述通常通过使用平均测量来完成。平均测量通过在特定时间测量一个变量的单一值来提供过程或产品的特性描述。例如，食品干燥过程中的平均水分含量或乳液在一个温度和一个剪切速率下的剪切粘度。平均测量在表征给定过程方面很有用，并且在许多情况下足以用于过程设计或产品开发。然而，这些单点测量并不能提供关于在加工或储存过程中控制产品特性的现象的重要信息。关于控制或影响过程性能和产品质量的物理和化学过程的更多信息应该会带来生产效率的提高、产品质量的改善以及新产品的出现。磁共振成像提供了新的方法和途径来研究和量化产品在其内部随时间和位置变化的属性。可以量化的属性范围从材料的组成（水分含量、脂肪含量）到物理结构，再到流体中剪切应力与剪切速率关系等派生特性。
