Quality assessment of milk by sensory and instrument methods

Heat and other processing treatments can adversely affect the sensory characteristic of milk and dairy products. Taste and aroma are the most affected and studied attributes in milk. This work reviewed the human sensory tests as well as the instrumental development in this field and their application in milk. For many years, human sensory-like discrimination (e.g., triangle and Duo-trio) and descriptive methods (e.g., quantitative descriptive analysis) have been used for milk assessment. The discrimination tests give general differences between samples, whereas descriptive methods give a more detailed description of the attributes and their intensity which is mostly measured by a 15-line scale. Affective methods were also applied to assess consumer acceptability using the hedonic scale (e.g., 9-point scale). Special facial scale successfully used to assess children acceptability instead of verbal scale. Application of GC/O, e-nose, and e-tongue in fluid milk assessment gives a more clear explanation of the flavor cause, development, and its impact character compounds. The e-nose and e-tongue showed comparable results with human sensory tests. Future enhancement and development in sensors can improve the response to cover a wide range of chemical compounds.