External quality characteristics, those that can be perceived by the senses of sight and touch without ingesting the product, are important in product differentiation, particularly in purchase decision and food preparation.
For example, the totality of the sensory characteristics (such as appearance, smell, size, shape color, texture, aroma, taste, and mouth feel) of food influences the decision to buy fruit and vegetables to a greater or lesser extent.
There is a good deal of evidence that the sensory characteristics such as taste and aroma have a specific effect on the consumer’s food choice.
In the modern system, the appearance and external quality of the product can be evaluated automatically by machine vision systems. These have video cameras that take images of the units of the product traveling underneath and send them to a computer where they are conveniently analyzed.
Unfortunately, the computer system has some draw backs that make it unsuitable for certain industrial applications. It is inefficient in the case of objects of similar colors, inefficient in the case of complex classification, unable to predict quality attributes and it is inefficient for detecting invisible defects.
External quality of food