Main Contents of the Video Lesson
Vision is the first sense to evaluate food quality from its colour and appearance. Fruit such as apples, bananas, avocados contain polyphenols, antioxidants, which help our body to fight against free radicals and various illnesses. As we know, fruits become brownish after being cut. This happens because of enzymatic oxidation. Polyphenol oxidase changes the polyphenols into brown pigments. It influences the quality, as products do not look attractive.
Not everyone may become a sensory evaluator. First, it is necessary to take different tests. For example, Ishihara test diagnoses a person's colour blindness. Also, knowledge of parameters of different food products is necessary to know what chemical alterations occur to products during storage and processing. The knowledge on sensory and food chemistry acquired at the university is very useful.

Learning Object
introduction to agri-food products alterations (Pdf)