Why is it necessary to use purified flavours in flavour training?
The first reason concerns safety. Impure chemicals present a poisoning risk. All chemicals used in flavour training and validation must comply with the requirements of the Food Chemicals Codex. The second reason concerns flavour quality. Trace amounts of flavour-active impurities can confer an atypical character to a flavour standard. Although the chemical purity of a reference substance might seem ok, this is not enough. For example, suppose that a substance was 99.9% pure, this means it contains 0.1% of a contaminant. Now suppose that the contaminant was 1000 times more flavour-active than the reference compound, under these circumstances the flavour of the contaminant is likely to be very evident in the reference standard (it will have a similar flavour impact to that of the reference compound). In other words, the standard will not smell or taste like it should.
