Handbook on discolourations provides easy reference
but on foods they may indicate problems with manufacturing
processes or storage.
A review from Campden & Chorleywood Food Research Association examines the causes of the individual colours on specific foods, providing quality managers with a way to pinpoint problems. "Food discolourations that bear little resemblance to the expected coour of the food have a major impact on saleable quality," authors Helen Brown and Brian Adams state. "However the reactions leading to discolouration are often only partially understood, or are inferred from other evidence. This is due to their inherent complexity, to the variability in raw material, and to the practical difficulties in isolating and characterizing newly-formed pigments" For each discolouration, raw and processed foods are examined separately. The review has separate subsections on fruits, vegetables, cereals, meats, fish and diary products. The specific foods are arranged alphabetically within each sub-section. The text is supplemented by an extensive list of references, allowing managers to follow up on research into specific discolourations. For example, the chapter on red discolourations contains information on fruits, vegetables, heat processed products, bread, meat, dairy and fish. A pinking discolouration in white poultry meat may suggest underprocessing to the consumer, but could be due to the effect of residual nitrates, according to studies. The review assesses the various chemical and biochemical causes of each food discolouration, where there is sufficient evidence from the studies. The two authors conclude that further research is needed to obtain a more complete understanding of the effects of raw materials, processing and storage conditions, and microbial growth. "These studies would be expected to lead to the development of more efficient methods of controlling food discolouration based on the inhibition of key reaction pathways," they stated.
