Tracking bioactive compounds with colour changes in foods – A review

• Chemical transformation of biocompounds in foods may imply colour changes in foods.
• Colour instrumentation is a suitable technique to measure the colour changes during the transformation of bioactive components.
• A statistical evaluation of the bioactive compounds and the colour changes in foods reveal that both aspects may be related.
• The colour measurement is a fast and practical way to indirectly estimate the contents of biocompounds in foods.

Colour is one of the major attributes that affect the consumer perception of food quality. Several pigments in foods, measurable by colourimetric instrumentation, possess biological activity. The present work is a review of studies that assessed the colour changes (by the CIELAB parameters) and the bioactive compound content, analysing statistically their correlation in a broad spectrum of foods. An emphasis was placed on the contribution of phenolics, carotenoids, chlorophylls and betalains on the food colour characteristics during different processing and storage conditions. The correlation between these compounds and the colour changes of some foods had r-values higher than 0.72, according to the Pearson correlation analysis. This suggests that colour instrumentation may be an efficient and practical technique to indirectly estimate the presence of bioactive components. This approach potentially facilitates the real-time quality control of biological compounds during the food industry processes.