Tristimulus colorimetric pigment prediction in food: a review

Carotenoid and anthocyanin pigments are responsible for a large range of fruit and vegetable colour (carotenoids: yellow to red; anthocyanins: red to purple-black). The colour of food is suggested to stimulate appetite and digestion and has been reported as an indicator of fresh produce quality for consumers. Importantly, their relatively unstable chemical structure makes the both pigment groups potent antioxidants when consumed in the diet.
Colorimetric analysis is proposed as a non-destructive method to estimate carotenoid and anthocyanin content in different foods, a more accessible aid and/or alternative to traditional chemical assays (eg., high-performance liquid chromatography, spectrophotometry, etc.). Colour can be measured quantitatively with tristimulus colorimeters or digital image analyses via standardised three-dimensional colour spaces (eg., CIELab/Ch, RGB) and their individual colour parameters. However, the results of current literature in the field of colorimetric pigment prediction are inconsistent. Therefore, a literature review was performed to report and compare the current findings in the field of colorimetric prediction of carotenoid and anthocyanin content in different kinds of foods.