Color stability and pH-indicator ability of curcumin, anthocyanin and betanin containing colorants under different storage conditions for intelligent packaging development

8.8 MT of food wastes are annually generated in the EU, in part due to the lack of real-time food freshness information provided by current food data labels. To address this issue, intelligent packaging strategies are being developed. In this study, in search of new natural and food grade pH-indicators, color stability and variability of curcumin (E−100), betanin (E−162), and anthocyanin (E−163) containing food colorants were studied in solution under different food storage conditions and pHs by light absorbance, color, pH and turbidity measurements. E−100 provided color variations (yellow/brown-yellow) at pH > 9 and was particularly photosensitive since a color loss of 67% was observed after 1 day of storage. E−162 and E−163 colorants, however, were thermosensitive and showed significant lower loss of color (30%) after 28 days of storage. E−163, especially, presented a broader color response (red-purple-blue-green) over a wider pH range. Furthermore, color variations at different pHs were dependent upon colorant type and concentration.