Anthocyanins of Lycium ruthenicum (LR) are valuable, whereas stabilities, especially colour stabilities, constrain development. This study investigates stored temperature effects on the stability of powdered anthocyanin extracts of LR in anaerobic conditions and colour changes in simulated applications. We found that temperature had limited effects on anthocyanin contents but negative effects on colour. Colour differences (ΔE) were amplified in simulated applications, 4 °C had the most changes in ΔE in simulated applications, 37 °C caused shrinkage of the colour range towards the yellow area, and changes in ΔE at pH 7 and 9 were summarized by models. In conclusion, during anaerobic storage of powdered anthocyanins, asynchronous changes occur between anthocyanin contents and colour. High storage temperature attenuates colour intensity, but low storage temperature causes more ΔE in applications. Established models are beneficial for decreasing the visual differences in products, deepening the understanding, and offering a new perspective on colour analysis.
Fig. 5. Levenberg–Marquardt modelling showing the effects of time and temperature on the colour changes of powdered anthocyanin extracts. (A) Models in pH 7
buffer; (B) Models in pH 9 buffer
This result was published in Food Chemistry with the title of “Improved colorimetric analysis for subtle changes of powdered anthocyanins extracted from Lycium ruthenicum Murr.”.
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