Background. There is a tendency in food industry to replace synthetic yellow food dyes with the naturally derived alternatives. However, the instability of existing natural product derived yellow colorants has hindered their utilization by the food industry. The yellow pigments from lemon peel represents a potentially useful byproduct of lemon that could be isolated and prepared after the generation of juice and essential oils. Objective. This investigation into the components of lemon peel aimed at discovery of new stable, water-soluble, low-cost, and obtainable yellow colorants that showed great potential as a future colorant in industry. Methods. The dried lemon peel was extracted with ethyl acetate, ethanol, and water. The ethanol part was purified by the combination of Sephadex LH-20 columns, silica gel columns and HPLC. The structure of a yellow pigment gained therefrom was carefully assigned on the basis of spectroscopic data, including 1D and 2D NMR spectroscopy, and the absolute configuration was established by comparison of the experimental CD with calculated electronic circular dichroism (ECD) spectral data. CIELAB values and Delta CIELAB were measured and compared to other natural products used as food colorants. Results. A yellow colorant, called lemon yellow #15, was isolated and characterized (Figure 1). The color parameter values of it and two commercially available yellow colorants, curcumin and crocin, were measured (Table 1). Conclusion. This compound possesses much greater light stability than curcumin and crocin according to the values of ΔE*. In addition, lemon yellow #15 is highly water-soluble, which makes its extraction, isolation and utility to food products more effective. Finally, the abundance of lemon peel, a byproduct of lemon juice production assures that its availability and production will be cost-effective.

Development of highly stable, water soluble food colorants from the peel of Citrus limon

2019 Spring National Meeting

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