Green color is one of the main quality characteristics of green olives. This parameter can undergo significant changes during the processing to which the product is subjected to prolong its shelf life. However, according to European Union regulations, green olives cannot be adulterated with food colorants as E-141 (ii) (chlorophyllin copper complex). In this work a new analytical method is proposed for the determination of such colorant both in olives and their brine. In particular, the developed methodology is based on the pigment extraction in liquid phase, followed by chromatographic analysis (HPLC). The authors point out that the proposed method is quick and easy (chromatographic analysis requires only 12 minutes), especially in the case of brine. As a matter of fact pigment extraction from an aqueous solution is much easier than extraction from a complex matrix with high lipid content (like that of olives). The analysis is based on the fact that chlorophyll derivatives in the product are different from those in E-141 colorant. This is true also in the case of olives with degradation phenomena. In conclusion, the authors affirm that this method can also be applied to products with less complex matrices than olives.
B. Gandul-Rojas et al., Food Science and Technology, 46, 2012, 311-318