Validated liquid chromatography separation methods for identification and quantification of anthocyanins in fruit and...

Food composition data are challenged by data availability and quality. Anthocyanins are the bright colored pigments found in fruits and vegetables with growing evidence for health benefits. For the estimation of anthocyanin content in the foods, it is imperative to find an ideal analytical method. To quantify anthocyanin components, liquid chromatography-based methods are commonly used. This review addresses the variability of liquid chromatography (LC) mass spectrometry (MS) methods for the identification and quantification of anthocyanins. Published studies for all years until February 2020 reporting LC methods for anthocyanins in fruits and vegetables were screened from 7660 studies. Only 29 studies met the eligibility criteria of method type and of these, only 13 studies reported a validated LC method. A wide range of validation parameters were identified including specificity, calibration, stability, and limits of detection. Differences in the sampling amounts for extraction were observed in all of the included studies. The quantification of multiple anthocyanin types without their corresponding analytical standards was observed in eight studies. The included 13 studies used reverse phase liquid chromatography separation with C₁₈ type or similar stationary phases and acidified aqueous or acidified aqueous: organic (usually methanol or acetonitrile) binary gradient mobile phases. Although all of the studies used mass spectrometry for identification, ultraviolet absorbance quantification was often used in conjunction with a photo-diode array (DAD/PDA) detector using reference standards where available. Extraction and preparation of samples remains the key concern for analysis as the oxidative stability of anthocyanins are a major impediment for accurate quantification of the components in foods. This review provides a summary of validated LC methods to assist analysts and nutritionists in the quantification of anthocyanin food components as the nutrient profiles of foods are challenged by the variability of the analytical methods.