Hass avocado (Persea americana) seed extract as a natural colorant

The global natural colors market is estimated to reach US $ 1.7 billion by 2016. This is due in part to increasing consumer desire for natural food ingredients and the desire of food companies to produce “clean-label” products. We examined the seed of avocados (Persea americana) as a potential source of natural colorants. A polyphenol oxidase-catalyzed (PPO) reaction resulted in the formation of a shelf- and heat-stable colored extract. We hypothesize that the pigments in this extract are novel benzotropolone based compounds. Though the color is stable at room temperature, liquid chromatography-mass spectrometry (LC-MS) indicate that the individual compounds are not. Using LC-MS-based metabolomics analysis and principle component analysis (PCA) of the colored and PPO-inhibited-uncolored extracts, we found approximately thirty-five masses unique to the colored or uncolored extract. Gallic acid, fisetin and flavone were present only in the colored extract while perseitol and caffeic acid were present in both. The most abundant colored fraction showed an ion [M+H]⁺ with m/z 603 in positive mode. Based on the presence of an abundant m/z 441 fragment (Δm/z 162), we hypothesize that this compound is a glycosylated benzotropolone compound. Here, we report the results of our on-going studies to chemically characterize this new orange pigment. We also provide some preliminary studies on its colorant properties in various food products. The results will support a new, value-added use for avocado seeds which are frequently viewed as a low-value waste product.