Anthocyanins, chlorophylls and xanthophylls in pistachio nuts (Pistacia vera) of different geographic origin

The pistachio seed is particularly appreciated for its flavour and emerald-green colour. The aim of this paper was to study simultaneously the major coloured compounds in pistachio nuts collected from different geographic origins. Qualitative and quantitative analyses of pigments in commercial samples of pistachio nuts (coming from Greece, Iran, Italy and Turkey) were performed by HPLC. The results highlighted the presence of both of cyanidine-3-galactoside and cyanidine-3-glucoside, in the external skin of kernels, chlorophyll a, chlorophyll b and lutein in the inner hull. The degree of ripeness and the origin of the products influenced pigment concentration as well as colour parameters. Cyanidine-3-galactoside was absent or present in very low levels (21 mg/kg) in unripe products, with about 300–400 mg/kg in ripe samples. Chlorophylls (sum of a+b) were about 150 mg/kg in pistachios sold as “green” products, with a chlorophyll a/b ratio of about 3. The lowest chlorophyll value (25 mg/kg) was found in a ripe Turkish product. Lutein was the main carotenoid found in pistachio kernels, ranging from 18 to 52 mg/kg. The ripe Italian samples always had the highest pigments concentration.