Identification of Phenolic and Carotenoid Compounds in Coffee (Coffea Arabica) Pulp, Peels and Mucilage by HPLC Electrospray Ionization Mass Spectrometry

Abstract

Coffee pulp, peels, and mucilage are by-products accruing from wet coffee processing. Like coffee seeds, the se fruit tissues contain substantial amounts of polyphenols and other bioactives. In the present study, polyphenols and carotenoids were identified separately in different tissues (pulp and peels) of coffee cherries from five coffee varieties planted in Costa Rica, and in the mucilage obtain ed after commercial coffee cherry depulping. Peels and pulp of each fruit were manually separated and pooled. After extraction, polyphenols and carotenoids were characterized by high-performance liquid chromatography (HPLC) coupled to mass spectrometry. Most polyphenols detected were chlorogenic acids (CGAs), such as isomeric caffeoylquinic acid (CQA), feruloylquinic acids (FQA), and p-coumaroylquinic acids. Differences in the concentration of several phenolics were found among coffee varieties and by-products (pulp and peels). Other phenolic compounds, such as epicatechin and proanthocyanidin B, were also detected. Besides typical accessory carotenoids of chloroplasts, like violaxanthin, neoxanthin, lutein, β-carotene, α-carotene and various lutein esters were also identified.