Chemical profiling of seed, pulp and skin of argentinean tree tomato (Solanum Betaceum)

Abstract

Introduction: The tree tomato (Solanum betaceum), commonly known as “chilto”, is a native food plant from the tropical Andes, cultivated in the Yungas of northern Argentina. The ripe fruits are consumed fresh in salads and juices, or processed as jams and liquors. In the industrial processes, only the pulp is considered edible, while the skin and seeds are discarded. The aim of this study was to characterize the polyphenolic composition of the fruit pulp, skin and seeds, in order to generate a profile of the nutraceutical components of this food resource. Materials and Methods: The ripe fruits of S. betaceum (orange-yellow cultivar) were collected in Parque Sierra de San Javier, Universidad Nacional de Tucuman, Argentina, between February-March of 2014-2015. The fruits were washed and skin, pulp and seeds were separated. Each fraction was lyophilized, grinded and then extracted three times with 95% ethanol in an ultrasonic bath. The extracts were centrifuged and combined to obtain a phenolic enriched extract (PEE). The PEE was analyzed by HPLC-DAD-ESI-MS/MS to obtain the profile of phenolic compounds. The main phenolics were quantified using external calibration curves prepared with pure standards. Results and Discussion: The HPLC-DAD-ESI-MS/MS analysis of the PEEs allowed the tentative identification of 12 caffeic acid derivatives and related phenolics, 10 rosmarinic acid derivatives and 7 flavonoids. The main compounds were 3-caffeoylquinic acid and rosmarinic acid in pulp, skin and seeds. The content of 3-caffeoylquinic acid (mg/100g extract) was 1724.1 ± 80.7, 1324.8 ± 49.6 and 1663.4 ± 4.5 for the skin, pulp and seed extracts, respectively. The content of rosmarinic acid (as mg/100g extract) was 871.8 ± 3.5, 497.8 ± 6.8 and 345.1 ± 10.6 for skin, pulp and seed extracts, respectively [1]. The main compounds identified and quantified were in agreement with samples of S. betaceum collected in Ecuador [2].