Evaluation of the individual phenolic compounds of regional cultivars of pears (Pyrus communis L.) by Liquid Chromatography combined with High Resolution Mass Spectrometry

Abstract

Pear (Pyrus communis L.) is a fruit of great interest because their consumption offers nutritional as well as medicinal advantages [1]. The most well-known and studied properties associated with pears are antioxidant and anti-inflammatory properties [2] these are associated with the presence of phenolic compounds, mainly in the peels but also, in smaller amounts, in its mesocarp (pulp) [3]. In this work, an Ultra-High Performance Liquid Chromatography combined with Time-of-Flight Mass Spectrometry (UHPLC-ToF-MS) method was optimized and validated for the determination of individual phenolics in the pulp and by-products of fruits. The main phenolic compounds found in the studied regional pear cultivars (6 cultivars from Alcobaça region) were catechin, epicatechin, caffeic acid, chlorogenic acid, and vanillic acid. The pear by-products (peels and seeds) presented higher phenolic content than mesocarp, mainly peels samples. One example of this is the Carapinheira Roxa cultivar, wherein the peels had the highest concentration of chlorogenic acid (26.26 ± 0.65 g/g) and lower levels were found in the seeds (3.11 ± 0.19 g/g) and in the pulp (4.27 ± 0.03 g/g). Other very well recognized pear phenolics, were quantified in all the pear cultivars, at different levels. For example, in the peels portion, the level of epicatechin varied between 0.19 g/g in the Torres Novas cultivar and 37.30 g/g in the Lambe-os-Dedos cultivar. The studied regional pear cultivars, in particular their by-products, presented high levels of phenolic compounds, showing potential to be valorized.