Reversed-Phase HPLC following Thiolysis for Quantitative Estimation and Characterization of the Four Main Classes of Phenolic Compounds in Different Tissue Zones of a French Cider Apple Variety (Malus domestica Var. Kermerrien)

Abstract

Phenolic compounds, which are present in the epidermis zone, parenchyma zone, core zone, and seeds of fruit (Malus domestica var. Kermerrien), were extracted from freeze-dried material by three successive solvent extractions. The dry methanol extract and the dry aqueous acetone extracts were analyzed using reversed-phase HPLC coupled with diode array detection following thiolysis to quantify phenolic compounds according to their classes (hydroxycinnamic acid derivatives, flavan-3-ols, flavonols, and dihydrochalcones). The method is suitable for the determination of the relative proportions of the different classes of polyphenols and provided information on the constitutive units and the average degree of polymerization of oligomeric and polymeric procyanidin structures. Results showed that procyanidins are the predominant phenolic constituents in cider apple fruits, much of them corresponding to highly polymerized structures. Keywords: Apple; phenolics; procyanidins; cider; HPLC; thiolysis

Oligomeric Cocoa Procyanidins Possess Enhanced Bioactivity Compared to Monomeric and Polymeric Cocoa Procyanidins for Preventing the Development of Obesity, Insulin Resistance, and Impaired Glucose Tolerance during High-Fat Feeding

“…Thiolysis (see schematic, Figure 2.4) was employed to determine the average polymer chain length (mDP) that comprised each cocoa fraction. Thiolysis was carried out based on the method described by Guyot et al 109 and Gu et al 40 with modifications.…”

Combined Drying of Apple Cubes by Using of Heat Pump, Vacuum-Microwave, and Intermittent Techniques

“…This is because of the native procyanidins of apple, which could inhibit polyphenol oxidase (PPO) activity; however, initial drying was conducted at low drying temperature. Procyanidins were the most abundant polyphenol in apple followed by hydroxycinnamic acids, dihydrochalcones, flavonols, anthocyanins, and flavan-3-ols (Heras-Ramírez et al 2012;Oleszek et al 1988;Guyot et al 1998;Sanoner et al 1999;Tsao et al 2003;Alonso-Salces et al 2004). The inhibitory effect of oxidized procyanidins was twice that of native procyanidins of apple (Le Bourvellec et al 2004).…”

Liquid chromatographic method for quantifying polyphenols in ciders by direct injection

“…It should be noted that sample preparation is the time determining step of whole analytical procedure, which represents 2/3 of the total analysis time, and it is the primary source of error differences in the results obtained by different laboratories [14]. Polyphenols are compounds very reactive and substantial changes in sample composition may occur due to: isomerizations under exposure to UV radiation or daylight, the oxidative transformation and hydrolysis phenomena as result of the extraction procedure [15][16][17][18][19]. Therefore, a direct injection of the sample could be considered as an alternative to simplify the analysis of phenolic compounds, and to prevent many errors and any polyphenols degradation during the sample handling [19][20][21][22].…”