Physicochemical, phytochemical, structural, and rheological characterisation and chemometric classification of exudate gums of five Prunus armeniaca varieties

The objective of this study was to determine the physicochemical, phytochemical, rheological, and structural properties of exudates collected from five distinct apricot varieties (Hacıhaliloğlu, Hasanbey, Kabaaşı, Soğancı, Zerdali) to identify their potential as additives and to clarify any differences between the varieties. The pH, solubility, ash and protein contents, emulsion capacity, and stability of the gums were determined to be 4.72–4.86, 84.49–87.58 %, 3.37–3.72 %, 1.28–1.87 %, 68.16–70.90 %, and 69.68–71.78 %, respectively. The monosaccharides detected in all gums were rhamnose (2.45–3.06 %), arabinose (48.25–51.22 %), xylose (6.78–7.45 %), mannose (1.61–9.53 %), glucose (4.13–4.82 %), and galactose (28.70–31.91 %). Protocatechuic acid, 4-hydroxybenzoic acid, catechin, epigallocatechin gallate, procyanidin A2, pinocembrin, quercetin, and kaempferol were determined in all samples. The structural characteristics of the varieties were observed to be largely similar, exhibiting an arabinogalactan-like structure. The solutions of all gums exhibited shear-thinning flow and viscoelastic liquid-like behaviour. According to chemometric classification, Hacıhaliloğlu and Hasanbey were similar in terms of rheological properties and antioxidant capacity; Kabaaşı, Soğancı, and Zerdali varieties were similar in terms of flow behaviour index, and gum arabic was different from all apricot varieties in terms of emulsion properties. Consequently, variations in the functional properties of gum varieties may influence their potential application as additives.