Diversity in phenolic compounds, biochemical and pomological characteristics of Arbutus unedo fruits

Strawberry trees (Arbutus unedo L.) are naturally grown in particular Black Sea and Mediterranean regions of Turkey with great diversity due to continuous seed propagation for centuries. The trees differ in terms of most of the horticultural characteristics. We investigated the phenolic compounds and the biochemical and pomological characteristics of the fruits of eight strawberry tree selections naturally grown in the western part of Turkey. Significant differences were found among the genotypes in terms of their phenolic compounds and their biochemical and pomological characteristics. Among soluble sugars, fructose (11.63 g 100 g⁻¹) was the dominant sugar, followed by glucose (6.10 g 100 g⁻¹) and sucrose (1.44 g 100 g⁻¹) for all the genotypes. Positive correlation was found between fruit weight and soluble sugar content. Malic acid was the major organic acid (0.67-2.33 g 100 g⁻¹), and the second major organic acid in strawberry tree fruits was citric acid (0.25-0.87 g 100 g⁻¹). Vitamin C content was an average of 56.22 g 100 g⁻¹ for the eight genotypes. Among phenolic compounds, gallic acid was dominant (1.62-7.29 mg 100 g⁻¹), followed by chlorogenic acid (1.23-3.14 mg 100 g⁻¹), on an average basis.