Pomological and Biochemical Changes Observed at Different Sampling Times in Arbutus andrachne L. Fruit Development

Arbutus andrachne L. (Greek strawberry tree) is an underutilized fruit tree species widely distributed in coastal regions of Türkiye and it is mainly used for small-scale fruit production. Because its fruits require an extended period to reach full ripeness, understanding the physiological and biochemical changes occurring during fruit development is of considerable importance. Fruit samples were collected from July to December 2022, representing the progression from green to red fruits at six sampling times (ST I-VI). Fruit width (8.78 mm), length (7.56 mm) and weight (0.38 g) increased significantly throughout development, reaching their highest values of 11.05 mm, 11.04 mm and 0.82 g at ripeness, respecitely. Total phenolics (21.06 mg GAE g-1 FW) and flavonoid (14.79 mg catechin g-1 FW) and CUPRAC (314.99 µmol Trolox g-1 FW) and DPPH (88.29 µmol Trolox g-1 FW) values peaked at ST IV to reach their maximums, followed by significant declines during ST V and ST VI. In contrast, soluble sugars content increased continually from ST I (2.68 mg g-1 FW) to VI (31.25 mg g-1 FW), whereas reducing sugars accumulated most markedly at ST VI (17.95 mg g-1 FW). Protein content was lowest at ST I (3.39 mg g-1) and was highest at ST V (6.18 mg g-1). Correlation analysis revealed 19 significantly positive correlations between pomological and biochemical parameters. The results demonstrate that distinct metabolic processes take place at different stages of fruit development, with ST IV characterized by maximum antioxidant capacity and phenolics accumulation, and ST VI associated with sugar accumulation. These results indicate that A. andrachne fruits undergo physical biochemical changes during growth and ripening.