Relationship between ripening time and sugar content of apricot (Prunus armeniaca L.) kernels

Apricot seeds could be obtained as a byproduct in different juice or conserve producing industries. Disposal of large amount of apricot seeds is wasting of potentially precious sources of phytochemicals. This study encompassed apricot cultivars that have different origin and flowering time with the aim of providing valuable information about the sugar content in its kernels. High-performance anion-exchange chromatography with pulsed amperometric detection was used for the determination of 22 sugars in the kernels of 70 apricot cultivars. The most common sugars in the apricot kernels are sucrose, fructose, and glucose whose ratio proved to be ripening time dependent (1:1:1 in the early, 1:2:3 in medium and 1:3:3 in the late cultivars). The kernels of the apricot with shorter vegetation period had the highest sum of glucose and fructose compared to other groups. Other sugar components were present in different levels as minor constituents depending on the ripening time. Also, most common sugars and some low-level sugars were strongly correlated to each other, indicating the normal metabolic carbohydrate pathway. To understand the distribution modes of sugars, a principal component analysis was performed.