Metabolic profiling of red raspberry (Rubus idaeus) during fruit development and ripening.

Red raspberry (Rubus idaeus) fruit quality at different harvest stages is a function of the fruit’s metabolite content, which results from physiological changes during fruit growth and ripening. In order to investigate raspberry fruit development, targeted GC-MS metabolic profiling analysis was conducted. Principal component analysis (PCA) was employed to explore the polar metabolite profiles and represent a strong separation between fruit samples at four developmental stages. Each stage of fruit development had a characteristic metabolic profile. Significant changes in metabolite levels were found in fruits turning red in comparison with fruits over-ripening. The levels of free amino acids decreased gradually before the red ripening stage, but increased in the over-ripening stage. In addition, fruit development is characterized by rapidly increasing sugar levels and decreasing organic acids.