Blueberry fruits rank high in antioxidant activity among fresh fruits and vegetables. Blueberries belong to the genus Vaccinium species, and are characterized as a small fruit-shaped berry, blue-black in color, originating from the northern Europe and North America.
Blueberry, like most berries, is rich in flavonoids, tannins and phenolic acids. Anthocyanins are confined principally to the blueberry skin in the epidermal and subepidermal cell layers.
High levels of anthocyanidin compounds are found mostly located in the water-soluble purple pigment of the skin. Anthocyanins are present in the blueberry in the glycosylated form of aciloglicosilada and anthocyanidins, and present with a sugar residue attached mostly at the 3-position on the ring, or less often, to the position of 5 or 7.
These molecules promote collagen synthesis, this being one of the main structural components of dermal connective tissue, providing benefits to the skin and also supporting the vascular system. Blueberries are also reported to have beneficial effects on vision.
The protective effects of blueberry fruit juice or skin extracts have been shown to alleviate insulin resistance, reduce obesity and dyslipidemia. Antioxidants provide protection against oxidative stress, a condition that has been suggested to contribute to a wide variety of diseases, including atherosclerosis, Parkinson’s disease, and cancer. Oxidative stress occurs when reactive oxygen species (ROS) and reactive nitrogen species (RNS) increase to levels that propagate oxidative injury to DNA, lipids and proteins.
The juice extraction residue (pomace) contains approximately 52% of the antioxidant activity of the fruit (on a dry basis), showing that the compounds present in the skin contribute to the antioxidant properties of blueberry, likely due to the higher anthocyanin content.
Factors that may impact fruit antioxidant activity and composition include preharvest environmental conditions, postharvest conditions and processing.
Blueberry skin rich antioxidants
