Nutrients in blueberry skin

Blueberry harvest is extensively based on the skin color of fruits, beginning 4 or 5 days after the first berries turn 100% blue to ensure a fruit size and sugar levels accepted by consumers.They can be eaten without peeling or removing seeds, and they are considered to have health-enhancing properties due to high antioxidant levels.

Blueberries are high in vitamins, minerals, micronutrients, fiber and antioxidants. The skin of the blueberry is packed with biologically produced chemicals called anthocyanins. Anthocyanins are natural pigments that run the range from dark red, to blue, to indigo, and deep violet depending on the acidity level of the pigment itself.

Study shows that skin extracts have significantly higher TAA (Total antioxidant activity) than those detected for whole fruit and pulp. Thus, in ripe fruits TAA values in skin were around 7 and 192 times higher than in whole fruit and pulp, respectively (J. Soil Sci. Plant Nutr. v.10 n.4).

The skin of both high-bush and low-bush blueberries contains the highest amount of phenolic compounds. The total phenolic content of blueberries ranges from 21.7 to 47.4 mg/g of dry matter.

Blueberries contain a plant compound called anthocyanin. More than 15 different anthocyanins have been detected in blueberries, with malvidin and delphinidin being the predominant compounds.

These anthocyanins seem to be concentrated in the skin of the fruit. Therefore, the outer layer of the berry is the most nutritious part. The anthocyanins that are present in blueberries have shown cardioprotective, neuroprotective, antidiabetic, and vision-improving properties.
Nutrients in blueberry skin

Antioxidant in blueberry peel

Blueberry, like most berries, is rich in flavonoids, tannins and phenolic acids. Anthocyanins are confined principally to the blueberry peel in the epidermal and subepidermal cell layers.

High levels of anthocyanidins are found mostly in the water-soluble purple pigment of the peel. 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 peel extracts have been shown to alleviate insulin resistance, reduce obesity and dyslipidemia.

Additionally, these antioxidant molecules are able to prevent the deleterious effects of oxidation, inhibiting the onset of lipid peroxidation, sequestering free radicals and protecting aerobic organisms from oxidative stress, which is defined as an increase in the formation of reactive oxygen species.

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 peel contribute to the antioxidant properties of blueberry, likely due to the higher anthocyanin content.
Antioxidant in blueberry peel