Frozen blueberries improves antioxidant availability

July 20, 2019

BLUBERRIES pack a powerful antioxidant punch, whether eaten fresh or from the freezer.

Anthocyanins, a group of antioxidant compounds, are responsible for the color in blueberries, she explains. Since most of the color is in the skin, freezing the blueberries actually improves the availability of the antioxidants.

“Blueberries go head to head with strawberries and pomegranates in antioxidant capacity,” said professor Basil Dalaly.  In addition, blueberries are second only to strawberries in terms of the fruits.

Blueberries are beneficial for the nervous system and brain, cardiovascular system, eyes and urinary tract.

South Dakota State University graduate Marin Plumb analyzed the content of frozen blueberries and she found that the anthocyanin never decreased on frozen for one, three or even up to five months. She said the anthocyanin in frozen fruit were equally the same fresh berries.

Since blueberries are frozen soon after they are picked, “they are equal in quality to fresh,” Plumb said.

The leaching that occurs from freezing actually increased the anthocyanin concentration. “The ice crystals that form during freezing disrupt the structure of the plant tissue, making the anthocyanins more available.”

Antioxidants, such as anthocyanins, eliminate free radicals, which are produced through common biological reactions within the body and outside factors such as the sun, pesticides and other pollutants, Dalaly explained. If left to roam free, these free radicals can attack DNA, proteins and lipids resulting in cellular changes that lead to development of diseases such as cancer.

“They have a domino effect,” Dalaly said. “That is why we need to consume at least seven to nine servings of fruits and vegetables a day.”

Phytochemicals are the naturally-occurring chemical compounds in fruits and vegetable, many of which have the potential to boost the immune system and impact diseases, such as cancer and heart disease. They said the greener, or redder the fruits or vegetables, the better. (ScienceDaily/South Dakota State University)