Freezing Blueberries Improves Antioxidant Availability (2024)

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Freezing Blueberries Improves Antioxidant Availability? ›

Studies conducted at the South Dakota State University show that freezing blueberries makes their powerful antioxidants more available to the human body. This is because anthocyanins, the antioxidant compounds that make blueberries blue, are found in the skin of the berry.

Since most of the color is in the skin, freezing the blueberries actually improves the availability of the antioxidants. The food science major from Rapid City, who received her bachelor's degree in December, did her research as part of an honors program independent study project.

Numerous studies have found that frozen berries contain the same nutritional elements as fresh berries that have just been harvested.

However, cell breakages occurring during freezing and frozen storage can lead to the release of antioxidant compounds and their degradation due to chemical and enzymatic oxidation reactions, and thus, they could present a lower antioxidant activity compared to the corresponding fresh product.

The freeze-drying process is extremely efficient and, therefore, preserves all of the antioxidants and various nutrients of the fresh blueberry. Blueberry powder is also rich in natural fiber and very low in sugar.

Generally, adding a 1/2 to 1 cup of fresh or frozen blueberries to your daily diet is a healthy and reasonable amount. Even 1/3 cup a day has been associated with a reduced disease risk. This amount provides a substantial dose of antioxidants, vitamins and fiber.

While blueberries are generally considered to be a healthy food, they can sometimes cause digestive issues like constipation or diarrhea. If you eat too many blueberries, you may experience stomach pain or cramping. To avoid these issues, eat blueberries in moderation and make sure to drink plenty of water.

Frozen blueberries, on the other hand, are the greatest source of antioxidants due to the frozen structure of the blueberry skin making nutrients more accessible to the human body.

While a cup of fresh or frozen blueberries comes in at 85 calories and 14 grams of sugar, half a cup of the dried version has more than triple the number of calories and nearly double the amount of sugar! Thus, eating frozen blueberries may edge out on eating the dried kind.

More nutrient-dense

Frozen fruits and vegetables are often more nutritious than their fresh counterparts. Produce harvested to be frozen is picked at its ripest time. The nutrients are then frozen in during this process, which preserves the vitamins, minerals and other phytonutrients.

Do frozen blueberries have more antioxidants than fresh blueberries? ›

According to a study from South Dakota State University, we can better access the antioxidants in these fruits more easily when they're frozen. "They are equal in quality to fresh," said Professor Basil Dalaly from the university.

In two out of three cases, frozen fruits and veggies packed higher levels of antioxidants, including polyphenols, anthocyanins, lutein, and beta-carotene. So freezing produce does not destroy its nutrients.

It is observed that the decomposition of the antioxidant starts at around 120 °C. The DSC curve shows an evident endothermic peak at around 60 °C indicating the melting point of the compound, which is volatile in the temperature range of 100-240 °C.

And in case you didn't know, 99% of the Wild Blueberry crop is frozen 24 hours after harvest, locking in taste and nutrition. The South Dakota State University study reveals that freezing blueberries increases their concentration of anthocyanins, a type of antioxidant.

Açaí berries are one of the best sources of antioxidant polyphenols and may contain as much as 10 times more antioxidants than blueberries ( 44 ). When consumed as a juice or pulp, açaí berries can increase blood antioxidant levels and reduce chemicals involved in oxidative stress ( 45 , 46 ).

Another study determined that eating 2.5 ounces (75 grams) of blueberries with a main meal significantly reduced the oxidation of “bad” LDL cholesterol ( 20 ). The antioxidants in blueberries have been shown to reduce a predominant risk factor for heart disease by preventing oxidative damage to “bad” LDL cholesterol.

Because most frozen fruits and veggies are frozen shortly after they're harvested, they're allowed to ripen fully, which means they're chock full of vitamins, minerals, and antioxidants, and freezing "locks in" many of their nutrients, according to the Academy of Nutrition and Dietetics.

Second, despite preserving foods' antioxidant content, the high porosity of freeze-dried products allows easy access to oxygen, which may lead to higher levels of oxidation or degradation of bioactive compounds ( 2 , 7 ).

If the dew point is 26°F or lower and frost forms on flowers or berries, they will be killed. If the dew point temperature is 30°F or higher and frost forms on flowers or berries, they may not be damaged.