Nutritionally, preserved fruits and vegetables can be equivalent or superior to fresh, said Diane Barrett, UC Cooperative Extension specialist in the Department of Food Science and Technology at UC Davis.
By the time a stalk of broccoli makes it from the farm to the supermarket to your refrigerator, it has already lost some of its nutritional value. "Fruits and vegetables are frozen within hours of harvest, so that actually allows you to retain those nutrients," Barrett said.
Barrett's analyses show that vitamin C, fiber, potassium and zinc remain intact during the freezing process. Blanching before freezing may make vitamins A and E more digestible.
Mother Jones senior editor Kiera Butler turned to Carl Winter, also a UCCE specialist in the Department of Food Science and Technology at UC Davis, for information about pesticide residue in fresh and processed food.
Processed fruits and vegetables generally have less pesticide residue than fresh conventional produce, Winter said. This is because some fruits and vegetables are washed in a machine that jostles them around to remove dirt and debris before they are processed. Some are also blanched and peeled.