Comparison of the nutritional values of fresh and frozen fruits and vegetables

Researchers compared nutritional values between frozen, fresh and fresh-stored fruits and vegetables.
Prior studies showed that fresh fruits or vegetables are frequently picked before peak ripeness and their nutrient qualities are affected during post-harvest exposure to periods of storage and transportation at temperatures above freezing. Storage, packaging and production techniques were therefore improved over the years. Nevertheless, the degradation continues at the customers’ home, when modified atmosphere packages are opened, for example. Freezing fruits and vegetables could be a solution to this problem, but recent studies show that public opinion still associate freezing with diminishing nutritional qualities.

A team of researchers from the University of Georgia, USA, recently published in the Journal of Food Composition and Analysis a two-year study comparing nutritional values between frozen, fresh and fresh-stored fruits and vegetables, considering the period between purchasing the products and consuming them. The authors assumed that “the nutritional quality of fresh produce specifically after a period of refrigerated storage has not received prior investigation”.
Broccoli, cauliflower, corn, green beans, green peas, spinach, blue berries and strawberries nutritional values were studied, over the span of two years in different times frames, depending on the seasons, for example from summer to fall. The products were purchased in different supermarkets around Athens (Georgia) to account for variables such as growing conditions or time in the supply chain. The nutrients examined were L-ascorbic acid contents (vitamin C), trans-ß-carotene content (provitamin A), and total folate concentration.

There was no significant differences in the levels of these nutrients between fresh, fresh-stored and frozen food right after purchasing. But after five days of refrigerated storage, significant differences were observed: refrigerated storage showed a negative association with nutrient concentration. Frozen produce samples had higher nutrient contents than fresh stored more frequently than the inverse. It suggests that the time a consumer stores their fresh products prior to consumption is an important factor in determining comparative nutritional value. The common belief of consumers that fresh food has significantly greater nutritional value than its frozen counterpart is then refuted.

The study is available on Frozen Food Facts website.