Without a doubt, a diet rich in plant-based foods, particularly fruits and vegetables, forms the cornerstone of any healthy eating pattern. Fruits and vegetables are packed with essential vitamins, minerals, and fiber, making them the ultimate low-energy, nutrient-dense foods. However, fruits and veggies can be finicky. Many of the most scrumptious plants reach their peak ripeness only once a year, and for a limited time window. Also, once these fruits and vegetables are picked, they often don't last long, expiring quickly in supermarkets or in our kitchens. To overcome these challenges, various storage methods of produce were developed to extend their shelf life and preserve their freshness. Naturally, we wonder how the way we store these fruits and vegetables—whether we toss them in the fridge or freezer—affects their nutritional value. In the following post, we explore the different ways food storage can potentially impact the nutritional content of these valuable dietary components and how (perhaps if) this has any significant impact for us!
Fresh Fruits and Vegetables
We are all familiar with fresh fruits and vegetables. They’re often the first food to greet us when we walk into any grocery store; their vibrant colors and inviting textures make them the epitome of nutrition. Fresh fruits and vegetables are typically harvested either at peak ripeness or just before for those that ripen off the vine and develop their tastiest flavors after a few days. At this stage, produce is at peak nutrient density. Packed with flavor, ripe produce proudly touts their vitamin, mineral, fiber, and water content with their lurid hues and mouth-watering texture. However, it is important to consider that many fruits and vegetables found in grocery stores undergo significant transportation from the farm to the store which can invariably lead to certain chemical changes. Additionally, any physical processing, packaging, and treatments can further modulate not only the nutritional value but also the flavor and texturet. Since fruits and vegetables contain a high percentage of water (ranging from approximately 70% to 90%), transportation can trigger respiration, moisture loss, and nutrient degradation (Barrett, n.d.). It's worth noting that different types of fruits and vegetables exhibit varying levels of nutrient degradation; for example, strawberries tend to spoil faster than sweet potatoes. Moreover, certain minerals and vitamins (like water-soluble vitamins) are highly sensitive to post-harvest losses, such as vitamin C and the B vitamins (Food and Agriculture Organization of the United Nations, n.d.). When purchasing fresh produce, your best bet is to purchase from a reputable seller who is directly responsible for growing, harvesting, and transportation. As always, your local farmers market is a great place to start!
Refrigerated Fruits and Vegetables
Refrigerators serve a crucial role in slowing down microbial spoilage and prolonging the shelf life of numerous food products. When we place fruits and vegetables in the refrigerator or freezer, we effectively reduce the time that produce spends in the "temperature danger zone" where bacteria thrive; this significantly reduces water loss and mitigates microbial spoilage. Several studies have examined the impact of refrigeration on the nutritional composition of fruits and vegetables, revealing that this effect varies depending on the specific produce (Galani et al., 2017). For instance, refrigerating carrots can actually increase their beta-carotene content, while in the case of green beans, it can lead to a 10% decrease in beta-carotene levels (Barrett, n.d., 2017). These findings highlight the importance of understanding how refrigeration can simultaneously enhance and diminish certain nutritive compounds in each individual fruit or vegetable. Our overall takeaway: Refrigeration is a great option to extend shelf life, preserve freshness, and any losses in nutrient content are (generally) negligible!
Frozen Fruits and Vegetables
Frozen fruits and vegetables are typically harvested at their peak ripeness and then undergo a blanching process, which involves briefly boiling to minimize nutrient loss. Similar to refrigeration, freezing fruits and vegetables significantly extends their shelf life, while also preserving their original flavors. The convenience of frozen produce cannot be overstated, as it is often pre-processed (peeled, sliced, and ready to cook) and can be a lifesaver in a time crunch. As a bonus, frozen produce is often cheaper too! Moreover, purchasing frozen fruits and vegetables in bulk, storing them, and resealing as needed can contribute to reducing food waste. However, freezing produce can alter the nutritional content. Water-soluble vitamins, like vitamin C and B may leach during the initial blanching process. Additionally, storing produce in the freezer for too long may cause freezer burn during which cell walls rupture. This cellular lysing ultimately leads to unappetizing changes in texture, color, and flavor. However, when stored properly, frozen produce is a wonderfully cost-effective way to consume fruits and veggies year round. Interestingly, new research is showing that while freezing produce may result in some nutrient loss, it also may boost some nutritive compounds!
Comparing Fresh vs. Refrigerated vs. Frozen Fruits and Vegetables
In a comprehensive 2-year-long study, researchers investigated the nutrient levels in fresh, frozen, and "fresh-stored" fruits and vegetables (Li et al., 2017). The team analyzed the impact of different storage methods on the levels of folate, trans-β-carotene (a form of vitamin A), and L-ascorbic acid (vitamin C) in broccoli, cauliflower, corn, green beans, green peas, spinach, blueberries, and strawberries. Surprisingly, the study revealed that for the most part, the different storage methods had no significant differences in nutrient levels. While each fruit or vegetable responded uniquely to the different storage methods, the authors concluded that these differences were marginal (Li et al., 2017). Similarly, another study compared the levels of ascorbic acid, riboflavin, α-tocopherol, and β-carotene in corn, carrots, broccoli, spinach, peas, green beans, strawberries, and blueberries when refrigerated versus frozen. This study yielded similar findings, indicating that frozen foods often had comparable, and occasionally higher, vitamin content than fresh produce for the majority of vitamins analyzed (Bouzari et al., 2015). Granted, these studies explored both different fruits and veggies and vitamins but the greater conclusion remains: everything can impact the nutritional value of produce. And this begs the question: for the average consumer, does it really matter?
The Big Takeaway
Certainly, these studies highlight storage methods that directly influence vitamin and mineral content. Almost everything we do with food can affect nutrient levels, cooking itself can both amplify and reduce vitamin quality. This leaves us at an impasse where, regardless of how we consume or cook, some nutrient loss is inevitable. But we’d argue that, for most of us without nutrient deficiencies, the importance of maximizing nutrient content through storage (or cooking) becomes secondary to consuming a diverse array of fruits and vegetables. Our focus should shift away from fixating on whether fresh or frozen or refrigerated “is better” and instead promote flexibility both in the grocery store and the kitchen. We must encourage the consumption of fresh, frozen, and refrigerated fruits and vegetables. By incorporating a range of produce into our diet, regardless if frozen, fresh, boiled, steamed, grilled, baked, or even raw, we can ensure a well-rounded nutrient intake.
A Note from the Authors:
When we speak of food storage in the above article, we are referring to how produce is purchased from the grocery store or stored at home (fresh, from the refrigerated section or placed into the refrigerator, or frozen). Proper produce storage at home is absolutely essential to maximize shelf life and flavor. As such, we’ve included the below for a few helpful tips on produce storage!
A Note on Fresh Fruits and Vegetables
Proper fruit storage of fresh fruit and vegetables is absolutely essential to maximize shelf life, retain flavor, and minimize food waste! See below for a few helpful websites and tips:
- https://www.seattle.gov/util/cs/groups/public/@spu/@conservation/documents/webcontent/1_037049.pdf
- https://www.almanac.com/how-store-vegetables-and-fruit-keep-it-fresh
- https://extension.purdue.edu/foodlink/includes/pubs/Storing%20Fruits%20and%20Veggies.pdf
References
Barrett, D. M. (n.d.). Maximizing the nutritional value of fruits and vegetables - UC Davis. https://fruitandvegetable.ucdavis.edu/files/197179.pdf
Bouzari, A., Holstege, D., & Barrett, D. M. (2015). Vitamin retention in eight fruits and vegetables: a comparison of refrigerated and frozen storage. Journal of agricultural and food chemistry, 63(3), 957–962. https://doi.org/10.1021/jf5058793
Food and Agriculture Organization of the United Nations. (n.d.). Processing, Preservation and Storage . IMPROVING NUTRITION THROUGH HOME GARDENING. https://www.fao.org/3/X3996E/x3996e42.htm
Galani, J. H. Y., Patel, J. S., Patel, N. J., & Talati, J. G. (2017). Storage of Fruits and Vegetables in Refrigerator Increases their Phenolic Acids but Decreases the Total Phenolics, Anthocyanins and Vitamin C with Subsequent Loss of their Antioxidant Capacity. Antioxidants (Basel, Switzerland), 6(3), 59. https://doi.org/10.3390/antiox6030059
Li, L., Pegg, R. B., Eitenmiller, R. R., Chun, J.-Y., & Kerrihard, A. L. (2017). Selected nutrient analyses of fresh, fresh-stored, and frozen fruits and vegetables. Journal of Food Composition and Analysis, 59, 8–17. https://doi.org/10.1016/j.jfca.2017.02.002
— Oliver Gonzalez-Yoakum and Latifa Alshaikh
Published Wednesday, Jun 28, 2023
