4 ways to preserve fruits and vegetables

In this brief guide, we are going to answer the question “4 ways to preserve fruits and vegetables” and discuss 4 ways to preserve fruits and vegetables along with the advantages and disadvantages of each method.

4 ways to preserve fruits and vegetables

Fruits and vegetables are important for the prevention and management of chronic diseases, yet US national data show that in 2013, fewer than 18% of adults consumed the recommended amount of fruits and fewer than 14% consumed the recommended amount of vegetables (1).

4 commonly used methods to preserve fruits and vegetables are:

  1. Freezing
  2. Dehydrating
  3. Pickling
  4. Canning

The method of preservation depends on the fruits or vegetables to be preserved. 

Methods such as dehydrating and pickling have been done for ages while freezing and canning are modern preservation methods.

All fruits and vegetables can be preserved for up to some extent using one or more of the above methods.

Preserving fruits and vegetables by freezing

Freezing is the most widely used method to preserve fruits and vegetables since it can be done easily at home by anyone. 

Freezing food reduces the enzyme activity in food that causes spoilage. Freezing also crystallizes the water in the food so microorganisms cannot use it for growth.

Fruits and vegetables are perishable foods with extremely rapid deterioration; this means that their stability after harvesting and during sub-sequent storage is critical.Preservation of foods usually involves technologies that prevent microbial growth as well as retard quality degradation reactions. Among such processes, freezing is a proven and efficient method (2).

Freezing itself does not significantly reduce the nutrient content of food. However blanching before freezing and defrosting will cause the loss of some nutrients, mainly water-soluble nutrients such as vitamin C.

Most fruits and vegetables can be frozen either raw or after being blanched. Some endogenous enzymes are responsible for undesirable changes, such as off-flavors and odors, and color and nutritive alterations, during frozen storage. These deteriorative enzymes may have to be inactivated by applying particular treatments before the freezing step. Therefore, blanching is the most important pre-freezing treatment for vegetable tissues stabilization (2).

Fruits and vegetables that must not be frozen include:

  • Raw potatoes
  • Onions
  • Garlic
  • Cucumbers
  • Celery
  • Pepper

Preserving fruits and vegetables by dehydrating

Dehydrating is one of the oldest methods of food preservation. Dehydrating works by removing the water from food, thereby reducing the growth of microbes that cause spoilage. Dehydrated food has a long shelf-life. Most dried fruits can be stored for 1 year at 60 ºF, 6 months at 80 ºF. Vegetables have about half the shelf-life of fruits (4). and can be stored for up to 5 years under the proper conditions.

Except for freeze drying, applying heat during drying through conduction, convection and radiation are the basic techniques used to force water to evaporate, while forced air is applied to encourage the removal of vapor (3).

For dehydration, the moisture can be removed by several methods such as sun-drying, heating at a low temperature setting in an oven or using a food dehydrator.

Some commonly dehydrated fruits and vegetables include:

  • Bananas
  • Apples
  • Sweet potatoes
  • Zucchini
  • Mangoes

Preserving fruits and vegetables by pickling

Pickling is a method of preserving food by immersing in a solution of acidic brine or vinegar. Pickling adds a distinct flavor to food and pickles are used as side dishes and garnish in many cuisines.

Properly produced pickles can be stored for about a year. However, they must be refrigerated after being opened.

Some commonly pickled fruits and vegetables include:

  • Limes
  • Cucumbers
  • Kamias
  • Mangoes
  • Radishes

Preserving fruits and vegetables by canning

Canning preserves food by killing the microorganisms that cause spoilage. Canning can be done at home using the correct equipment and proper sterilization of jars but it is time-consuming and needs practice.

Pickled fruits and vegetables are made by immersing raw materials in brine containing vinegar (acetic acid) and salt, and then heat treated. Spices and sugar are used as additional ingredients to improve flavor. Therefore, salt, acetic acid, and heat are considered as major factors for increasing the microbial safety of pickled products. However, sometimes other preservatives (such as benzoate and sorbate) are also added to enhance microbial safety (5).

Canned foods are shelf-stable for years and do not need refrigeration until they are opened. However, the heating process during canning reduces the nutrient content of food.

Some commonly canned fruits and vegetables include:

  • Beans
  • Tomatoes
  • Pineapple
  • Mushroom
  • Corn

Advantages and disadvantages of preservation methods

  1. Freezing 

Advantages

  • Freezing is the fastest preservation method and mostly requires no preparation time except when the food has to be blanched or cooked before freezing. 
  • Freezing also does not require added preservatives.

Disadvantages 

  • Freezing changes the texture and flavor of certain fruits and vegetables.
  1. Dehydrating 

Advantages

  • Dehydration requires little to no preparation time.
  • Dehydrating food retains the nutrients and there are no added preservatives.  
  • Most dehydrated food can be easily eaten as a snack without further preparation.

Disadvantages

  • Time: The main disadvantage of dehydration is the long time taken for the dehydration process. The process of dehydrating may take from a few hours up to a day depending on the method used. The fastest and most reliable method is to use a food dehydrator. 
  • Change in texture and appearance of food: dehydrating fruits will significantly alter their texture and flavor. 

Pickling:

Advantages

  • Imparting a new flavor: most pickled fruits and vegetables have a distinct flavor that is more appealing.
  • Pickled fruits and vegetables are a good source of nutrients.

Disadvantages 

  • Since the flavor of the fruits and vegetables permanently changes, they cannot be substituted for fresh ones in a recipe.
  • The high content of salt may increase blood pressure, so pickles must be eaten in moderate amounts.

Canning:

Advantages

  • Long preservation time.
  • Fruits and vegetables that cannot be preserved by other methods can be canned.

Disadvantages

  • Loss of taste: fresh fruits and vegetables always taste better than their canned counterparts.
  • Loss of nutrients: canning also reduces the vitamin and mineral content of fruits and vegetables by 65%
  • Technical difficulties: canning is a time-consuming process and the right knowledge and equipment are needed for the best results.

Other FAQs about Vegetables that you may be interested in.

How to preserve vegetables without a fridge

Conclusion

In this brief guide, we answered the question “4 ways to preserve fruits and vegetables”. We discussed 4 ways to preserve fruits and vegetables and looked at the advantages and disadvantages of each method.

If you have any questions or comments, please let us know.

References

  1. Hsiao, Bi-sek, et al. Mobile produce market influences access to fruits and vegetables in an urban environment. Public Health Nutr, 2018, 21, 1332-1344.
  2. Silva, Cristina LM, Elsa M. Gonçalves, and Teresa RS Brandao. Freezing of fruits and vegetables. Frozen food sci technol, 2008, 165.
  3. Sagar, V. R., and P. Suresh Kumar. Recent advances in drying and dehydration of fruits and vegetables: a review. J food sci technol, 2010, 47, 15-26.
  4. Andress, E. Drying Packaging and Storing Dried Foods. University of Georgia.
  5. Lee, Sun-Young, and D. H. Kang. Microbial safety of pickled fruits and vegetables and hurdle technology. Int J food safe, 2004, 4, 21-32.