6 ways to preserve fruit

In this brief guide, we are going to answer the question “6 ways to preserve fruit” and discuss 6 ways to preserve fruits along with the benefits and implications of each method.

6 ways to preserve fruit

e global production of fresh vegetables and fruits has increased by 30% over the last few years. It has increased from 30 million tons to 60 million metric tons (1).

6 common ways to preserve fruits are (2,3):

  1. Freezing
  2. Dehydrating
  3. Pickling
  4. Canning
  5. Making jams, marmalades, preserves and conserves
  6. Salting
  7. Making fruit leather

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

Preserving fruit by freezing

Freezing is the most widely used method to preserve fruits since it can be done easily at home by anyone and all fruits can be preserved by freezing. Freezing slows down the physicochemical and biochemical reactions by forming ice from water below freezing temperature and thus inhibits the growth of deteriorative and pathogenic microorganisms in foods (2).

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.

A disadvantage of freezing is that it alters the texture of the fruits. During freezing, the water within the cells expands and damages the cell walls. This makes the fruits mushy when defrosted. Freezing related to liquid, pulpy or semi-liquid products, like fruit juices, mango pulps, and papaya pulps is known as quick freezing. The ice crystals formed by quick freezing are much smaller and therefore cause less damage to cell structure or texture of the food (2).

Freezing itself does not significantly reduce the nutrient content of food (4). 

Preserving fruit 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 and can be stored for up to 5 years under the proper conditions.

Drying or dehydration is the process of removing water from a solid or liquid food by means of evaporation. The purpose of drying is to obtain a solid product with sufficiently low water content. Water is the prerequisite for the microorganisms and enzymes to activate food spoilage mechanisms. In this method, the moisture content is lowered to the point where the activities of these microorganisms are inhibited (2).

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 include:

  • Bananas
  • Apples
  • Mangoes
  • Pineapple
  • Watermelon

Preserving fruit by pickling

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

By pickling, fruits are preserved in vinegar, which is considered a type of preservation through fermentation. Vinegar fermentation takes place after alcohol fermentation. Acetobacter converts alcohol to acetic acid in the presence of excess oxygen. Vinegar fermentation results in acetic acid and water by oxidation of alcohol (2).

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

Some commonly pickled fruits include:

  • Olives
  • Mangoes
  • Apples
  • Peaches

Preserving fruit 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.

Thermal sterilization is a heat treatment process that completely destroys all the viable microorganisms (yeasts, molds, vegetative bacteria, and spore formers) resulting in a longer period of shelf life. Retorting and aseptic processing are two categories of thermal sterilization (2).

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 include:

  • Pineapple
  • Mangoes
  • Pears
  • Cherries

Preserving fruit by making jams, marmalades, preserves and conserves

Jams, marmalades, preserves and conserves are all made by the addition of sugar to fruits. Sugar acts as a preservative in all these products. Jams, marmalades, preserves and conserves can all be home-made and have a shelf-life of about a year. Sugar draw the water out of microorganisms and retard the growth of microorganisms (2).

The difference in the type of fruits, ingredients and consistency differentiates between these products. Acid must be present to form gel in marmalades and thickening in jams, preserves and conserves (5). 

Jams: Jams have a thick consistency and they are made from ground or crushed fruits.

Marmalades: Marmalades are usually made using citrus fruits. Pulp, as well as the peel of citrus fruits, are used in making marmalade.

Preserves: Preserves are made by immersing fruits pieces or whole fruits in thick sugar syrup.

Conserves: Conserves are similar to jams and they are made of a mixture of fruits.

Preserving fruits by salting

Salt is used in food preservation as it draws out water from the fruit. High salt concentration also kills microbes that cause spoilage. Since salt absorbs much of the water in food, it makes it difficult for microorganisms to survive (3).

Salting is best used to preserve sour citrus fruits such as oranges and tangerines. Raw mangoes can also be preserved by salting.

Salting preserves fruits for about 1 to 2 years at room temperature.

A disadvantage of salting is that the high salt content makes the fruit unsuitable to eat right out of the jar. Salted fruits are usually used in cooking, baking and as salad dressings.

Preserving fruits by making fruit leather

Fruit leather is a fruit roll made by drying or baking pureed fruit. Fruit leather can be made from one fruit or a combination of fruits. Fruits commonly made into fruit leather include strawberries, apricots, bananas, peaches, pineapples and dates.  Fruit leather is a sheet or flexible strip of dried fruit that is made typically by hot air drying of fruit puree or fruit juice concentrate, with or without the addition of other ingredients (6).

Making fruit leather is an easy way to preserve a selected combination of fruits and fruits leather makes a healthy and tasty snack. The final water activity must ensure product preservation from the reduction of both the microorganisms’ growth and the chemical reaction rates (6).

Fruit leather will preserve for about 1 month at room temperature and about 1 year when frozen.

Some recipes for fruit leather can be found here.

Conclusion 

In this brief guide, we answered the question “6 ways to preserve fruit”. We discussed 6 methods of fruit preservation and looked at the benefits and implications of each method.

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

References

  1. Balali, Gadafi Iddrisu, et al. Microbial contamination, an increasing threat to the consumption of fresh fruits and vegetables in today’s world. Int J Microbiol, 2020.
  2. Amit, S.K., Uddin, M.M., Rahman, R. et al. A review on mechanisms and commercial aspects of food preservation and processing. Agric & Food Secur 6, 51 (2017). 
  3. James, Ife Fitz. AD03E Preservation of fruit and vegetables. No. 3. Agromisa Foundation, 2003.
  4. Tosun, Berat Nursal, and Sevinç Yücecan. Influence of commercial freezing and storage on vitamin C content of some vegetables. Int j food sci technol, 2008, 43, 316-321.
  5. Schafer, W. Making jams, marmalades, preserves and conserves. 2021. University of Minnesota.
  6. da Silva Simão, R., de Moraes, J.O., Carciofi, B.A.M. et al. Recent Advances in the Production of Fruit Leathers. Food Eng Rev, 2020, 12, 68–82.