How to preserve zucchini

In this brief guide, we are going to answer the question “How to preserve zucchini?”, and discuss the different methods used to preserve zucchini.

How to preserve zucchini

Postharvest losses in vegetable value chains are typically large, estimated in many developing countries to be in the range of 30–50% of farm production volumes (1). To avoid such losses, it is necessary to properly preserve the vegetables.

Zucchini is preserved by :

• Refrigerating: Refrigerating preserves zucchini for up to 5 days (4)two weeks.
• Blanching and freezing: Blanching and freezing preserves zucchini for up to three months. However, if these vegetables are blanched before freezing they have a storage life of 18–24 months (6).
• Dehydrating: Dehydration preserves zucchini for at least a year (7).
• Fermenting: Fermentation preserves zucchini for four to 12 months in a refrigerator, given that there is 1 % – 2 % salt by volume of the fermented product (3).

How to preserve zucchini by refrigeration

The whole zucchini can be stored in the refrigerator for up to 5 days (4)two weeks.  Cold storage of zucchini for a minimum of 2–3 days at 4°C induces the appearance of pitting in the fruit surface, and accelerates fruit dehydration and softening. The fruit of most current commercial cultivars loses its commercial value when stored at 4°C for less than 7 days (9). To refrigerate zucchini :

• Make sure the zucchini is dry.
• Place the zucchini in a clean paper or plastic bag with an open end for ventilation.
• Place in the crisper drawer of the refrigerator.

How to preserve zucchini by freezing

There are two ways to preserve zucchini by freezing them.

• Freezing zucchini cut into small pieces: Zucchini pieces can be used in many dishes such as noodles, soups etc.
• Freezing shredded zucchini: Shredded zucchini can be used in baking. Some bakery products made from shredded zucchini are zucchini bread and zucchini muffins.

Studies showed that there are significant changes on the texture of zucchini after being frozen and thawed. Losses of minerals were also identified (5).

How to preserve zucchini pieces by freezing 

Zucchini can be cut up and frozen as follows.

• Choose young and tender zucchini.
• Wash the zucchini in clean water and cut them into pieces of about half an inch each.
• Blanch in water for about 3 minutes.
• Allow to cool down.
• Drain off all water. 
• Package into a clean container.
• Leave about a half-inch of space.
• Seal the jar and freeze it.

Commercial blanching conditions typically involve heating at 95–100°C for 3–10 minutes, depending on the type and size of material to be blanched. It is mainly to prevent enzyme-mediated oxidation reactions that most vegetables and some fruits are blanched before freezing (6).

How to preserve shredded zucchini by freezing 

• Choose young and tender zucchini.
• Wash the zucchini in clean water and grate it.
• Blanch the grated zucchini in steam for one to two minutes. Steam, blanching must be done until the zucchini becomes translucent.
• Package into clean containers.
• Leave about half an inch of the gap between the zucchini and the lid.
• Cool the jars by packing them in cold water.
• Seal the jars and freeze them.

How to use frozen zucchini

Frozen zucchini must be thawed before being used in dishes. Thawing frozen zucchini will release a lot of excess liquid which has to be discarded. 

How to preserve zucchini by dehydration

Zucchini can be dehydrated by (10) :

• Using a dehydrator
• Using an oven

In addition, microwave heating is one of the promising technologies that have the ability to penetrate the material and heat it volumetrically. Other advantages of microwave application include reduced processing time, environmental impact and power consumption (8).

Dehydrating zucchini using a dehydrator

• Clean and wash the zucchini.
• Slice into pieces of a quarter-inch thickness.
• Place the zucchini pieces on the dehydrator tray. Leave space around the pieces for airflow and consistent drying.
• Set the dehydrator to 135 F. The dehydration time is around 6 hours.
• Store the dehydrated zucchini in an airtight container in a cool dark place.

Dehydrating zucchini using an oven

• Clean and wash the zucchini.
• Slice into pieces of a quarter-inch thickness.
• Place the zucchini pieces on a baking sheet and cover them with another baking sheet or parchment paper.
• Set the oven to the lowest temperature. The ideal temperature for dehydrating is 135 F. 
• Place the zucchini in the oven.
• Keep the oven door about an inch open.
• The dehydrating time in an oven is around four to six hours.
• Store the dehydrated zucchini in an airtight container in a cool dark place.

How to use dehydrated zucchini

The main purpose of drying is to decrease water activity of the food to extend its shelf life. Drying is one of the oldest methods of food preservation. Drying preserves foods by removing enough moisture from food to prevent decay and spoilage. Water content of properly dried food varies from 5 to 25 percent depending on the food (10).

Dehydrated zucchini can be consumed on its own as a snack or it can be added to other dishes.

Dehydrated zucchini can also be rehydrated before adding to another dish.

To rehydrate zucchini :

• Soak the dehydrated crisps in boiling water.
• Let the crisps absorb water for about fifteen minutes.
• Pour off the excess water and use the rehydrated zucchini in a dish of your choice.

How to preserve zucchini by fermentation

When vegetables are either packed dry with 2 or 3 pounds of salt to every 100 pounds of material, as in the making of sauerkraut, or are covered with a brine containing 5 pounds of salt to every 12 gallons of water, as in the preparation of dill pickles, the sugars present in the vegetables are extracted from them and are fermented by the lactic-acid-forming bacteria which are present naturally m great numbers on the surface of the fresh material. After this action has gone on to a certain point, enough of this lactic acid is formed to kill the bacteria and prevent any further change in the material, provided certain precautions are taken to prevent the growth of molds (2).

Zucchini can be fermented to produce : 

• Zucchini kraut : Zucchini kraut uses grated zucchini preserved in salt. The mixture must be allowed to ferment for about five days before it is ready to eat. Zucchini kraut is a great addition to salads and sandwiches.
• Zucchini pickles: Zucchini pickles are produced in the traditional pickling method. Cut up zucchinis are allowed to ferment in sea salt. Spices and ingredients such as chillis, parsley, dill, onions and garlic can be added according to your preferred flavour. 

Zucchini pickles can be eaten with sandwiches, burgers and any other dish of your choice.

How to increase the shelf-life of fermented zucchini

The following steps ensure that fermented zucchini lasts longer.

• Properly clean the jars used to store the fermented zucchini. Jars can be sterilized by dipping in hot water.
• Store the pickles away from direct sunlight.
• Use 1 % – 2 % salt by volume of the fermented product.
• Store at 55°F and 75°F.

Conclusion

In this brief guide, we answered the question “How to preserve zucchini?”. We also discussed the different methods used to preserve zucchini such as refrigerating, freezing, dehydration, and fermenting. We also looked at different methods to refrigerate, freeze, dehydrate and ferment zucchini.

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

References

1. Schreinemachers, Pepijn, Emmy B. Simmons, and Marco CS Wopereis. Tapping the economic and nutritional power of vegetables. Global food secur, 2018, 16, 36-45.
2. Round, Lester Angell. Preservation of vegetables by fermentation and salting. No. 881. US Government Printing Office, 1917. 
3. Brandt, J. Pickling Vegetables. 2015. Oregon State University.
4. Home Food Storage. University of Nebraska Lincoln.
5. Paciulli, Maria, et al. Impact of the industrial freezing process on selected vegetables—Part I. Structure, texture and antioxidant capacity. Food Res Int, 2015, 74, 329-337.
6. Silva, Cristina LM, Elsa M. Gonçalves, and Teresa RS Brandao. Freezing of fruits and vegetables. Frozen food science and technology. 2008, 165.
7. Holmes, E. Making Dehydrated Cucumber and Zucchini Chips. 2021. University of Maine.
8. Kutlu, Naciye, and Asli Isci. Drying characteristics of zucchini and empirical modeling of its drying process. Int J Food Stud, 2017, 6.
9. Megías Z, Martínez C, Manzano S, et al. Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites. PLoS One. 2015, 10, e0133058.
10.  Kendall, Pat, et al. Drying vegetables. Colorado State University. Service in action, 2004, 9, 308.