How to preserve ugu leaves

In this brief guide, we are going to answer the question “how to preserve ugu leaves” and discuss the methods used to preserve ugu leaves.

How to preserve ugu leaves

Fluted pumpkin leaf at harvest has over 70% water content and after which it begins to undergo high rates of respiration, quality deterioration and potential microbial spoilage (1).

Ugu leaves can be preserved by:

• Refrigerating 
• Freezing 
• Air-drying

Ugu leaves, also known as fluted pumpkin leaves , are green leaves originating from Africa. Ugu leaves are rich in nutrients and are used in soups and other dishes.

How to refrigerate ugu leaves for preservation

As for most green leaves, refrigeration is the best short term preservation method for ugu leaves.

Refrigerating is the easiest way to preserve ugu leaves, and the flavor and texture are retained throughout. Ugu leaves can be refrigerated for about 1 week. However, a study showed that when leaves are blanched with solutions of ethylenediamine tetra-acetic acid, or EDTA (0.003%), sodium chloride (0.5%) or sodium benzoate (0.05%), the shelf life in the refrigerator can be prolonged for 1 month (1).

Blanching is an important process to extend the shelf life of vegetables. It destroys enzymes and bacteria and eliminates some anti-nutritious substances that are present in the green leaves, such as oxalate. However, it leaches vitamins and minerals (2).

To refrigerate green ugu leaves:

• Pick the ugu leaves from the stems.
• Rinse the ugu leaves and remove any yellow or damaged leaves.
• Dry the ugu leaves with a paper towel or a salad spinner. Make sure that the ugu leaves are completely dry as even a little moisture can cause spoilage.
• Wrap the ugu leaves with a paper towel or line an airtight container with paper towels. The ugu leaves can also be chopped if needed.
• Place the ugu leaves in a sealable bag or inside the airtight container.
• Seal, label and refrigerate for up to 1 week.

How to freeze ugu leaves for preservation

Freezing will preserve ugu leaves for about 8- 12 months. Both whole and chopped ugu leaves can be preserved by freezing. 

To freeze ugu leaves: 

• Pick the ugu leaves from the stems.
• Rinse the ugu leaves and remove any yellow or damaged leaves.
• Dry the ugu leaves with a paper towel or a salad spinner. Make sure that the ugu leaves are completely dry as even a little moisture can cause spoilage.
• Chop the ugu leaves if needed.
• Place the ugu leaves in a sealable bag or inside the airtight container.
• Seal, label and place it in the freezer.

It is recommended to blanch the ugu leaves prior to freezing. As mentioned before, blanching will reduce the amount of oxalate of the leaf. A study showed that unblanched frozen ugu leaves contain more oxalate after thawing than fresh leaves. In addition, it may extend the shelf life of the frozen ugu leaves (2).  

How to air-dry ugu leaves for preservation

Ugu leaves can also be preserved by air-drying. A study showed that vitamins and minerals were better preserved in pre-blanched dried ugu leaves than pre-blanched refrigerated ugu leaves after a period of 6 weeks (1). 

Drying will preserve ugu leaves for about a year. However, all the texture and some flavor and aroma will be lost by drying. Dried ugu leaves can be used in soups and pies.

Dried ugu leaves must be stored in an airtight container in a cool, dark place away from moisture. Dried ugu leaves can also be frozen for about a year and a half but once again, there will be a loss of flavor.

Air-drying is the recommended method to dry ugu leaves. Methods such as using a food-dehydrator and oven drying must not be used since they will reduce the nutrient content of the ugu leaves. Blanching the leaves is recommended before the drying procedure. A study showed that both drying in an oven and sun drying lead to loss of beta carotene in the ugu leaves. However, this loss was attenuated when leaves were blanched before (3).  

Air-drying ugu leaves can take anywhere from 3 days to a week, depending on the temperature of the surrounding area.

To dry ugu leaves by air-drying:

• Pick the ugu leaves from the stems.
• Rinse the ugu leaves and remove any yellow or damaged leaves.

• Blot dry the leaves using a paper towel.
• Tie the leaves together in a bunch using a twine.
• Hang the leaves upside down in a warm, dark and dry room with good ventilation. The leaves can also be spread out on a tray to air dry.
• Once the leaves are dry, transfer them into an airtight container. The leaves can also be powdered using a food processor.
• Store the dried ugu leaves in an airtight container. The ugu leaves can also be ground to powder in a food processor at this stage.

Alternatively, the ugu leaves can be dried in the oven (50°C for 8 h) (1) or sun-dried for 3 days by placing them in a tray and exposing them directly in the sunlight. By this procedure, there will be a loss in the beta carotene of the leaf (3).

Health benefits of ugu leaves

Pumpkin leaves are a good source of crude protein. In 100 g of crude ugu leaf, there are:19.97–28.77 g protein, 72.39–75.48 g carbohydrates. It is a good source of minerals: K – 1320 mg, Ca – 941 mg, Mg – 220 mg, P – 130 mg, Fe – 60 mg. The mineral content of this vegetable exceeds levels found in exotic vegetables, such as lettuce and cabbage (4).

• Ugu leaves are rich in antioxidants. The high content of antioxidants makes them a natural defense against cancer.
• Ugu leaves are high in dietary fiber. This makes ugu leaves beneficial for people with irritable bowel syndrome or constipation. The high content of dietary fiber also makes them suitable for weight-loss
• Ugu leaves are anti-diabetic. Consuming ugu leaves will reduce blood glucose levels.

• Ugu leaves are rich in many nutrients such as calcium, magnesium and potassium which make them a good inclusion for a balanced diet.
• Ugu leaves are a good source of beta carotene, an important antioxidant for eye health.

Some recipes using ugu leaves can be found here.

Tips for preserving ugu leaves

Refrigerating and freezing: Ugu leaves can be sliced before freezing. Take note that the sliced leaves will lose their quality faster than whole leaves. Try to use the chopped ugu leaves soon before their nutrient quality reduces.

Storing in the counter: If you have just harvested or purchased ugu leaves and are planning to use them shortly, they can be kept on the kitchen counter. To prevent the leaves from wilting, wrap them in an old newspaper or a kitchen towel. This will reduce moisture loss from the leaves.

Conclusion

In this brief guide, we answered the question “how to preserve ugu leaves” and discussed in depth the main methods used to preserve ugu leaves. 

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

References

1. Amaka, NNAMEZIE Anastasia, FAMUWAGUN Akinsola Albert, and GBADAMOSI Saka Olaunkanmi. Changes In Some Nutritional And Sensory Properties Of Treated And Stored Fluted Pumpkin Leaf.
2. Ogbadoyi, Emmanuel O., et al. The effect of processing and preservation methods on the oxalate levels of some Nigerian leafy vegetables. Biokemistri, 2006, 18.
3. Badifu, G. I. O., M. A. Akpapunam, and V. M. Mgbemere. The Fate of beta-carotene in processed leaves of fluted pumpkin (Telfairia occidentalis Hook. f.): A popular vegetable in nigerian diet. Plant Food Human Nutr, 1995, 48, 141-147.
4. Mashiane, Petunia, et al. Impact of household cooking techniques on color, antioxidant and sensory properties of African pumpkin and pumpkin leaves. Int J Gastro Food Sci, 2021, 23,  100307.