How to preserve uncooked ukwa

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

How to preserve uncooked ukwa 

Uncooked ukwa can be preserved by: 

• Refrigeration
• Immersion in water
• Fermentation
• Dehydration
• Cooking
• Chips production

What is ukwa?

Ukwa, known as African breadfruit in English. It is a starch-filled fruit that can be cooked into delicious dishes. 

Ukwa is a seasonal fruit. Preserving ukwa allows it to be used throughout the year. The fruits of breadfruit are globose to oblong, ranging from 12 to 20 cm wide and 12 cm long.  The rind is light green, yellowish-green or yellow when mature and the flesh is creamy white or pale yellow. Breadfruit is a good source of carbohydrates and low fat.  Compared with other staple starch crops, it is a better source of protein than cassava and is comparable to sweet potato and banana. It is a relatively good source of iron, calcium, potassium, riboflavin and niacin (1).

How to preserve ukwa by refrigerating 

Fruit quickly ripens in just 1–3 days after harvest. Shelf life can be extended by careful harvesting and pre-cooling fruit with chipped ice in the field and during transport. Covering fruit with water can also delay ripening for a few days (2). 

Ripe, uncooked ukwa can be stored in the refrigerator. The cool temperatures will halt the ripening process. Refrigerating will preserve ukwa for about a week. The optimum temperature to refrigerate ukwa is about 12 to 13°C.

To extend the shelf life of refrigerated ukwa, place the fruit in a paper bag before refrigerating.

When refrigerated, the skin of the ukwa would turn brown, but the flesh will remain edible.

Unripe ukwa must not be refrigerated. If refrigerated, it will develop a bitter taste.

Uncooked ukwa must not be frozen as it will lose both flavor and texture. If you need to freezer ukwa, you must boil or blanch it first. 

Peeled mature and ripe fruit can be frozen. Frozen fruit can be thawed, cooked, and mixed into dough that makes excellent extruded products. Frozen breadfruit “French fries” could replace imported fries made from potatoes (2).

How to preserve ukwa by immersing in water

Uncooked, whole ukwa can be preserved for a few days by immersing the whole fruits in cool water. Simply immerse the fruit in clean, cool water and place a weight on the fruit to prevent it from floating to the surface. 

Alternatively, minimally processed pulp has the appearance, texture, and taste of fresh breadfruit. Minimal processing involves placing slices or cubes of fruit in plastic bags, vacuum sealing, then immersing in boiling water so the heat penetrates through the bags and the surface of the pulp reaches at least 80°C (176°F) for 15 seconds. The pouches are immediately cooled using cold water to prevent overcooking. This is repeated 24 hours later and again on the third day. This technique results in pack sterility (2).

How to preserve ukwa by fermenting

Ukwa has been traditionally preserved by fermentation. During traditional fermentation, the ukwa fruit is peeled, cut, and then placed in pits lined with banana or ukwa leaves. The ukwa fruit is then covered with more leaves and stones. The pH in the pit decreased from 6.7 (close to neutral) for fresh fruit to a quite acidic value of 4.3 in 2 weeks, which extends the shelf life of the product by hindering bacterial growth (1).

Now ukwa fruit is fermented by keeping peeled fruits in glass jars for a couple of months. Once the fruit is completely fermented, it can be used in many recipes.

How to prepare ukawa for dehydration

Uncooked ukwa can be dehydrated and then stored either as slices or in powdered form.

Ukwa was traditionally dehydrated by sun-drying but now food-dehydrators are used.

Breadfruit can also be freeze-dried. The reconstituted cooked or boiled product will have slight differences if compared with the cooked or boiled fresh fruit (1).

To make ukwa flour:

Selecting the ukwa fruits

Select fresh ukwa fruits for dehydrating. Make sure that there are no patches and damages on the skin. Also, make sure that the fruits are from and completely mature. Mature fruits will be greenish-yellow in color.

Wash and sanitize the ukwa fruits if needed

Wash the fruit under running water. Use a soft brush to remove any debris. If you are not immediately cutting open the fruit, air-dry the fruit and then store it at a temperature less than 24 C. Make sure to use the fruit within 3 days.

Peeling and cutting

Use sanitized utensils for peeling and cutting. Cut the stem and peel the outer skin of the ukwa fruit. Then cut open the fruits and use a knife to remove the core. Slice the ukwa into pieces of thickness ¼ inch or less. This would speed up the drying process.

Dehydrating

The best method to dry ukwa is by using a food dehydrator. Arrange the ukwa slices on the dehydrator tray. Dehydrate at 71 C until the slices are crispy and completely dry. Dehydration will take around 8 hours.  If you want to store ukwa slices, skip the next milling step.

 A traditional method of drying involves roasting whole fruit in a fire, cutting it into small pieces, and drying over a hot fire. These pieces have a pleasant, smoky flavor (2). 

Milling into a powder

After dehydrating, allow the ukwa piece to cool down to room temperature. Grind the pieces to a powder in a food processor. Sift the flour using a sieve. Large pieces remaining on the sieve can be added back to the food processor. 

Breadfruit flour can be used as a partial substitute for imported wheat flour in breads, cakes, and pastries, and is suitable for export. Ground meal can be used as a component of animal feed (2). The flour contained 4.4% protein, 1.1% fat and 6.4% fiber and ash. It contained higher levels of two essential amino acids, lysine and threonine, than wheat flour (1).

Packaging

Pack the ukwa into or airtight containers. Seal the containers and label them with the production date.  Ukwa flour has a shelf-life of 6-12 months, you can include this in the label as well.

Storage

Store the container in a cool, dark, and dry area.

Cooking with ukwa flour 

Ukwa flour can be mixed with regular flour in both cooking and baking. Many regular recipes can be enhanced by substituting ukwa flour for regular flour.

Ripe and unripe ukwa

Breadfruits are harvested as needed and generally picked when mature but not yet ripe. When preserving ukwa, you must consider if the fruit is ripe or not. Different techniques are used to preserve ripe and unripe ukwa.

Ripe ukwa can be distinguished from its color. Ripe ukwa will have greenish-yellow skin. There will be cracks between the segments of the surface. When cut open, ripe ukwa. The flesh of a ripe ukwa is creamy white or yellow. Unripe ukwa is bright green. When cut open, the flesh is pale green. 

Studies to extend the shelf-life of breadfruit demonstrated that whole fruits can be stored in sealed polyethylene bags at low temperatures; however, fruits showed symptoms of chilling injury at temperatures below 12°C.  Fruits were successfully stored at 14°C for up to 10 days.  Unwrapped fruits ripened within 7 days at this temperature (1).

Unripe ukwa is usually not eaten. Even when cooked it has a watery taster with a rubbery feel.

Conclusion

In this brief guide, we answered the question, “how to preserve uncooked ukwa”, and discussed the different methods used to preserve uncooked ukwa.

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

References

1. Ragone, Diane. Breadfruit—Artocarpus altilis (Parkinson) Fosberg. Exotic Fruits. Academic Press, 2018. 53-60.
2. Ragone, Diane. Breadfruit. Artocarpus altilis 17, 1997.