How to preserve unripe plantains

In this brief guide, we are going to answer the question “how to preserve unripe plantains” and discuss the different methods of preserving unripe plantains.

How to preserve unripe plantains

West Africa is one of the major plantain-producing regions of the world, accounting for about 32% of worldwide production (1).

Unripe plantains can be preserved by :

• Refrigeration
• Freezing
• Dehydration

Plantains are often mistaken to have the same quality and taste as bananas but they are very different from bananas. Plantains are starchy with a low content of sugar and they cannot be eaten raw. Plantains are very versatile and can be used in both sweet and savory dishes. Plantains can be baked, fried, cooked or sauteed. Nutritionally, Musa spp. constitute a rich energy source, with carbohydrates accounting for 22 and 32% of fruit weight for banana and plantain, respectively, and rich in vitamins A, B6, C, minerals and dietary fiber (3).

Unripe, green plantain will ripen quickly at room temperature so it is necessary to use proper methods to preserve unripe plantains.

How to preserve unripe plantains by refrigeration

Cold storage with an optimum temperature range between (13–14°C or 55°F) is used for transportation of plantain (2).

Refrigerating will slow down the ripening process of plantains. However, it will cause chilling damage. Therefore, plantains should be kept at a temperature of minimum 12°C or 53°F (2).

The ripening behaviour of banana and plantain is temperature dependent. Unripe plantains can be stored in the fridge for about 3 to 4 weeks. However, refrigeration is not the best method to preserve unripe plantains since it is believed to alter the taste and texture. At room temperature, it takes about 15 days for the plantain to ripen to the full yellow stage (2).

How to preserve unripe plantains by freezing

Freezing is the simplest method to preserve unripe plantains. Plantains can be frozen in pieces or mashed. To freeze cut-up pieces of unripe plantains :

• Wash and then peel the plantains.
• Cut the peeled plantains. Plantains can be cut into big pieces, dices, or they can even be grated.
• Place the cut plantains in ziplock bags and squeeze out the air. 
• Seal the bags, label and place in the freezer.

A study showed that freezing had no significant change on the nutritional properties of plantain fruits. This was expected since during the freezing process, vitamins, minerals and macro-elements content remains substantially the same as in the fresh state (3).

Freezing mashed plantains

Plantains can also be mashed with lemon juice to make mashed plantains which are then frozen until needed. To make mashed plantains :

• Clean, peel and cut the plantains
• Place the plantains in a bowl.
• Add 1 teaspoon of lemon juice for every plantain in the mixture. The acidity of the lemon juice will prevent the browning of the exposed areas of the plantains.
• Mash the plantain and lemon juice mixture with a potato masher or a hand mixer.
• Transfer into an airtight container and place in the freezer.

Fruits such as bananas and apples darken quickly when exposed to air and during freezing. They also may lose flavor when thawed. Citric acid or lemon juice are sometimes used in place of ascorbic acid. To use, dissolve ¼ teaspoon crystalline citric acid or 3 tablespoons of lemon juice in a quart of cold water. Place prepared fruit in the mixture for 1 to 2 minutes. Drain and pack the fruit (4).

Frozen plantains can be stored without much change in texture and flavor for about 3 months. After 3 months the plantains may start losing flavor or discolor. However, blanching can extend the shelf life of frozen plantains. Steam blanching – raw samples treated with steam for 5 min showed a 96% reduction of polyphenol oxidase activity, the enzyme which causes browning of fruits, and a continuous decrease during frozen storage (5).

It is best to cook frozen plantains directly after removing them from the freezer. Thawing frozen plantains will alter their texture (3).

How to preserve unripe plantains by dehydration

Drying technology has been used as a method of food processing and preservation in developing economics. Drying methods ranging from the simple sun drying method to methods employing a forced draft of conditioned air all depend on removal of water (6). 

Unripe plantains can be dehydrated to make either plantain chips or plantain flour.

Dehydrated plantain chips can be made with both ripe and unripe plantains. Ripe plantains will add a sweet flavor to the chips. When making unripe plantain chips, it is best to add salt and some spices such as cinnamon or cardamom to enhance the flavor.

To make dehydrate unripe plantain chips :

• Clean, peel and slice green unripe plantains.
• Arrange the slices in the dehydrator tray.
• Sprinkle salt and spices as needed.
• Dehydrate until the chips are dry. The dehydration time depends on the ripeness and thickness of the plantain slices. Unripe plantains dehydrate faster than ripe ones.
• After dehydration, place in an airtight container in a cool, dry place.
• The dehydrated chips can be enjoyed as a healthy snack by itself or by adding a healthy dip.

A detailed recipe for making dehydrated plantain chips can be found here.

Unripe plantains can also be ground to make plantain flour. Plantain flour can be used to make pancakes, muffins and other baked goods (6).

To make plantain flour :

• Clean, peel, slice and dehydrate the plantains in the same method as that for making plantain chips.
• Transfer the plantain chips into a food grinder. 
• Grind the plantain chips until they form a powder.
• Transfer the flour into an airtight container.
• Seal label and store the plantain flour in a cool and dry place.
• Plantain flour can also be frozen for a few months (7).

Choosing the best unripe plantains for preservation

Regardless of the preservation method, the unripe plantains must be purchased in good condition. Things to look out for when choosing unripe plantains include :

• Color: Unripe plantains must be green without yellow or black spotting. A lot of black spotting indicates that the plantains are ripe. The green to golden yellow color change in plantain and banana during ripening is due to the unmasking of carotenoid pigments in the plastids through chlorophyll breakdown (2).
• Texture: Unripe plantains must be hard with no cracks, cuts and bruises on the peels. If the plantains are soft or oozing in places, discard them.

Shelf-life of preserved unripe plantains

The shelf-life of unripe plantains depends on the preservation method used.

• Refrigeration: 3 to 4 weeks. Temperature of storage must be above 12°C to avoid chilling damage.
• Freezing: Maximum shelf-life of 1 year, but there will be changes in flavors and texture after 3 months.
• Dehydration: 4 months without any additional preservatives. 6 months for plantain flour.

Conclusion

In this brief guide, we answered the question “how to preserve unripe plantains” and discussed the different methods used to preserve unripe plantains. We also looked at shelf lives of different preservation methods and how to choose the best plantains for preservation.

If you have any comments, please let us know.

References