If you buy bananas from any fruit vendor and take them home, you’ll notice that within just a day or two, they turn black and lose their freshness. But strangely, bananas at the vendor’s stall remain yellow, as if they were just picked!
And this phenomenon isn’t limited to bananas alone; it applies to most types of fruits and vegetables. They often appear fresh and vibrant at the vendor’s stall, but as soon as they reach home, they start to wilt and spoil quickly even before being placed in the refrigerator.
So, what’s the secret that fruit and vegetable vendors use to keep their produce fresh for longer? And can we apply these methods at home to preserve fruits and vegetables for as long as possible?
To understand why fruits and vegetables stay fresh at the vendor’s stall while spoiling quickly at home, we first need to identify the main cause of their deterioration: ethylene gas.
Most types of fruits and vegetables produce ethylene gas in varying amounts throughout all stages of their growth, from being green and unripe to reaching full ripeness.
When the fruit is unripe, ethylene gas activates enzymes within it, leading to the breakdown of cell walls, which makes the outer skin softer. At the same time, the starch content inside the fruit decreases, while the sugar levels increase, causing it to ripen and develop a sweeter taste.
The problem, however, is that ethylene production doesn’t stop at ripeness; instead, it continues at an increasing rate. As the gas keeps emitting, the fruit becomes overly ripe, causing its outer skin to soften excessively until it can no longer protect its contents eventually leading to rapid spoilage.
Not all fruits are the same when it comes to ethylene production; they are generally classified into two main types:
These are fruits that produce large amounts of ethylene, especially as they approach ripeness. They have the ability to continue ripening even after being harvested because ethylene keeps working inside them. Examples include:
- Banana
- Apple
- Watermelon
- Peach
- Kiwi
For this reason, if you buy unripe bananas or apples, you can leave them at room temperature to continue ripening, thanks to the effect of ethylene.
Unlike climacteric fruits, these fruits produce very little ethylene, meaning the ripening process almost completely stops once they are picked from the tree.
However, if exposed to high levels of ethylene from external sources (such as being placed next to a ripe climacteric fruit), they may continue ripening quickly and spoil. Examples include:
- Pineapple
- Grapes
- Orange
- Mandarin
- Lemon
Although most fruit and vegetable vendors haven’t studied the science behind ethylene gas, they gain extensive experience through practice, making them experts in preserving the quality of their produce for as long as possible.
Vendors rely on a practical understanding of fruit characteristics, especially climacteric fruits like bananas, which continue to ripen after being harvested due to their high ethylene production.
For this reason, bananas are picked weeks before they ripen, while they are still completely green and inedible.
This method gives vendors enough time to transport them from one place to another or even from one country to another without spoiling.
Once the bananas reach their destination, they are stored in special rooms known as "cooling chambers" or "ripening rooms."
However, these are not regular refrigerators like the ones we use at home.
Instead, they are carefully controlled environments with precise temperature and humidity levels to slow down the ripening process and keep the bananas green for as long as possible.
When the vendor needs to sell bananas, they don’t take them out all at once. Instead, they carry out a process known as "banana ripening," which involves:
Taking out only the required quantities from storage on a daily basis.
Wrapping banana bunches in a blanket or placing them in plastic bags for a few days, which helps trap ethylene gas around them and speeds up their yellowing process.
If the vendor allows all the bananas to ripen at once, they will face a major problem, as the bananas will spoil quickly before they can be sold completely.
Therefore, they only take out the required quantities each day to ensure that fresh bananas are always available in the store, while the green stock remains preserved for a longer period.
In fruit and vegetable stores, products are not arranged randomly or just for aesthetic appeal. Instead, they are organized based on ethylene emission levels to prevent certain types from spoiling too quickly.
Apples should not be placed next to mangoes because apples produce high amounts of ethylene, which can speed up the ripening process and cause mangoes to spoil faster.
Tomatoes should not be placed next to lemons because tomatoes are climacteric fruits that produce ethylene, which may accelerate the spoilage of lemons.
Bananas are one of the most ethylene-sensitive fruits they produce it in large amounts and are highly affected by it at the same time. This makes them like a ticking time bomb in terms of ripening and spoilage speed.
For this reason, most vendors take special care by:
- Keeping bananas away from other fruits and vegetables.
- Hanging them to prevent contact with other surfaces, which could increase ethylene production.
Climacteric fruits like apples produce much higher levels of ethylene when they get bruised or damaged, which can cause the surrounding fruits to spoil quickly.
For this reason, some types of imported or premium apples are individually wrapped in protective paper or mesh inside cartons to prevent excess ethylene from spreading to nearby fruits.
Now that we understand how vendors keep their produce fresh, we can apply some of these techniques at home to ensure that fruits and vegetables stay fresh for as long as possible.
Many of us store all fruits and vegetables together without considering the impact of ethylene, which leads to faster spoilage.
So: Do not mix ethylene-producing fruits with ethylene-sensitive ones, such as:
- Do not place apples next to mangoes.
- Do not store tomatoes next to lemons.
- Keep bananas away from all fruits, preferably hanging them.
- Avoid storing vegetables in sealed plastic bags, as they trap moisture and speed up spoilage.
- Be careful not to bruise fruits and vegetables during transport or storage, as any damage increases ethylene production.
Fruits and vegetables don’t always need refrigeration; it depends on their type. Grocery stores use fans to maintain a suitable temperature, and at home, we should know where to store each item:
- Onions, potatoes, and garlic: Should be stored in a dry, dark, and well-ventilated place, where they can stay fresh for months without refrigeration.
- Melon: Should not be refrigerated unless it has been cut.
Cucumber: Wilts quickly in the refrigerator. It is best stored in a dry place with a cloth or paper towel underneath to absorb moisture.
Avocado, mango, and apple can be kept at room temperature until they ripen, then placed in the refrigerator to slow down spoilage.
In large supermarkets, fruits and vegetables arrive while still unripe and are then stored in special warehouses where the amount of ethylene exposure is carefully controlled, allowing them to ripen gradually.
Only the required quantities are taken out daily, then exposed to precise levels of ethylene to reach the ideal ripeness before being placed on the shelves.
This is why, when visiting a supermarket, fruits appear freshly picked, even though they may have been stored for weeks! The secret lies in how supermarkets smartly manage the ripening process, ensuring they always offer fresh produce.
- Separate fruits and vegetables based on their ethylene sensitivity.
- Do not store everything in the refrigerator; some vegetables need dry air.
- Keep bananas hanging and store cucumbers away from cold temperatures.
- Avoid storing produce in sealed plastic bags to prevent moisture buildup.
- Handle fruits and vegetables carefully to avoid bruising or damage during storage and transport.
By using these simple methods, you can keep your food fresh for longer and reduce waste at home!