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Illustration of a plant hormone, ethylene, and a ripening banana

How to keep fruit fresh?

Fruit straight from the producer or fruit from the supermarket

Going to a tropical fruit producer’s farm to buy two avocados doesn’t make much sense. Neither does visiting an oil mill to buy a 250ml bottle of oil.

When you buy straight from the producer, either by going to their farm or shopping online, you tend to buy large amounts. Nothing like the amount you buy when you go to the supermarket, where you can weigh, label, and take home an avocado and two lemons.

Buying fruit straight from the producer doesn’t seem to be in line with the current trend of offering the consumer what they want, whenever they want. The whole concept requires a mindset shift. It requires patience and learning how to keep the fruit fresh or how to use it before it goes off.

When it comes to the environmental impact, buying larger amounts directly from the farmer reduces the carbon footprint per kilo transported. The fruit travels fewer kilometres in less time because it’s sent straight from the farm to the consumer’s home. And it doesn’t travel alone! CrowdFarming farmers share loads on trucks to make sure they’re full.

Illustration of a forest with trees beneath a shoe


Supermarket fruit, even if organic, usually undergoes skin preservation treatments to make it last longer. In direct sales, farmers collect the fruit you have ordered and send it to your home without wax or skin preservation treatments.

Climacteric and non-climacteric fruits

The colour of the skin of some fruits, such as bananas, gives away their ripeness. A Canary Island banana with green skin tells us that it isn’t ripe yet. If you buy it green and put it in the fruit bowl, after a few days this banana will turn yellow and if you leave it for a few more days, it will end up being black or dark brown.

Illustration of a jar with lemons and bananas and a calendar



It’s more difficult to see a lemon change colour, though. If you buy a yellow lemon and forget about it in the fridge, after a month it will probably still be yellow. With drier skin and a duller colour, but still yellow.

The banana is a climacteric fruit and the lemon is a non-climacteric fruit. Climacteric fruits continue to ripen after being picked and non-climacteric fruits stop their ripening process when they’re taken off the plant.

The difference in ripeness is due to the presence of a plant hormone called ethylene. Yes! Plants have hormones too! Ethylene is a gaseous hormone that plants and their fruits give off naturally. As a result of ripening, the starch in fruits is transformed into sugar (fructose and glucose), the tannins (characteristic compounds of ‘green’ fruit that give it a bitter taste) are reduced, and the pH increases, thereby reducing acidity.

Climacteric fruits give off ethylene when they breathe and react to the concentrations of ethylene and then produce more ethylene, so the process speeds up as the concentration of this gas increases. Meanwhile, respiration accelerates as the temperature increases. The higher the temperature, the higher the respiration and the higher the ethylene production. Non-climacteric fruits do not have the ‘respiratory climacteric’, which is the part that interacts with ethylene, so they’re not affected as much by this hormone.

Harvesting point and optimal point of consumption

In the case of climacteric fruits, the picking point doesn’t have to coincide with the point of consumption. As this topic can sometimes cause confusion, here are some examples:

The optimal point for harvesting mangos is determined by the concentration of sugar in their pulp. They begin to be harvested when they reach 8 degrees Brix (8 grams of sugar for every 100 grams of fruit). At this point, they’re still hard and cannot be eaten.

In the case of an avocado, the same thing happens. For example, the Hass variety is harvested when it has a minimum of 22% dry matter, which correlates with the amount of fat in the fruit, and is the variable that determines the optimal point for harvesting. When they’re harvested, they are hard and cannot be eaten for a few days.

When climacteric fruits are separated from the plant, they continue to produce ethylene. This process makes the organoleptic properties evolve until reaching the point of consumption.

Climacteric fruits: Picking point < Point of consumption

FruitPicking pointPoint of consumption
Mangos> 8 degrees Brix> 15 degrees Brix
Avocados (Hass)> 22% dry matter> 25% dry matter
Kiwis> 7 degrees Brix> 13 degrees Brix

In non-climacteric fruits, the point of ripeness and the point of consumption coincide. They do not ripen after harvest. Citrus fruits such as oranges, tangerines, lemons, or grapefruits are examples of non-climacteric fruits and in which ethylene doesn’t regulate ripening. However, ethylene is present and performs other functions such as speeding up the degradation of chlorophylls, which are the pigments responsible for the green colour of fruits.

Non-climacteric fruits: Picking point = Point of consumption

Supermarket fruit goes through preservation chambers before reaching the point of sale. The main goal of these chambers is to slow down the metabolic processes of the fruit and extend its shelf life. Low temperatures and oxygen concentrations, along with high levels of relative humidity within the chamber, reduce respiration, transpiration and ethylene production.

Meanwhile, a certain degree of colouring is required to sell citrus fruits at a supermarket. This also involves the use of chambers, but this time to artificially apply ethylene in order to make these fruits lose their green colour quicker. In other words, for aesthetic reasons.

How to keep climacteric fruits (mangos, avocados, kiwi, etc.) fresh

The first thing you should do when you receive a box of fruit sent by a farmer is to open it and check how the fruit has arrived. CrowdFarming farmers always include a few pieces of fruit as a gift in case one goes off en route.

Depending on the time of the season, the fruits may arrive harder or softer. As you’ve learned before, hardness doesn’t indicate that the fruit was picked too early. For example, if it’s very early in the Hass avocado season (December-January), it may take more than fifteen days for the fruit to reach its point of consumption. However, if you receive the same variety in March or April, you can probably eat some on the same day as the order arrives. The heat they experience during the journey may accelerate their ripening. The boxes usually have holes in them to ventilate the ethylene produced by the fruits, thereby preventing them from building up and causing them to ripen too quickly.

As the amounts you receive from farmers are large and it’s not usual for one household to consume all of them at once, a good tip is to separate the fruit into three portions.

The first portion will be the fruit you want to consume soon. You can put it in a warm place without transpiration alongside other climacteric fruits (apple, bananas, kiwis). This will favour the concentration of ethylene and the fruit will ripen faster.

You can leave the second portion in a place where they can breath. For example in a fruit bowl on the counter but making sure that they do not receive direct sunlight. This way they will ripen more slowly.

Finally, you can keep the third portion in the fridge. The cold slows down respiration and consequently the concentration of ethylene and ripening.

Illustration of the stages of fruit preservation

Note: if the fruit you’ve received is already ripe, we recommend keeping all the pieces in the fridge. Even more so if it’s a hot time of the year.

How to keep non-climacteric fruits (oranges, grapes, lemons, etc.) fresh

Non-climacteric fruits need less attention, as their state of ripeness will hardly change and you’ll be able to consume them on the same day as you receive them. When you receive your box, check to see whether any of the fruits have split, cracked, or gone off. If so, separate them from the rest to prevent possible fungi from passing from one fruit to another. CrowdFarming farmers include extra pieces of fruit to compensate for these potential losses.

As for storage, we recommend keeping them in a cool, airy place. You can even keep some in the fridge so that they last longer. Non-climacteric fruits can last a long time, but they run the risk of dehydrating and rotting over time. If the place where you store them is very humid, they may go off more easily.

Conclusions

One: buying straight from the farmer reduces the environmental impact of transporting food, but requires buying larger amounts than you usually buy at the supermarket.

Two: not all fruits ripen in the same way. How and where to store them influences the speed of ripening, especially when it comes to climacteric fruits.

Three: receiving a hard climacteric fruit doesn’t mean that it was picked too early. A hard fruit may be ripe and take a few days to reach the point of consumption.