Research brings flavorful Dwarf Lady Finger bananas to Europe

The fruit needs to be green when it reaches its destination, when it will go through the ripening process.

The Dwarf Cavendish is the top selling banana in the world, but contrary to what you might think, it is far from being the most popular variety in banana producing countries. For example, in Brazil most of the 100 thousand tons exported every year are Dwarf Cavendish but 60% of the bananas eaten in the country are the Lady Finger variety. The Dwarf Cavendish are more resistant to the exportation process than the other varieties of the fruit. This fact caught the attention of producers in the north of the state of Minas Gerais, Brazil, who asked for help from the Federal University of Viçosa to take the flavor of the Dwarf Lady Finger variety to Europe.

The demand for applied research to enable the Dwarf Lady Finger banana to enter the European market, starting with Portugal, came from the Central Association of Fruit-growers of the North of Minas (Abanorte), in Janaúba, MG, who have a huge potential to produce this variety. The first contact at the university’s department of Crop Sciences was Luiz Carlos Chamhum Salomão and with the assistance of the Federation of Agriculture and Animal Husbandry of the State of Minas Gerais (Faemg) the first contact took place in 2011. After an agreement was signed in 2012, the researcher coordinated a series of experiments, aiming to send a container of Dwarf Lady Finger bananas good enough to be sold in Portugal.

According to Luiz Carlos, bananas are only exported to Europe by ship; a journey of 24 to 25 days. The fruit must be green on arrival to go through the forced ripening process so that t has the quality to be sold and eaten. At the moment, the Dwarf Cavendish dominates the world market because it is the most resistant to this process. Other varieties have a short post-harvest life, like the Dwarf Lady Finger, which ripens and then quickly becomes overripe.

Experiments
The professor says that he had done experiments on the conservation of bananas at the UFV in the past but the research conditions were very different. Next he invited researchers linked to the Janaúba campus to the State University of Montes Claros to take part in the work, initially on a small scale – with groups of three bananas.

At first they worked on three aspects of the post-harvest: the harvesting point, for the fruit to be able to stay green for several days; the storage temperature and the absorption of ethylene – the hormone that stimulates ripening. “There were a series of experiments before we reached a result”, said Luiz Carlos.

The ideal harvesting point for the Dwarf Lady Finger is a diameter of 32 millimeters, a “thinner” fruit that takes longer to ripen because it is less likely to react to ethylene. The ideal storage temperature is 14.5°C. Professor Luiz Carlos explains that in the experiments carried out in Viçosa the bananas were refrigerated at 10°C for 25 days, after which they ripened perfectly. “When we tried to put the banana from Junaúba in the cold chamber, the peel went black. This shows the importance of the growing region.” Once the team reached 14.5°C and the skin did not darken they moved on to the next phase: to absorb the ethylene produced by the fruit. The substance that has this property is potassium permanganate, which was used in sachets placed inside the exportation packaging, which is made of an airtight plastic bag and a cardboard carton.

Once the initial experiment gave the expected results, it was time to test the process on a commercial scale. This happened in August 2014 when the research team carried out an experiment with 240 twenty kilo boxes of Dwarf Lady Finger bananas (almost five tons in total). They were stored in a refrigerated container for 25 days and when they were opened the results were not very encouraging: around 25% of the fruit were already ripe. One difficulty was the lack of time for new experiments. The solution was to carry out a final definitive test, as the container would be sent to Europe.

In the final attempt, the plastic that was used to wrap the bananas was substituted for a thicker airtight one that guaranteed a smaller exchange of gases between the interior and the exterior of the packaging and the functioning of the ethylene absorber. So in October new cartons of bananas were sent to Portugal.

In November, the container truck arrived in Lisbon after being unloaded at the port of Rotterdam, in the Netherlands. When opened, there was a surprise: only three bunches of fruit were ripe. “It was a success!” said Professor Luiz Carlos, who considered the experience a challenge in his professional career. “We want to contribute something that has some impact, which gives Brazil a competitive advantage. I’ve been working with research into bananas for 30 years, so it was very satisfying and enriching.”

Although they have reached their initial goal, Luiz Carlos says the research is not over yet. Now the team is going to conduct more detailed economic evaluations to lower the cost of exporting the Dwarf Lady Finger. “Our idea is to try to decrease the concentration of the ethylene absorber at the storage temperature. We are fine tuning to optimize our results,” says the coordinator.