Reaping the best of fruit
This fourth article of our series, Science from the Field to the Fork, looks at the life of fruits after being harvested and how to achieve the best quality results!
Science from the field to the fork
This article, the fourth in our series, Science from the Field to the Fork, has become a regular feature in the Les vergers Boiron magazine and our newsletter. The series, supervised by Corinne Tisné, Project Head, Research and Development Les vergers Boiron, is designed to heighten awareness on the link between science, agronomy, growing practices and the techniques used for the transformation of fruits, and how these factors impact gastronomy, pastry-making and mixology. We began this series with an article on the notion of the terroir, followed by the reproduction of fruits and the complex makeup of fruits and their incredible variety worldwide. This time, we look at the life cycle of fruit, their natural evolution after being picked and the factors that come into play so that the fruit is processed and consumed at the height of its organoleptic development.
N° 4 - The natural evolution of fruit: the three stages of life
Let’s begin with the reminder that fruit is a living organism and has three distinct stages in its lifecycle: its evolution while it is still attached to its plant base, followed by its maturing process after having been picked and, finally, its ultimate cycle of deterioration or rotting. This lifecycle occurs through a series of biochemical and physiological changes. The high point, in terms of human consumption, occurs when it fully expresses its organoleptic characteristics: flavor, aromas, color, juiciness, texture, etc. This genetically programmed process must be fully mastered by growers and processors to draw out the very best qualities of the fruit to make it ideal for human consumption!
A fruit can be considered to be ripe when it has reached the height of its development, when it can easily be detached from its plant base and when it is pleasant and healthy to consume. There is no one rule to define the apex of its taste qualities. This is determined by several criteria: scientific, cultural and the use of the fruit in different dishes.
A mango, for example, is at times used before it comes to full maturity in salads or in savory dishes, as though it was a vegetable (in particular in Asia), while the ripe fruit is generally eaten raw or as a processed ingredient in different desserts in most other countries. The graphic below shows the ripening cycle of the mango and its use during its four edible phases, from mature green to late maturity, each with different characteristics as time goes on.
Ripen or rot, an essential choice
Certain fruits ripen and develop to free up their organoleptic qualities after they have been harvested. Others must be picked when they are ripe and do not evolve in a positive way after that. In both cases, after having matured, the fruit enters a stage of senescence or rotting, which most often makes it less tasty and, ultimately, unfit to be eaten.
According to the maturation pattern, fruits are divided into two groups:
• Climacteric fruits continue to ripen after they have been harvested, naturally discharging a gas, ethylene, which acts as a hormone to accelerate ripening.
• Non-climacteric fruits that do not depend on ethylene to ripen. The activation of their maturing process remains an unknown phenomenon. These fruits therefore do not ripen at all after having been harvested and enter directly into the phase of senescence or rotting.
La maturation (ou mûrissement) se traduit par les réactions suivantes :
- Ethylene synthesis, which self-accelerates the ripening of fruits that produce it naturally, but also fruits that are exposed to the gas. If you place apples or avocadoes near ripe bananas, the ethylene the bananas emit accelerates the ripening of the other fruits
- The modification or synthesis of certain pigments, which explains why fruits change in color when they ripen
- The solubilization of pectic components, which causes the fruit to soften
- The emission of volatile aromas, which explains that ripe fruits smell more
- Starch hydrolysis and its transformation into simple sugars, which explains the increase in sweetness in taste over time
- The lowering of organic acids, accentuating the sweetness
- Protein synthesis, in particular of enzymes.
These reactions enable fruits to achieve their ideal organoleptic stage, before senescence begins.
It should be noted that all of these reactions are activated by enzymes, which are the catalysts of all the functions of a living organism that live in an oxygenated environment. These enzymes are also the source of unwanted reactions, once the fruit is bruised, damaged, cut or mashed. These reactions can at times result in the deterioration of the organoleptic features.
These microorganisms are the second external factor that cause alterations in fruits, impacting their organoleptic quality, but also may be a hazard for human health when consumed at an advanced state of senescence.
This will be discussed in a future article.
What can be done to control the ripening of fruits?
Even if the transformation cycle of fruits is inexorable, it is possible to adjust several factors to extend their freshness or their degree of ripeness (in particular to extend their shelf life beyond their natural seasonality) or to attain an optimal level of tastiness:
- Lower the preservation temperature of fruits by refrigeration or by stocking them in controlled environments, generally between 0°C and 5°C, which affects the speed of reactions that are thermo-dependent
- Lower or raise the concentration of ethylene around climacteric fruits, by either confining fruits or, on the contrary, putting them in the vicinity of other fruits
- Lower the concentration in oxygen and/or increase the concentration of carbonic gas in the vicinity of the fruit to accelerate or slow down the ripening cycle.
To produce purées, the control of the level of maturation is essential to ensure the highest organoleptic quality of the final product. Les vergers Boiron is particularly attentive to harvest non-climacteric fruits (those that do not ripen after they are picked) at the very height of their ripeness so that they can express their full organoleptic qualities!
For climacteric fruits, such as those that grow in orchards, they must pass qualification tests at the time of reception, allowing us to monitor their level of maturity. If they are not fully ripe upon arrival, they are stored for the time needed to achieve the optimal level of maturity, to ensure the very best taste, color, texture and sugar/acid balance.
Les Vergers Boiron is particularly demanding in the specifications it imposes on fresh fruit growers and carefully controls raw materials upon reception. This is the first stage in our processes to ensure that our purées are always of the highest quality.