Multi-sensor

Artículos científicos

• Morales F, Irigoyen JJ, Antolín MC, Goicoechea N, Santesteban H, Oyarzun M, Luquin J, Barbarin M, Urdiain A, Pascual I (2022) Novel, technical advance: A new grapevine transpiration prototype for grape berries and whole bunch based on relative humidity sensors. Computers and Electronics in Agriculture, 196: 106890.
  https://www.sciencedirect.com/science/article/pii/S0168169922002071
• Pascual I, Antolín MC, Goicoechea N, Irigoyen JJ, Morales F (2022) Grape berry transpiration influences ripening and must composition in cv. Tempranillo (Vitis vinifera L.). Physiologia Plantarum, 174:e13741. https://onlinelibrary.wiley.com/doi/full/10.1111/ppl.13741

Congresos

• Cabodevilla A, Morales F, Pascual I (2022) Transpiración del racimo de uva y su influencia en la maduración en condiciones de cambio climático. Acta de Horticultura n.91. pp 149-152.

Why did the Multi-sensor project emerge?
Transpiration is the process by which live tissue loses water in the form of water vapour. It also occurs in plants, largely on the leaves but also on the fruit. When we started planning the project, we saw that there was very little scientific evidence for a possible relation between the transpiration of a bunch of grapes and the ripening speed of the grapes. Such a relationship could be very important, because one of the effects of climate change is precisely the acceleration of the development and ripening of grapes.

How does climate change affect grape quality?
In the last 30 years, it has been observed that grapes are harvested earlier and earlier, ripening sooner and under climate conditions that are far from optimal, in the presence of high temperatures that diminish the quality of the grapes. It is known that climate change is causing an imbalance between the accumulation of sugars and anthocyanins (which create the colour and, partially, the stability of wine in barrels) in grapes. If grapes are harvested with an optimum sugar level they do not have the anthocyanin concentration that they should, and if you wait until the anthocyanin is optimum the grapes are over-ripe and have a high sugar concentration that creates wine with a high alcohol content. It is thought that early ripening may be related with greater bunch transpiration. However, when this project was first planned there was scarce scientific evidence of it. On the other hand, climate change seems to be related with lower organic acid levels in grapes, which could produce must and wine with lower acidity.

How can those effects be anticipated so wines stay like the ones we know today?
In order to stay ahead of the effects of climate change we need to have deep knowledge of the physiological and metabolic changes that it causes in fruit development, and this project seeks to make progress in that direction. We are using prototypes developed in the course of the project to study the ripening process of grapes under high temperature conditions combined with a high concentration of CO2. Knowing how ripening advances with the prototypes we developed will let wine growers take action on their crops early and in a way based in data and make decisions to try to lessen the negative effects of the climatology. The actions wine growers do may be related with whether or not to water or deleaf, etc.

What are the prototypes we developed?
We worked on two prototypes, one for transpiration and the other for respiration. The transpiration prototype measures the amount of water, in the form of water vapour, the bunch emits into the atmosphere depending on environmental conditions. It is based on using relative humidity sensors. The respiration prototype measures the CO2 emitted and O2 consumed by the bunch as a consequence of the respiratory process. The prototype measures both gasses simultaneously and it is based on using CO2 and O2 sensors. The first one lets us know how fast ripening occurs, and the second one lets us know the final acidity of the wine grape. Both prototypes can be adapted to measure a complete bunch or separate berries.

Who could benefit from the prototypes?
The possible beneficiaries would be research groups working on wine grapes, wine growers and winemakers. In addition, the prototypes we have developed could be adapted for use with other kinds of fruit. The respiration of fresh fruit during post-harvest storage, for example, is closely related with the speed of progress towards ageing, so respiration rates are very important to determine the best handling and conservation conditions for those products, and so they reach consumers in the best possible conditions. That could be another potential application.

What are the material results of the project?
From a technical point of view, two prototypes used routinely in our research groups can be used to keep developing the grape vine line and climate change. From a scientific point of view, (i) we showed that transpiration determines ripening speed, which conditions the quality of the grape; and (ii) that grapes change the substrates they breath during the ripening process, from sugars to organic acids, which conditions the acidity of the must that will subsequently be made into wine.

What are the next steps for the project?
The project ended in November 2022, but we are still working along the same lines, so the prototypes developed will be used in upcoming grape vine and climate change experiments. Furthermore, we have some avenues of improvement in mind, like greater portability, using other sensors, miniaturising the ones we are using now, wireless data capturing could be used (Bluetooth to mobile phone), etc.