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Improved flavour of herbs and vegetables grown in greenhouses with UV light

Victor Castro-Alves in greenhouse.

Victor Castro-Alves is one of many researchers contributing to the university’s initiative within food and health.

“Plants cannot choose to stay out of the sun or use sunscreen. Instead they produce substances that protect them from the sun’s UV light. These substances have an effect on flavour, colour and nutritional value,” says Örebro researcher Victor Castro-Alves. His research examines how we, by using UV light, can improve the flavour of greenhouse herbs and vegetables.

Örebro University gathers research on what is really near and dear to us - food and health - to make sure that it benefits society. Read more about the strategic initiative Food and Health.  

There are many advantages with greenhouses. They make it possible to grow plants all year round and they provide protection against various types of damage and disease. They do however shut out UV light. This gives the plants a different flavour compared to vegetables grown outdoors.

“We’ve got a hunch as to why plants growing outdoors taste better – but we don’t as yet know the exact processes taking place in the plants.”

Researchers are comparing plants growing under different kinds of light – various kinds of UV light but also different forms of visible light: blue, green or red.

“Not all plants react in the same way. We have chosen to start with basil and dill since they are common greenhouse products in Sweden,” says Victor Castro-Alves.

Key group of molecules

The analyses of which molecules develop in the cells of the plant are compared with sensory analyses performed by the School of Hospitality, Culinary Arts and Meal Science.

“We repeat the experiments at least three times to identify which key group of molecules affects good taste, and to understand which light is needed for these to be produced. ”

The first results for dill are done.

“We have used UVA and UVB light and have come close to what a sensory panel from the School of Hospitality, Culinary Arts and Meal Science has defined as gold standard when it comes to flavour.”

In time, the research will involve more plants, such as cucumbers, and also study how UV light affects the nutritional content of vegetables.

Part of Food and Health

This research sorts under the university’s focus area Food and health, and Victor Castro-Alves is one of nine postdoctoral researchers in this initiative.

“It was as if this position was made for me. It combines chemistry, plant science and sensory analysis. It is everything I have done before,” he says.

Originally from Brazil, Victor Castro-Alves has for a number of years worked with agricultural breeding programmes, both at a Brazilian national corporation and within academia. He has for instance examined how the surrounding environment of a crop influences the quality of the fruit, in this case bananas.

“Bananas that are surrounded by a diversity of other plants are better prepared to withstand various damage and disease. In addition, they keep longer. A banana that has grown in the middle of a banana plantation keeps for about 8-9 days after harvest, while a banana surrounded by various other plants keeps for 20 days. It’s a big difference,” says Victor Castro-Alves.

What happens inside fruit

The main thread of his work is the quest to understand what happens inside fruit and vegetables if you want a better-quality product. However, his doctoral thesis in food science from the University of São Paulo had a different focus:

“My PhD thesis explored dietary fibres and their effects on the immune system. But even there, I examined various structures in fruit and fungi to understand what is best for strengthening our immune system.”

Text and Photo: Linda Harradine
Translation: Charlotta Hambre-Knight