Italian scientists tailor iodine and potassium content of radishes, peas, rocket, and chard

Using a soilless cultivation approach, the research team were able to produce iodine-biofortified microgreens to address iodine deficiency, and potassium-reduced microgreens for chronic kidney disease-affected people.

“Biofortification is the process of increasing the bioavailable concentration of a nutrient in the edible portion of cultivated plants through agronomic interventions or genetic selection,” explained study co-author Dr Massimiliano D’Imperio. 

“This emerging frontier of biofortification aims to customise plant nutrition, producing tailored foods for specific population groups,” added D’Imperio, who is based at the Institute of Sciences of Food Production (ISPA) National Council of Research (CNR). 

“The goal of this research is to demonstrate that calibrated vegetables can be obtained in common production contexts, such as the Ortogourmet company, without modifying production systems but by intervening solely through agronomic techniques.”

Personalised nutrition to ease medical complaints?

Along with Dr Francesco Serio, also based at the ISPA and CNR; and Dr Massimiliano Renna, professor of agricultural and environmental science at the University of Bari Aldo Moro, Italy, the team believes the approach could form part of a bespoke nutritional plan to address complex medical needs.

They grew microgreens with a 45% reduction in potassium levels, to cater for chronic kidney disease sufferers – for whom its intake must be restricted to avoid health complications. Similarly, the team successfully cultivated plants with iodine content up to 14 times higher than unfortified microgreens, which could be an alternative iodine source to table salt.

“Propelled by an ever-growing awareness of the importance of following dietary recommendations, interest in personalised nutrition is on the rise,” said Renna. “Soilless biofortification of vegetables has opened the door to the potential for adapting vegetable production to specific dietary requirements.”

Study conducted in the commercial setting of Ortogourmet

The study, which appears in the Journal of the Science of Food and Agriculture, was conducted at Ortogourmet, a working microgreen farm in Italy that supports the viability of cultivating customised microgreens on a large scale while maintaining optimal agronomic performance.

Commenting on future plans to assess the bioaccessibility of mineral elements in different microgreen species, D’Imperio said: “It is possible to assess the amount of nutrients released from the plant matrix during the digestion process, allowing an analysis of the potential impact of the matrix itself.

“Indeed, the release of nutrients from the plant matrix depends on its composition and how other components can influence release and, subsequently, absorption in the gastrointestinal tract. With an interdisciplinary approach, it is possible to evaluate which species could potentially provide a greater quantity of nutrients from a nutritional perspective.” 

Reducing nutrient concentration without compromising on yield and marketable quality

The researchers are also turning their attention to reducing potassium concentration in plants without negatively impacting yield and marketable quality.

This is proving to be a challenge since vegetables are generally particularly rich in potassium (up to 10% of plant dry weight).

“There are several approaches to reduce potassium without excessively influencing crop performance and chemical composition,” said D’Imperio. “Some of these include identifying vegetable species, cultivars, or varieties that are less sensitive to reduced potassium in the nutrient solution commonly used in soilless cultivation systems.

"Another approach is to reduce potassium supplied to the plants in the days leading up to harvest. This way, plants are not overly stressed, but a significant reduction in potassium content in the edible portion can still be achieved. In summary, balancing potassium reduction with the need to maintain crop quality and yield is an important challenge for farmers and researchers in horticulture.”