Rice, it is known, is a food considered staple in most of the world’s gastronomies, and it contributes in a good way to the caloric intake of the human diet. However, as it is a cereal, it does not stand out especially for its protein content, and that is why the possibility of incorporating this type of nutrients is a permanent challenge in food improvement strategies.
However, there is a variety that was generated almost 20 years ago at the Faculty of Agricultural and Forestry Sciences of the National University of La Plata within the framework of the “Rice Program”, dedicated at the time to the improvement of the species, which had the characteristic of having 30 percent more protein than commercial rices for mass consumption.
The variety in question is called Nutriar, and it is an inexpensive product that does not require processing such as grinding for its intake, and given its characteristics it is of great importance for human consumption given its high nutritional value.
The issue is that now, another team of researchers from Conicet La Plata managed to describe the physiological mechanisms by which this variety conserves 30 percent more protein, which caused international interest, since the results of this work were recently published. in the scientific journal “Plant Physiology and Biochemistry”.
“Within the framework of our study topic – describes Lucrecia Puig, first author of the scientific work – we were interested in characterizing the processes that allow this plant to have a grain with a high protein content, something that makes it very valuable because we were also able to verify that this feature does not detract from its performance compared to conventional rices for mass consumption ”.
Is that, according to local researchers, this variety preserves practically the same yield as common rice, which is 9 thousand kilograms per hectare, but with 30 percent more protein of high final quality, which would be due to the existing differences in the level of photosynthesis between this variety and the most common ones.
To determine this process, the scientists analyzed the electron transport chains, which are what give the plant the energy necessary to convert carbon dioxide (CO2) into sugars that the plant uses for its growth, which happens in a first phase, called light, in which the sunlight is captured by structures called photosystems.
“In the comparison – highlights Puig – we saw that Nutriar disarms its photosystems much faster, and we believe that here is the key”.
According to figures from the “Rice Program”, in Argentina between 8 and 9 kilos of rice are consumed per capita each year, a low number compared to other countries, although as it is a highly demanded food, especially from the most vulnerable social sectors , its improvement is a strategic point because it can contribute to considerably enrich the quality of the diet, for example in neighborhood or school canteens, according to specialists.
“There is something paradoxical – says Puig – and it is the fact that there are food companies that add protein to common rice in the form of soups or dehydrated stews, which shows the importance of betting on a crop that can be nutritionally superior without need of aggregates ”.
THE SECRETS OF THE “SUPER RICE”
Since the improvement of species is a complex process that requires many years of trials and tests, the “Nutriar” is still in development.
Alfonso Vidal, director of the “Rice Program” during the emergence of this protein variety, says that “generally we received grains from other parts of the world with a certain characteristic in particular, we evaluated them and crossed our own lines with some other outstanding characteristic. This work takes several generations to achieve stability, because it is necessary to analyze the offspring plant by plant to verify not only that they maintain the protein, but that they inherit the gene that predisposes to that higher protein concentration, and that the best specimens be selected. And so this grain arose, which once obtained had to be tested in the field with producers to see how it responded over several cycles to temperatures, soil fertility and other conditions ”.
Researchers from La Plata point out that there are many types of rice, aromatic, glutinous, reddish or black, or for different uses, such as sushi or risotto. But high protein varieties are not very common, let alone perform as well in large crops.
Santiago Maiale, also a researcher at Conicet La Plata, when explaining how they compared the behavior in the different phases of photosynthesis of the Nutriar crop with others of common rice, points out that “by means of chlorophyll fluorescence, a measurement technique does not destructive, we measured several times over time how the photosystems behaved, and then we related it to the transport of nitrogen within the plant to the grain, which we observed to do so at a faster rate and in greater quantity. This would show that the cultivar takes better advantage of the absorbed nitrogen, and that this step of the process is decisive in its condition as high protein rice ”.
These measurements and studies during photosynthesis were carried out mainly on the so-called “flag leaf”, as the last one that comes out before fruiting is called, that is, the spike or panicle sprouts in grasses, a family of plants that includes the rice, barley or wheat.
“It is the one that receives the greatest amount of radiation – Maiale details – because it is located above all, with which it does not have shadows. In this way, it contributes the largest amount of photoassimilates, which are the substances synthesized by plants from CO 2, to the panicle that contains the grains. In addition, being the newest blade, it has all the systems working optimally ”.
It was thus that, repeatedly, the experts analyzed different parameters, such as number of stomata or chlorophyll concentration, to unravel the physiological mechanisms that increase the level of protein in grain, which serves as a guide for breeders when performing the test. selection process, until achieving the best protein results from the super rice from La Plata.