Qualidade tecnológica de grãos de arroz biofortificados com minerais

Abstract

Mineral deficiency affects millions of people worldwide causing public health issues. Grain biofortification is a viable alternative to minimize this problem and rice crops are a prominent potential for biofortification. The objectives of this study were to analyze the influence of the agronomic biofortification on the technological quality of rice grains, verify the effect of these mineral sources on different application forms (leaf and soil), and evaluate the mineral concentrations in the peel, bran + germ, and endosperm of the grains. In the present study, samples were analyzed using 16 treatments: A (control, application of soil nitrogen, phosphorus, and potassium (NPK)); B (NPK + soil fertilization with a source of ZnSO4.7H2O); C (NPK + two leaf fertilizations with a source of ZnSO4.7H2O); D (NPK + two leaf fertilizations with a source of ATP Releaf); E (NPK + two leaf fertilizations with a source of KIO3); F (NPK + two leaf fertilizations with a source of KIO3 + KNO3); G (NPK + two leaf fertilizations with a source of ADOB-ZnIDHA); H (NPK + two leaf fertilizations with a source of ADOB-Basfoliar); I (leaf fertilization with a source of Kali-EPSO-Zn and urea); J (NPK + leaf fertilization with a source of Zn); K (NPK + two leaf fertilizations with a source of Bayer Antracol-Zn); L and M (NPK + leaf fertilization with micro spray leaf cocktail I and II, respectively); N and O (NPK + soil fertilization with a source of Ca + Mg, differing only in the concentration of Mg (gypsum)), and P (NPK + leaf fertilization with a source of Quimofol Znitro). In the first study, we evaluated the influence of the agronomic biofortification by analyzing the yield income (%) and grain yield (%). The results showed that, despite some biofortification treatments having improved these parameters, the samples did not present a good classification since, according to the Ministry of Agriculture, Livestock, and Supply, only the sample with treatment B was classified as type 4, while the others were atypical. In the second study, we analyzed the influence of the agronomic biofortification on the technological quality of the rice grains through the cooking test. We also aimed at determining the contents of protein and ashes and conducted the instrumental color analysis in the grains. The results obtained from the cooking test showed that the biofortification positively altered the samples in the treatments C, M, and N by reducing their cooking times and maintaining the other analyzed parameters. Regarding the instrumental color analysis, we note that the samples in the treatments C, D, H, J, K, M, and P did not differ from the control and, together, they presented better results among the others, presenting higher clarity, neutral colors, and yellowish saturation. The results for the ash analysis were satisfactory in some biofortification treatments, with the samples of treatments I and L presenting the highest concentrations of fixed mineral residue. When analyzing the protein content, the samples in the treatments E, F, H, I, J, L, M, N, and O presented the best results. Finally, the third study analyzed the efficiency of agronomic biofortification on rice grains and sought to identify in which part of the grain the highest concentration of Zn was found. The results showed that the biofortification did not significantly alter the concentration of Zn in the endosperm and that, in general, the highest concentrations are found in the bran and germs. The treatment C presented a higher concentration of Zn in the peels. Therefore, to obtain effective biofortification, we recommend the consumption of whole grains or the application of a parboiling treatment for the minerals to migrate to the endosperm of the grains.