Avaliação dos parâmetros químicos, físicos e tecnológicos do sorgo produzido em Moçambique

Abstract

Sorghum (Sorghum bicolor (L.) Moench) is a staple food in many semi-arid and tropical areas of the world, particularly in sub-Saharan Africa, due to its adaptation to hostile environments. There is a growing interest in the use of sorghum in human food due to the low production cost and nutritional characteristics that allow its use as a functional ingredient. The sorghum breeding process to develop cultivars with high yields and acceptable grain quality at the Agricultural Research Institute of Mozambique (IIAM) resulted in obtaining of new cultivars with characteristics of interest that are not yet known and evaluated, making it difficult to understand their use. Thus, the objective of this study was to evaluate the chemical, physical , and technological parameters of the sorghum grain produced in Mozambique, as well as the extraction and characterization of its starch. Samples of 3 sorghum cultivars (Mucuveia, Otela, Tocole) and one variety (criola) named Local were evaluated. The grains were characterized according to the weight of a thousand grains, hectoliter weight, dimensions, and color. Proximal composition, in vitro digestibility of starch, soluble protein, protein digestibility, anti-nutritional factors, phytochemical content, and total and antioxidant activity were determined in grains transformed into flour. Starch from sorghum grains was extracted and quantified for extraction yield, purity, amylose content, paste properties, swelling power, solubility, transmittance, thermal properties, relative crystallinity, in vitro digestibility, and morphology. The protein content, lipids, tannins, anthocyanins, estimated glycemic index, protein digestibility, soluble proteins, thousand-grain weight, and hectoliter weight were lower in the cultivars in relation to the variety (criola) Local, characteristics achieved with the improvement oriented to increase yield; in contrast, it showed a higher value in carbohydrate, ash, free phenolic, fiber, starch yield, flavonoids, and antioxidant activity. The feasibility of using sorghum flour as a high source of resistant starch (RS) was confirmed, as the cultivars had a higher RS content, being beneficial for human nutrition. The sorghum starch granules showed a polyhedral and spherical structure. Starches showed a type A diffraction pattern. Starches from Tocole and Mucuvea cultivars had higher and lower percentages of starch hydrolysis, respectively. The cultivars showed higher gelatinization temperatures, denoting the need for more energy to gelatinize. The variety (criola) Local had a higher viscosity peak, demonstrating good potential for use as a thickener. These results will contribute to the generation of scientific knowledge about the composition and technological properties of the cultivars Mucuvea, Tocole, and Otela and variety (criola) Local.