Extraction and characterization of starches from pigmented sorghum and its possible applications in the food

Resumo

Sorghum is a starchy cereal cultivated worldwide but is primarily common as a human food in Africa and Asia. Sorghum starch is not a very exploited product despite its great nutritional potential and low added value, mainly because it has varieties with a high content of pigment compounds, and it impacts the final product's appearance. This work aimed to extract and characterize the starch of three colored sorghum cultivars (Commercial Red, SSG150T and BRS Ponta Negra) and evaluate the physicochemical properties, morphological, technological and bioactive properties of starches. In addition, suggest applications of these starches with natural pigments in the food industry. The extraction made was aqueous, and the starches were characteristics regarding its proximal composition, instrumental parameters of color, the content of amylose, thermal properties, admission profile and texture profile, X-ray, crystallography, IR spectroscopy and microstructure by scanning electron microscopy (SEM). To verify the properties of bioactive compounds and pigments, the content of phenolic compounds and antioxidant activity were analyzed by DPPH and mass spectrometry using catechin, quercetin and gallic acid as standard. Moreover, the analysis of principal components is based on the variables studied. The results show differences among the starches of the tested varieties. Principal component analysis showed that two principal components were needed to explain 78.44% of the total variance, spanning 18 of 23 vectors. The sorghum starches are considered native and have several applications since they have pigmenting and bioactive compounds that extend their benefits into consumer-demanded applications for more natural and functional use. Other studies may be carried out to understand better the uses and functionalities of these naturally pigmented starches.