Amidos de sorgos pigmentados com potencial para aplicação na indústria de alimentos

• Ano de defesa: 2022
• Autor(a) principal: Telles, Alice Duarte Mendonça
• Orientador(a): Caliari, Márcio
• Banca de defesa: Caliari, Márcio, Ribeiro, Alline Emannuele Chaves, Oliveira, Aryane Ribeiro
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Ciência e Tecnologia de Alimentos (EA)
• Departamento: Escola de Agronomia - EA (RMG)
• País: Brasil
• Palavras-chave em Português: Amido pigmentado; Sorgo colorido; Extração de amido; Propriedades tecnológicas; Compostos bioativos
• Palavras-chave em Inglês: Pigmented starch; Colored sorghum; Starch isolation; Technological properties; Bioactive compounds
• Área do conhecimento CNPq: CIENCIAS AGRARIAS
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/12634

Sorghum (Sorghum bicolor [L.] Moench) is the fifth most-produced cereal in the world, but it is not homogeneously present in human food worldwide. Like the other species of the Poaceae family, sorghum is rich in nutrients, mainly starch. Because it has several varieties, sorghum has different colors and is rich in natural pigments, mainly phenolic acids and antioxidant compounds. Starch extracted from colored sorghum is a naturally pigmented product and is generally ignored by the industry as it does not meet the white-bright standard. Therefore, this work aims to extract and characterize starches from different cultivars of pigmented sorghum and evaluate their potential for use in the food industry. Initially, a bibliographic review was carried out about starches extracted from colored raw materials, aiming to understand and identify their characteristics and properties. Afterward, the aqueous extraction and characterization of the starch of three colored sorghum cultivars (Comercial Vermelho, SSG150T, and BRS Ponta Negra) were carried out. Aqueous extraction of the starches was carried out, whose yields varied between 4 and 6%. Starches were separated into types A and B for red commercial sorghum and BRS Ponta Negra sorghum. Sorghum SSG150T had only one type of starch. In total, five different starches from 3 sorghum varieties were analyzed. The starches were characterized according to their proximal composition, indicating moisture between 8.32 and 10.84%, ash content close to zero, and water activity between 0.31 and 0.48. As for the color analysis, the starches had variations in brightness between 75.67 and 95.52, chroma between 3.46 and 9.94, and Hue angle between 32.63 and 79.48. The amylose content present in the starches varied between 28.50 and 38.50%. The viscosity profile showed maximum viscosity peaks between 1314.5 and 2656.2 cP and minimum viscosity between 710 and 1086.3 cP. Paste temperatures varied between 67.1 and 68.4 C. The texture profile was carried out, showing results of hardness between 1.95 and 6.62 N. The X-ray diffraction analysis showed crystallinity results of starches between 15.10 and 21.02%. As for the thermal properties analyzed via RVA, the samples presented initial temperature between 64.01 and 66.91 C, peak temperature between 70.19 and 73.09 C, and final temperature between 80.12 and 87.25 C to the enthalpies of gelatinization of the samples between 4.70 and 11.56 J/g. Fourier Transform IR spectrometry analysis demonstrated that the starches are in their native form. The SEM analysis showed that starches have spherical and polyhedral shapes, and some extracted starches have several non-starch compounds and brittle granules. The antioxidant content of the starches was analyzed using the DPPH discoloration method, highlighting the BRS Ponta Negra type B sorghum starch with 64.24% discoloration. The other starches showed percentages of discoloration between 2.26 and 6.25%, and the red type A commercial sorghum starch did not obtain tangible results. The content of phenolic compounds was analyzed by the Folin-Ciocalteu method. It was not possible to obtain results for starch from commercial red sorghum, sorghum SSG150 T obtained content of 12.44 µg of gallic acid per ml, and starches from BRS Ponta Negra sorghum type A and type B obtained, respectively, with contents of 0.11 and 63.23 µg of gallic acid per ml. Mass spectrometry analysis was performed using catechin, quercetin, and gallic acid as standard, and the three compounds were identified in extracts of all starches. Finally, principal component analysis (PCA) was performed using the results found. The results show the potential for using sorghum starch in various branches of the food industry, such as applications that require using natural dyes and foods enriched in bioactive compounds.