Avaliando o potencial do sorgo para a alimentação humana: efeitos de diferentes métodos de processamento térmico sobre a composição nutricional e de bioativos, atividade antioxidante e resposta glicêmica
Arquivos
Data
2024-06-25
Autores
Aguiar, Etiene Valéria 
Orientadores
Capriles, Vanessa Dias
Tipo
Tese de doutorado
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Resumo
O sorgo (Sorghum bicolor (L.) Moench) tem atraído o interesse de pesquisadores, da indústria de alimentos e de consumidores devido a sua composição nutricional e de bioativos, isenção de glúten e potencial como ingrediente alimentar. Este grão integra a alimentação humana em países asiáticos e africanos e vem ganhando popularidade em outras regiões. No Brasil a sua produção ainda é destinada, quase exclusivamente, para a alimentação animal. Considerando o potencial deste grão para promover a saúde humana e a segurança alimentar e nutricional, é necessário estudar técnicas de processamento que viabilizem o seu consumo. Assim, o objetivo deste trabalho foi estudar os efeitos do processamento na composição, na atividade antioxidante, e na resposta glicêmica do sorgo. Foram utilizados grãos de sorgo dos genótipos BRS 305 com taninos e BRS 373 sem taninos e estudados os processos de cocção por calor úmido, pipoqueamento e cocção por extrusão, que são usualmente empregados no processamento dos cereais habitualmente consumidos. As amostras de sorgo cru, cozido, pipocado e extrudado foram avaliadas quanto à composição centesimal e de bioativos e à atividade antioxidante in vitro. Foi avaliada a permeação de glicose e a capacidade do sorgo após a digestão em inibir a atividade das enzimas α-amilase e α-glicosidase in vitro. Também foram avaliadas a resposta glicêmica em humanos e a saciedade ocasionadas após o consumo das amostras de sorgo cozidas, pipocadas e extrudadas. Os resultados mostraram que o grão cru do sorgo com taninos apresentou níveis mais elevados de fibra alimentar, amido resistente (AR), antocianinas, fenólicos totais e atividade antioxidante do que os teores de sorgo cru sem taninos. As três técnicas de processamento térmico ocasionaram redução nos teores de fibra alimentar e do AR, além de causar mudança na digestibilidade in vitro do amido, caracterizada pelo grande aumento na fração de amido rapidamente digerível (ARD). Dentre os processos, a cocção por calor úmido foi o que causou menor perda de AR nos dois genótipos de sorgo. Apesar das perdas causadas pelo processamento, os produtos obtidos com o sorgo com taninos apresentaram maior teor de compostos bioativos (fibra alimentar, AR, taninos, antocianinas e ácidos fenólicos) do que os produtos à base de sorgo sem taninos. Porém, isso não foi suficiente para influenciar a resposta glicêmica do sorgo cozido, estourado ou extrudado, de acordo com os resultados obtidos em testes in vitro e em humanos. Não houve diferença no índice glicêmico, na carga glicêmica e no índice de saciedade entre os produtos com ou sem taninos. Porém, comparados ao arroz cozido, à pipoca e ao extrudado de milho, os produtos de sorgo se destacaram pelos maiores teores de proteínas, fibras e compostos bioativos e uma menor carga glicêmica. Portanto, o sorgo apresenta grande potencial para a obtenção de produtos alimentícios nutricionalmente melhorados, que podem ser utilizados para consumo direto ou como ingrediente na elaboração de preparações culinárias.
Sorghum (Sorghum bicolor (L.) Moench) has attracted the interest of researchers, the food industry and consumers due to its nutritional and bioactive composition, gluten free and potential as a food ingredient. This grain is part of human food in Asian and African countries and is gaining popularity in other regions. In Brazil, its production is still destined, almost exclusively, for animal feed. Considering the potential of this grain to promote human health and food and nutritional security, it is necessary to study processing techniques that enable its consumption. Thus, the objective of this work was to study the effects of processing on the composition, antioxidant activity and glycemic response of sorghum. Grains of sorghum genotypes BRS 305 with tannins and BRS 373 without tannins. The processes of moist heat cooking, popping and extrusion cooking, which are usually used in the processing of commonly consumed cereals, was studied. Raw, cooked, popped and extruded sorghum samples were evaluated for centesimal and bioactive composition and in vitro antioxidant activity. Total phenolics, tannins, digestible and resistant starches, and dietary fiber were determined. Glucose permeation in models of Caco-2 cells was evaluated, as well as the ability of sorghum after digestion to inhibit in vitro the activity of α-amylase and α-glucosidase enzymes, and the in vivo determination of the glycemic index (GI) and glycemic load (GL) from a short-term human trial. Raw ST presents higher levels of dietary fiber, resistant starch (RS), tannins, anthocyanins, total phenolics and antioxidant activity than SNT. The three thermal processing techniques caused a reduction in the levels of dietary fiber and RS, in addition to causing changes in the in vitro starch digestibility, characterized by a large increase in the rapidly digestible starch fraction (RDS). Among the processes, moist cooking was the one that caused the greatest increase in RDS and the greatest retention of RS for the two sorghum genotypes. Despite the losses caused by processing, products obtained from sorghum with tannins have a higher content of bioactive compounds (dietary fiber, RS, tannins, anthocyanins, and phenolic acids) than products based on sorghum without tannins. However, this was not enough to influence the glycemic response of cooked, popped, or extruded sorghum, according to the results obtained in vitro and human trials. There is no difference in the glycemic index (GI), glycemic load (GL) and satiety index between products obtained with or without tannins. However, compared to cooked rice, popcorn, and extruded corn, sorghum products stand out for their higher levels of protein, fiber and bioactive compounds and a lower GL. Therefore, sorghum shows a great potential for obtaining nutritionally improved and ready-to-eat food products, which can be used for direct consumption or as an ingredient to be used in culinary preparations.
Sorghum (Sorghum bicolor (L.) Moench) has attracted the interest of researchers, the food industry and consumers due to its nutritional and bioactive composition, gluten free and potential as a food ingredient. This grain is part of human food in Asian and African countries and is gaining popularity in other regions. In Brazil, its production is still destined, almost exclusively, for animal feed. Considering the potential of this grain to promote human health and food and nutritional security, it is necessary to study processing techniques that enable its consumption. Thus, the objective of this work was to study the effects of processing on the composition, antioxidant activity and glycemic response of sorghum. Grains of sorghum genotypes BRS 305 with tannins and BRS 373 without tannins. The processes of moist heat cooking, popping and extrusion cooking, which are usually used in the processing of commonly consumed cereals, was studied. Raw, cooked, popped and extruded sorghum samples were evaluated for centesimal and bioactive composition and in vitro antioxidant activity. Total phenolics, tannins, digestible and resistant starches, and dietary fiber were determined. Glucose permeation in models of Caco-2 cells was evaluated, as well as the ability of sorghum after digestion to inhibit in vitro the activity of α-amylase and α-glucosidase enzymes, and the in vivo determination of the glycemic index (GI) and glycemic load (GL) from a short-term human trial. Raw ST presents higher levels of dietary fiber, resistant starch (RS), tannins, anthocyanins, total phenolics and antioxidant activity than SNT. The three thermal processing techniques caused a reduction in the levels of dietary fiber and RS, in addition to causing changes in the in vitro starch digestibility, characterized by a large increase in the rapidly digestible starch fraction (RDS). Among the processes, moist cooking was the one that caused the greatest increase in RDS and the greatest retention of RS for the two sorghum genotypes. Despite the losses caused by processing, products obtained from sorghum with tannins have a higher content of bioactive compounds (dietary fiber, RS, tannins, anthocyanins, and phenolic acids) than products based on sorghum without tannins. However, this was not enough to influence the glycemic response of cooked, popped, or extruded sorghum, according to the results obtained in vitro and human trials. There is no difference in the glycemic index (GI), glycemic load (GL) and satiety index between products obtained with or without tannins. However, compared to cooked rice, popcorn, and extruded corn, sorghum products stand out for their higher levels of protein, fiber and bioactive compounds and a lower GL. Therefore, sorghum shows a great potential for obtaining nutritionally improved and ready-to-eat food products, which can be used for direct consumption or as an ingredient to be used in culinary preparations.
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Citação
AGUIAR, Etiene Valéria. Avaliando o potencial do sorgo para a alimentação humana: efeitos de diferentes métodos de processamento térmico sobre a composição nutricional e de bioativos, atividade antioxidante e resposta glicêmica. 2024. 160 f. Tese (Doutorado em Nutrição) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP). São Paulo, 2024.