Thermal Processing Strategies Enhance the Safety and Quality of Whole-Grain Pearl Millet Flour
DOI:
https://doi.org/10.17921/1415-6938.2026v30n2p231-243Abstract
Pearl millet grains harvested in the field undergo physical cleaning to remove extraneous materials and impurities; however, these processes do not avoid microbiological contamination. This study aimed to evaluate the effects of cooking, extrusion, and roasting of whole-grain pearl millet flours on the reduction of microbial contamination, color and water absorption capacity. Thermal processes significantly reduced contamination across all treated samples, with raw flour showing the highest contamination (up to 6.19 log10 for enterobacteria). In contrast, extruded, roasted, and pre-cooked flours had lower contamination levels (ranging from 1.00 to 2.1 log10). No Salmonella was detected, and E. coli and Bacillus cereus were within safe limits. Pre-cooking led to significant darkening, while extrusion preserved brightness. Furthermore, the water absorption index was notably higher (4.12 g/g) in extruded flour, suggesting improved functionality for hydration-demanding applications. In contrast, roasted flour exhibited the lowest water absorption capacity (2.08 g/g), indicating application in products with dry texture. The thermal processing improves the microbiological safety of whole-grain pearl millet flour, making it a safe option for the cereal processing industry.
Keywords: Food Contamination. Food Industry. Food Safety. Technological Properties. Whole-Grain Cereal.
Resumo
Os grãos de milheto coletados no campo passam por limpeza física para remover materiais estranhos e impurezas; entretanto, esses processos não evitam a contaminação microbiológica. Este estudo objetivou avaliar os efeitos do cozimento, extrusão e torrefação de farinha de milheto integral na redução da contaminação microbiana, na cor e na capacidade de absorção de água. Os processos térmicos reduziram significativamente a contaminação em todas as amostras tratadas, com a farinha crua apresentando maior contaminação (até 6,19 log10 para enterobactérias). Em contraste, as farinhas extrudadas, tostadas e pré-cozidas tiveram níveis de contaminação menores (variando de 1,00 a 2,1 log10). Salmonella não foi detectada e E. coli e Bacillus cereus estavam dentro dos limites seguros. O pré-cozimento levou a um escurecimento significativo, enquanto a extrusão preservou a luminosidade. Além disso, o índice de absorção de água foi mais alto (4,12 g/g) na farinha extrudada, sugerindo uma funcionalidade melhorada para aplicações que demandam hidratação. Em contraste, a farinha tostada exibiu a menor capacidade de absorção de água (2,08 g/g), indicando aplicações em produtos com textura seca. O processamento térmico melhora a segurança microbiológica da farinha de milheto integral, tornando-a uma opção segura para a indústria de processamento de cereais.
Palavras-chave: Cereal Integral. Contaminação de Alimentos. Indústria de Alimentos. Propriedades Tecnológicas. Segurança de Alimentos.
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Copyright (c) 2026 Isabella Maciel Costa, Cosme Damião Cosme Damião, Bruna Maria Salotti de Souza, Carlos Wanderlei Piler de Carvalho, Felipe Machado Trombete , Camila Argenta Fante
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