Search

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2019. O câncer é a segunda maior causa de morte humana na atualidade. É considerada uma doença multifatorial, podendo estar associado a fatores ambientais como a dieta. Esta tese, composta por cinco capítulos, teve como principal objetivo elucidar a formação dos mutagênicos 2-metil-1,4-dinitro-pirrol (DNMP) e do ácido etilnitrólico (ENA) na reação entre conservantes utilizados no processamento de carnes. Para isso, diversas ferramentas analíticas e modelos estatísticos foram desenvolvidos com êxito proporcionando inovação química a esse cenário. Os resultados obtidos corroboram a decisão da Agência Internacional de Pesquisa sobre Câncer (IARC) de classificar as carnes processadas como cancerígenas para humanos. Mais de 100 amostras comerciais foram analisadas e 38% continham adição irregular de nitrito e sorbato. Além da utilização excessiva de conservantes, ENA (> 5,00 µg kg-1) e DNMP (> 12,0 µg kg-1) foram detectados em amostras de mortadela, bacon, linguiça calabresa e patê. Além disso, mortadelas produzidas em escala piloto com 0,3% de nitrito e 0,034% de sorbato, sem eritorbato de sódio, apresentaram altas concentrações de ENA e DNMP. Esses resultados alertam sobre um grande problema de saúde pública, demandando incremento da fiscalização e Ciência dos Alimentos para sua resolução. Dessa forma, o micro-organismo Lactobacillus bulgaricus (LB-UFSC 001) foi empregado em um tratamento experimental para que, através da fermentação, pudesse biodegradar ENA e DNMP na mortadela fabricada em escala piloto. Houve diferença significativa (p < 0,05) das concentrações de ENA e DNMP nas mortadelas antes e após o tratamento. A identificação dos principais metabólitos contribuiu para a elucidação das principais rotas metabólicas, demonstrando que LB-UFSC 001 utiliza-se de nitrorredutases e hidratases nitrílicas para modular os compostos mutagênicos na matriz cárnea. Esta tese demonstrou que compreender os mecanismos envolvidos na formação e inibição de carcinógenos, bem como a composição química e microbiológica da matriz, pode fornecer evidências mais claras sobre as classificações de risco de câncer atribuídas mundialmente ao consumo de carnes processadas. Abstract: Cancer is the second leading cause of human death today. It is considered a multifactorial disease and may be associated with environmental factors such as diet. This thesis, composed of five chapters, aimed to elucidate the formation of mutagens 2-methyl-1,4-dinitro-pyrrol (DNMP) and ethyl nitrolic acid (ENA) in the reaction between preservatives used in meat processing. For this, several analytical tools and statistical models have been successfully developed providing chemical innovation to this scenario. The results corroborate the decision of the International Agency for Research on Cancer (IARC) to classify processed meats as carcinogenic to humans. More than 100 commercial samples were analyzed and 38% contained irregular addition of nitrite and sorbate. In addition to non-compliant of preservatives, ENA (> 5.00 µg kg-1) and DNMP (> 12.0 µg kg-1) were detected in samples of mortadella, bacon, pepperoni, and pâté. Moreover, high concentrations of ENA and DNMP were quantitated in mortadella produced on a pilot scale with 0.3% nitrite and 0.034% sorbate without sodium erythorbate. These results warn of a major public health problem, demanding the improvement of official inspection and food science for its resolution. Thus, the microorganism Lactobacillus bulgaricus (LB-UFSC 001) was used in an experimental treatment to biodegrade ENA and DNMP by fermentating mortadella samples produced in pilot scale. There was a significant difference (p < 0.05) in ENA and DNMP concentrations in the mortadellas before and after treatment. The identification of the main metabolites contributed to the elucidation of the main metabolic pathways, demonstrating that LB-UFSC 001 uses nitro reductases and nitrile hydratases to modulate mutagenic compounds in the meat matrix. This thesis has shown that understanding the mechanisms involved in carcinogen formation and inhibition, as well as the chemical and microbiological composition of the matrix, can provide clearer evidence on the cancer risk ratings attributed to the consumption of processed meats worldwide.

Background: β-glucans (1-3: 1-4) are soluble fibers applied to foods due to their technological properties (water binding capacity, viscosity, emulsification and stabilization) and their beneficial effects on health. The functional properties of β-glucans can be lost during the extraction and purification processes. The high viscosity of β-glucans is related to a high molecular weight and its physiological properties in the intestine. Therefore, to characterize the fiber after its extraction and purification is fundamental to understand its possible applications in foods. Objectives: characterize β-glucans extracted (EβG) and compare them with three commercial β-glucans (CβG-A, CβG-B and CβG-C) to identify its possible applications in foods and to evaluate if enzymatic purification affects molecular and structurally the β-glucans. Methods: barley β-glucans were extracted (EβG), characterized by chemical analyzes, rheological behavior, and color, and compared to three commercial β-glucans samples. Then, the extract was purified and its structural and molecular characteristics were calculated. Results: EβG contained 64.38 ± 3.54% of β-glucans, high starch contamination (12.70 ± 1.73%), high content of calcium (8894 mg/kg), pseudoplastic behavior, and dark color (L* = 52.77 ± 0.7). All commercial samples showed low starch contamination, lighter color, and Newtonian behavior. After purification starch and protein contamination decreased (0.85 ± 0.46% and 5.50 ± 0.12% respectively), increased the content of βG (69.45 ± 0.81%) and increased brightness (L* = 92.60 ± 1.70). Purified β-glucans (PβG) showed a molar weight of 690 ± 1.6 kDa and species with degree polymerization 3 (DP3) to 11 (DP11) were identified on the structure. Conclusions: EβG extracts before the purification presented a high viscosity and contamination. The enzymatic purification process was effective and allowed to maintain a high molar mass of PβG and its distinctive molecular structures (species with DP3 and DP4). The commercial samples CβG-A and CβG-B showed a low content of β-glucans. Finally, CβG-C presented the best physicochemical and rheological properties for its subsequent application in food. RESUMEN Antecedentes: los β-glucanos (1-3: 1-4) son fibras solubles aplicadas a los alimentos debido a sus propiedades tecnológicas (capacidad de retención de agua, viscosidad, emulsificación y estabilización) y a sus efectos beneficiosos en la salud. Las propiedades funcionales de los β-glucanos pueden perderse durante los procesos de extracción y purificación. La alta viscosidad de los β-glucanos está relacionada con un alto peso molecular y con sus propiedades fisiológicas en el intestino. Por lo tanto, caracterizar la fibra después de su extracción y purificación es fundamental para comprender sus posibles aplicaciones en alimentos. Objetivos: caracterizar β-glucanos extraídos (EβG) y compararlos con tres marcas comerciales (CβG-A, CβG-B y CβG-C) para identificar su futura aplicación en alimentos y evaluar si la purificación enzimática afecta molecular y estructuralmente los β-glucanos. Métodos: se extrajeron β-glucanos de cebada (EβG), caracterizados por análisis químicos, comportamiento reológico y color, y se compararon con tres muestras comerciales. Posteriormente, el extracto (EβG) se purificó y se identificaron sus características estructurales y su peso molecular. Resultados: EβG contenía 64.38 ± 3.54% de β-glucanos, alta contaminación con almidón (12.70 ± 1.73%), alto contenido de calcio (8894 mg / kg), comportamiento pseudoplástico y color oscuro (L* = 52.77 ± 0.7). Todas las muestras comerciales mostraron una baja contaminación con almidón, color más claro y comportamiento newtoniano. Después de la purificación de EβG, la contaminación con almidón y proteína disminuyó (0.85 ± 0.46% y 5.50 ± 0.12%, respectivamente), aumentó el contenido de βG (69.45 ± 0.81%) y aumentó su luminosidad (L* = 92.60 ± 1.70). Los β-glucanos purificados (PβG) mostraron un peso molar de 690 ± 1,6 kDa y se identificaron en la estructura especies con grado de polimerización desde 3 (GP3) hasta 11 (GP11). Conclusiones: los EβG antes de la purificación presentaron alta viscosidad y contaminación. El proceso de purificación enzimática fue efectivo y permitió mantener una alta masa molar de la fibra y sus estructuras moleculares características (especies con GP3 y GP4). Las muestras comerciales CβG-A y CβG-B mostraron un bajo contenido de β-glucanos. Finalmente, la CβG-C presentó las mejores propiedades fisicoquímicas y reológicas para su posterior aplicación en alimentos.

The use of sorbate and nitrite in meat processing may lead to the formation of 2-methyl-1,4-dinitro-pyrrole (DNMP), a mutagenic compound. This work was aimed at developing and validating an analytical method for the quantitation of DNMP by liquid chromatography-tandem mass spectrometry. Full validation was performed in accordance to Commission Decision 2002/657/EC and method applicability was checked in several samples of meat products. A simple procedure, with low temperature partitioning solid-liquid extraction, was developed. The nitrosation during the extraction was monitored by the N-nitroso-DL-pipecolic acid content. Chromatographic separation was achieved in 8 min with di-isopropyl-3-aminopropyl silane bound to hydroxylated silica as stationary phase. Samples of bacon and cooked sausage yielded the highest concentrations of DNMP (68 ± 3 and 50 ± 3 μg kg−1, respectively). The developed method proved to be a reliable, selective, and sensitive tool for DNMP measurements in meat products. FAPESP