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Influência do processamento no perfil lipídico de alimentos processados: aspetos nutricionais e toxicológicos
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Abstract(s)
Nas últimas décadas, com a industrialização e a globalização dos sistemas alimentares, o processamento dos alimentos evoluiu rapidamente, contribuindo para a grande variedade de alimentos sujeitos a diferentes tipos de processamento, com diferentes impactos na saúde. Por seu lado, os consumidores contribuem para esta situação pois procuram cada vez mais os alimentos processados por serem práticos, saborosos, atrativos, acessíveis e económicos. O consumo inadequado deste tipo de alimentos está associado ao desenvolvimento precoce de doenças crónicas não transmissíveis, principalmente por terem elevados teores de sal, gordura (saturada e trans) e açúcar. Estima-se que os hábitos alimentares inadequados contribuam, na população portuguesa, para a perda de 15,4% de anos de vida saudável.
O processamento dos alimentos está, frequentemente, relacionado com potenciais consequências negativas na qualidade nutricional e segurança dos alimentos. Podem formar-se compostos indesejáveis com potencial toxicológico, como por exemplo, os 4-hidroxi-2-alcenais, cloropropanóis e ésteres glicidílicos de ácidos gordos. O 4-hidroxi-2-nonenal e o 4-hidroxi-2-hexenal são produtos da peroxidação lipídica de ácidos gordos polinsaturados, ómega-6 e ómega-3, respetivamente. Devido à elevada reatividade e atividade biológica destes compostos, os trabalhos de investigação sobre a sua ocorrência em alimentos aumentaram significativamente, especialmente em óleos e gorduras. Os cloropropanóis (3-monocloropropano-1,2-diol e 2-monocloropropano-1,2-diol) e os ésteres glicidílicos de ácidos gordos tornaram-se mais uma preocupação para a saúde, devido à sua presença em alimentos. São considerados tóxicos e potencialmente mutagénicos, sendo contaminantes do processamento alimentar. Estão já definidos teores máximos destes compostos para diferentes categorias de alimentos.
Os objetivos principais desta tese consistiram em desenvolver e aprofundar o conhecimento científico relativo à qualidade nutricional e segurança dos alimentos processados, com vista à identificação de áreas prioritárias de intervenção; aprofundar o conhecimento sobre a formação, ocorrência e mitigação de compostos potencialmente carcinogénicos e tóxicos; e contribuir com informação fundamental para a formulação de políticas alimentares e de nutrição que visem a melhoria de estado de saúde e nutricional da população.
A qualidade nutricional e a conformidade da rotulagem foram avaliadas em 9 categorias de alimentos processados (produtos de pastelaria, produtos de panificação, snacks, fast-food, batatas, cereais, frutos secos e oleaginosas, refeições prontas a comer e molhos). Sempre
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que possível foram adquiridas amostras de produtos similares de marcas diferentes, e também com e sem glúten. Para avaliação da qualidade nutricional determinaram-se analiticamente os teores de sal, gordura, colesterol e composição em ácidos gordos. Foram aplicadas diferentes técnicas de processamento (fritura e/ou confeção no forno) a alimentos com composição nutricional distinta, nomeadamente nuggets de frango pré-fritos, óleos alimentares, batatas ultracongeladas e pizas frescas. Para avaliar a conformidade da rotulagem, foram incluídos os resultados obtidos após aplicação dos valores das tolerâncias, definidas na legislação, para o teor de sal, de gordura e de ácidos gordos saturados.
De uma forma geral, a maioria das categorias de alimentos processados continuam a apresentar teores de sal e de gordura saturada acima dos valores desejados. No entanto, os teores de ácidos gordos trans encontrados foram baixos, indicando que estes alimentos são seguros relativamente a este parâmetro. Os resultados da avaliação da conformidade dos valores declarados nos rótulos, evidenciam que apenas 50% das amostras apresentaram valores dentro das tolerâncias definidas para o teor de sal, mas a maior parte das amostras estavam em conformidade para os teores de gordura e de ácidos gordos saturados.
Óleos, gorduras e alimentos com alto teor de ácidos gordos polinsaturados, requerem especial atenção relativamente à ocorrência dos 4-hidroxi-2-alcenais. A tendência atual de consumo de alimentos ricos nestes ácidos gordos, poderá representar um aumento no risco de exposição a estes compostos. O óleo de palma e derivados apresentaram uma elevada variabilidade na ocorrência de cloropropanóis e ésteres glicidílicos, que se deve sobretudo a diferentes práticas pré- e pós-colheita do fruto da palma, bem como às condições de processamento. Para ambos os compostos são necessários mais trabalhos sobre o impacto dos métodos de confeção, nomeadamente a fritura, utilizando condições reais (utensílios, temperatura e diferentes tipos de alimentos).
Devido ao elevado consumo dos alimentos processados pelas diferentes faixas etárias da população, e pelo seu impacto na saúde, é fundamental continuar a desenvolver investigação, sem conflito de interesses, promovendo estratégias que envolvam a indústria alimentar e as autoridades com competências em Saúde Pública, visando contribuir para alimentos processados mais seguros e equilibrados nutricionalmente.
In the last decades, with the industrialization and globalization of food systems, food processing has grown rapidly, contributing to the wide variety of foods subject to different types of processing, with different health impacts. Furthermore, consumers also contribute to this situation, because they are increasingly looking for processed foods, which are practical, tasty, attractive, and economic. The inadequate consumption of this type of food is associated with the early development of noncommunicable diseases, mainly due to the high levels of salt, saturated and trans fats, and sugar. It is estimated that inadequate eating habits contribute, in the Portuguese population, to the loss of 15.4% of healthy life years. Food processing is often related to potential negative consequences on the nutritional quality and food safety. Undesirable compounds with toxicological potential can be formed, for example 4-hydroxy-2-alkenals, chloropropanols and glycidyl esters of fatty acids. 4-hydroxy-2-nonenal and 4-hydroxy-2-hexenal are lipid peroxidation products of omega-6 and omega-3 polyunsaturated fatty acids, respectively. Due to the high reactivity and biological activity of these compounds, research on their occurrence in foods has increased significantly, especially in oils and fats. Chloropropanols (3-monochloropropane-1,2-diol and 2-monochloropropane-1,2-diol) and glycidyl esters of fatty acids have become a health concern due to their presence in food. They are contaminants of food processing, being considered toxic and potentially mutagenic. Maximum levels of these compounds have already been defined for different food categories. The main objectives of this thesis were to develop and deepen the scientific knowledge regarding the nutritional quality and safety of processed foods, in order to identify priority areas for intervention; to deepen knowledge about the formation, occurrence and mitigation of potentially carcinogenic and toxic compounds; and to contribute with fundamental information for the implementation of food and nutrition policies aiming to improve the health and nutritional status of the population. The nutritional quality and compliance of the labelling were evaluated in 9 categories of processed foods (pastry products, bakery products, snacks, fast food, potatoes, cereals, nuts and oilseeds, ready-to-eat meals and sauces). Whenever possible samples of similar products from different brands were obtained, as well as foods with and without gluten. To evaluate the nutritional quality, the levels of salt, fat, cholesterol and fatty acid composition were analytically determined. Different processing techniques (frying and/or oven baking) were applied to foods with distinct nutritional composition, namely pre-fried chicken nuggets, edible oils, pre-fried potatoes and fresh pizzas. In order to assess the accuracy of xx the labelling, the results obtained after applying the tolerance values defined by the legislation for the salt, fat and saturated fatty acids content were included. In general, most categories of processed foods continue to have contents of salt and saturated fat above the desired levels. However, the amounts of trans fatty acids found were low, indicating that these foods are safe for this parameter. The results of the accuracy assessment of the declared values on the labels show that only 50% of the samples had values within the defined tolerances for the salt content, but most of the samples were in compliance for fat and saturated fatty acids content. Oils, fats and foods with a high content of polyunsaturated fatty acids require special attention on the occurrence of 4-hydroxy-2-alkenals. The current trend of consumption of foods rich in these fatty acids may represent an increased risk of exposure to these compounds. Palm oil and derivatives showed a high variability in the occurrence of chloropropanols and glycidyl esters, which is mainly due to different pre- and post-harvest practices applied to the palm fruit, as well as the processing conditions. For both compounds, more work is needed on the impact of cooking methods, namely frying, using real conditions (equipment, temperature and different types of food). Due to the high consumption of processed foods by the different age groups of the population, and their impact on health, it is fundamental to continue developing research, with no conflict of interest, by promoting strategies that involves the food industry and authorities with responsibilities in Public Health, aiming to contribute to safer and nutritionally balanced processed foods.
In the last decades, with the industrialization and globalization of food systems, food processing has grown rapidly, contributing to the wide variety of foods subject to different types of processing, with different health impacts. Furthermore, consumers also contribute to this situation, because they are increasingly looking for processed foods, which are practical, tasty, attractive, and economic. The inadequate consumption of this type of food is associated with the early development of noncommunicable diseases, mainly due to the high levels of salt, saturated and trans fats, and sugar. It is estimated that inadequate eating habits contribute, in the Portuguese population, to the loss of 15.4% of healthy life years. Food processing is often related to potential negative consequences on the nutritional quality and food safety. Undesirable compounds with toxicological potential can be formed, for example 4-hydroxy-2-alkenals, chloropropanols and glycidyl esters of fatty acids. 4-hydroxy-2-nonenal and 4-hydroxy-2-hexenal are lipid peroxidation products of omega-6 and omega-3 polyunsaturated fatty acids, respectively. Due to the high reactivity and biological activity of these compounds, research on their occurrence in foods has increased significantly, especially in oils and fats. Chloropropanols (3-monochloropropane-1,2-diol and 2-monochloropropane-1,2-diol) and glycidyl esters of fatty acids have become a health concern due to their presence in food. They are contaminants of food processing, being considered toxic and potentially mutagenic. Maximum levels of these compounds have already been defined for different food categories. The main objectives of this thesis were to develop and deepen the scientific knowledge regarding the nutritional quality and safety of processed foods, in order to identify priority areas for intervention; to deepen knowledge about the formation, occurrence and mitigation of potentially carcinogenic and toxic compounds; and to contribute with fundamental information for the implementation of food and nutrition policies aiming to improve the health and nutritional status of the population. The nutritional quality and compliance of the labelling were evaluated in 9 categories of processed foods (pastry products, bakery products, snacks, fast food, potatoes, cereals, nuts and oilseeds, ready-to-eat meals and sauces). Whenever possible samples of similar products from different brands were obtained, as well as foods with and without gluten. To evaluate the nutritional quality, the levels of salt, fat, cholesterol and fatty acid composition were analytically determined. Different processing techniques (frying and/or oven baking) were applied to foods with distinct nutritional composition, namely pre-fried chicken nuggets, edible oils, pre-fried potatoes and fresh pizzas. In order to assess the accuracy of xx the labelling, the results obtained after applying the tolerance values defined by the legislation for the salt, fat and saturated fatty acids content were included. In general, most categories of processed foods continue to have contents of salt and saturated fat above the desired levels. However, the amounts of trans fatty acids found were low, indicating that these foods are safe for this parameter. The results of the accuracy assessment of the declared values on the labels show that only 50% of the samples had values within the defined tolerances for the salt content, but most of the samples were in compliance for fat and saturated fatty acids content. Oils, fats and foods with a high content of polyunsaturated fatty acids require special attention on the occurrence of 4-hydroxy-2-alkenals. The current trend of consumption of foods rich in these fatty acids may represent an increased risk of exposure to these compounds. Palm oil and derivatives showed a high variability in the occurrence of chloropropanols and glycidyl esters, which is mainly due to different pre- and post-harvest practices applied to the palm fruit, as well as the processing conditions. For both compounds, more work is needed on the impact of cooking methods, namely frying, using real conditions (equipment, temperature and different types of food). Due to the high consumption of processed foods by the different age groups of the population, and their impact on health, it is fundamental to continue developing research, with no conflict of interest, by promoting strategies that involves the food industry and authorities with responsibilities in Public Health, aiming to contribute to safer and nutritionally balanced processed foods.
Description
Tese de Doutoramento em Ciências Farmacêuticas, Especialidade Nutrição e Química dos Alimentos, apresentada à Faculdade de Farmácia da Universidade do Porto, 2018.
Orientadores: Professora Doutora M. Beatriz P.P. Oliveira, Faculdade de Farmácia da Universidade do Porto; Doutora Helena Soares Costa, Departamento de Alimentação e Nutrição, Instituto Nacional de Saúde Doutor Ricardo Jorge.
O trabalho apresentado nesta Tese foi realizado nas seguintes instituições: Unidade de Investigação e Desenvolvimento do Departamento de Alimentação e Nutrição do Instituto Nacional de Saúde Doutor Ricardo Jorge, I.P.; Departamento de Ciências Químicas da Faculdade de Farmácia da Universidade do Porto e REQUIMTE/LAQV.
Orientadores: Professora Doutora M. Beatriz P.P. Oliveira, Faculdade de Farmácia da Universidade do Porto; Doutora Helena Soares Costa, Departamento de Alimentação e Nutrição, Instituto Nacional de Saúde Doutor Ricardo Jorge.
O trabalho apresentado nesta Tese foi realizado nas seguintes instituições: Unidade de Investigação e Desenvolvimento do Departamento de Alimentação e Nutrição do Instituto Nacional de Saúde Doutor Ricardo Jorge, I.P.; Departamento de Ciências Químicas da Faculdade de Farmácia da Universidade do Porto e REQUIMTE/LAQV.
Keywords
Perfil Lipídico Alimentos processados Qualidade Nutricional Cloropropanóis 4-hidroxi-2-alcenais Ácidos Gordos Trans Sal Declaração Nutricional Segurança Alimentar Nutritional Quality Processed Foods Chloropropanols 4-hydroxy-2-alkenals Food Labelling Food Safety