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Óleos alimentares usados: selecção de indicadores de degradação de qualidade
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Advisor(s)
Abstract(s)
Óleos alimentares usados (OAU) são usualmente designados como óleos de fritura. A
degradação, por reutilizações sucessivas ou durante o armazenamento, pode ocorrer
por diferentes vias: contacto, química, enzimática e microbiana. A degradação
oxidativa é, provavelmente, a mais importante e estudada: é uma das maiores
preocupações económicas da indústria, pois afecta a qualidade sensorial e nutritiva
dos óleos alimentares, com a formação de compostos potencialmente tóxicos para
consumo humano. Em Portugal, embora se implemente a recolha obrigatória dos
OAU’s (que incorre na sua mistura, com perda de rastreabilidade), o principal destino
final é ainda o envio para a rede de esgotos, prática proibida mas recorrente, um
problema ambiental e um desperdício de matéria-prima, que pode e deve ser
requalificada e valorizada, inclusive por novas abordagens, uma vez conhecido o seu
perfil. Na outra face da questão, a caracterização físico-química específica de OAU’s é
uma área de I&D insuficientemente explorada. Neste projecto, pretende-se identificar
parâmetros físico-químicos de baixo custo, com resposta rápida e rigorosa no contexto
da análise de OAU’s, com fim à selecção de Indicadores de Degradação da Qualidade
(IDQ). Aplicando Melhores Práticas Laboratoriais Disponíveis (MPLD), a partir do
normativo foram criados procedimentos internos ESAS, identificando variáveis críticas
e redefinindo gamas de trabalho e condições de ensaio. As conclusões são
preliminares. Os ensaios exploratórios mostram diferenças significativas nos três lotes
e em parâmetros estudados. AT, IA, IP, cor CIELab e aw, são promissores como IDQ’s.
IndI, cor CIE e Absorvência UV, perfilam-se como métodos de referência.
Used edible oils (UFO) are usually designated as frying oils. Degradation by successive reuse or during storage, may occur through different pathways: contacting, chemical, enzymatic and microbiological, where the oxidative pathway is probably the best known and studied process of degradation. Is a major economic concern of the industry, as it affects the sensory and nutritional quality of edible oils, with the formation of potentially toxic compounds for human consumption. In Portugal, although the mandatory collection of UFO's it implemented (which incurs in its mixture, with loss of traceability), its primary end use still is sending to the sewerage system, a prohibited but common practice, an environmental problem and a waste of raw materials, which should be requalified and valued, even by new technical approaches, once UFO's profile is known. In addition, the specific physicochemical characterization of UFO's is a research area insufficiently explored. The present project aims to identify low-cost physicochemical parameters, with rapid and accurate response in the context of analysis of UFO's, in order to recommend them as Quality Degradation Indicators (QDI). Applying Best Laboratory Practices Available (BLPA), internal procedures (ESAS) were created, based on standards, identifying critical variables and redefining working range and test conditions. Conclusions are still preliminary. The previous tests show significant differences in the three oils and in parameters studied. TA, AI, IP, CIELab color and aw, seem promising as QDI's. IndI, CIE color and UV Absorbency, profiling reference methods.
Used edible oils (UFO) are usually designated as frying oils. Degradation by successive reuse or during storage, may occur through different pathways: contacting, chemical, enzymatic and microbiological, where the oxidative pathway is probably the best known and studied process of degradation. Is a major economic concern of the industry, as it affects the sensory and nutritional quality of edible oils, with the formation of potentially toxic compounds for human consumption. In Portugal, although the mandatory collection of UFO's it implemented (which incurs in its mixture, with loss of traceability), its primary end use still is sending to the sewerage system, a prohibited but common practice, an environmental problem and a waste of raw materials, which should be requalified and valued, even by new technical approaches, once UFO's profile is known. In addition, the specific physicochemical characterization of UFO's is a research area insufficiently explored. The present project aims to identify low-cost physicochemical parameters, with rapid and accurate response in the context of analysis of UFO's, in order to recommend them as Quality Degradation Indicators (QDI). Applying Best Laboratory Practices Available (BLPA), internal procedures (ESAS) were created, based on standards, identifying critical variables and redefining working range and test conditions. Conclusions are still preliminary. The previous tests show significant differences in the three oils and in parameters studied. TA, AI, IP, CIELab color and aw, seem promising as QDI's. IndI, CIE color and UV Absorbency, profiling reference methods.
Description
Keywords
Óleo alimentar usado Fritura Degradação Qualidade Propriedade físico-química Used edible oil Frying Degradation Quality chemicophysical properties
Citation
Laranjeira, C.; Ribeiro, M.; Lima, M. & Henriques, M. (2014).Óleos alimentares usados: selecção de indicadores de degradação de qualidade. Revista da Unidade de Investigação do Instituto Politécnico de Santarém, 4 (2), 163-181
Publisher
Unidade de Investigação do Instituto Politécnico de Santarém (UIIPS)