RESUMO
Head-space solid-phase microextraction (HS-SPME)-based procedure, coupled to comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-TOF-MS), was employed for fast characterisation of honey volatiles. In total, 374 samples were collected over two production seasons in Corsica (n=219) and other European countries (n=155) with the emphasis to confirm the authenticity of the honeys labelled as "Corsica" (protected denomination of origin region). For the chemometric analysis, artificial neural networks with multilayer perceptrons (ANN-MLP) were tested. The best prediction (94.5%) and classification (96.5%) abilities of the ANN-MLP model were obtained when the data from two honey harvests were aggregated in order to improve the model performance compared to separate year harvests.
Assuntos
Análise de Alimentos/métodos , Mel/análise , Redes Neurais de Computação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Análise de Componente Principal/métodos , Reprodutibilidade dos Testes , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análiseRESUMO
This study deals with age estimation based on colour changes of human tissue from the intervertebral discs, Achilles tendon and rib cartilage. The investigated colour changes are the result of the accumulation of non-enzymatic browning products in the tissue. Samples of excised tissues were photographed with a digital camera and the pictures were evaluated using the image analysis processor Lucia G 4.11 processor. The values of the intensities of the RGB channels (MeanRed, Mean Green, MeanBlue) and parameters from the IHS system (MeanSaturation, HueTypical, HueVariation, BrightVariation and MeanBrightness) were evaluated. The results confirm that colour changes of some tissues depend on ageing and are a good tool for age estimation.
Assuntos
Tendão do Calcâneo/patologia , Envelhecimento/patologia , Cartilagem/patologia , Cor , Ciências Forenses/métodos , Disco Intervertebral/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Feminino , Ciências Forenses/instrumentação , Produtos Finais de Glicação Avançada/metabolismo , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Fotografação , Reprodutibilidade dos Testes , CostelasRESUMO
The new method exploits the characteristic of staphylococcal protease V8, which specifically splits peptide bonds where l-glutamic or l-aspartic acid participate. Those peptide bonds where d-aspartic acid is present remain unsplit because of the stereospecifity of enzymes. In accordance with expectations, fewer peptide bonds are split by this protease at more advanced ages and larger peptide fragments are thus formed due to the higher content of d-amino acid residues in the proteins of older people. The samples of acid-extracted non-collagenous proteins from dentin were separated using high performance liquid chromatography after enzymatic hydrolysis. A peak with a retention time of 45.3 min was chosen and his enlarging area showed a linear correlation with increasing age. Although the linear correlation with age was proved, the scattering of values decreases the usefulness of the proposed method for age estimation.
