RESUMO
This communication assesses the use of a portable near infrared (NIR) instrument to measure quantitative (fatty acid profile) properties and qualitative ('Premium' and 'Non-premium') categories of individual Iberian pork carcasses at the slaughterhouse. Acorn-fed Iberian pigs have more unsaturated fats than pigs fed conventional compound feed. Recent advances in miniaturisation have led to a number of handheld NIR devices being developed, allowing processing decisions to be made earlier, significantly reducing time and costs. The most common methods used for assessing quality and authenticity of Iberian hams are analysis of the fatty acid composition of subcutaneous fat using gas chromatography and DNA analysis. In this study, NIR calibrations for fatty acids and classification as premium or non-premium ham, based on carcass fat measured in situ, were developed using a portable NIR spectrometer. The accuracy of the quantitative equations was evaluated through the standard error of cross validation or standard error of prediction of 0.84 for palmitic acid (C16:0), 0.94 for stearic acid (C18:0), 1.47 for oleic acid (C18:1) and 0.58 for linoleic acid (C18:2). Qualitative calibrations provided acceptable results, with up to 98% of samples (n = 234) correctly classified with probabilities ⩾0.9. Results indicated a portable NIR instrument has the potential to be used to measure quality and authenticity of Iberian pork carcasses.
Assuntos
Ácidos Graxos/química , Análise de Alimentos/métodos , Produtos da Carne/análise , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Animais , Gordura Subcutânea/química , SuínosRESUMO
It has been hypothesized that there is an adrenal abnormality in the polycystic ovary syndrome (PCO). This study was undertaken to examine this hypothesis in a more physiological way, by enhancing the ACTH secretion in response to ovine corticotropin releasing hormone (oCRH) injection so that adrenal androgen and glucocorticoid responsiveness to endogenous stimulation could be examined. Plasma ACTH and the ACTH and cortisol (F) response to oCRH were normal. The plasma T and dehydroepiandrosterone (DHEA) responses were also normal. The androstenedione (A) response, however, was exaggerated. This study supports the hypothesis that the adrenal gland in patients with PCO produces increased amounts of androstenedione in response to ACTH stimulation.