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Martelo-Vidal M.J., Vázquez M. (2014): Evaluation of ultraviolet, visible, and near infrared spectroscopy for the analysis of wine compounds. Czech J. Food Sci., 32: 37-47.Spectroscopy of UV-VIS-NIR combined with chemometric analyses was used as a non-destructive technique to build models for the quantitative characterisation of the main compounds of wine. The work in mixtures can give insight into how interferences affect the performance of calibrations in wines. Ethanol, glycerol, glucose, tartaric acid, malic acid, lactic acid, and acetic acid were evaluated as pure compounds and in mixtures. Different pre-treatments for the spectra and modelling strategies such as partial least squares (PLS) regression or Principal Component Regression (PCR) were evaluated. All pure compounds studied showed a good relationship between spectra and concentrations. However, interferences were observed in the mixtures and only good models for ethanol, tartaric acid, and malic acid were obtained. The best model was obtained in the NIR region for ethanol and in the UV region for tartaric acid and malic acid. The results indicate that NIR spectroscopy could be used as an alternative to conventional chemical methods for ethanol determination and UV spectroscopy for the determination of tartaric acid and malic acid.

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Atlantic mackerel (Scomber scombrus) is a pelagic and migratory species that is usually caught with other fish as bycatch. The aim of this work was to obtain low-salt restructured fish products from Atlantic mackerel resembling turkey breast using transglutaminase (0.2 U/g) as binder. NaCl concentration (0-20 g/kg), temperature (25-40 °C) and time of incubation (30-90 min) were assayed. The texture parameters (Warner-Bratzler force and Warner-Bratzler work) and expressible water were compared to those of turkey breast. Mathematical models were obtained to determine the effect of these variables on the texture of Atlantic mackerel restructured products. Optimal conditions to obtain a similar texture than turkey breast were found. The overall optimization point out that the treatment at 31.8 °C for 63.35 min using a NaCl concentration of 8.45 g/kg allowed to obtain restructured products from Atlantic mackerel with texture and expressible water similar to those of turkey breast. Color parameters (L*, a* and b*) of the product were also similar to those of turkey breast. The results showed the feasibility of producing low-salt restructured products from Atlantic mackerel resembling turkey breast using transglutaminase.

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