Margarine products quality monitoring using reflectance UV-VIS-SWNIR spectroscopy

Margarine is a term that can indicate any of a wide range of butter substitutes. Due to the great diversity of the raw material, margarine end-product quality characteristics are expected to be highly diversified. This article proposes the use of reflectance UV-VIS-SWNIR spectroscopy to monitor the margarine end-product quality properties. The main effort in this work was the development of a fast monitoring procedure to assess the quality of the manufactured margarines. 
The study was performed on two margarine products: regular margarine (less than 80% fat) and reduced-fat margarine (less than 60% fat). The nine product samples were collected during the production line normal operating conditions on different days. The samples had the surface cleaned in order to remove any sign of oxidized material. Then, spectra were collected by a reflectance probe normal to the sample surface. The samples temperature was recorded (10.0± 2.0ºC) and the probe-sample distance was kept constant for all the samples. The integration time was set to 40s for the collection of the five UV/VIS spectra per samples; the three VIS/NIR spectra per sample were collected using a 10s integration time.
The data analysis was performed on each product and for each spectral range independently. The spectra were normalized by its maximum intensity and the corrected for using a robust multiplicative scatter correction algorithm. A principal component analysis was performed to the pre-process spectra and the multivariate statistical process control limits were determined with bootstrap for each product/spectral range.
Results show that UV-VIS-SWNIR reflectance spectroscopy provides a quick and fast assessment of these products characteristics and thus it can be used as an indication of the overall product variability

Catalytic ozonation of phenolic acids over a Mn-Ce-O catalyst

Catalytic ozonation of a simulated phenolic wastewater composed by six acids: syringic, vanillic, 3,4,5-trimethoxybenzoic, veratric, protocatechuic and 4-hydroxybenzoic normally present in olive mill wastewaters was studied over a Mn-Ce-O laboratorial catalyst under different operating conditions. A high improvement in total organic carbon (TOC) degradation was observed even when low catalyst concentrations were used when compared with single ozonation. The influence of the medium pH in the performance of both single and catalytic ozonation was assessed in a wide range of pH values. An inhibitory effect in TOC removal was observed in the catalytic process performance at high pH values. The use of radical scavengers proved that this catalytic system does not follow a free radical pathway. No differences were observed between fresh and used catalyst structure and morphology by SEM and XRD. Nevertheless, a decrease on BET surface area was detected. Leaching of Mn as well as carbon adsorption due to organic intermediates deposition at the catalyst surface was analyzed for the recovered catalyst at the end of the experiments. The role of the catalyst in the catalytic ozonation pathway was discussed being concluded that the main mechanism should be developed through surface reactions involving both pollutants and ozone adsorption. A series of feed-batch trials was performed to test Mn-Ce-O activity along the time. A slight decrease on TOC removal was observed from the first to the second use, remaining the catalyst performance constant after the third ru

Goat milk free fatty acid characterization during conventional and ohmic heating pasteurization

The disruption of the milk fat globule membrane can lead to an excessive accumulation of free fatty acids in milk, which is frequently associated with the appearance of rancid flavors. Solid-phase microextraction and gas chromatography techniques have been shown to be useful tools in the quantification of individual free fatty acids in dairy products providing enough sensitivity to detect levels of rancidity in milk. Therefore, the aim of this study was to characterize the short-chain and medium-chain free fatty acid profile in i) raw untreated goat milk; ii) raw goat milk passing through pumps and heating units (plate-and-frame heat exchanger and ohmic heater); and iii) processed goat milk by conventional and ohmic pasteurization to determine the influence of each treatment in the final quality of the milk. Multivariate statistical analysis has shown that the treatments studied were not responsible for the variability found on free fatty acid contents. In particular, it was possible to conclude that ohmic pasteurization at 72°C for 15 s did not promote an extended modification of free fatty acid contents in goat milk when compared with that of conventional pasteurization. Furthermore, principal component analysis showed that the capric acid can be used to discriminate goat’s milk with different free fatty acid concentrations. Hierarchical cluster analysis showed evidence of the existence of correlations between contents of short and medium chain free fatty acids in goat milk

Application of a high-throughput process analytical technology metabolomics pipeline to Port wine forced ageing process

Metabolomics aims at gathering the maximum amount of metabolic information for a total interpretation of biological systems. A process analytical technology pipeline, combining gas chromatography–mass spectrometry data preprocessing with multivariate analysis, was applied to a Port wine “forced ageing” process under different oxygen saturation regimes at 60 °C. It was found that extreme “forced ageing” conditions promote the occurrence of undesirable chemical reactions by production of dioxane and dioxolane isomers, furfural and 5-hydroxymethylfurfural, which affect the quality of the final product through the degradation of the wine aromatic profile, colour and taste. Also, were found high kinetical correlations between these key metabolites with benzaldehyde, sotolon, and many other metabolites that contribute for the final aromatic profile of the Port wine. The use of the kinetical correlations in time-dependent processes as wine ageing can further contribute to biological or chemical systems monitoring, new biomarkers discovery and metabolic network investigations.The author Castro C.C. (SFRH/BD/46737/2008) gratefully acknowledges her Doctoral grant to the Fundacao para a Ciencia e Tecnologia (FCT). This research was funded by the projects PTDC/BIO/69310/2006, PTDC/AGR-ALI/121062/2010, FCOMP-01-0124-008775 through FCT, and partially supported by CBMA, IBB and ESB/UCP plurianual funds through the POS-Conhecimento Program that includes FEDER funds through the program COMPETE (Programa Operacional Factores de Competitividade)

Characterization of wine fermentations using fiber optic LWUV-Vis-SWNIR spectroscopy

Spectroscopy is widely used in biological sciences, being applied to liquids, pastes, powders, films, fibers, gases and surfaces. It makes possible to characterize proteins, peptides, lipids, membranes and carbohydrates in pharmaceuticals, foods, plants or animal tissues. It can also provide detailed information about the structure and mechanism of action of molecules. In this work we explore the use of fiber optics UV-VISSWNIR spectroscopy to characterize grape must fermentations of 114 different Saccharomyces cerevisiae strains. Results show that fiber optics UVVIS- SWNIR spectroscopy is a robust technique for characterize different wine fermentations, being able to characterize and differentiate the fermentation of different strains of S. cerevisiae based on their origins, by each spectroscopic fingerprint

Sistemas computacionais para a previsão da qualidade e segurança alimentar : evolução e sistemas complexos

Os sistemas computacionais para a previsão da qualidade e segurança alimentar assumem hoje maior relevância na prototipagem e simulação da cadeia de distribuição (e.g. gestão do armazenamento, transporte e exposição). Este artigo descreve a evolução dos sistemas de previsão até aos actuais sistemas baseados em sistemas complexos (SC), para avaliar o impacto na qualidade e segurança dos alimento