Validación y aplicación de un método de análisis para la determinación de compuestos carbonílicos traza del vino usando SBSE-TD-GC-MS

Este estudio presenta la validación y la aplicación de un método de análisis para la determinación de compuestos carbonílicos traza relevantes en el aroma del vino, concretamente, los alquenales. El método se basa en la combinación de diferentes técnicas analíticas, como son la Extracción en Fase Sólida (SPE) con derivatización en cartucho utilizando PFBHA, y la posterior Extracción por Sorción sobre Barra Agitadora (SBSE) de las oximas generadas. Estas oximas permiten alcanzar una elevada sensibilidad al detectarse por cromatografía de gases-espectrometría de masas (GC-MS) utilizando ionización química negativa (NCI) como fuente de ionización. Para la realización de este estudio, se hace uso de unas condiciones optimizadas en un trabajo anterior, pero adaptadas a las necesidades actuales. Antes de llevar a cabo el estudio se examinaron otras características del método, como la correcta identificación de los compuestos, ajustando sus tiempos de retención y sus relaciones de masas, o el cálculo de la pureza de los estándares. Los parámetros de calidad del método fueron en general satisfactorios: linealidad, con rangos de lineales que cubrían desde los 0,16 hasta los 16 μg/L (r2>0,992); límites de detección inferiores a 2 μg/L, incluso con la presencia de los analitos en los blancos (debido a factores externos); el casi nulo efecto matriz que presentaban los distintos vinos (p>0,05); precisión adecuada en términos de repetibilidad y reproducibilidad (en general, inferiores al 14%). Además, este método se ha empleado para la cuantificación de los alquenales en distintas muestras comerciales. En conclusión, estos resultados tienen potencial para ampliar este método a otras familias de compuestos carbonílicos traza relevantes del vino, como son los alquenales o las cetonas.<br /

Adaptación de un método de análisis para la determinación de compuestos carbonílicos clave del aroma del vino mediante un método de desorción térmica y GC-MS.

Este estudio presenta la adaptación de un método de análisis para la determinación de compuestos carbonílicos traza del vino. La estrategia propuesta se basa en la Extracción por Sorción sobre barra agitadora (SBSE, de sus siglas en inglés) de las oximas previamente generadas de estos compuestos. De esta forma, se llega a tener una elevada sensibilidad que permite detectar los compuestos en GC-MS. Se ha optimizado el método cromatográfico, localizando los tiempos de retención y las principales relaciones m/z de cada uno de los analitos. Se estudiaron disolventes de distinta polaridad y su volumen necesario para la elución de las oximas en la primera etapa del análisis. Se ha realizado también la optimización de la extracción con los Twisters, donde se estudiaron varios parámetros como el factor de dilución del extracto en agua, la cantidad de analito en masa a adicionar y el estudio de la necesidad de aumentar o no la fuerza iónica de la disolución. Por último, se estudió el tiempo de extracción óptimo para maximizar la extracción de los analitos con el Twister. Los resultados obtenidos tienen el potencial de dar lugar a un método analítico validado para la cuantificación de compuestos carbonílicos traza en el vino. <br /

Enzyme-Assisted Extraction of Fish Oil from Whole Fish and by-Products of Baltic Herring (Clupea harengus membras)

Baltic herring (Clupea harengus membras) is one of the most abundant commercially caught fish species from the Baltic Sea. Despite the high content of fat and omega-3 fatty acids, the consumption of Baltic herring has decreased dramatically over the last four decades, mostly due to the small sizes and difficulty in processing. At the same time there is an increasing global demand for fish and fish oil rich in omega-3 fatty acids. This study aimed to investigate enzyme-assisted oil extraction as an environmentally friendly process for valorizing the underutilized fish species and by-products to high quality fish oil for human consumption. Three different commercially available proteolytic enzymes (Alcalase®, Neutrase® and Protamex®) and two treatment times (35 and 70 min) were investigated in the extraction of fish oil from whole fish and by-products from filleting of Baltic herring. The oil quality and stability were studied with peroxide- and p-anisidine value analyses, fatty acid analysis with GC-FID, and volatile compounds with HS-SPME-GC-MS. Overall, longer extraction times led to better oil yields but also increased oxidation of the oil. For whole fish, the highest oil yields were from the 70-min extractions with Neutrase and Protamex. Protamex extraction with 35 min resulted in the best fatty acid composition with the highest content of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) but also increased oxidation compared to treatment with other enzymes. For by-products, the highest oil yield was obtained from the 70-min extraction with Protamex without significant differences in EPA and DHA contents among the oils extracted with different enzymes. Oxidation was lowest in the oil produced with 35-min treatment using Neutrase and Protamex. This study showed the potential of using proteolytic enzymes in the extraction of crude oil from Baltic herring and its by-products. However, further research is needed to optimize enzymatic processing of Baltic herring and its by-products to improve yield and quality of crude oil.</p

Effects of Aromatic Herb Flavoring on Carotenoids and Volatile Compounds in Edible Oil From Blue Sweet Lupin (Lupinus angustifolius)

This study investigates the carotenoid and volatile compositions of one sample of lupin oil (Lupinus angustifolius) and five samples of lupin oil flavored with aromatic herbs, namely, basil, chives, rosemary, sage, and thyme. Flavored oils are obtained by macerating lupin oil with the herbs for 15 days, in the dark at 151 degrees C. Overall 11 carotenoids are identified by HPLC-DAD-MS-(APCI). (all-E)-Lutein and -carotene are the most abundant. Thyme flavored oil results the richest in carotenoids, with a cumulative carotenoid content of 19513gmL(-1). Volatile organic compounds are detected by HS-SPME-GC/MS analysis. Overall, 50 aroma compounds are determined, with alcohols, furans, and terpenoids being the most abundant classes. Chives flavored oil is the only sample to provide organosulfur compounds. Qualitatively, terpenoids are responsible for great differences among the samples, since unique terpenoid profiles are observed, for example, isoterpinolene is detected only in sage flavored oil, -myrcene in rosemary flavored oil, and thymol in thyme flavored oil. The relative odor activity value (ROAV) is determined and employed to evaluate the contributions of the single compounds to the overall odor. The compounds with the greatest odor activity are 3-hexen-1-ol, hexanal, -pinene, eucalyptol, and 2-pentylfuran.Practical Applications: Aromatic herbs have been traditionally used to enhance the flavor of food. The effects of herbs addition on lupin products has not been investigated yet. Additionally, this is the first study that explores some quality characteristics of commercial lupin oil. Data indicate that the maceration of lupin oil with aromatic herbs has limited effects on the content of total carotenoids, nonetheless, it modifies markedly the composition and relative proportions of the volatile organic compounds, and likely the overall aromas. Consumers are generally not familiar with the culinary use of lupin oil, nevertheless, the aromatization with herbs could increase its use. Lupin oil results rich in carotenoids. This is useful information for the production of functional products with healthy properties. Lupin oil can be recommended as a carotenoid-rich product and as an alternative to more traditional table oils. Data from this study can contribute to the economic valorization of lupin oil

Green technologies for production of oils rich in n-3 polyunsaturated fatty acids from aquatic sources

Fish and algae are the major sources of n-3 polyunsaturated fatty acids (n-3 PUFAs). Globally, there is a rapid increase in demand for n-3 PUFA-rich oils. Conventional oil production processes use high temperature and chemicals, compromising the oil quality and the environment. Hence, alternative green technologies have been investigated for producing oils from aquatic sources. While most of the studies have focused on the oil extraction and enrichment of n-3 PUFAs, less effort has been directed toward green refining of oils from fish and algae. Enzymatic processing and ultrasound-assisted extraction with environment-friendly solvents are the most promising green technologies for extracting fish oil, whereas pressurized extractions are suitable for extracting microalgae oil. Lipase-catalysed ethanolysis of fish and algae oil is a promising green technology for enriching n-3 PUFAs. Green refining technologies such as phospholipase- and membrane-assisted degumming deserve investigation for application in fish and algal oils. In the current review, we critically examined the currently existing research on technologies applied at each of the steps involved in the production of oils rich in n-3 PUFAs from fish and algae species. Special attention was placed on assessment of green technologies in comparison with conventional processing methods.</p

La Tècnica FISH i el microscopi confocal aplicats a la determinació de fraccions de biomassa en un reactor aerobi nitrificant

Vegeu el resum del projecte de final de carrera en el document adjunt ResumPFCMarso

Characterization and Quantification of Nonanthocyanin Phenolic Compounds in White and Blue Bilberry (Vaccinium myrtillus) Juices and Wines Using UHPLC-DAD−ESI-QTOF-MS and UHPLC-DAD

The nonanthocyanin phenolic compounds in juice and wine produced from fruits of white bilberry, a nonpigmented mutant of Vaccinium myrtillus, and blue bilberry (pigmented variety) were analyzed using liquid chromatography with a diode array detector (LC-DAD) and LC-DAD−electrospray ionization-quadrapole/time of flight hybrid mass spectrometry (ESI-QTOF-MS). On the basis of elution order, UV−vis spectra, accurate mass data, and fragmentation pattern and standards, 42 compounds including 22 phenolic acids, 15 flavonols, and 5 flavan-3-ols, were identified in juices and wines prepared from the two bilberry varieties. The levels of most individual nonanthocyanin phenolic compounds in white bilberry products were significantly lower than those in pigmented ones. In bilberry juices, phenolic acids were the most predominant, accounting for approximately 80% of total phenolic content, with p-coumaroyl monotropeins and caffeic acid hexoside being the major phenolic acids. After fermentation, the total contents of phenolic acids, flavonols, and nonanthocyanin phenolic compounds significantly increased, while the content of total flavan-3-ols decreased significantly. p-Coumaroyl monotropeins still dominated in the wine products, while caffeic acid content showed dramatic elevation with the significant drop of caffeic acid hexoside.</p