Development of Head Space Sorptive Extraction Method for the Determination of Volatile Compounds in Beer and Comparison with Stir Bar Sorptive Extraction

A headspace sorptive extraction method coupled with gas chromatography-mass spectrometry (HSSE-GC-MS) was developed for the determination of 37 volatile compounds in beer. After optimization of the extraction conditions, the best conditions for the analysis were stirring at 1000 rpm for 180 min, using an 8-mL sample with 25% NaCl. The analytical method provided excellent linearity values (R-2 > 0.99) for the calibration of all the compounds studied, with the detection and quantification limits obtained being low enough for the determination of the compounds in the beers studied. When studying the repeatability of the method, it proved to be quite accurate, since RSD% values lower than 20% were obtained for all the compounds. On the other hand, the recovery study was successfully concluded, resulting in acceptable values for most of the compounds (80-120%). The optimised method was successfully applied to real beer samples of different types (ale, lager, stout and wheat). Finally, an analytical comparison of the optimised HSSE method, with a previously developed and validated stir bar sorptive extraction (SBSE) method was performed, obtaining similar concentration values by both methods for most compounds

Desarrollo ontogénico de Acipenser Naccarii (Bonaparte 1836). Posible aplicación en acuicultura

La información sobre el desarrollo embrionario y primeros estadios de A. naccarii es muy escasa e incompleta. En este trabajo se describe por primera vez la secuencia del desarrollo embrionario desde la fecundación, a partir de huevos de A. naccaríi fecundados 'in vitro', hasta la etapa juvenil, 3 meses postfecundación. La eclosión se produjo en condiciones controladas de piscifactoría, llevadas a cabo en dos años consecutrivos (2002 y 2003) durante los meses de junio y julio, para tres cohortes reproductivas. La eclosión se produjo a los 5 días postfecundación pará una temperatura de incubación de 17 °C y a los 7 días a 15 °C (Estadios 1 - 35). El periodo de embrión de vida libre abarca desde la eclosión de los embriones basta la reabsorción de la totalidad del saco vitelínico y comienzo de la alimentación activa (Estadios 37 - 45). Mientras que para la Etapa Juvenil se han propuesto seis estadios de desarrollo (Estadios 46- 51) hasta los 3 meses post-fecundación. Para A. naccarü, se han determinado diferentes estadios en el desarrollo de A. naccarii que se engloban en tres periodos: fecundación - eclosión, que a 17°C, comprende los Estadios (1 -36) y tiene una duración deS días (120 h) a 17°C y 7 días 18 h (186 h) a 15°C; embrión de vida libre, comprende los estadios (37-45) que duras días (120 h) a 17°C y 7 días (168 h) a 15 ° C; y el desarrollo juvenil, que se extiende durante 1752 h (73 días). En conjunto el desarrollo estudiado se ha extendido durante 83 días (1992 h) a 17°C y 88 días (2106 h) a 15°C. Cada uno de los periodos en los que se ha dividido el desarrollo embrionario requiere un tiempo determinado y dentro de cada uno de ellos cada estadio transcurre también en una secuencia temporal determinada. A. naccarii, presenta un desarrollo embrionario más rápido que otros Acipenséridos, alcanzándose antes los estadios de desarrollo incluso a temperaturas más bajas. Además, para la etapa juvenil se ha descrito de forma pormenorizada la evolución de diferentes estructuras tales como aletas pares e impares, pínnulas y escudetes dorsales, laterales y ventrales. Así mismo se han realizado análisis morfométricos de la región cefálica, saco vitelínico, aletas pectorales y aleta caudal. Describimos por primera vez para un Acipensérido, la aparición de los escudetes dorsales secundarios (SD2°) que no aparecen al mismo tiempo que los primarios y se presentan en número variable y en posiciones diferentes a lo largo de la fila de escudetes dorsales. En generál, el desarrollo embrionario de los diferentes Acipenséridos es muy similar y distintos autores han defendido la similitud de los patrones de desarrollo a lo largo de este grupo (Dettlaff et al., 1993; Gisbert et al., 1998) La temperatura influye claramente en el tiempo de eclosión. El desarrollo de A. naccarii, es más rápido que la de otros esturiones incluso a menor temperatura. Se ha elaborado por primera vez para A. naccarii un modelo global que relaciona la morfogénesis a nivel macroscópico y los diferentes sistemas orgánicos, obteniéndose un mejor conocimiento sobre sus pautas de desarrollo y se establece un cronoprama de aparición de las princinales estructuras

Application of Microwaves as an Advanced Technique for the Development of Sherry Vinegar Macerated with Pineapple

This work proposes the elaboration of a product based on the maceration of Sherry Vinegar together with pineapple in order to extract certain volatile compounds that can be found in pineapples, giving a final product with new organoleptic properties and increased polyphenolic content. Maceration trials were carried out with the application of microwaves and ultrasound, which reduced the maceration time from the traditional three-day solid-liquid maceration to just a few minutes. In addition, through maceration, the total polyphenol index increased significantly with respect to unmacerated vinegar, and the volatile profile of the vinegars was significantly modified. The tasting scores placed the pineapple macerated vinegar sample obtained by traditional maceration in the first place with respect to pineapple aroma; however, the microwave extraction samples were better rated in terms of overall quality. It can be concluded that the application of extracting energies, such as microwaves, can be a viable alternative for the production of sherry vinegar macerated with pineapple

Changes in the juvenile fish assemblage of a Mediterranean shallow Posidonia oceanica seagrass nursery area after half a century

The within-year dynamics of the juvenile fish community in a shallow seagrass-dominated nursery habitat (Posidonia oceanica) in a Mediterranean bay were compared between two surveys separated by 50 years (1960 and 2012-2013). A nocturnal survey over depths ranging from 2 to 10 m over patchy seagrass meadows was conducted for one year (2012-2013) through 72 epibenthic tows spread fortnightly in 4 nearby stations, mimicking a survey conducted in 1960 in terms of sampling intensity, sampling zone, temporal coverage and sampling gear. Although a large proportion of the fish species were similar among surveys, remarkable and statistically significant differences were detected. A striking feature was that one of the most common and abundant Sparidae species currently, Diplodus annularis, did not appear in 1960. Other strong differences included the nonappearance of the European eel Anguilla anguilla in the recent survey. Furthermore, one of the most valuable species for artisanal fisheries in the area, the black scorpionfish Scorpaena porcus, was almost 10 times less abundant in 1960. A finer-scale study of the 2012-2013 survey allowed a quantitative analysis between species composition and potential environmental drivers through redundancy analysis that well described the current pattern of time-dependent recruitment pulses in nearshore meadows of the area throughout the year, with marked effects of surface temperature and photoperiod. The comparison between surveys suggests that some major differences between surveys are not likely to be attributable to interannual stochasticity in recruitment or environmental variability but may be related to i) unaccounted-for habitat transformation and/or ii) the strong decrease in juvenile fishing mortality in this shallow nursery area since the enforcement of bans on littoral epibenthic trawling activities characteristic of this area

A software tool for monitoring legal minimum lenght of landings: Case study of a fishery in sourthern Spain

Herramienta de interés para el control y la gestión de pesqueríasThe regulation of minimum legal size(MLS) of catches is a tool widely applied in the management of fisheries resources, although the MLS does not always coincide with the length at first maturit(LFM). The optimization of this management tool requires a series of quality control in fish markets and transportation. A software application has been developed to make the control of the landings of several target species easier and faster. In order to test and make this tool operational,six species of commercial interest were selected: four species of fish hand two species of bivalves. It is proposed to estimate the proportion of illegal specimens in the studied lot from the proportion of illegal individuals found in the samples taken from this lot.The input data for the application are the minimum legal size(MLS) of the species and the total length(TL)of each specimen sampled. The out put data is a statistical summary of the percentage of specimens of size less than the legal minimum(TL<=MLS)within different confidence intervals(90%,95% and 99%). The software developed will serve as a fast,efficient and easy to manage tool that allows inspectors to determine the degree of compliance on MLS control and to make a decision supported by statistical proof on fishing goods

Effect of climatic oscillations on small pelagic fisheries and its economic profit in the Gulf of Cadiz

Several studies have shown the effect of climatic oscillations on fisheries. Small pelagic fish are of special global economic importance and very sensitive to fluctuations in the physical environment in which they live. The main goal of this study was to explore the relationship between the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), and the Arctic Oscillation (AO) on the landings and first sale prices of the most representative small pelagic commercial species of the purse-seine fisheries in the Gulf of Cadiz (North East Atlantic), the European anchovy Engraulis encrasicolus and the European sardine Sardine pilchardus. Generalised linear models (GLMs) with different data transformations and distribution errors were generated to analyse these relationships. The best results of the models were obtained by applying a moving average of order 3 to the dataset with a double weighted median. Our results demonstrate relationships between NAO, AO, and EA and European anchovy and sardine landings. These cause an indirect effect on the first sale price in markets through catch variations, which affect the price according to the law of supply and demand. The limitations of this study and management implications are discussed.Postprint2,5

A Comparative Assessment on the Recovery of Pectin and Phenolic Fractions from Aqueous and DES Extracts Obtained from Melon Peels

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThis work evaluates the purification of melon peel extracts obtained by two eco-friendly methods: autohydrolysis and sodium acetate/urea/water extraction (1:3:1.6), an alkaline deep eutectic solvent (DES). For that, sequential ethanol precipitation and resin adsorption/desorption stages were proposed for the separate recovery of the pectic and phenolic fractions. In order to screen the optimal purification conditions, in a first step, the effect of ethanol concentrations (from 70 to 85%) on the precipitation of pectic oligosaccharides was assayed. Subsequently, the influence of the selected resin (Amberlite XAD4, XAD16HP and XAD7HP), liquid/resin ratios, and desorption sequences (varying ethanol concentrations and pH) on the phenolic compounds was also studied. The highest pectin yields were achieved with 85% ethanol: 16.11 and 18.05 g pectin/100 g water-insoluble solids (WIS) for autohydrolysis and DES extracts, respectively. All pectins presented a galacturonic acid content of about 45%, while autohydrolysis pectin presented a higher amount of neutral sugar side chains. The presence of low methoxyl GalA and both linear and branched OGalA with DP from 2 to 20 was also confirmed by FTIR and HPAEC-PAD analysis, respectively. Concerning the phenolic fraction, the resin adsorption and desorption steps at the selected conditions (XAD4 resin, liquid/resin ratio of 2 mL/g, eluted with 50% ethanol thrice) resulted in 79.55 and 4.08 mg GAE/g non-volatile content (NVC) for autohydrolysis and DES extracts, respectively, with improved antioxidant capacity. Moreover, some phenolic acids (protocatechuic and ferulic acids) and flavonoids (orientin, vitexin and naringenin) were quantified in the extracts by HPLC–PDA-MS/MS.Agencia Estatal de Investigación | Ref. RYC2018-026177-IXunta de Galicia | Ref. ED431C 2018/47Xunta de Galicia | Ref. reference ED481A-2018/300Xunta de Galicia | Ref. ED431F 2020/0

Evaluation of strategies for enhanced bioethanol production from melon peel waste

Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGMelon peels can be a low-cost raw material for the production of bioethanol due to its high worldwide production and contents in cellulose, protein and minerals. In this work, several strategies were proposed for this purpose. Centrifugation of the raw material and autohydrolysis of the washed solid were used as pretreatment for the recovery of a sugar rich juice and a glucan rich solid, respectively. The enzymatic hydrolysis of the autohydrolysis spent solid was studied by response surface assessment. High glucose concentrations (35.15 g/L after 24 h) and yields were obtained operating at a liquid solid ratio of 10 g/g and cellulase to solid ratio of 17.5 FPU/g. In the selected conditions, the simultaneous saccharification and fermentation (SSF) of the solid was studied using the juice (virgin and concentrated) in the formulation of the media. Moreover, the separate fermentation of the juice (virgin and concentrated) was also evaluated, as well as a pre-fermentation followed by SSF. Finally, several scenarios were proposed, achieving the maximum bioethanol production by SSF and separate juice fermentation (17.84 g/100 g melon peel), and the maximum concentration by SSF using concentrated juice in the formulation of the medium (56.24 g/L).Xunta de Galicia | Ref. GRC ED431C 2018/47Xunta de Galicia | Ref. ED431F 2020/03Ministerio de Economía y Competitividad | Ref. RYC2018- 026177-IXunta de Galicia | Ref. ED481A-2018/30

Biotechnological Processes in Fruit Vinegar Production

The production of fruit vinegars as a way of making use of fruit by-products is an option widely used by the food industry, since surplus or second quality fruit can be used without compromising the quality of the final product. The acetic nature of vinegars and its subsequent impact on the organoleptic properties of the final product allows almost any type of fruit to be used for its elaboration. A growing number of scientific research studies are being carried out on this matrix, and they are revealing the importance of controlling the processes involved in vinegar elaboration. Thus, in this review, we will deal with the incidence of technological and biotechnological processes on the elaboration of fruit vinegars other than grapes. The preparation and production of the juice for the elaboration of the vinegar by means of different procedures is an essential step for the final quality of the product, among which crushing or pressing are the most employed. The different conditions and processing methods of both alcoholic and acetic fermentation also affect significantly the final characteristics of the vinegar produced. For the alcoholic fermentation, the choice between spontaneous or inoculated procedure, together with the microorganisms present in the process, have special relevance. For the acetic fermentation, the type of acetification system employed (surface or submerged) is one of the most influential factors for the final physicochemical properties of fruit vinegars. Some promising research lines regarding fruit vinegar production are the use of commercial initiators to start the acetic fermentation, the use of thermotolerant bacteria that would allow acetic fermentation to be carried out at higher temperatures, or the use of innovative technologies such as high hydrostatic pressure, ultrasound, microwaves, pulsed electric fields, and so on, to obtain high-quality fruit vinegars

Effect of the type of acetic fermentation process on the chemical composition of prickly pear vinegar (Opuntia ficus-indica).

BACKGROUND: In several countries, the cactus plant (Opuntia ficus-indica (L). Mill) knows renewed attention due to its ecological, socio-economic, and environmental role. In this study, prickly pear vinegar was produced employing two types of acetification processes: surface and submerged culture. Both acetification processes were performed at different temperatures (30 °C, 37 °C, 40 °C) by using two different species of thermo-tolerant acetic acid bacteria (Acetobacter malorum and Gluconobacter oxydans). Polyphenols and volatiles compounds analyzed by UPLC/DAD and SBSE-GC/MS, respectively, were considered as the main variables to determine the effect of the acetification process on the quality of the vinegar. RESULTS: As a result, fifteen polyphenols and seventy volatile compounds were identified and quantified in the vinegar samples produced by both acetification processes. The results showed that the surface acetification method led to an increase in the concentration of phenolic components, which was higher than that in the submerged process. However, a significant increase of volatile compounds predominated by esters and acids was observed when submerged culture acetification was employed, whereas alcohols were predominant in surface culture vinegars. Moreover, the multivariate statistical analysis showed that the components that mostly contributed to the differentiation between all vinegar samples were the volatile compounds. CONCLUSION: It has been proved that prickly pear vinegar could be successfully produced at higher temperatures than usual, by employing thermo-tolerant bacteria, and that the type of acetification method significantly affects the final quality of the vinegar produced. This article is protected by copyright. All rights reserve