1,720,963 research outputs found
A versatile splitless injection GC-FID method for the determination of mineral oil paraffins in vegetable oils and dried fruit
No full textA splitless injection GC-FID method for determining mineral paraffins in food was set up. The method has
been developed on vegetable oils and subsequently adjusted and applied to dried fruits, a food matrix not
yet investigated from this point of view. The method avoids the saponification step foreseeing only a
clean-up on silica gel SPE, and allows the quantification of mineral paraffins with a limit of quantification
(LOQ) of 15 mg kg-1 and a detection limit (LOD) of 5 mg kg-1 in the oils. LOQ and LOD for the analysis of
dried fruit samples are respectively 1.0 and 0.3 mg kg-1.
Eighteen samples of dried fruit were analysed (apricots, plums, raisins, coconut, dates, mango, pineapple).
Two samples of apricots showed high values of contamination, 23.0 and 28.2 mg kg-1 of mineral
paraffins, while all the other samples contained less than 6.4 mg kg-1 of mineral paraffins and in four
samples mineral paraffins were undetectable
EVALUATION OF MINERAL OIL CONTAMINATION IN FISH SPECIES FROM ADRIATIC SEA
No full textMineral oil contamination concerns potentially any food due to the wide number of applications of these petroleum derivatives.1 Despite its important role in Mediterranean diet and its high nutritional value, fish is a food matrix which has been little investigated from this point of view.2 Thus, our study was aimed at developing a research in this field. Alkanes (branched, cyclic and linear), being the main constituents of mineral oils, were quantified in the tissue and organs of several fish species from Adriatic Sea (anchovies, red mullets, mackerels, sardines, flathead mullets). After saponification of the hexane extract, alkanes fraction has been isolated from insaponifiable matter by SPE3 and then analyzed by GC-FID. Organs contained much higher values of contamination with respect to muscular tissues which resulted in most of the cases containing undetectable amount of mineral oil (lower than 2 mg kg-1. Among the 5 samples of organs analyzed, 2 contained significant levels of mineral oil: 66 mg kg-1 in red mullet extract and 37 mg kg-1 in flathead mullet extract. Contaminating mineral oils were medium and low viscosity oils.4 Thus, since the contamination regards only the nonedible portion, the results are not alarming from the food safety point of view, even if they evidence a certain level of environmental pollution from petroleum derivatives
Knowing our local wines: chemical profiling
No full textWine is mainly consumed and appreciated for its sensory attributes which are due to a complex combination of several compound classes. In the overall assessment of the sensory characteristics of a food, and particularly of a wine, volatile molecules play a fundamental role, being recognized as the major contribution to the food flavor. Likewise, also polyphenols are strictly related to the sensory characteristics, being associated to the taste and to the color of the product. Furthermore, polyphenols content of red wines has also been invoked in the explanation of the French paradox, being demonstrated that their intake is associated with a low incidence of coronary heart diseases. Thus, aiming at the valorization of local food products, we have studied the composition of a local wine1,2 investigating some of the most important chemical molecules contributing to the flavor and to the beneficial effects associated with the consumption of red wines, in order to widen the knowledge on this beverage that has been only partially investigated in the past.3 We have developed and applied a HS-SPME-GC-MS/FID method to identify and quantify the volatile compounds. Among the most abundant molecules detected (esters, alcohols, phenols, hydrocarbons, organic acids), eleven compounds have been quantified. The determination of phenolic compounds, i.e. gallic acid, p-coumaric acid, trans-ferulic acid, caffeic acid, trans-resveratrol, (+)-catechin and (-)-epicatechin, was performed by using HPLC-ESI-MS with direct injection of wine samples. Both volatiles and polyphenols have been quantified in wines produced from the different harvest years and having different aging before the third fermentation. Results will be presented and discussed
Development of a Method for Analysing Volatile Compounds in Sparkling Red Wines: Application to the “DOCG Vernaccia di Serrapetrona”
No full text“Vernaccia di Serrapetrona” is an appreciated sparkling red wine produced in Marche Region (Italy), in a small area of the hinterland. The grapes for its production should be composed by at least 85 % “Vernaccia Nera” as established in its production's technical policy, acknowledging the certification DOCG (“Denominazione di Origine Controllata e Garantita”)1 to this wine. The aroma of this “spumante” red wine derives from the volatile compounds either specific to the grapes, formed during the different fermentation steps, and also during the aging. By determining its volatile composition, typical markers could be identified, making the product recognizable and affording tools to safeguard this DOCG wine, never evaluated from this point of view3. Thus, we are developing an HS-SPME-GC method to identify and quantify the volatile compounds in sparkling red wines and particularly in the local product “Vernaccia di Serrapetrona”. Among the most abundant volatiles (esters, alcohols, phenols, hydrocarbons, organic acids), the identity of more than twenty compounds has been confirmed and several parameters are being evaluated for the method optimization, as fiber coating, extraction time and temperature, salt type. The effect of an additional adsorbent phase in the system HS - fiber coating - sample is also being under consideration. Results will be presented and discussed
DEVELOPMENT OF A HS-SPME-GC-MS METHOD FOR CHARACTERIZING VOLATILE COMPONENTS OF THE DOCG WINE “VERNACCIA DI SERRAPETRONA”
No full text“Vernaccia di Serrapetrona” is a DOCG (Denominazione di Origine Controllata e Garantita) Italian red wine produced in Marche Region (Italy), in a small area of the hinterland. Its peculiar production process involves three fermentations leading to a “spumante” red wine having a high content of sugars, obtained by using at least 85 % of grapes “Vernaccia Nera” (Potentini, R., 2007). Its volatile composition has never been studied and together with other chemical and sensory characteristics (Boselli, E. et al., 2004), it could afford a fingerprint of this wine, depending both on the grape cultivar and on the production process. Thus, we are involved in the development of a method to characterize the volatile composition of “Vernaccia di Serrapetrona” by HS-SPME-GC-MS. Fiber selection, extraction time, extraction temperature and salt effect are being evaluated in order to find out the best conditions to achieve the highest sensitivity and precision. The main compounds extracted are esters, alcohols, phenols, hydrocarbons, organic acids. Among the SPME coatings evaluated, DVB/CAR/PDMS 50/30 μm afforded the highest sensitivity and precision followed by the PDMS 100 μm. Extraction times, temperature and type of salt are under investigation and results will be presented and discussed
Valutazione della contaminazione da olio minerale in specie ittiche del Mare Adriatico
No full textLa contaminazione da parte di oli minerali è un problema che interessa moltissime matrici alimentari dato il numero molto vasto di applicazioni che questi derivati del petrolio possono avere. Una matrice poco studiata da questo punto di vista, sono i prodotti ittici, nonostante il loro elevato valore nutritivo ed il loro importante ruolo nella dieta mediterranea. Pertanto, abbiamo voluto portare un contributo in questo settore avviando un’approfondita ricerca. Gli alcani (ramificati, ciclici e lineari), che rappresentano i principali costituenti degli oli minerali, sono stati quantificati in diverse specie ittiche del mare Adriatico (alici, sgombri, sarde, cefali, triglie). Dopo saponificazione dell’estratto esanico, la frazione di alcani è stata isolata dalla frazione insaponificabile attraverso SPE ed in seguito analizzata attraverso GC-FID. Il contenuto di alcani di origine minerale è risultato non rilevabile nella maggior parte dei campioni di tessuto analizzati, mentre gli organi sono risultati contenere livelli di olio minerale molto più elevati. La metodologia utilizzata ed i risultati ottenuti vengono presentati
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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