Search results for " Analytic"
showing 10 items of 1718 documents
Volatile compounds in strawberry jam : influence of cooking on volatiles
1991
Volatile constituents of strawberry jam were identified and their olfactive impact estimated by HRGC effluent sniffing. Amounts of volatiles in jam were only slightly affected by addition of sugar, but were closely related to design of the cooker and to the pressure used. Losses by evaporation during cooking were studied. Different types of behaviour were observed for the specific aromatic components. Cooker design largely influenced flavor losses at low pressures. Condensation of vapors during cooking and incorporation of the condensate in pectin solutions could result in a more flavorfull product.
Vapour partition of aroma compounds in strawberry flavoured custard cream and effect of fat content
2008
International audience; Gas–matrix partition coefficients (k) of volatile compounds of a strawberry flavour added to a complex model system (custard dessert, COST action 921 recipe) were determined. The influence of fat content on the volatility of the strawberry aroma compounds was investigated using full fat milk- (FFM) and skimmed milk- (SM) custards. For the purpose of this study, the phase ratio variation (PRV) method was used because of its easy application for a mixture of volatiles without requiring any calibration. From the 15 aroma compounds present in the flavouring mixture, seven were volatile enough to be detected and concentrated enough to allow the calculation of k values. Ga…
Influence of flavour transfer between different gel phases on perceived aroma
2007
International audience; Multiphasic models of stirred fruit yoghurts made from a bilayer that consisted of a pectin and a dairy gel were developed in order to study the transfer of strawberry flavour compounds between the two phases. Several parameters (i.e., the flavour concentration, the fat content of the dairy gel and the storage temperature) affecting flavour compound transfer, using an experimental design, together with their effect on sensory perception were investigated. Strawberry flavour transfer between the two gels was high enough to affect the sensory perception of the dairy gels. The parameters that modified the partitioning of ethyl esters between the pectin and dairy gel (i.…
Retention/release equilibrium of aroma compounds in fat-free dairy gels
2010
BACKGROUND: The replacement of fat by thickeners in fat-free yoghurts leads to an important modification of aroma compound partitioning, with an impact on aroma perception. Investigation of retention/release equilibria allows a good understanding of aroma compound behaviour depending on food composition. RESULTS: Vapour/liquid equilibria of ten aroma compounds (two esters, two ketones, three aldehydes and three alcohols) in several media were studied to investigate the influence of pectin addition to fat-free dairy gel on the retention/release equilibrium. The partition coefficient of each aroma compound was measured by headspace analysis at equilibrium in six media (pure water, low-methoxy…
Phytochemical Evaluation of Tinctures and Essential Oil Obtained from Satureja montana Herb
2020
Winter Savory (Satureja montana L.) has been used in traditional medicine and as a spice or natural food preservative in the Mediterranean region for centuries. In this paper, some technological and analytical aspects of the S. montana tinctures development and an evaluation of the essential oil composition are provided. The total phenolic and flavonoid contents and phenolic compounds profile analyzed spectrophotometrically and by high-performance thin-layer chromatography (HPTLC), respectively, were evaluated in the developed tinctures. The results showed that the tinctures prepared from the S. montana herb by maceration or remaceration are rich in polyphenols, and there is an influence of…
Reuse of Food Waste and Wastewater as a Source of Polyphenolic Compounds to Use as Food Additives
2020
Abstract The problem of waste and byproducts generated from agro-industrial activities worldwide is an increasing concern in terms of environmental sustainability. In this ambit, the quantity of food wastes—produced in all steps of the whole food chain—is enormous, and it may be forecasted that food waste could amount to more than 120 billion tonnes by 2020. The reuse of food waste and wastewater as source of polyphenolic compounds could be an interesting discussion in this ambit. In fact, polyphenols obtained in this way might be used for food and non-food purposes by means of new, improved, and safe extraction methods. In light of the opportunity represented by the treatment of agro-indus…
A methodological approach exploiting modern techniques for forest road network planning
2016
A well-developed road network allows all forest activities, including wood harvesting, firefighting and recreational activities. However, forest road construction and maintenance involve economic and environmental costs. For these reasons, forest road network planning is a fundamental phase of forest management, maximising the benefits and reducing costs and impacts. Thanks to modern technologies in data collection both for terrestrial and forest characteristics, new methods and tools have been developed to improve and facilitate road planning. The aim of this study was the development of a Decision Support System for helping managers during forest road network planning, exploiting Multi-Cr…
Incorporation of zeolitic imidazolate framework (ZIF-8)-derived nanoporous carbons in methacrylate polymeric monoliths for capillary electrochromatog…
2017
A series of metal organic frameworks-derived nanoporous carbons originating from zeolitic imidazolate framework-8 (ZIF-8) crystals as precursors have been prepared via varying the preparation conditions. The ZIF-8-derived carbons were subsequently admixed in the methacrylate monomers containing polymerization mixtures and polymerized to obtain monolithic columns for capillary electrochromatography (CEC). The effect of particle size and content of the ZIF-8-derived carbon materials in the polymerization mixture on the performance of the hybrid monolithic columns was investigated in detail. The resulting composites were characterized using scanning electron microscopy. Using short time UV-ini…
Boronate affinity sorbents based on thiol-functionalized polysiloxane-polymethacrylate composite materials in syringe format for selective extraction…
2021
Abstract In this work, two novel boronate affinity monolithic materials able to extract glycopeptides within a polypropylene syringe are described and compared. The first material was synthesized from glycidyl methacrylate (GMA)-based monoliths modified with poly-3-mercaptopropyl-methylsiloxane (PMPMS) followed by attachment of 4-vinylphenylboronic acid (VPBA) via thiol-ene click reaction. The second material was prepared by using gold nanoparticle (AuNP)-modified monoliths as substrate followed by subsequent attachment of PMPMS and VPBA. The resulting materials were used as sorbents for solid-phase extraction (SPE) to selectively preconcentrate glycopeptides from horseradish peroxidase (HR…
Application of field portable EDXRF spectrometry to analysis of pigments of Levantine rock art
2010
The results of the analyses of elemental composition of red and black pigments of Levantine rock art from La Saltadora rock shelters (Valltorta gorge, Castellon, Spain) are presented in this paper. Nondestructive analyses were carried out using a portable energy dispersive X-ray fluorescence (EDXRF) spectrometer developed for in situ analysis. The results revealed the strong presence of calcium in all the analyzed locations due to the contribution of the underlying calcareous bedrock and the overlying crust. Iron is the main element detected in red pigments and manganese in black pigments. Iron and calcium ratios have been found indicative of the degree of preservation of the pictorial laye…