1,720,973 research outputs found
Effect of sugar addition on liquid-vapour partition coefficients of volatile compounds in coffee beverages.
No full textWater antiplasticisation effect in starchy buscuits as affected by glucose and sucrose addition.
No full textEffect of sugars on liquid-vapour partition of volatile compounds in ready-to-drink coffee beverages
No full textAroma Release and Sensory Perception of Fruit Candies Model Systems
No full textAbstractThe release of volatile compounds from food matrices is governed by kinetic and thermodynamic phenomena. Intrinsic properties of the food matrix, extrinsic factors (temperature, pressure) as well as the interaction with non volatile compounds in the food matrix are involved in both the release rate and the aroma concentration in equilibrium. The objective of this study was to investigate the influence of the composition (i.e. gelling agents - gelatine, starch pectin- and sugars) on the release and sensory perception of aroma compounds from candy model systems added with a standard strawberry flavour. Model candies were prepared by using gelatine gelatine and starch, starch and pectin (P). All samples were added with the same concentration of a strawberry aroma (0.25%db) and with the exception of Aes, all models, after setting, were dried under the same process conditions and stored in HDPE bags until analysis. Evaluations of the release of aroma compounds under equilibrium conditions were carried out by Head Space Gas Chromatography and Electronic Nose both on the model candies and the same submerged in water to mimic the dissolution in the mouth. The kinetics of the aroma release from the models during dissolution to reach the equilibrium were also investigated. Sensory evaluations and mechanical analyses under standardised procedure were also carried out. The partitioning of strawberry aroma compounds from the candy model systems at equilibrium in the head space was highly affected by the gelling agent type and sugar content. The affinity of the aroma compound for the biopolymer/s of the candy model system and structural properties are implied in the different release in the vapour phase of EA (more polar) and EH (more apolar). The kinetics of the volatiles release from the candies in water varied depending on the aroma nature and the physical properties of the systems as affected by the gelling agen
Release of aroma compounds in binary and ternary carbohydrate model systems.
No full textThe release of volatile compounds from food matrices is governed by kinetic and thermodynamic phenomena; both of them are affected by several compositional and environmental factors. Simple model systems are in general used to evaluate the impact of a single chemical (e.g. composition) or physical properties (e.g. viscosity) on the kinetics of the aroma release, especially in the case of saccharides. This study is thus, aimed to evaluate the release kinetics of aroma compounds added to binary and ternary model systems made with disaccharide and maltodextrins and the effects of their physical (viscosity) and physico-chemical (in particular, aw) properties.Sucrose (S), trehalose (T) and Maltodextrines (MD, DE 7-9) were used in different concentrations to make up binary (water-sugar, S or T) and ternary (water-sugar-maltodextrin) model systems. Moreover, the ternary systems were prepared to keep the same molarity of the disaccharide as in the correspondent binary system. A mix of 4 esters at different molecular weight and hydrophobicity (ethyl acetate-EA, ethyl butirate-EB, isopentyl acetate-IA, and ethyl hexanoate-EE) were added in the model system to achieve a final concentration in the solution of 0,01% v/v for EA, EB and IA and 0,005% v/v for EE. The kinetic curves of the release of the volatiles up to the equilibrium were evaluated by gas-chromatografic analysis. The initial apparent rate of release, Rappi (min-1) of each aroma compound was computed in agreement to Seuvre et al. (2007) as well as to Anese et al. (1999). The latter model allowed to determine the a kinetic index of the release in the gas phase (d) of the aroma compounds in the various model systems.Binary model systems made with disaccharides with a concentration up to 50% of solute vary their aw values from 0.999 to 0.946 and 0.950 for T and S. The presence of MD in the ternary systems did not meaningfully affected the water activity of the binary system made with the same sugar whilst it significantly increased their viscosity. The kinetics of the aroma release resulted to be influenced differently by the nature of the aroma compound, the molecular complexity and concentration of the saccharide as well by the viscosity and water activity of the model systems. In binary solutions made with increasing concentration of T or S, where limited aw decrease and viscosity increase occurred, only EE and EA showed a slower release rates, while EB and IA were not affected. On the other hand, binary systems made with increasing concentration of MD besides a negligible aw change showed a significant decrease in the release rate. In ternary model systems in presence of both the saccharide and MD, competitive and/or synergic effects occurred and it differently increased or decreased the rate of the aroma release.Anese M. et al. (1996). In Ricerche e innovazioni nell’industria alimentare. Vol. 2 Chiriotti Editore, Torino, 891-899.Seuvre A-M. at al. (2007). Food Research International 40, 480-492.[...
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
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