1,721,032 research outputs found
An itinerant sensory approach to investigate consumers' perception and acceptability at a food exhibition
No full textIn a food exhibition where several producers of the same product category are present at the same time, consumers usually have the opportunity to taste several free samples of the same product type, thus they can experience and compare the sensory characteristics of each and evaluate their liking for each sample tasted. This study assessed the potential of an itinerant sensory data collection in understanding the consumers' perception and acceptance of cheese during a multiple tasting experience at a food exhibition. Subjects tasted seven samples of Parmigiano Reggiano cheese aged for different times (24 and 36 months) at seven producer stands and recorded their evaluations using tablets, on which an application specifically developed for this study was installed. This evaluation situation was defined as “pseudo-natural,” in opposition to the “natural” and the “naturalistic” settings. The itinerant sensory session comprised a liking test, a rate-all-that-apply (RATA) test using a just about right (JAR) scale, a food pairing test, and a questionnaire. Consumers significantly (p b 0.05) discriminated the cheeses as a function of the aging time, describing with different attributes the 24 months (sweetness, fresh fruit, grass, yogurt, butter flavors, elasticity, and humidity) and the 36 months (saltiness, bitterness, sourness, spicy, aromatic herbs, cheese rind flavors, crumbliness, ranularity, hardness, and hotness) aged products. The combined application of regression models, Penalty-Lift analysis, and decision tree models in investigating the relationships between liking and the RATA data, provided results revealing that the attributes elasticity, sweetness, humidity, fresh fruit, and butter were the main drivers of liking. Whereas, the attributes sourness, bitterness, and hardness were the main drivers of dislike. Therefore, even though no significant differences in terms of liking were observed among the tested cheeses, consumers preferred the attributes more frequently perceived in the least aged products. In conclusion, the presented itinerant sensory approach had provided meaningful information to understand the consumers' cheese perception and acceptability. In the future, it could advantageously be applied for studying food perception in other situations in which subjects naturally choose or consume several products while freely moving from one to another (e.g. self-service restaurant)
Indagine sulle condizioni di illuminazione dei prodotti alimentari nei punti vendita della grande distribuzione organizzata
No full textA survey of the light sources was carried out in 10 different large-scale retail stores around Milan, noting the typology of the lamps used in the different sections. For each light source the irradiance in the UVA region (Wm-2) and illuminance (lux) were also measured at the level of different foods. The survey showed that 72% of the total light sources was represented by fluorescent lamps and 22% by halogen lamps. The remaining 6% was represented by a combination of both. Among the fluorescent lamps it was possible to distinguish the light sources as a function of the colour temperature and emission spectra of the lamps. The analysis of the principal components (PCA) was used to find a relationship between the lamps and their use in the lighting of different food categories. The first two principal components made it possible to distinguish foods as function of the typology of the lamps. The most widely recorded illuminance values ranged from 1000 to 3000 lux and UVA irradiance values from 0 to 20 mWm-2. 2007
Shelf life evaluation of fresh-cut pineapple using an electronic nose
No full textThe aim of this work was to investigate the applicability of a commercial electronic nose in monitoring freshness of minimally processed fruit (packaged pineapple slices) during storage. The pineapple samples
were taken at the beginning of their commercial life and stored at three different temperatures(4–5, 7–8, and 15–16 ◦C) for 6–10 days. The measurements were performed by applying two analytical
approaches using an electronic nose: a discontinuous method being a series of analyses on samples taken
at various stages of storage, and a continuous method where the headspace around the fruit was automatically
monitored by the electronic nose probe during the preservation of slices in a storage cell. The
results obtained by the discontinuous approach showed that the electronic nose was able to discriminate
between several samples and to monitor the changes in volatile compounds correlated with quality
decay. The second derivative of the transition function, used to interpolate the PC1 score trend versus
the storage time at each temperature, was calculated to estimate the stability time. Results revealed that
fruit freshness was maintained for about 5 days at 5.3 ◦C, 3 days at 8.6 ◦C and 1 day at 15.8 ◦C. Moreover,
from the time–temperature tolerance chart, a Q10 value of 4.48 was derived. These data were confirmed
applying the continuous method: the fruit freshness was maintained for about 5 days at 4 ◦C, 2 days
at 7.6 ◦C and 1 day at 16 ◦C. An interesting future development could be an application in-line of the
continuous electronic nose method
Light-induced changes in an aqueous betha-carotene system stored under halogen and fluorescent lamps, affected by two oxygen partial pressures
Full text linkThe aim of this work was to investigate the reaction kinetics of beta-carotene in an aqueous medium as a function of exposure to commercial lights (halogen and fluorescent sources) and oxygen partial pressures. The evolution of the pigment concentration, the changes in color and the accumulation of a volatile compound (beta-ionone) were monitored during storage.
The kinetics of degradation were mathematically modeled in order to compare the effects of lighting conditions and oxygen partial pressures. Lighting was a critical variable also in the presence of a low oxygen partial pressure (5 kPa) and in these conditions the beta-carotene degraded completely during storage, even if more slowly than at 20 kPa of O2. The pigment degradation was correlated to illuminance and UVA irradiance values but the different decay rates of the fluorescent lamps were explained by the differences in the blue region of the energy emission spectra. Halogen lamp gave the minor negative effects on beta-carotene degradation
Degradation of b-carotene in an aqueous medium exposed to fluorescent and halogen lights under different oxygen partial pressures
No full textDuring distribution and at retail level, transparent packages are exposed to natural and artificial light which may impair food quality and marketability, due to the photosensitivity of the product. The aim of this work was to study the influence of different light sources and various oxygen partial pressures on the degradation rate of b-carotene in aqueous medium. Firstly, a survey of the light sources used in commercial display areas was performed in order to investigate the most common conditions of illumination. As a function of the obtained results, three types of light (a cool white, a warm white and a halogen lamp) were chosen for the experimental phase. An aqueous solution of b-carotene was closed in clear glass vials and stored under various conditions of lighting and oxygen partial pressure. The pigment photodegradation was monitored in terms of b-carotene concentration and colour evolution. The pigment degradation was correlated to illuminance and UVA irradiance values of the selected lamps. In particular, the fluorescent lamps caused a degradation higher than the halogen lamp because of the emission on the blue region of the spectrum, where b-carotene absorbs. Lighting was a critical variable also in the presence of a low oxygen partial pressure (5 kPa) and even if more slowly than at 20 kPa of O2, the b-carotene degradated completely during storage
LIGHT INDUCED CHANGES ON A MEAT MODEL SYSTEM
No full textThe appearance of fresh meat and meat products is the most important factor that influence the consumers’ selection. In fact, whereas food flavour and consistency affect subsequently purchase decisions, meat colour plays a direct role in the freshness perception and acceptability of the product at the purchase moment. The meat colour basically depends on the redox state of the myoglobin: the physiologically active species are the purple reduced pigment (deoxymyoglobin) and the oxygenate bright cherry-red form (oxymyoglobin), whereas the oxidized specie (metmyoglobin) appears brown-red. During storage, meat is characterized by a continuous dynamic conversion among the above mentioned three different myoglobin states. However the appearance of the meat surface is not affected only by the real product colour but also by the lighting conditions where it is observed. For this reason, in stores are generally used the lamp typologies able to improve the natural colour of meat. Nevertheless, often, the marketing specialist choices do not consider the potential damage induced on food by electromagnetic radiations. In fact, it is known that light causes the deterioration of lipids, vitamins, proteins and natural pigments which result in off-flavours, loss of nutrients and colour fading.
The aim of this work was to investigate the effect of different light storage conditions on the quality evolution of a meat model system.
For the experimental phase, fresh minced beef meat was homogenized with a phosphate buffer in order to obtain a final solution with a pH of 7. To avoid the microbial growth during all the experimental time, chloramphenicol was added as preservative. The obtained model system was stored in clear glass vials under two different modified atmospheres. A set of vials was closed under 60 kPa of oxygen and 40 kPa of carbon dioxide, while another set was conditioned under 3 kPa of oxygen and 97 kPa of carbon dioxide. These conditions were chosen to emulate modified atmosphere and under vacuum packaging.
During storage, the samples were exposed to constant temperature under lighting conditions produced by different light sources commonly used by retailers to illuminate meat products. In particular, a cool white lamp (Osram Dulux El Longlife 30W/840) and a nature® lamp (with high emission in the red region of the visible spectrum) were chosen. For each selected light source, the light intensity that reached the samples was recorded under real storage conditions. A series of sample was kept in the dark as reference. At different times, the samples were analysed in triplicate in order to monitor the changes occurred in the meat model system. The changes in the vial headspace gas composition, the amount of different myoglobin species and the colour (CIE L*a*b* parameters) of the model system were evaluated during time. Moreover, the lipid degradation phenomena were investigated by means of the determination of oxidation product
Messa a punto di un metodo gravimetrico per la determinazione della permeabilità ai vapori organici di film plastici
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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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