427 research outputs found
Adding molecules to food, pros and cons – A review on synthetic and natural food additives
The pressing issue to feed the increasing world population has created a demand to enhance food production, which has to be cheaper, but at the same time must meet high quality standards. Taste, appearance, texture, and microbiological safety are required to be preserved within a foodstuff for the longest period of time. Although considerable improvements have been achieved in terms of food additives, some are still enveloped in controversy. The lack of uniformity in worldwide laws regarding additives, along with conflicting results of many studies help foster this controversy. In this report the most important preservatives, nutritional additives, coloring, flavoring, texturizing, and miscellaneous agents are analyzed in terms of safety and toxicity. Natural additives and extracts, which are gaining interest due to changes in consumer habits are also evaluated in terms of their benefits to health and combined effects. Technologies, like edible coatings and films which have helped overcome some drawbacks of additives, but still pose some disadvantages, are briefly addressed.
Future trends like nanoencapsulation and the development of “smart” additives and packages, specific vaccines for intolerance to additives, use of fungi to produce additives, and DNA recombinant technologies are summarized.The authors are grateful to Proder nº 46577 PlantLact for financial support of this work, to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU for CIMO strategic project PEst-OE/AGR/UI0690/2011 and LSRE strategic project PEst-C/EQB/LA0020/2011. The authors also state that they do not have any conflicts of interest
Localized modes at a D-brane--O-plane intersection and heterotic Alice strings
We study a system of -branes intersecting -branes and
-planes in 1+1-dimensions. We use anomaly cancellation and string dualities
to argue that there must be chiral fermion zero-modes on the -branes which
are localized near the -planes. Away from the orientifold limit we verify
this by using index theory as well as explicit construction of the zero-modes.
This system is related to F-theory on K3 and heterotic matrix string theory,
and the heterotic strings are related to Alice string defects in
Super-Yang-Mills. In the limit of large we find an
dual of the heterotic matrix string CFT.Comment: 44 pages, typos corrected, version published in JHE
Modern extraction techniques optimized to extract betacyanins from Gomphrena globosa L.
Gomphrena globosa L. is a source of betacyanins, molecules with high colorant power. In order to replace conventional extraction techniques, microwave (MAE) and ultrasound assisted extraction (UAE) processes were optimized by the response surface methodology (RSM) to maximize the recovery of betacyanins from G. globosa. A five-level full factorial design of 24 combinations and 4 replicates was implemented for MAE and UAE. The optimum processing conditions for MAE (t = 8 min; T = 60 °C; Et = 0%; and S/L = 5 g/L) conducted to an extraction yield of 39.6 ± 1.8 mg/g dry weight, while for UAE (t = 22 min; P = 500%; Et = 0%; and S/L = 5 g/L) a value of 46.9 ± 4.8 mg/g was achieved, validating the UAE more suitable to obtain the target compounds. This technique can provide extracts rich in betacyanins and with high potential to be used as natural colorants.The authors thank the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013) and L. Barros (SFRH/BPD/107855/2015) and C.L. Roriz (SFRH/BD/117995/2016) grants. This work was also financially supported by: Project POCI-01-0145-FEDER-006984 – Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through FCT – Fundação para a Ciência e a Tecnologia. To Xunta de Galicia for financial support for the post-doctoral researcher of M.A. Prieto. The authors also thank Ana Maria Carvalho for the plant donation.info:eu-repo/semantics/publishedVersio
Measuring the 3D Clustering of Undetected Galaxies Through Cross Correlation of their Cumulative Flux Fluctuations from Multiple Spectral Lines
We discuss a method for detecting the emission from high redshift galaxies by
cross correlating flux fluctuations from multiple spectral lines. If one can
fit and subtract away the continuum emission with a smooth function of
frequency, the remaining signal contains fluctuations of flux with frequency
and angle from line emitting galaxies. Over a particular small range of
observed frequencies, these fluctuations will originate from sources
corresponding to a series of different redshifts, one for each emission line.
It is possible to statistically isolate the fluctuations at a particular
redshift by cross correlating emission originating from the same redshift, but
in different emission lines. This technique will allow detection of clustering
fluctuations from the faintest galaxies which individually cannot be detected,
but which contribute substantially to the total signal due to their large
numbers. We describe these fluctuations quantitatively through the line cross
power spectrum. As an example of a particular application of this technique, we
calculate the signal-to-noise ratio for a measurement of the cross power
spectrum of the OI(63 micron) and OIII(52 micron) fine structure lines with the
proposed Space Infrared Telescope for Cosmology and Astrophysics. We find that
the cross power spectrum can be measured beyond a redshift of z=8. Such
observations could constrain the evolution of the metallicity, bias, and duty
cycle of faint galaxies at high redshifts and may also be sensitive to the
reionization history through its effect on the minimum mass of galaxies. As
another example, we consider the cross power spectrum of CO line emission
measured with a large ground based telescope like CCAT and 21-cm radiation
originating from hydrogen in galaxies after reionization with an interferometer
similar in scale to MWA, but optimized for post-reionization redshifts.Comment: 21 pages, 6 figures; Replaced with version accepted by JCAP; Added an
example of cross correlating CO line emission and 21cm line emission from
galaxies after reionizatio
The 21 cm Signature of Shock Heated and Diffuse Cosmic String Wakes
The analysis of the 21 cm signature of cosmic string wakes is extended in
several ways. First we consider the constraints on from the absorption
signal of shock heated wakes laid down much later than matter radiation
equality. Secondly we analyze the signal of diffuse wake, that is those wakes
in which there is a baryon overdensity but which have not shock heated. Finally
we compare the size of these signals compared to the expected thermal noise per
pixel which dominates over the background cosmic gas brightness temperature and
find that the cosmic string signal will exceed the thermal noise of an
individual pixel in the Square Kilometre Array for string tensions .Comment: 10 pages, 4 figures, Appendix added, version published in JCA
Demonstrating the Feasibility of Line Intensity Mapping Using Mock Data of Galaxy Clustering from Simulations
Visbal & Loeb (2010) have shown that it is possible to measure the clustering
of galaxies by cross correlating the cumulative emission from two different
spectral lines which originate at the same redshift. Through this cross
correlation, one can study galaxies which are too faint to be individually
resolved. This technique, known as intensity mapping, is a promising probe of
the global properties of high redshift galaxies. Here, we test the feasibility
of such measurements with synthetic data generated from cosmological dark
matter simulations. We use a simple prescription for associating galaxies with
dark matter halos and create a realization of emitted radiation as a function
of angular position and wavelength over a patch of the sky. This is then used
to create synthetic data for two different hypothetical instruments, one aboard
the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and another
consisting of a pair of ground based radio telescopes designed to measure the
CO(1-0) and CO(2-1) emission lines. We find that the line cross power spectrum
can be measured accurately from the synthetic data with errors consistent with
the analytical prediction of Visbal & Loeb (2010). Removal of astronomical
backgrounds and masking bright line emission from foreground contaminating
galaxies do not prevent accurate cross power spectrum measurements.Comment: 12 pages, 6 figures, Submitted to JCA
Betacyanins from Gomphrena globosa L. flowers: Incorporation in cookies as natural colouring agents
A betacyanin rich extract was obtained from the flowers of Gomphrena globosa L. by ultrasound-assisted extraction
and dried either by lyophilization or spray-drying, was tested as a natural colourant in cookies and
compared to a commercial colourant. The extracts were characterized in terms of betacyanin content and antioxidant
potential. The effects of the colourants incorporation in the cookies were assessed through proximate
composition, soluble sugars, fatty acids, color, texture and microbial load, over a shelf life of 30 days.
Considering all the assays and analyzing the results through a 2-way analysis of variance, the cookies incorporated
with spray-dried colourant showed the most intense pink coloration while cookies incorporated with
lyophilized extract lost less color intensity over time. Thus, betacyanin extracts have potential as pink natural
alternatives to synthetic colourants in the food industry.The authors are grateful to the Foundation for Science and
Technology (FCT, Portugal) for financial support by national funds
FCT/MCTES to CIMO (UIDB/00690/2020); C. L. Roriz PhD’s grant
(SFRH/BD/117995/2016), L. Barros and Isabel P. Fernandes to FCT,
P.I., through the institutional scientific employment program-contract
for their contract and the individual scientific employment program contract
for S.A. Heleno’s contract. The authors are also grateful to the
European Regional Development Fund (ERDF) through the Regional
Operational Program North 2020, within the scope of project
Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®. M. Carocho
also acknowledges ValorNatural® for his contract. Finally, P. Morales is
also grateful to UCM ALIMNOVA Research Group (GR105/18).info:eu-repo/semantics/publishedVersio
Factores socioculturales y personales relacionados con el mensaje mediático del culto al cuerpo influyentes en el bienestar de los jóvenes
Este trabajo estudia los factores personales y socioculturales relacionados con el culto al cuerpo que pueden influir en el bienestar de los jóvenes. Se pretende agruparlos en dimensiones de influencia y profundizar en el papel de los medios de comunicación y sus mensajes, como elementos también relacionados con el culto al cuerpo. Se ha realizado un análisis multivariable con una muestra de 452 jóvenes y se han obtenido tres dimensiones socioculturales de influencia: “la dimensión social y personal”, “la sociocultural mediática” y “la de imágenes de culto al cuerpo”. Las diferencias en cuanto a su valoración difieren de forma significativa para hombres y mujeres
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