Article

Abstract

-Carbonyl analysis was used in order to follow the main reactions involved in the process of deterioration of milk powders. This method was applied after the milk had been processed using microfiltration and ultrafiltration, freeze-drying or spray-drying. The milk powders were then stored at a temperature of 45 o C and aw ranging from 0.7, 0.11, 0.23 and 0.33 to 0.5 for a period of twenty days. Water adsorption was influenced by powder composition on one hand, with a maximum water adsorption of whey proteins at 0.20 aw, and by the physical state of molecules on the other hand. At certain conditions such as 45 o C and 0.33 aw, amorphous lactose released the water molecules and turned into crystallised lactose. All powders studied exhibited a minimum deterioration, except those rich in lactose, at 0.20 ± 0.5 aw. For the products rich in lactose this minimal deterioration was observed at two aw values: 0.10 and 0.30. The determination of the monolayer moisture was carried out either theoretically with the BET model or experimentally so as to predict the most favourable degree of dehydration of dehydrated products.Carbonyl / powder stability / sorption isotherm / water activity / monolayer value Résumé -L'utilisation du dosage des carbonyles pour suivre les principales réactions intervenant dans la détérioration des produits laitiers déshydratés : prédiction du degré de déshydra-tation le plus favorable. Un dosage des carbonyles a été utilisé afin de suivre les principales réactions intervenant dans la détérioration des poudres de lait. Cette méthode a été appliquée à des Carbonyle / stabilité des poudres / isotherme de sorption / activité de l'eau / couche monomoléculaire d'eau

Measuring Spacetime: From the Big Bang to Black Holes

“…The answer so far is still maybe, because the characteristic spot size has turned out to be so close to 0.5 • that we still cannot tell whether space is perfectly flat or very slightly curved either way. The sharpest current limits on the curvature radius, obtained by combining all CMB experiments with galaxy clustering data [18,19] to constrain other parameters affecting the spot sizes (mainly the cosmic matter budget), are |R| > 20h −1 Gpc ≈ 10 27 m. This is in sharp contrast to a few years ago, when the most popular models had negatively curved space with |R| ≈ 4h −1 Gpc. In other words, space now seems to be either infinite or much larger than the observable universe, whose radius is about 9h −1 Gpc.…”

“…Such fluctuation measures have constrained matter to make up no more than about a third of the critical density needed to explain why space is flat. This Enron-like accounting situation provides supernova-independent evidence for dark energy [18,19,50].…”

“…In this so-called concordance model [18,19,50,51], the cosmic matter budget consists of about 5% ordinary matter (baryons), 30% cold dark matter, 0.1% hot dark matter (neutrinos) and 65% dark energy based on CMB and LSS observations, in good agreement with LyαF [18,52,53], lensing [54][55][56][57][58][59][60] and SN Ia [27,28]. The seed fluctuations created in the early universe are consistent with the inflation prediction of a simple power law P (k, z) ∝ k n early on, with n = 0.9 ± 0.1 [18,19]. Galaxy formation appears to have heated and reionized the universe not too long before redshift z = 6 based on the LyαF [61,62].…”

“…4. Measurements of the current (z = 0) power spectrum of density fluctuations computed as described in [63], assuming the matter budget of [19] and reionization at z = 8. The CMB measurements combine the information from all experiments to date as in [63].…”

“…The LyαF points are from a reanalysis [66] of [52] and have an overall calibration uncertainty around 17%. The curve shows the concordance model of [19].…”