Examining the possibilities of applying high pressure to preserve yoghurt supplemented with probiotic bacteria

Natural yoghurt was subject to pressures of 200 and 250 MPa/4 and 18°C/15 min, after which milk-activated inocula of Lactobacillus acidophilus and Bifidobacterium sp. were added. The yoghurts were stored for 4 weeks at refrigeration temperature. After preparation and each week of storage, the count of bacteria, acidity, antibacterial property and an organoleptic assessment was determined. The highest survival rate was demonstrated by the bacteria of Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus and Bifidobacterium sp. in the yoghurt pressurised 200 MPa/15min at 4°C. Acidity increases in the control yoghurts were higher than in the pressurised ones. Pressurised yoghurts demonstrated weaker antibacterial effect in comparison to control yoghurts. Slight changes in the smell and taste were observed after pressurisation. Yoghurts pressurised at 18°C were characterised by more favourable organoleptic properties. Better conciseness of the curd and lower whey seep out were observed in pressurised yoghurt.     

Thermal decomposition kinetics of palladium(II) 1‐allylimidazole complexes

Thermal dehydration and decomposition processes of a Pd(II) coordination compound, [PdL₄]Cl₂·3H₂O ( 1 ), (where L is 1‐allylimidazole) were studied by simultaneous TG/DSC techniques under constant heating rates condition. The released gas products were analyzed by online coupling a FTIR spectrometer to the TG equipment. The so obtained evolved gas analysis confirmed that only two ligand molecules were released and that a new 1‐allylimidazole Pd(II) complex, trans‐[PdL₂Cl₂] ( 2a ), was obtained. The same coordination compound was also prepared by heating 1 at 413.15 K in air atmosphere until a constant weight was reached 2b . Thermal decomposition mechanisms for the 2a and 2b complexes examined were proposed according to the three mass loss steps derived by TG data. Based on the model‐free isoconversional method described by Flynn–Wall–Ozawa (FWO), the dependencies of activation energy on the degree of conversion were determined. A model‐free “single point” method was also applied using the Kissinger equation, and derived results were compared to those of the former method. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 667–674, 2005     

Conformational studies by nuclear magnetic resonance. VII—The direct observation of rotational isomers in some enamino carbonyl compounds and their thione derivatives by carbon magnetic resonance

Carbon-13 magnetic resonance spectra of the s-cis and s-trans rotamers of enamino ketones and thiones of the general formula \documentclass{article}\pagestyle{empty}\begin{document}${\rm X =}\mathop {\rm C}\limits^{\rm 1} {\rm (}\mathop {\rm R}\limits^{\rm 1} {\rm)}\mathop {\rm C}\limits^{\rm 2} {\rm H =}\mathop {\rm C}\limits^{\rm 3} {\rm HN}\mathop {{\rm R}_{\rm 2}}\limits^{\rm 4}$\end{document} (where × = O or S and R-1, R-4 = alkyl) have been obtained. With dimethylaminoacrolein and its thione analogue, restricted rotation could only be observed in the latter. The chemical shift differences between rotamers and homologues are attributed to changes in conjugation and to induced bond polarisation, both these factors resulting from steric strain. In particular, nonplanar deformations of the s-trans rotamers are deduced from their C-2 chemical shift values.     

The Pinsker partition of the generalized Lorentz gas

It is shown that the Pinster partition of the generalized Lorentz gas is given by the relation (Q,X)∽(Q′, X′) iff Q=Q′, where Q, Q′ are configurations of discs and X, X′ are sets of infinitely many particles.     

Studies on the reactions of selenite ion with 1,2-dimercaptoethane or thioacetic acid

The reactions are reported between selenite and 1,2-dimercaptoethane (DME) or thioacetic acid (TAA) to form moderately stable derivatives having an enhanced absorptions in the 230–360 nm region in combining molar ratios 3:2 and 4:1, respectively. Both reactions invariably yield one product corresponding to the selenium-containing derivative of DME or TAA. The formation of products is a pH dependent process. The equilibrium constants of reactions between selenite and DME or TAA were measured.     

Degrees in a digraph whose nodes are graphs

By an f-graph we mean an unlabeled graph having no vertex of degree greater than f. Let D(n, f) denote the digraph whose node set is the set of f-graphs of order n and such that there is an arc from the node corresponding to graph H to the node corresponding to the graph K if and only if K is obtainable from H by the addition of a single edge. In earlier work, algorithms were developed which produce exact results about the structure of D(n, f), nevertheless many open problems remain. For example, the computation of the order and size of D(n, f) for a number of values of n and f have been obtained. Formulas for the order and size for f = 2 have also been derived. However, no closed form formulas have been determined for the order and size of D(n, f) for any value of f. Here we focus on questions concerning the degrees of the nodes in D(n,n − 1) and comment on related questions for D(n,f) for 2 f < n − 1.     

A chelate-forming resin prepared by the modification of anion-exchange resin amberlyst A-26 with thoron and its application

Summary A new chelate-forming resin was prepared from common anionexchanger Amberlyst A-26 and thoron. Thoron-loaded resin is stable and resistant to mineral acids. To differentiate the selectivity of thoron-loaded resin trien as competitive reagent was used. In the presence of trien thoron-loaded resin is almost selective for Fe(III) as a counter ion. The application of the resin to the analysis of iron in brass and the preconcentration and determination of iron in natural waters was described.     

14N chemical shifts in the enamino ketone quaternary ammonium salts

The ¹⁴N chemical shifts were measured for a series of quaternary ammonium salts of enamino ketones. An upfield shift of the ¹⁴N resonance signals upon quaternization has been observed. The interpretation in terms of the approximate theory of nuclear magnetic shielding is given. The calculations for some model systems result in a general agreement with the experimental data.