Identification of the taste enhancer alapyridaine in beef broth and evaluation of its sensory impact by taste reconstitution experiments

An essential compound imparting the sweet taste to beef broth was investigated. Taste activity-guided fractionation of beef broth by ultrafiltration, gel permeation chromatography, and HPLC in combination with the recently developed comparative taste dilution analysis enabled the localization of a fraction possessing sweetness-enhancing activity upon degustation. Comparison of the chromatographic, spectroscopic, and sensory data with those of the synthetic reference compound led to the identification of the sweetness-enhancing N-(1-carboxyethyl)-6-(hydroxymethyl)pyridinium-3-ol inner salt, named alapyridaine, which was recently isolated from heated aqueous solutions of hexoses and l-alanine. After quantification of alapyridaine in beef broth, sensory analysis of synthetic beef taste recombinates spiked with synthetic alapyridaine in its "natural" concentration of 419 mug/L and comparison to the taste quality of a tastant recombinate lacking the alapyridaine revealed a significant increase in sweetness and umami character only when the alapyridaine was present in the recombinate. These data demonstrate for the first time that, in "natural" concentrations, the alapyridaine exhibited a pronounced effect on the overall taste quality of beef broth, in particular, on the sweet and umami character.     

Adapting the Profile Model to Calculate the Critical Loads for East Asian Soils by Including Volcanic Glass Weathering and Alternative Aluminum Solubility System

Adaptation of the steady-state soil chemistry model PROFILE was studied, on the following two parts, to calculate the critical loads for East Asian soils: (1) Dissolution rate coefficients of volcanic glass were derived from published experimental data, and calculated field weathering rate was compared with the rate estimated based on Sr isotope analysis. When BET surface area of sand fraction was regarded as mineral surface area, the calculated rates fairly agreed with the estimate, suggesting that sand fraction surface area is a reasonable estimate of weatherable mineral surface area of volcanic soils. (2) In repeated leaching experiments, Al solubility of a number of Japanese soils was explained by a model which assumed complexation of Al to soil organic matters. Such an Al solubility model is more appropriate for predicting soil chemistry than apparent gibbsite dissolution equilibrium.     

Surrogate taxa for biodiversity in agricultural landscapes of eastern Austria

In an agricultural landscape in eastern Austria eight terrestrial organism groups were investigated as potential biodiversity indicators. We present a cross-taxon congruence assessment obtained at the landscape scale using two groups of plants (bryophytes and vascular plants), five groups of invertebrates (gastropods, spiders, orthopterans, carabid beetles and ants) and one vertebrate taxon (birds). We tested four different approaches: correlated species counts, surrogate measures of the overall species richness that was assessed, a multi-taxa (or shopping basket) approach and a simple complementarity algorithm. With few exceptions, pairwise correlations between taxa, correlations between one taxon and the species richness of the remaining groups, and correlations between a combination of the richness of two taxa and the remaining species richness were highly positive. Complementarity-derived priority sets of sampling sites using one taxon as a surrogate for the pooled species richness of all other taxa captured significantly more species than selecting areas randomly. As an essential first step in selecting useful biodiversity indicators, we demonstrate that species richness of vascular plants and birds showed the highest correlations with the overall species richness. In a multi-taxa approach and in complementarity site selection, each of the eight investigated taxa had the capability to capture a high percentage of the overall species richness.     

Steady-State and Dynamic Assessment of Forest Soil Acidification in Switzerland

The European steady-state Simple Mass Balance (SMB) model and the dynamic soil acidification model SAFE were used to assess the risk of future forest soil acidification in Switzerland. 2010 deposition forecasts on a 150×150 km grid resolution as well as corresponding ecosystem protection levels were obtained from RAINS model runs based on the 1999 Gothenburg Protocol obligations under the UN/ECE LRTAP Convention. Deposition values for 2010 on the national resolution were derived by scaling down present 1×1 km deposition values according to the deposition trends at the 150×150 km grid resolution. Meeting the Protocol obligations will reduce the percentage of Swiss forest ecosystems not protected against acidification between 1990 and 2010 from 41 to 4% according to the RAINS assessment and from 63 to 16% according to the assessment with the SMB at the 1×1 km resolution. The dynamic approach indicates, however, that soil conditions may not improve as much as these steady-state models suggest. By 2010, 39% of the sites considered will still have soil solution Bc/Al molar ratios below 1 at least in one soil layer. Nevertheless, deposition reductions obtained from the implementation of the new protocol will prevent the major part of Swiss forest soils from further acidification. Aiming at recovery of the more sensitive forest ecosystems would require emission reductions beyond the Protocol's obligations.     

Taxonomy and evolution of cultivated plants: Literature review 1987/1988

Summary Important papers on taxonomy and evolution of cultivated plants published in 1987 and 1988 were compiled and briefly discussed.

---

Taxonomie und Evolution der Kulturpflanzen: Literaturübersicht 1987/1988

Zusammenfassung Wichtige Arbeiten über Taxonomie und Evolution der Kulturpflanzen aus den Jahren 1987 und 1988 wurden zusammengestellt und kurz kommentiert.

---

¶rt; : 1987/1988

, 1987/1988 . .

     

The calculation of base cation release from the chemical weathering of Scottish soils using the profile model

To investigate the weathering rates of different soil parent materials which occur in Scotland, a study has been undertaken in which detailed soil mineralogy has been used to calculate base cation release. To calculate base cation release, this data, and supplementary soil chemistry and physical attribute data, have provided the input to the PROFILE model. The model is a multi-layer, steady state, deterministic model in which the soil is represented by a series of mixed tank reactors, each of which has the mineralogical, physical and chemical attributes measured for individual soil horizons. The major parent materials from which Scottish soils have developed are glacial till, derived from acid to basic igneous rocks, schist and other metamorphic types, Lower Palaeozoic greywackes and shales, Old Red Sandstone sediments, Carboniferous sediments and Permo-Trias sediments. For each of the parent materials, three soil profiles were analysed and used with the PROFILE model. The base cation release rates, calculated for these parent materials in the top 50cm of the soil profile, varies between 0.2 and 3.2 keq/ha/yr, although, for a given parent material, the range was usually quite small. In general, these results compare very favourably with those suggested for the calculation of critical loads using an empirical approach proposed at Skokloster. In comparison with current rates of deposition, this suggests many of these soils are being acidified and that for many soil-plant combinations, the critical load may be exceeded.     

Terrestrial liming as a tool to mitigate acidification of woods lake,NY

The Soil Liming Model (SLiM) has been used to simulate lake and stream water quality response to different strategies for the application of limestone to subcatchment soils in the Woods Lake, NY watershed. Simulations using doses of 3, 10, or 30 t ha⁻¹ forecast that a dose in excess of 10 t ha⁻¹ must be applied to discharge areas in order to sufficiently improve water quality in the lake. At 3 t ha⁻¹ inlet stream water quality could support fish populations. As expected, treatment effectiveness is strongly influenced by subcatchment hydrologic flow paths. Where shallow flow predominates, soil liming provides a more effective tool for lake water quality improvement. In subcatchments drained primarily by ground water, the effect of liming on water quality is less pronounced albeit of longer duration. Based upon the results of these model simulations, the authors compare results of conventional lake liming to simulated watershed treatment predictions.     

Verhalten einiger radioaktiver Nuklide (freigesetzt durch den Reaktorunfall in Tschernobyl) in typischen Böden Norddeutschlands

Behavior of Some Radioactive Nuclides (Released During the Tchernobyl Disaster) in Typical North German Soils Initial studies carried out after the Tchernobyl disaster on the behavior of radionuclides J-131, Cs-134, Cs-137, Ru-103 and Ru-106 on typical north german soils (podzol both rich and poor in humus, gleysol and fluvisol) showed that after initial distribution, no further shifting of the nuclides took place. Generally, Cs-134 remained in the upper 4–6 cm of the soils; the same was found for Ru-103 in gleysol and podzol rich in humus. In podzol poor in humus and fluvisol, Ru-103 was more detectable in deeper soil sections than the radionuclide Cs-134. During the period of investigations it was found that over 90% Cs-134 was present in the top subsamples of the analyzed soils. Over 90% Ru-103 was detectable in the top sub-samples of the podzol rich in humus and gleysol, while in the top sub-samples of the humus-poor podzol and fluvisol, only 70% or 76% Ru-103 was discovered.     

Quantitative model studies on the efficiency of precursors in the formation of cooling-active 1-pyrrolidinyl-2-cyclopenten-1-ones and bitter-tasting cyclopenta-[b]azepin-8(1H)-ones

The yields of the cooling-active compounds 3-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (1) and 5-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (2) as well as the bitter tastants 7-methyl-2,3,6,7-tetrahydrocyclopenta-[b]azepin-8(1H)-one (3) and 7-methyl-2,3,4,5,6,7-hexahydrocyclopenta-[b]azepin-8(1H)-one (4) obtained by heating mixtures of possible Maillard-type precursors in model systems varying in temperature, pH value, or water content were determined quantitatively. The results showed that hexose-derived cyclotene is the common precursor for all four tastants and that the formation of each individual tastant is strongly determined by the structure of the nitrogen-containing precursor, e.g., reaction of cyclotene with pyrrolidine formed by thermal decarboxylation of L-proline produced the cooling compounds 1 and 2 only, whereas in the presence of 1-pyrroline formed upon Strecker reactions of L-proline, the bitter tasting azepinone 3 was produced exclusively. In contrast, the structure of the secondary amino acid L-proline enabled the formation of compound 4, whereas the pyrrolidine and 1-pyrroline, respectively, do not generate this tastant. In addition, a nonvolatile, tasteless intermediate, (S)-3-methyl-2-[(2'-carboxy)-1-pyrrolidinyl]-2-cyclopenten-1-one (5), was isolated from the cyclotene/L-proline reaction mixture and could be confirmed as an efficient precursor for the cooling compound 1. The data, obtained by these studies, are the scientific basis to tailor the desired overall flavor of foods by means of a more controlled Maillard-type technology.     

Metabolic and cometabolic degradation of herbicides in the fine material of railway ballast

Microbial degradation of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) and mineralization of 4-chloro-2-methylphenoxyacetic acid (MCPA) were studied in soil samples taken from the ballast layers of three Swedish railway embankments. The degradation of diuron followed first-order kinetics and half-lives ranged between 122 and 365 days. The half-lives correlated strongly with microbial biomass estimated by substrate-induced respiration (SIR; R=-0.85; p<0.05) and with the amount of organic matter measured as loss on ignition (R=-0.87; p<0.05). Accumulation of the metabolites 1-(3,4-dichlorophenyl)-3-methyl urea (DCPMU) and 1-(3,4-dichlorophenyl) urea (DCPU) was observed in all samples and these were only detectably degraded in the sample with the highest SIR. Addition of ground lucerne straw to the ballast samples stimulated microbial activity and led to increased formation of metabolites, but further transformation of DCPMU and DCPU was not enhanced. Mineralization of MCPA followed growth-linked kinetics and the time for 50% mineralization was 44.5±7.1 days in samples of previously untreated ballast. In samples of ballast that had been previously treated with the herbicide formulation MCPA 750, the time for 50% mineralization was reduced to 13.7±11.3 days. The number of MCPA degraders, quantified using an MPN technique, was clearly increased but highly variable. An average yield of 0.18 cells pg⁻¹ of MCPA was estimated from the kinetic data. The yield estimates correlated with the amount of nitrogen in the ballast, indicating that mineralization of MCPA was nitrogen-limited in the railway embankments studied. This has practical implications for weed control using herbicides on railways.