Wine aroma is influenced by a number of volatile compounds. This article describes the validation of the method for 26 volatile compounds found in wine. Volatile compounds were determined with ...discontinuous liquid-liquid extraction and GC-MS detection. It was determined, that the method is linear with square correlation coefficient ranging from 0.961 to 0.999. Limits of quantitative determination range from 0.52 μg/L to 14.8 μg/L. Recoveries range from 71.1% to 105.7% except for two compounds with lower recoveries. Measurement uncertainty ranges from 5.0% to 28.9%. According to the validation, the method is suitable for the determination of at least 24 volatile compounds common to wine. A practical method application was presented on Zelen wine variety from two different production procedures.
Na aromo vina vplivajo številne hlapne spojine. Ta članek opisuje validacijo metode za 26 hlapnih spojin, ki jih najdemo v vinu. Hlapne spojine so bile določene z diskontinuirano ekstrakcijo tekoče-tekoče in GC-MS detekcijo. Določili smo, da je metoda linearna, z razponom kvadrata korelacijskega koeficienta od 0,961 do 0,999. Meje kvantitativne določitve imajo razpon od 0,52 μg/L do 14,8 μg/L. Izkoristki imajo razpon od 71,1% do 105,7%, razen za dve spojini, katerih izkoristek je nižji. Merilna negotovost ima razpon od 5,0% do 28,9%. Z ozirom na validacijo lahko potrdimo primernost metode za določanje vsaj 24 hlapnih spojin značilnih za vino. Praktični prikaz uporabe metode smo predstavili na vinih sorte Zelen iz dveh različnih postopkov pridelave.
The effect of substrate pH level (4.7, 3.3 and 7.3) on the anthocyanin, quercetin compounds, catechin and phenolic acids concentrations in petals of Rosa x hybrida L. ‘KORcrisett’ and on the number ...of flowers per plant was investigated. The phenolic profiles of this plant were established for the first time by the use of HPLC/MS. Plants potted in a substrate with pH 4.7 developed significantly more flowers compared to those planted in an acidic (3.3) and alkaline (7.3) pH levels. However, the concentration of anthocyanins, quercetin compounds, catechin and phenolic acids was always lowest in the petals of ‘KORcrisett’ rose plants potted in pH level 4.7. Compared to the first sampling, a significant increase in the concentration of major and total anthocyanins and quercetin compounds was measured in the petals of plants potted in pH level 3.3 and 7.3, but not in the plants potted in pH level 4.7, respectfully.
Preučevali smo vpliv pH substrata (4,7, 3,3 in 7,3) na koncentracije antocianov, kvercetinov, katehina in fenolnih kislin v petalih Rosa x hybrida L. ‘KORcrisett’ ter spremljali število cvetov na posamezno rastlino. Sestava in koncentracija fenolnih spojin je bila pri tej rastlini prvič določena s pomočjo HPLC/MS tehnike. Rastline, ki so bile posajene v substrat s pH 4,7, so razvile statistično značilno več cvetov, kot rastline, posajene v kisel (3,3) oziroma bazičen (7,3) pH, vendar pa so bile koncentracije antocianov, kvercetinov, katehina in fenolnih kislin v pH 4,7 najnižje. V primerjavi s prvim vzorčenjem, je koncentracija prevladujočih in skupnih antocianov v petalih močno narasla pri rastlinah, ki so bile posajene v substrat s pH 3,3 in 7,3. Podobnega trenda nismo opazili pri rastlinah, posajenih v pH 4,7.
The changing dynamics of organic acids, sugars, phenolics and antioxidant potential in apples from technological to edible maturity was studied. During the time of storage, the content of citric and ...malic acids generally decreased. The content of sucrose, fructose and glucose decreased significantly in some varieties, while it increased in others. The content of total sugars changed only slightly over the storage period. In the apple pulp, the content level of single phenolics generally changed to a minor extent during storage. In the peel, the content levels of the rutin and quercetin-3-rhamnoside flavonoids remained generally constant during storage, while the level of p-coumaric acid increased slightly; on the other hand, the content levels of epicatechin and catechin decreased. In the pulp of most cultivars, there was no significant decrease in total phenolics at edible maturity. In contrast, the apple peel usually has a higher content level of total phenolics at edible maturity than at the time of technological maturity. Therefore, the antioxidant activity of the peel increased from technological to edible maturity.
Proučevali smo dinamiko spreminjanja organskih kislin, sladkorjev, fenolnih spojin in antioksidativnega potenciala jabolk od tehnološke do užitne zrelosti. Vsebnost citronske in jabolčne kisline se je med skladiščenjem na splošno zmanjševala. Vsebnost saharoze, fruktoze in glukoze se je v času skladiščenja pri nekaterih sortah značilno zmanjšala, pri drugih pa povečala. Vsebnost skupnih sladkorjev se je med skladiščenjem le malo spreminjala. Na splošno se je vsebnost posameznih fenolov v pulpi jabolk v času skladiščenja le malo spreminjala. V kožici je ostala vsebnost flavonoidov rutina in kvercetin-3-ramnozida v obdobju skladiščenja približno enaka, vsebnost p-kumarne kisline se je malo povečala, medtem ko se je količina epikatehina in katehina zmanjšala. Pri večini sort je opaziti v pulpi neznačilno zmanjšanje skupnih fenolov v užitni zrelosti. Nasprotno je kožica jabolk pri večini sort v užitni zrelosti imela večjo vsebnost skupnih fenolov kot v tehnološki zrelosti. Iz tega tudi izhaja, da se je antioksidativna aktivnost kožice od tehnološke do užitne zrelosti povečala.
The domain of catalytic hydrogenation continues to grow fast, reflecting the wide range of chemical applications that can be enhanced by the easy use of molecular hydrogen. The advances in ...characterization techniques and their application have improved our understanding of the catalytic processes and mechanisms occurring in both homogeneous and heterogeneous catalysis. The aim of this volume, although not exhaustive, is to provide a general overview of new progress of the hydrogenation reactions. This volume comprises a series of various contributions, as reviews or original articles, treating heterogeneously and homogeneously catalyzed hydrogenation reactions. It is composed of three parts: hydrogenation reactions in fine organic chemistry, hydrogenation reactions in environmental chemistry and renewable energy, and special topics in hydrogenation.
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