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This paper reports on the investigation of experimental conditions relevant for spontaneous precipitation of significant amount of pure calcium oxalate dihydrate (COD). For this purpose, the hydrodynamic and thermodynamic parameters, such as mode of agitation, temperature, supersaturation and concentration of additives (citrate ions), have been studied. The results show that in the model systems, without the citrate addition and applied mechanical stirring, calcium oxalate monohydrate (COM) was observed as dominant modification after 20 min of aging, while the magnetic stirring resulted in a formation of a mixture of COM and calcium oxalate trihydrate (COT), regardless of the temperature applied. In the mechanically stirred systems, the addition of citrate ions in the range of concentrations, 0.001 mol dm−3

Oxidation mechanism of quercetin in three different electrolytes (KCl, NaCl and LiCl) was studied by cyclic and differential pulse voltammetry. The results have shown that quercetin oxidation is reversible and diffusion controlled process in all three investigated electrolytes. Calibration diagram of quercetin was obtained in KCl, so this electrolyte was selected for total polyphenol content determination in apple peel extracts. Total polyphenol content was analysed by differential pulse voltammetry (dpv) and spectrophotometric Folin-Ciocalteu method (FC) in several ancient Croatian apple varieties and a wild apple variety grown in Croatia by using quercetin as a standard. Very high correlation for TP content obtained by two methods was observed since the TPdpv/TPFC ratio was around 1 and a correlation coefficient (R2) for TPdpv vs. TPFC was 0.98. The highest total polyphenol content was found in Slavonska srčika variety. This work is licensed under a Creative Commons Attribution 4.0 International License.

Two new macrocyclic Schiff bases m 3 and m 4 (m 3 = 1,5-diaza-2,4:7,8:17,18-tribenzo-9,16-dioxa-cyclononadeca-1,5-dien; m 4 = 1,5-diaza-2,4:7,8:18,19- tribenzo-9,17-dioxa-cycloeicosa-1,5-dien) were synthesized by reactions of the appropriate dialdehyde and diamine. The compounds were characterized by means of FT-IR and NMR spectroscopy, TG/DSC and elemental analysis. The crystal and molecular structures were determined by the single crystal X-ray diffraction method. Both molecules are N2O2-donor macrocyclic Schiff bases with 19 and 20 atoms in their inner macrocyclic rings and of a similar molecular structure. A different crystal packing arrangement of the molecules is caused by the differences in macrocycle planarity. The extraction experiments of the aforementioned compounds were performed by using metallic picrate salts, and simultaneously for the previously synthesized 17- and 18- membered macrocyclic analogues (m 2 and m 1). The metal cation extractability was determined for m 1, m 2, m 3 and m 4 by UV–Vis spectrophotometry in order to find correlation of structural features and the extraction capabilities of the Schiff bases. The highest metal cation extraction percentage was determined for the Hg2+ ion in the case of the m 2 macrocycle.

Prelaz mišića u meso složen je biokemijski proces ovisan o različitim parametrima. Kako bi se proizvelo što kvalitetnije meso privlačno kupcima, potrebno je poznavati biokemijske promjene koje se događaju u mišićnom tkivu ante mortem, odnosno post mortem. Izraz glikolitički potencijal označava potencijal pojedinog mišića za stvaranje laktata. Laktat i glikogen (potencijalni izvor dodatnog laktata) u mišićnom tkivu mogu se precizno izmjeriti enzimskim metodama. U ovome radu je sažeto opisana enzimatska metoda za određivanje glikolitičkog potencijala., Muscle to meat conversion is a complex biochemical process, depending on various parameters. The understanding of biochemical changes occurring ante-mortem and post-mortem in muscle tissue is necessary for production of high quality meat, attractive to potential customers. The term glycolytic potential defines the potential of individual muscle to form lactate. A. large amount of lactate generated in the short time causes a rapid fall of meat pH, and formation of poor quality meat. Lactate and glycogen (potential source of additional lactate) in muscle tissue can be precisely determined by enzymatic methods. In this article a concise description of enzymatic assay for glycolitic potential determination is presented.

Prelaz mišića u meso složen je biokemijski proces ovisan o različitim parametrima. Kako bi se proizvelo što kvalitetnije meso privlačno kupcima, potrebno je poznavati biokemijske promjene koje se događaju u mišićnom tkivu ante mortem, odnosno post mortem. Izraz glikolitički potencijal označava potencijal pojedinog mišića za stvaranje laktata. Laktat i glikogen (potencijalni izvor dodatnog laktata) u mišićnom tkivu mogu se precizno izmjeriti enzimskim metodama. U ovome radu je sažeto opisana enzimatska metoda za određivanje glikolitičkog potencijala.