Nanostructured materials for sensing Pb(II) and Cd(II) ions: Manganese oxohydroxide versus carbonized polyanilines?

Nanostructured materials including three different carbonized polyanilines and manganese oxyhydroxide were prepared and evaluated as electrode materials for sensing of lead and cadmium ions in aqueous media. Anodic stripping voltammetry results indicated that all prepared materials could be successfully used for determination of these two heavy metal ions. Carbonized polyaniline-based electrodes have higher signal and lower limits of detection (10-7 М) compared to manganese oxyhydroxide-based electrode. Among the three studied carbonized polyanilines, the one that was derived from polyaniline precursor produced in the presence of 3,5-dinitrosalicyclic acid showed the highest electrocatalytic activity towards the lead and cadmium oxidation. [Projekat Ministarstva nauke Republike Srbije, br. OI172043 i br. III45014

Study on preparation and properties of novel functionalized polyester copolymers based on siloxanes

Novel functionalized macroporous copolymers were synthesized by reaction of the pendant epoxy groups of poly(glycidyl methacrylate)-co-poly(ethylene glycol dimethacrylate)s with 1,3-bis(3-aminopropyl)tetramethyldisiloxane (TMDS) and α,ω-diamino propyl poly(dimethylsiloxane) (PDMS). It was found that the optimal conditions for the synthesis of functionalized copolymers were: reaction temperature of 80 o C, reaction time of 10 h and a mixture of N-methyl-2-pyrrolidone/toluene (1/3 v/v) as the solvent. The effects of the type of siloxanes and concentration of glycidyl methacrylate on the structure and properties of functionalized copolymers were investigated by solid-state 13C and 29Si NMR spectroscopy, FTIR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The structure of functionalized copolymers was confirmed by solid-state NMR and FTIR spectroscopy. The DSC results showed that the glass transition temperatures of copolymers were in the range from 63 to 65 o C and they slightly depend on the copolymer composition exclusively. The thermal stability was better for copolymers functionalized with TMDS in comparison with PDMS based copolymers. Thermal degradation of the synthesized copolymers starts between 276 and 290 o C. The TG curves of all copolymers display two stages of degradation at 308-368 o C (stage 1) and 395-430 o C (stage 2) which are associated with the ester and siloxane bonds. The results indicated that the thermal stability depends on the type of siloxanes and copolymer composition. The surface and crosssection morphology was investigated by SEM and the porous copolymer beads were confirmed by SEM analysis. SEM studies with energy dispersive X-ray mapping revealed that siloxanes migrate to the surface of samples due to their low surface energy. By varying the structure of siloxanes and copolymer composition, functionalized copolymers can be designed and synthesized with diverse physical properties for different purposes

Novel siloxane based polyurethane nanocomposites

A series of novel thermoplastic polyurethanes (TPUs) nanocomposites based on α,ω–dihydroxy ethoxy propyl poly(dimethylsiloxane) (EOPDMS), 1,4-butanediol (BD) and 4,4'-diphenylmethane diisocyanate (MDI) was synthesized by in situ two-step polyaddition reaction in solution using modified clay (Cloisite 30B). The clay percentage in the nanocomposites was 1, 3, 5, 8 and 10 wt% in relation to the polymers. The aim of this study was to improve some properties of TPUs by the addition of clay nanoparticles. The prepared nanocomposites were characterized using FTIR, AFM and DSC analyses. The influence of nanoparticles dispersion on the morphology and thermal properties of TPUs was investigated

Rosemary essential oils as a promising source of bioactive compounds: Chemical composition, thermal properties, biological activity, and gastronomical perspectives

Rosemary (Rosmarinus officinalis L.) is a plant worldwide cultivated mainly for essential oils, extracts, and as a spice. Up-to-date results showed diversity in composition of the essential oils, which may influence their quality, biological activity, and thermal properties. Therefore, the aim of this study was to investigate the chemical composition, antimicrobial activity, and thermal properties of the rosemary essential oils originating from Serbia and Russia. Additionally, oils were added to the sunflower oils in order to investigate possible antioxidant activity during the frying. Investigation of the chemical profile marked α-pinene, eucalyptol, and camphor as the most abundant compounds in both oils. However, overall composition influenced in such manner that Russian oil showed significantly higher antimicrobial activity, while Serbian oil proved to be better antioxidant agent in case of frying of sunflower oil. This would significantly influence possible application of the oils, which could be used as an antioxidant agent for extension of the food shelf life, or antimicrobial agent for protection against different microbial strains

THE GLASS TRANSITION OF OSMOTICALLY DEHYDRATED PORK MEAT STAKLASTI PRELAZ OSMOTSKI DEHIDRIRANOG SVINJSKOG MESA

ABSTRAC

Functionality and Palatability of Yogurt Produced Using Beetroot Pomace Flour Granulated with Lactic Acid Bacteria

Following the idea of sustainability in food production, a yogurt premix based on beetroot (Beta vulgaris) pomace flour (BPF) was developed. BPF was granulated with lactose solution containing lactic acid bacteria (LAB) by a fluidized bed. Particle size increased ~30%. A decrease in Carr Index from 21.5 to 14.98 and Hausner ratio from 1.27 to 1.18 confirmed improved flowability of granulated BPF, whereas a decrease in water activity implied better storability. Yogurts were produced weekly from neat starters and granulated BPF (3% w/w) that were stored for up to one month (4 °C). High viability of Streptococcus thermophilus was observed. Less pronounced syneresis, higher inhibition of colon cancer cell viability (13.0–24.5%), and anti-Escherichia activity were ascribed to BPF yogurts or their supernatants (i.e., extracted whey). Acceptable palatability for humans and dogs was demonstrated. A survey revealed positive consumers’ attitudes toward the granulated BPF as a premix for yogurts amended to humans and dogs. For the first time, BPF granulated with LAB was used as a premix for a fermented beverage. An initial step in the conceptualization of a novel DIY (do it yourself) formula for obtaining a fresh yogurt fortified with natural dietary fiber and antioxidants has been accomplished

Recovery of Polyphenolic Compounds and Vitamins from the Stinging Nettle Leaves: Thermal and Behavior and Biological Activity of Obtained Extracts

Stinging nettle (SN) is an extraordinary plant from the Urticaceae botanical family. It is well-known and widely used in food and folk medicine to treat different disorders and diseases. This article aimed to study the chemical composition of SN leaves extracts, i.e., polyphenolic compounds and vitamins B and C, because many studies ascribed high biological potency to these compounds and their significance in the human diet. Besides the chemical profile, the thermal properties of the extracts were studied. The results confirmed presence of many polyphenolic compounds and vitamins B and C. It also showed that the chemical profile closely correlated with the applied extraction technique. The thermal analysis showed that analyzed samples were thermally stable up to about 160 °C. Thermal degradation of samples UAE, MAE, and MAC took place in four steps, and sample SE in three steps. Altogether, results confirmed the presence of health-beneficial compounds in stinging nettle leaves and indicated the possible application of its extract in pharmaceutical and food industries as both a medicinal and food additive

Rosemary essential oils as a promising source of bioactive compounds: Chemical composition, thermal properties, biological activity, and gastronomical perspectives

Rosemary (Rosmarinus officinalis L.) is a plant worldwide cultivated mainly for essential oils, extracts, and as a spice. Up-to-date results showed diversity in composition of the essential oils, which may influence their quality, biological activity, and thermal properties. Therefore, the aim of this study was to investigate the chemical composition, antimicrobial activity, and thermal properties of the rosemary essential oils originating from Serbia and Russia. Additionally, oils were added to the sunflower oils in order to investigate possible antioxidant activity during the frying. Investigation of the chemical profile marked α-pinene, eucalyptol, and camphor as the most abundant compounds in both oils. However, overall composition influenced in such manner that Russian oil showed significantly higher antimicrobial activity, while Serbian oil proved to be better antioxidant agent in case of frying of sunflower oil. This would significantly influence possible application of the oils, which could be used as an antioxidant agent for extension of the food shelf life, or antimicrobial agent for protection against different microbial strains.Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4793

Rosemary Essential Oils as a Promising Source of Bioactive Compounds: Chemical Composition, Thermal Properties, Biological Activity, and Gastronomical Perspectives

Rosemary (Rosmarinus officinalis L.) is a plant worldwide cultivated mainly for essential oils, extracts, and as a spice. Up-to-date results showed diversity in composition of the essential oils, which may influence their quality, biological activity, and thermal properties. Therefore, the aim of this study was to investigate the chemical composition, antimicrobial activity, and thermal properties of the rosemary essential oils originating from Serbia and Russia. Additionally, oils were added to the sunflower oils in order to investigate possible antioxidant activity during the frying. Investigation of the chemical profile marked α-pinene, eucalyptol, and camphor as the most abundant compounds in both oils. However, overall composition influenced in such manner that Russian oil showed significantly higher antimicrobial activity, while Serbian oil proved to be better antioxidant agent in case of frying of sunflower oil. This would significantly influence possible application of the oils, which could be used as an antioxidant agent for extension of the food shelf life, or antimicrobial agent for protection against different microbial strains

Chemical and thermal analysis of berry seeds

Cilj ovog rada bio je da se ispitaju hemijske i termalne osobine i oksidativna stabilnost ulja i brašna iz semena kupine (R. fruticosus L., sorta Čačanska bestrna) i maline (Rubus idaeus L., sorta Vilamet). Analiziran je i uticaj sastava ulja (sadržaj masnih kiselina) i antioksidanata, koji su prirodno prisutni u uljima, na termalne osobine i oksidativnu stabilnost ovih ulja. Određeni su kinetički parametri: energija aktivacije (Ea), predeksponencijalni faktor (A) i konstanta brzine (k) procesa oksidacije ulja, u izotermskim i neizotermskim uslovima, i analizirano je kako zastupljenost pojedinih masnih kiselina u sastavu ulja utiče na njih...The objective of the present work was investigation of chemical and thermal properties of blackberry (R. fruticosus L., Čačak Thornless cultivar) and raspberry (Rubus idaeus L., Willamette cultivar) seed flours and oils, as well as oxidative stability of these berry seed oils. The impact of fatty acid composition of examined berry seed oils on their oxidative stability and thermal characteristics was analyzed, as well as the effect of antioxidants, which are naturally present in oils, on their oxidative stability. Comparison with the oxidative stability of pure fatty acids was performed. Also, the kinetic parameters (activation energy, Ea, pre-exponential factor, A, and rate constant, k) related to the oxidation process of analyzed oils were determined in isothermal and non-isothermal conditions..