RIOFH - Repository of Institute of General and Physical Chemistry
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Application of semiconductor continuous and Nd:YAG pulsed laser processing for nondestructive cleaning of the historical paper
No full textPreservation of cultural legacy is essential for ensuring its availability for future generations. Long-term indoor storage can sometimes cause the papers to adhere, which can result in the transfer of ink stamps or prints from paper to paper, and subsequently, there emerges the need to remove these types of stains. Laser cleaning emerged as a promising technique for paper surface cleaning. This work presents the laser cleaning of a historical paper dated to the end of the 19th century using the Nd:YAG laser in a nanosecond pulsed regime, at two wavelengths, 532 and 1064 nm, and a semiconductor laser in a continuous regime, at a 552 nm wavelength. The cleaned areas are observed by optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and spectrophotometry. The obtained results are discussed in terms of the laser cleaning efficiency characterized by several aspects. The results obtained by green and near-IR laser irradiation in pulsed and continuous regime are compared, showing favorable effects regardless of the laser wavelength. However, in some cases, laser cleaning at 1064 nm wavelength damaged the surface layer of the paper. Cleaning at 532 nm wavelength did not completely remove the ink, and the ink traces were visible under the microscope or spectrometer. The proposed efficient cleaning method for stain, dust, and stamp ink removal from historical papers includes a semiconductor laser at 552 nm, owing to the continuous action of its beam
Comparison between Organic and Conventional Spelt and Wheatgrass juice
No full textThis work is aimed to compare antioxidant and scavenger properties of conventionally and organically produced speltgrass. Moreover, the antioxidant status of spelt was compared with wheatgrass. Three spelt varieties were analyzed:Nirvana, Ebners-Rotkorn variety and Eco-10. Antioxidant enzymes, superoxide-dismutase and guiacol-peroxidase, were determined as well as ferric reducing antioxidant power and DPPH-antiradical power. Total soluble proteins and total phenols were determined and also lipid peroxidation as a parameter of oxidative stress. The organically produced spelt was exposed to the higher levels of oxidative stress than conventionally produced spelt, and also DPPH antiradical power was induced by conventional production, which is also demonstrated using the relative antioxidant capacity index. The best antioxidant properties, better than wheat, showed organically produced spelt genotype Ebners-Rotkorn which is determined by the highest phenol content, superoxide-dismutase activity, DPPH antiradical power and ferric reduced antioxidant power and consequently with the lowest lipid peroxidation intensity
Quantification and determination of household food waste and its relation to sociodemographic characteristics in Croatia
No full textEvery year in the EU alone, almost 90 million tonnes of food is lost. The sectors contributing the most to this amount are households, accounting for 53% of total food waste. Bearing in mind the fact those twothirds of this amount refers to the occurrence of waste which is theoretically avoidable, the greatest attention should be paid to the generation of food waste in households. In Croatia, there is no data on the quantities of food waste produced, but only estimates on the amount of such waste. The aim of this research paper was to determine the type and amount of household food waste and the differences in production of waste relative to the socio-demographic characteristics of household members. The research was carried out by 115 Croatian households, who self-reported the amount of food waste during seven days. According to the results, on average, 2.57 portions of food waste were reported as the amount of discarded food per household member per day, equivalent to 0.21 kg of food waste mass. In general, the typical Croatian household generates 75 kg of food waste per person on average. The age of respondents positively affected the prevention of waste, while the income level and the number of children under the age of 18 in the household had an adverse impact
Tomato pomace extract and organic peppermint essential oil as effective sodium nitrite replacement in cooked pork sausages
No full textThe effect of supercritical fluid extract of tomato pomace (TP) and essential oil of organic peppermint (PM) on pH, color, residual nitrite content, lipid oxidation (TBARS value) and total plate count (TPC) of cooked pork sausages produced with 50 mg/kg of sodium nitrite was investigated. Five batches were produced: T1: 100 mgkg of sodium nitrite; T2: 50 mg of sodium nitrite; T3: 50 mg of sodium nitrite and 0.150 mu L/g TP; T4: 50 mg of sodium nitrite, 0.075 mu L/g TP and 0.075 mu L/g PM; T5: 50 mg of sodium nitrite and 0.150 mu L/g PM. The lowest residual nitrite content and TBARS value were observed in treatment T4. The inclusion of TP increased redness of cooked pork sausages. TPC was the lowest in treatment T5. The results of this study showed that the addition of TP and PM enhanced quality of cooked sausages produced with reduced level of sodium nitrite
Conventional versus microwave-assisted hydrodistillation of sage herbal dust: Kinetics modeling and physico-chemical properties of essential oil
No full textSage herbal dust generated as a by-product from filter-tea factory contains various bioactive compounds which secured its economic potential towards valorization of under-utilized stream. The aim of this work was to utilize sage herbal dust as raw material for the recovery of value-added product. Comparative evaluation of hydrodistillation (HD) and microwave-assisted hydrodistillation (MWHD) processes applied for isolation of sage herbal dust essential oil (EO) were applied for this purpose and EO yield varied from 0.50 to 1.90%. Distillation experiments performed at different levels of power and kinetics of EO recovery were monitored, while four empirical kinetic equations were successfully applied for modeling of process kinetics according to appropriate values of statistical parameters (R2 and AARD). GC-MS analysis was applied for chemical characterization of sage EOs, while DPPH assay was used to determine in vitro bioactivity and results suggested that power affected terpenoid profile and antioxidant activity in case of HD and MWHD. Thermal analysis of obtained EOs was utilized to establish correlation between thermal behavior and terpenoids profile. Results suggested that MWHD could provide excellent alternative for production of high-quality sage EO with high content of oxygenated terpenoids and adequate bioactivity
Physicochemical analysis and phenolic profile of polyfloral and honeydew honey from Montenegro
No full textThe research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm(-1) for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region
Influence of extruded camelina seed and natural colourants addition in laying hens diet on eggs yolk colour and fatty acid composition
No full textThe aim of this study was to investigate the effects of inclusion of camelina-corn meal co-extrudate (CCM) and natural pigments in hen's diet on colour, fatty acid composition and total tocopherols content of eggs. One hundred and twenty Lohmann Brown laying hens were fed with corn-soybean meal based diet with addition of CCM at different levels: 0% (control K1 and K2), 16.60% (C1) and 27.60% (C2). Control treatments were different in the amount of fat and content of pigments. Control treatment K1 contains 3% fat with no pigments added, while control treatment K2 contains 5% fat with the addition of synthetic pigments. Treatments C1 and C2, which contained 1% carrots and 0.5% paprika, achieved desirable colour, demanded by consumers, 12.67 and 13.28 RYCF (Roche Yolk Colour Fan), respectively. Eggs from hens fed with CCM had significantly higher level (p LT = 0.001) of alpha-linolenic (3.89% for C1 and 4.29% for C2), docosahexaenoic (1.38% for C1 and 1.34% for C2) and eicosapentaenoic (0.17% for C1 and 0.18% for C2) acids than eggs originated from hens fed with the control diets. The omega-6/omega-3 ratios of 1.74 and 1.73 in treatments C1 and C2 respectively, were significantly lower (p LT = 0.001) than omega-6/omega-3 ratios in the control treatments K1 and K2 (9.40 and 8.88, respectively). Hence, the obtained results showed the possibility of producing functional egg with desirable colour and fatty acid composition by adding CCM and natural pigments in hen's diet
Blending performance of the coupled Ross static mixer and vertical feed mixer - Discrete element model approach
No full textThe mixing quality of the pigeon diet mix was studied after the mixing in the Ross-type static mixer (pre-mixer) and the vertical feed mixer (final mixer in the line). Three different experiments were performed: firstly, the possibilities of static mixer were investigated, secondly the blending performance of the vertical feed mixer, and the combination of these approaches in the third experiment. The Discrete Element Method was used in numerical modelling of granular flow in the pre-mixer and the vertical feed mixer, to predict the inter-particle mixing quality, and the results of the mixing. The results of the model were compared with appropriate experiments. The main goal was to foresee the behaviour of mixture in two type of mixers and to evaluate the combined mixing action of these two mixers, in order to explore the possibilities to increase the mixing quality, shorten the mixing time and to reduce the energy consumption
Prediction of denitrification capacity of alkalotolerant bacterial isolates from soil - An artificial neural network model
No full textIn the past decades, the bioremediation process based on denitrification by aerobic heterotrophic bacteria was extensively studied for different engineering approaches. Besides the fact that only non-pathogenic and non-biofilm forming bacteria must be used, it is very important to isolate bacteria or a group of bacteria in nature with the capacity to remove completely nitrate without accumulation of nitrogen oxides or ammonia as intermediates. In this article, the denitrification capacity of 43 bacterial strains isolated from slightly alkaline and calcite soils along the Danube River were investigated by artificial neural network (ANN) modelling. According to the obtained results, an ANN model was developed for the prediction of denitrification capacity of bacterial soil strains based on six signification denitrification indicators: biomass and N2 gas production, nitrate and nitrite concentration as well as nitrite and ammonia formation. The ANN model showed a reasonably good predictive capability of the outputs (overall R2 for prediction was 0.958). In addition, the experimental verification of the ANN in laboratory testing indicated that the ANN could predict the denitrification capacity of soil bacteria during the denitrification process in laboratory conditions
The rheological properties of wheat dough containing zeolite residue
No full textThe use of natural zeolite - clinoptilolite, to protect wheat grain from storage insects within environmentally-friendly storage techniques can lead to the presence of small amounts of zeolite residues in flour. This study investigated the influence of as-received zeolite clinoptilolite (Z) and sodium-rich clinoptilolite (NaZ) in wheat dough on the dough rheological properties. Zeolites were added to dough at 0.5-1.5 wt% flour basis level, which is a range expected to remain in the grain (flour) after treatment to control storage pests. The effects were studied in two types of wheat, conventional (Triticum aestivum) and spelt (T aestivum spp. spelta) because they initially differ in rheological properties. NaZ was used to discern whether the presence of increased concentration of Na+ in the zeolite was able to exert a higher strengthening effect as compared to as-received zeolite (Z). NaZ exerted the highest dough strengthening effect which was mainly reflected as decreased dough softening and increased water absorption. The fact that the presence of NaZ was the most effective factor in improving the dough rheological profile suggested that the presence of movable cations in the zeolite lattice might have a pronounced role in the mechanism by which zeolite affects dough behaviour