Comparison of antioxidant and antimicrobial activities of extracts obtained from Salvia glutinosa L. and Salvia officinalis L.

Antioxidant and antimicrobial activities as well as total phenols and flavonoids contents of Salvia glutinosa L. (glutinous sage) and Salvia officinalis L. (sage) extracts were studied. Methanol and aqueous ethanol (70% v/v) were used for extraction of bioactive compounds, both in the presence and the absence of ultrasound, from herb and the spent plant material remaining after the essential oil hydrodistillation. The ratio of plant material to extracting solvent was 1:10 g/ml. Antioxidant and antimicrobial activities of the extracts were found to depend on the type of plant material and the extraction conditions. The plant materials from which essential oil had been recovered were proven to be valuable raw materials for making various herbal preparations

The application of natural organic compounds in bakery industry

Investigations include the analysis of the impact of commercial products: complex additive (0.1, 0.3, and 0.5%), L-ascorbic acid (0.002, 0.004 and 0.012%), diacetyl ester of tartaric acid with monoglycerides (DATEM E472e, 0.1, 0.3, and 0.5%), α-amylase (0.002, 0.006 and 0.012%), xylanase (0.004, 0.012 and 0.024%), alcohol extract of rosemary, thyme or sage (0.5, 1.0 and 2.0%), as well as the combination of complex additive and rosemary, thyme and sage extract on rheological characteristics of dough. The study includes amylograph, farinograph and extensograph analysis of dough with and without additives (control sample). The volume of lost CO2 gas (mL) is the lowest in dough samples with an added combination of complex additive and thyme extract (0.05 and 0.5%) and rosemary extract (2.0%). In the samples with thyme extract (1.0%) added, the volume of lost gas is at a level of samples with added complex additive, DATEM, and L-ascorbic acid

Antioxidant activity, the content of total phenols and flavonoids in the ethanol extracts of Mentha longifolia (L.) Hudson dried by the use of different techniques

In this study, we have examined the yield of extracted substances obtained by means of extraction using 70 % ethanol (v/v), the content of total phenols and flavonoids, as well as the antioxidant activity of the extracts obtained from the samples of the herbs dried by means of different techniques. Wild mint Mentha longifolia (L.) Hudson was dried naturally in a laboratory oven at a temperature of 45 °C and in an absorptive low temperature condensation oven at 35°C. The highest yield of extracts was obtained from the naturally dried herbs and the lowest from the herbs dried in the low temperature condensation drying oven. The content of total phenols and flavonoids was determined by spectrophotometric methods with an FC reagent and by the complexation reaction with aluminium-chloride, respectively. The extract of the naturally dried herbs had the highest overall content of phenols (113.8±2.0 mg of gallic acid/g of the dry extract) and flavonoids (106.7±0.3 mg of rutin/g of the dry extract). The highest antioxidant activity determined by the FRAP and DPPH assay was determined in the extracts obtained from naturally dried herbs (2.76±0.15 mmol Fe2+/mg of the dry extract and EC50=0.022±0.001 mg/ml), while the lowest was obtained from the extracts of herbs dried in the laboratory oven (1.13±0.11 mmol Fe2+/mg of the dry extract and EC50=0.033±0.001 mg/ml). The HPLC-DAD analysis result show that the greatest content of phenolic compounds show extract obtained from naturally dried plant material. The dominant phenolic component in the all extracts is Kaempferol 3-O-glucoside. The content of all phenolic compound strongly depend on the drying conditions

Insight into the Aroma Profile and Sensory Characteristics of ‘Prokupac’ Red Wine Aromatised with Medicinal Herbs

Autochthones grape variety of ‘Prokupac’ (Vitis vinifera L.) is being increasingly cultivated in the Republic of Serbia and is one of the predominant varieties in the vineyards of southern Serbia. ‘Prokupac’ grapes are used to produce red wine with specific and distinctive varietal aromatic characteristics. Medicinal herbs can be effectively combined in alcoholic beverages. The aim of this study was to evaluate the effect of medicinal herbs on the aroma profile and sensory characteristics of ‘Prokupac’ red wine. The analysis of the aromatic composition was conducted on ‘Prokupac’ wine (control) and ‘Prokupac’ wine aromatised with selected medicinal herbs: anise (Pimpinella anisum L.), cinnamon (Cinnamomum verum J. Presl.), wormwood (Artemisia absinthium L.) and licorice (Glycyrrhiza glabra L.). The analysis of volatile aromatic compounds in the wines, performed by the gas chromatography-mass spectrometry (GC/MS) method, identified 48 compounds that were classified in the following groups: alcohols, aldehydes, ketones, acids, ethyl esters and terpenes. Sensory analysis of wines was performed including visual, olfactory, gustatory and gustatory-olfactory perceptions. Terpenes were not identified in the ‘Prokupac’ control wine, while the highest content of all identified aromatic compounds was found in wines aromatised with anise, wormwood and cinnamon. The results indicated that selected medicinal herbs affected the composition and content of volatile aromatic compounds, as well as the sensory characteristics of analyzed wines. The unique aroma profile and pleasant taste of the wine aromatised with cinnamon contributed to its differentiation from other wines, and classification as very good wine

Pyrite oxidation by Acidithiobacillus ferrooxidans bacteria

The kinetic model of pyrite particle dissolution by the action of bacteria Acidithiobacillus ferrooxidans in a shaken Erlenmeyer flask was presented. The model agreed well with the experimental data for the extracted iron and the number of cells in the liquid phase. The specific growth rate of the adsorbed cells was evaluated (μA = 1,6 d-1) by fitting the experimental data to the model curve. Also, the relevance of the two proposed mechanisms for the bacterial dissolution of sulphide (direct and indirect) was discussed, indicating that the indirect one was dominant. The adsorption process of A. ferrooxidans to the pyrite surface was well correlated by a Langmuir type isotherm

Biodiesel production by enzyme-catalyzed transesterification

The principles and kinetics of biodiesel production from vegetable oils using lipase-catalyzed transesterification are reviewed. The most important operating factors affecting the reaction and the yield of alkyl esters, such as: the type and form of lipase, the type of alcohol, the presence of organic solvents, the content of water in the oil, temperature and the presence of glycerol are discussed. In order to estimate the prospects of lipase-catalyzed transesterification for industrial application, the factors which influence the kinetics of chemically-catalysed transesterification are also considered. The advantages of lipase-catalyzed transesterification compared to the chemically-catalysed reaction, are pointed out. The cost of down-processing and ecological problems are significantly reduced by applying lipases. It was also emphasized that lipase-catalysed transesterification should be greatly improved in order to make it commercially applicable. The further optimization of lipase-catalyzed transesterification should include studies on the development of new reactor systems with immobilized biocatalysts and the addition of alcohol in several portions, and the use of extra cellular lipases tolerant to organic solvents, intracellular lipases (i.e. whole microbial cells) and genetically-modified microorganisms ("intelligent" yeasts)

Original scientific paper Validation of an HPLC–UV method for the determination of digoxin residues on the surface of manufacturing equipment

Abstract: In the pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace amounts of drugs have, therefore, to be considered with special attention. An HPLC–UV method for the determination of digoxin residues on stainless steel surfaces was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with methanol were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 85.9, 85.2 and 78.7 % for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD), were below 6.3 %. The method was validated over a concentration range of 0.05–12.5 µg mL-1. Low quantities of drug residues were determined by HPLC–UV using a Symmetry C18 column (150×4.6) mm, 5 µm) at 20 °C with an acetonitrile–water (28:72, v/v) mobile phase at a flow rate of 1.1 mL min-1, an injection volume of 100 µL and were detected at 220 nm. A simple, selective and sensitive HPLC–UV assay for the determination of digoxin residues on stainless steel was developed, validated and applied

THE APPLICATION OF NATURAL ORGANIC COMPOUNDS IN BAKERY INDUSTRY

Investigations include the analysis of the impact of commercial products: complex additive (0.1, 0.3, and 0.5%), L-ascorbic acid (0.002, 0.004 and 0.012%), diacetyl ester of tartaric acid with monoglycerides (DATEM E472e, 0.1, 0.3, and 0.5%), α-amylase (0.002, 0.006 and 0.012%), xylanase (0.004, 0.012 and 0.024%), alcohol extract of rosemary, thyme or sage (0.5, 1.0 and 2.0%), as well as the combination of complex additive and rosemary, thyme and sage extract on rheological characteristics of dough. The study includes amylograph, farinograph and extensograph analysis of dough with and without additives (control sample). The volume of lost CO2 gas (mL) is the lowest in dough samples with an added combination of complex additive and thyme extract (0.05 and 0.5%) and rosemary extract (2.0%). In the samples with thyme extract (1.0%) added, the volume of lost gas is at a level of samples with added complex additive, DATEM, and L-ascorbic acid. SCIENTIFIC PAPER UDC 664.6:66.022.3 DOI: 10.2298/HEMIND100709046

Direct ultrasound-assisted extraction and characterization of phenolic compounds from fresh houseleek (Sempervivum marmoreum L.) leaves

The effects of ultrasound power and frequency on the yield of total extractive substances (TES), total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (AOA) of fresh houseleek leaves extracts obtained by direct ultrasound-assisted extraction (DUAE) were studied. Preliminary extraction of plant material was performed using methanol, acetone and 2-propanol by Soxhlet extraction. It was found that maximum TES yield could be obtained by methanol extraction (2.91±0.02), followed by acetone and 2-propanol with a TES yield of 2.32±0.01 and 2.01±0.03 g per 100 g of fresh plant material, respectively. In the fresh houseleek leaves extracts obtained by DUAE and methanol as the chosen solvent, TPC, TFC and AOA were in the ranges of: 40.5–85.9 mg gallic acid/g dry extract, 12.7–19.3 mg rutin/g dry extract and 24.6–108.2μg/ml, respectively. The results showed that the increase in the ultrasound power and extraction time have positive and significant (p < 0.05) effects on the TPC, TFC and AOA, while the increase in the ultrasound frequency leads to a decrease in the TPC, TFC and AOA of the extracts. A chromatographic analysis of crude extract identified the following: kaempferol 3-O-(6’’-O-malonylglucoside)- 7-O-glucosyde, kaempferol 3-O-glucoside-7-O-rhamnoside, luteolin 5-O-(6’’-O-malonylglucoside), kaempferol 3-O-(6’’-O-acetylglucoside)-7-O-rhamnoside, genkwanin 5-O-glucoside, luteolin 5-O-(6’’-O-malonylglucoside), kaempferol 3-O-(6’’-O-malonylglucoside), kaempferol 3-O-rhamnoside, quercetin, genkwanin 4’-O-glucoside and hyperoside. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172047

Kinetics of sunflower oil methanolysis catalyzed by calcium oxide

The methanolysis of sunflower oil was studied in the presence of CaO previously calcined at various temperatures and the optimal temperature for CaO calcination was determined. The sigmoidal process kinetics was explained by the initial triglyceride (TG) mass transfer controlled region, followed by the chemical reaction controlled region in the latter reaction period. The TG mass transfer limitation was due to the small available active specific catalyst surface, which was mainly covered by adsorbed molecules of methanol. In the later phase, the adsorbed methanol concentration decreased, causing the increase of both the available active specific catalyst surface and the TG mass transfer rate, and the chemical reaction rate become smaller than the TG mass transfer rate