23 research outputs found
Effect of fermentation conditions on content of phenolic compounds in red wine
The evidence of compounds that increase the nutritive value of red wines has been presented in a number of papers. These compounds include catechins and proanthocyanidins among others. Their protective effect on the cardiovascular system and anticarcinogenic properties has been proved. The effect of maceration conditions and increased solid grape parts content, seed in the first place, on the content of phenolic compounds of wine was investigated. Several micro-trials were performed with Cabernet sauvignon sort; in some variants time and temperature of maceration were varied, while the ratio of residual stem and content of seed was increased several times, resulting in a significant change of phenolic compounds content in the obtained wine samples. The presence of ripe stem yielded good results, but only during six days of maceration, while in the case of longer maceration, the change of colour quality was negative. Supplementary quantities of seeds during maceration resulted in an increase of total phenols and catechins. A significant influence on colour of wines was also observed, especially in wines obtained applying shorter maceration
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%), Ī±-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
Production of ethanol from Kantata wheat variety
Processing parameters of Kantata wheat variety indicate that it is not suitable for bread making. Therefore, an investigation was carried out to evaluate the suitability of the variety for ethanol production. Wheat was cultivated at the following sites: Kovin, Zrenjanin, PanÄevo and Vrbas. Ethanol yields depend on the location on which the samples were grown and on the temperature during thermal and enzymatic preparation of flour samples. Wheat sample cultivated on the Vrbas site gave the highest ethanol yield
Optimization of cultivation medium for the production of antibacterial agents
Optimization of the cultivation medium for production of antibiotic effective
against pathogenic bacteria Staphylococcus aureus using strain of
Streptomyces spp. isolated from the environment represents the aim of this
study. After the biosynthesis, the medium was analyzed by determining
residual sugar and nitrogen, and the antibiotic activity was determined using
diffusion-disc method. Experiments were carried out in accordance with the
Box-Behnken design, with three factors varied on three levels (glucose: 10.0,
30.0 and 50.0 g/L; soybean meal: 5.0, 15.0 and 25.0 g/L; phosphates: 0.5, 1.0
and 1.5 g/L) and for the optimization of selected parameters Response Surface
Methodology was used. The obtained model with the desirability function of
0.985 estimates that the lowest amounts of residual sugar (0.89 g/L) and
nitrogen (0.24 g/L) and the largest possible inhibition zone diameter (21.88
mm) that with its antibiotic activity against S. aureus creates the medium
containing 10.0 g/L glucose, 5.0 g/L soybean meal and 1.04 g/L phosphates
Modelling the effects of transglutaminase and l-ascorbic acid on substandard quality wheat flour by response surface methodology
Over the past decade, extreme variations in climatic conditions have been observed, which in combination with inadequate agro techniques lead to decreased quality of mercantile wheat, i.e. flour. The application of improvers can optimise the quality of substandard wheat flour. This paper focuses on systematic analysis of individual and interaction effects of ascorbic acid and trans-glutaminase as dough strengthening improvers. The effects were investigated using response surface methodology. Transglutaminase had much higher linear effect on the rheological and fermentative properties of dough from sub-standard flour than L-ascorbic acid. Both transglutaminase and L-ascorbic acid additions had a significant linear effect on the increase of bread specific volume. Effects of transglutaminase and ascorbic acid are dependent on the applied concentrations and it is necessary to determine the optimal concentration in order to achieve the maximum quality of the dough and bread. Optimal levels of tested improvers were determined using appropriate statistical techniques, which applied the desirability function. It was found that the combination of 30 mg/kg of transglutaminase and 75.8 mg/kg of L-ascorbic acid achieved positive synergistic effects on rheological and fermentative wheat dough properties, as well on textural properties and specific volume of bread made from substandard quality flour
Effect of nitrogen sources on the production of antifungal metabolites by Streptomyces hygroscopicus
Biotechnologically produced antifungal compounds for control of plant
diseases caused by phytopathogenic fungi represent a promising alternative
to synthetic pesticides. Fungi from the genera Alternaria and Fusarium are
listed among important storage pathogens of apple fruits. A. alternata
causes significant annual losses of apple fruit. Also, F. avenaceum is one
of the most commonly encountered Fusarium species identified as the causal
agent of a wet apple core rot. Species of the Streptomyces genera are soil
bacteria that produce significant quantities of bioactive compounds in
appropriate media. Defining the culture medium composition is the basis of
bioprocesses development. Nitrogen source is critical component of
cultivation medium and also the most useful tool for stimulation of the
antifungal metabolites production. The aim of this study was to select the
best nitrogen sources in medium for the production of antifungal compounds
effective against A. alternata and F. avenaceum by S. hygroscopicus.
Activity of the cultivation liquids on A. alternata and F. avenaceum
isolates was tested in vitro using well diffusion method. The results
inĀdicate that maximum inhibition zone was reached in medium with soybean
meal as nitrogen source with inhibition diameter more than 35 mm for both
tested fungi. [Project of the Serbian Ministry of Education, Science and
Technological Development, Grant no. TR-31002
The contribution of bioethanol to sustainable development in Serbia
The pollution caused by the use of fossil fuels for the production of mechanical or electrical energy is one of the most important environmental issues nowaĀdays. In this respect, biofuels represent a viable source of energy. Bioethanol as a renewable energy source is derived from organic material of plant origin, so-called biomass, thus reducing environmental pollution. The aim of this study was to analyze the potential of bioethanol in meeting future energy demands in the Republic of Serbia. [Projekat Ministarstva nauke Republike SRbije, br. TR31002: The improvement of bioethanol production from sugar beet processing products
Effect of the initial glycerol concentration in the medium on the xanthan biosynthesis
This study is concerned with the effect of different initial glycerol
concentrations in the medium on xanthan production by Xanthomonas campestris
ATCC 13951. Xanthan biosynthesis was carried out in batch mode under aerobic
conditions at a temperature of 30oC and agitation rate of 150 rpm for 7 days.
The process efficiency was estimated based on the values of raw xanthan
yield, average molecular weight of the polymer and residual content of
glycerol, total nitrogen and phosphorus. Based on these results, the initial
concentration of glycerol as a carbon source in the production medium was
suggested. In the applied experimental conditions, high raw xanthan yield
(12.15 g/l) of good quality (Mw = 2.86ā¢105 g/mol) and the lowest amount of
residual nutrients (glycerol 2.75 g/l, nitrogen 0.46 g/l and phosphorus 0.67
g/l) was achieved in the medium with the initial glycerol content of 20 g/l.
The obtained results are the basis for optimization of xanthan production on
glycerol containing media in order to increase the product yield and quality
Activation of waste brewer's yeast Saccharomyces cerevisiae for bread production
The waste brewer's yeast S. cerevisiae (activated and non-activated) was compared with the commercial baker's yeast regarding the volume of developed gas in dough, volume and freshness stability of produced bread. The activation of waste brewer's yeast resulted in the increased volume of developed gas in dough by 100% compared to non-activated brewer's yeast, and the obtained bread is of more stable freshness compared to bread produced with baker's yeast. The activation of BY affects positively the quality of produced bread regarding bread volume. The volume of developed gas in dough prepared with the use of non-activated BY was not sufficient, therefore, it should not be used as fermentation agent, but only as an additive in bread production process for bread freshness preservation. Intense mixing of dough results in more compressible crumb 48 hrs after baking compared to high-speed mixing
The biotechnological production of xanthan on vegetable oil industry wastewaters. Part I: Modelling and optimization
The aim of this research was to examine the possibility of using the vegetable oil industry wastewater as the basis of the cultivation media for xanthan production, using Xanthomonas campestris ATCC 13951, in order to reuse the wastewater obtained in one industry as a raw material in another. Furthermore, the aim was to optimize the composition of wastewater based media in terms of carbon, nitrogen, and phosphorus content. Experiments were carried out in accordance with the Box-Behnken design with three factors on three levels (glucose: 10.00- -30.00 g/L; nitrogen: 0.02-0.20 g/L; phosphorus: 0.0045-0.045 g/L) and three repetitions at the central point. The success of biosynthesis was assessed by analysing broths to determine xanthan yield, cultivation broth apparent viscosity, residual carbon, nitrogen, and phosphorus content. Graphical and numerical optimization using response surface methodology was performed to determine the optimal content values of the carbon source, nitrogen, and phosphorus content. The results of graphical optimization suggest that for the defined response interval values, the defined model predicts that the xanthan production is possible when 15.00-16.00 g/L of the carbon source, 0.02-0.09 g/L of nitrogen and 0.01-0.02 g/L of phosphorus are added to the media that as a basis contains vegetable oil industry wastewater