A strain of Saccharomyces cerevisiae used in the food industry was propagated in the presence of zirconium ascorbate or zirconium citrate complex. The propagation of the yeast was slightly inhibited by zirconium (Zr) in a complex form, but it was not toxic. The Zr content in the fermentation medium decreased faster when using ascorbate complex than the citrate complex. The ascorbate complex was better accumulated by the yeast (4300 mg Zr g-1 dry mass) than the citrate complex (1600 mg Zr g-1 dry mass). The total amino acid content of the yeast cells decreased in the presence of both complexes. The concentration of some amino acids [threonine (Thr), proline (Pro), phenylalanine and cysteine (Cys)] was increased by 10-39% in the medium containing Zr ascorbate, while that of other amino acids [arginine (Arg), serine (Ser), methionine (Met) and glutamic acid (Glu)] decreased by 18-60%. As a result of the presence of zirconium citrate the concentration of Glu, aspartic acid (Asp), leucine (Leu), Thr, valine (Val), Ser, Arg, Pro and Met decreased by 19-32%, and the concentration of Cys increased by 59%.
Authors:K. Berković, S. Kovač, and J. Vorkapić-Furač
The compounds of interest in the present study were the natural compounds rutin and quercetin, which are strong antioxidants and have beneficial effects on human health (Myake & Shibamoto, 1997). They are present in everyday foods and beverages and in this way they are used as an integral part of human diet. Therefore, it seemed interesting to investigate the influence of these valuable natural compounds on corrosion processes of aluminium, an ambalage material often used in food industry (Jovanovic et al., 1994). All the investigations were performed in 3% solution of sodium chloride, in aqueous rutin and quercetin solutions as well as in rutin and quercetin solutions in 3% sodium chloride solution. Concentrations of rutin and quercetin solutions used ranged from 10-2 to 10-5 mol dm-3, and investigations involved electrochemical methods. The results obtained showed that rutin and quercetin previously dissolved in 0.1 M NaOH and added to the 3% sodium chloride solution at concentrations of 10-4 and 10-5 mol dm-3 acted as aluminium corrosion inhibitors, while at higher concentrations (10-2 and 10-3 mol dm-3) their effects were opposite. The efficiency of the corrosion inhibition of aluminium by rutin and quercetin solutions was the result of forming protective film on the metal surface. Therefore, the diluted rutin and quercetin solutions could be used as corrosion inhibitors of aluminium.
Recently several studies have focused on the antioxidant activity of lycopene such as quenching of singlet oxygen and scavenging of peroxyl radicals. These properties may play a role in the prevention of different cancer and heart diseases. Tomato is one of the most important sources of lycopene. The main information on the effect of environmental parameters on quality and health-retaining constituents of tomato fruit is mostly related to temperature (air- and fruit canopy temperature) and light effects that might provide a stress to the fruit. Nowadays little is know about the direct effect of elevated CO2.The aim of the present work was to evaluate the effects of elevated CO2 in Perspex open top chambers (OTC) on the lycopene content of tomato fruit.Experiments on the effects of elevated CO2 concentrations showed mixed results. In this work it was found that concentrations of lycopene in a fruit decreased significantly when elevated CO2 was used. Elevated nitrogen sources generated only slight, but not significant difference in the lycopene concentration of tomato fruit.
Authors:K. Szentmihályi, M. Szilágyi, J. Balla, L. Ujhelyi, and A. Blázovics
Magnesium participates in numerous enzymatic reactions in the human body and it has essential role in the maintenance of the antioxidant system. Since several magnesium compounds have been applied in the food and pharmaceutical industry, our purpose was to investigate the antioxidant/free radical scavenging activity of some magnesium compounds in vitro. The antioxidant/prooxidant effect of inorganic salts (e.g. MgCl2) and organic complexes (e.g. Mg-gluconate) was determined with chemiluminometric method (H2O2/•OH-microperoxidase-luminol) and heme mediated LDL oxidation (LDL-heme-H2O2 ) in vitro. It has been stated that the chemiluminescence method and LDL (low density lipoprotein) oxidation measurement is applicable in the presence of magnesium salts and complexes. Most of the compounds do not generate free radicals and the antioxidant/prooxidant effect depends on the quality of the ligand and the concentration. In the concentration range used, some representatives of the magnesium compounds (MgO, Mg-gluconate, Mg-polygalacturonate) investigated showed radical generating activity measured with chemiluminescence method, whereas the LDL oxidation has not been affected. Magnesium citrate and malate proved to be antioxidants measured with the chemiluminescence method and they slightly accelerate the LDL oxidation in the system and in the concentration applied. In vitro some of the ligands of magnesium compounds showed antioxidant activities.
Authors:M. Abu-Darwish, M. Gonçalves, C. Cabral, C. Cavaleiro, and L. Salgueiro
Juniperus phoenicea L. (Cupressaceae) is an evergreen small tree or shrub, distributed throughout the Mediterranean area from Portugal to Israel and North Africa. J. phoenicea has been used for centuries in traditional medicine and its berries are widely used in flavours, perfumes, and to aromatize alcoholic beverages.The aim of the present work was to evaluate the chemical composition and antifungal activity of essential oils of Juniperus phoenicea berries from Jordan.The essential oils of the berries were isolated by hydrodistillation and analysed by GC and GC-MS. Minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the essential oils against dermatophytes, yeasts and Aspergillus species.The essential oils were characterized by high percentage of α-pinene (75.5 and 84.2%), which distinguish them from oils from other countries where α-pinene is usually present in lower percentages. Essential oils exhibited high antifungal activity against dermatophytes and Cryptococcus neoformans with MIC values ranging from 0.32–2.5 μl ml−1.These results support that essential oils from J. phoenicea berries may be useful in the treatment of dermatophytosis. Further studies should be stimulated in order to evaluate toxicity and optimal concentrations for clinical applications.
Eight Lactobacillus, five Saccharomyces and one Streptococcus strains were chosen to perform mono and mixed culture fermentations, focusing on interaction investigation via agar diffusion and analysis of cell growth kinetics, both serving as selection criteria. Mixed culture fermentations with four lactic acid bacteria (Lb. bulgaricus, Lb. paracasei SF1, Lb. plantarum 2142, and Lb. casei Shirota) and four yeast strains (S. cerevisiae W66, S. cerevisiae WS34/70, S. cerevisiae W120, and S. carlsbergensis 843) were performed in wort with initial cell ratio of 1:1. It was determined that during fermentations, cell concentration of lactic acid bacteria exceeded that of yeasts by one order of magnitude. Three strain combinations (S. carlsbergensis with Lb. bulgaricus, Lb. 2142, and Lb. Shirota) were chosen for further fermentations. Basic behaviour of them in wort was studied in mono culture, which helped to determine interaction type between bacteria and yeast in mixed culture. It resulted in higher Lactobacillus cell concentration in mono cultural than in mixed culture fermentation, which refers to competition. Cell ratio was changed to 1:10 (lactobacilli:yeasts), to favour growth of yeast and avoid lower pH. Despite the higher initial concentration of yeast, results turned in favour of lactobacillus already at the 24th hour.
Authors:L.A. Castillo A., L. Mészáros, and F. Kiss
The microbiological spoilage of foods depends on the initial microbiological contamination and some factors which influence the growth of microorganisms. Therefore, reducing the initial cell count is necessary for both extending shelf-life and improving food safety. Physical, chemical and combined treatments serve this purpose. In these experiments, the effect of trisodium phosphate dipping (0-15% solutions) was studied. Chicken wings were used, which after dipping (1 min) in the solution were packed in PE-PA-PE pouches and stored at 4 °C. Aerobic mesophilic (Nutrient Agar, Merck), pseudomonad (Pseudomonas Selective Agar, Oxoid), and Enterobacteriaceae counts (VRBD Agar, Merck) were determined by Spiral Plate Technique at 30 °C incubation temperature. Effect of 3.8, 5.7, 7.6% trisodium phosphate dipping solutions was studied as a function of storage time. Immediately after treatment, total colony count was reduced by maximum 1.5 log cycles. Pseudomonads were the most sensitive. One day after treatment with these low concentration solutions, the colony count was reduced by 2 log cycles. Na3PO4concentration higherthan 7.6% practically did not result in higher effectivity. The growth rate and maximum cell count of surviving fraction were estimated as a function of trisodium phosphate concentration. It can be concluded from fitted survival curves that immediately after treatment the initial viable cell count was reduced and the critical spoilage level (107g-1) has been reached 2-3 days later than in case of the untreated samples, i.e. the shelf-life was extended.
Authors:K.C. Hor, L.C Lew, S.B. Choi, and M.T. Liong
The oral administration of hyaluronic acid has been shown to improve skin health. This study aimed at utilizing ultrasound treatment to enhance the production of hyaluronic acid by lactobacilli. Among the 16 strains of lactobacilli screened, a higher production of hyaluronic acid (P<0.05) was observed from seven strains namely, Lactobacillus casei BT 2113, Lactobacillus casei BT 1268, Lactobacillus casei BT 8633, Lactobacillus casei FTDC 8033, Lactobacillus acidophilus FTDC 1231, Lactobacillus gasseri FTDC 8131 and Lactobacillus rhamnosus FTDC 8313. Upon ultrasonic treatment, hyaluronic acid concentration increased significantly (P<0.05) in all the seven strains studied. The use of ultrasonication at 100% amplitude increased the hyaluronic acid content (P<0.05) up to 51.6 % with concentrations ranging from 0.262 mg ml−1 to 0.385 mg ml−1, while an amplitude of 20% yielded a lower increase ranging from 0.227 mg ml−1 to 0.310 mg ml−1. Increasing duration of ultrasonic treatment (from 1 min to 3 min) also significantly (P<0.05) improved the concentration of hyaluronic acid in some strains. Our data demonstrated that a sub-lethal physical treatment, such as ultrasonication, can be applied to increase the membrane permeability of lactobacilli cells and subsequently increase the release of bioactive metabolites.
Authors:M. Croitoru, I. Fülöp, M. Ajtay, G. Dudutz, O. Crăciun, and M. Dogaru
To date, monosodium glutamate is the most used flavour enhancing food additive. Because high levels of glutamate are toxic to brain concerns appeared regarding the safe use of glutamate and there is a 10 g kg
concentration limit in foodstuff. A simple HPLC-UV method, based on a derivatization procedure with
-phthaldialdehyde, was developed for determination of glutamate in meat products, soup bases and vegetable concentrates. Even if our method is less sensitive than the HPLC-fluorescence ones widely available, it is able to measure amounts at least 200 times smaller than the maximum allowed one, has good reproducibility (CV under 2% for intraday and under 3% for interday determinations), linearity and accuracy. Less expensive HPLC systems are required and the formed derivative is very stable (at least 1 week), good separation is obtained with the less expensive 5 μm particle C
columns and methanol as organic phase. Concentration of free glutamate ranged between 0.14 g kg
in sausage without added glutamate to as high as 2.16 g kg
in a pork sausage. Concentration in vegetable mixes and soup bases were between 80–120 g kg
Authors:Kalman Buzas, Peter Budai, and Adrienne Clement
One and a half year long field sampling was established in order to evaluate the contamination of storm water runoff. The event means (EMC) total petroleum hydrocarbons (TPH) concentration of the runoff was a function of the actual traffic intensity and the rainfall depth. It was concluded that this TPH, of which dominant component is the engine-oil (characteristically C28) does not form an ‘oil-in-water’ type emulsion in the condition of normal motorway-operation, but is interlocked to asphalt, rubber and soot particles of maximum some ten microns size. This condition influences the possibility, way and extent of separation alike. The separation equipments and their sizing applied so far are not suitable to achieve efficient surface water protection. Practical prevention method of accidental type environment pollution was also suggested. On the basis of the international literature evaluation, technical solutions capable to decrease the runoff pollution were summarized. Among these, useful calculation method was developed for designers to determine the sufficient storage capacity (water quality volume) of reservoirs applied for water quality protection. Monitoring technique of runoffs, which are characterized time dependent, variable pollutant concentrations by their nature, was proposed. It was stated that the administrative regulation should aim at the EMC instead of current concentration. Beside TPH information was gained on polycyclic aromatic hydrocarbons (PAHs), suspended solids, heavy metals, pH, and nutrient (N, P) pollution of the runoff, which are valuable for the grounding of further research results.