Even if plants can contain high levels of nitrate and nitrite, milk and dairy products are not described as sources of these anions. The purpose of this paper was to measure the concentrations of nitrate and nitrite in forage, cow blood, and milk.The results show that the nitrate ratio of milk to plasma is very low, suggesting that milk contamination with nitrate is unlikely to occur. This finding also proves the lack of an active transport mechanism to transfer nitrate from blood to milk. The nitrite anion almost disappears from milk through an enzymatic conversion; usually levels of μg l−1 were measured.
Applying several hydrocolloids in ascending concentrations (0.1, 0.5 and 1% w/w flour basis) to bread making procedure was considered. Effect of hydrocolloids [guar, xanthan gum, carboxylmethylcellulose (CMC), and hydroxypropylmethylcellulose (HPMC)] as bread improver on Barbari (Iranian bread) was analysed in terms of microstructure. Image analysis parameters, hardness, and microstructure of fresh bread were analysed. The results confirmed the ability of hydrocolloids for improving fresh bread quality. Among all used hydrocolloids, HPMC and CMC produced the softest texture, smoothest and continuous structure, and improved overall the bread quality.
Lactic acid bacteria were isolated from tungrymbai, a traditional fermented soybean product of Meghalaya, India and assessed for their probiotic properties. Survival under simulated gastric conditions was tested and five acid tolerant strains were selected. By using 16S rDNA sequencing, these isolates were confirmed to be Enterococcus species. The strains exhibited good survivability in high concentrations of bile salts. The strains were susceptible to antibiotics and they were also found to inhibit growth of Staphylococcus aureus and Escherichia coli. The strains were gelatinase negative and non-haemolytic. The strains also assimilated cholesterol up to a certain level. The study confirmed that all identified five strains have in vitro probiotic properties.
characteristics, dissolved oxygen concentration, biomass amount). It has a long tradition to use Activated Sludge Models (ASM) model family [ 10 ], therefore a lot of experience is gained in model calibration and validation procedure. These models focus on
Heavy metals, including copper, are a serious environmental problem today. As an essential part of acid mine drainage they cause degradation of surface and subsurface water quality, including drinking water. Significant character of acid mine drainage is low value of pH, as a result of hydrogen cations releasing into aqueous environment during the process of pyrite oxidation and high concentration of heavy metals. Sorption techniques are widely used to remove heavy metal ions from large volumes of aqueous solutions. The fact of low pH must be taken in consideration because it has a relevant impact on the behavior of the sorbent during the sorption process.In order to study the optimal parameters of the sorption process of Cu(II) from acid mine drainage (pH=3–4), two sorbents under model conditions in solutions with pH of 4 were studied. For this purpose low cost natural sorbents turf brush PEATSORB and natural zeolite were selected. Different contact time and various initial concentrations of ions were tested as variables. The properties of the tested sorbents were compared from the point of view of their efficiency and sorption capacity. The impact of sorption on the pH change in solution was also studied.
Authors:N. Adányi, M. Váradi, I. Sziklai-László, P. Snyder, R. D. Snyder, and M. Á. Cser
Total daily Se intake was determined by duplicate diet collection, venous blood samples were taken and urine was collected over 24 h in order to measure selenium input and output in healthy, American and Hungarian children aged 8 to 17 living in Budapest. The American children consumed not only locally processed food. Food samples were weighed, mixed, homogenised and the Se content was determined by Instrumental neutron activation analysis (INAA). The Se concentration of blood, plasma and urine samples was determined by atomic absorption spectrometry-hydride generation (AAS-HG) after wet digestion. Se intake calculated for wet weight was 62±18.5 mg/day in American children. In the Hungarian children the mean Se intake was about 35% less than in the Americans. Se concentrations in plasma were 0.84±0.16, in whole blood 1.13±0.17 mmol l-1 in the Americans, higher than those in healthy Hungarian children (0.64±0.10 and 0.83±0.12 mmol l-1, respectively) of similar age and gender. Urinary Se output calculated for creatinin was higher in the children from abroad (27.0±9.5 mg Se/day/g creatinin) compared to Hungarians (11.0±5.0 mg Se/day/g creatinin).
Authors:N. Topic Popovic, A. Benussi Skukan, P. Dzidara, I. Strunjak-Perovic, S. Kepec, J. Barisic, and R. Coz-Rakovac
Listeria monocytogenes is a bacterium widespread in the environment, which has a capacity to survive and grow under various conditions. The bacterial growth results from interactions when subjected to various temperatures, pH levels, and NaCl concentrations were examined by measurements and predictive modelling. Good correlation across the range of growth conditions was shown among observed and predicted growth values, having similar trends and minimal deflections for pH levels 5.0 and 6.0. The growth condition in the 8% NaCl concentration (pH 7.0, temperature 4 °C) resulted with a growth curve of 1 log interval greater than the fitted curve for all the measurements. In all of the cases, there were consistent increases in the rates and decreases in the lag time when the growth temperature increased. Higher incubation temperatures provided higher growth rates as 30 °C and 35 °C yielded double increase of the fitted rate. Fitted and measured growth rates for salinity conditions were significantly different (P<0.05). Comparison of doubling times showed good compatibility, particularly at lower temperatures. Critical use of a model is suggested, although it may enable microbiologists to limit the need of challenge tests and to make rapid and realistic prediction of the growth of L. monocytogenes under conditions relevant to a range of aquatic and other products examined.
cells as a source of β-D-galactosidase were employed for the production of lactose hydrolysed whole milk. The yeast cells were permeabilised to overcome the problem of enzyme extraction and poor permeability of cell membrane to lactose. To analyse and optimise the process variables for lactose hydrolysis, the experiments were conducted according to the Central Composite Rotatable Design (CCRD) using response surface methodology. The independent process variables for lactose hydrolysis were biomass concentration, temperature, agitation and incubation time. Statistical analysis of the results showed that, in the range studied, linear terms of biomass concentration, incubation time and process temperature had a significant effect (P<0.01) on lactose hydrolysis, however, the effect of agitation on lactose hydrolysis was significant when compared with stationery conditions. Numerical optimisation technique was applied to achieve the maximum possible lactose hydrolysis value. The optimum process conditions for lactose hydrolysis were 120 mg biomass (dry wt), 33.6 °C temperature, 105 r.p.m. agitation and 147 min of incubation time. Corresponding to these optimum conditions, the predicted value of lactose hydrolysis was found to be 88.6%, which was experimentally verified.
Authors:E. Takács, A. Nagy, É. Gelencsér, and A. Székács
Reliable determination of microbial or transgenic Cry toxins is an essential issue in food and feed analyses, and enzyme-linked immunosorbent assays (ELISAs) are the method of choice for quantifying these toxins currently in food and environmental analysis. Internal Quality Control (IQC) is an indispensable method to assess accuracy, precision, and reproducibility of analytical measurements. To assess the utility of the ELISA method, IQC was performed on EnviroLogix Cry1Ab/Cry1Ac QualiPlate ELISA with manufacturer supplied analytical standards. Applicability of negative and positive controls (C− and C+) was examined by Shewhart Control Charts for bias and Control Chart of the Range of Duplicates for precision. Linear regression (up to 5 ng ml−1 Cry1Ab concentration) of the commercial ELISA kit was compared to sigmoid calibration (up to 60 ng ml−1 Cry1Ab concentration). For immunoassay optimization process, possible matrix effects in different liquid and solid vertebrate tissues were examined by determination of the limit of detection values in these matrices.
This study contains data of seven blue cultivars of table grape (Vitis vinifera L. and Vitis labrusca L.): Attika, Early Cardinal, Eszter, Chasselas rosé, Königliche Esther, Muscat bleu, and Nero. The following were determined in intact berries: malic, tartaric, and titratable acids, pH values, sugar content, and antioxidant capacity. Concentrations of the following compounds were determined in the pulp of analysed berries: phenolic acids and catechins. The last analysis focused on skins; in addition to the same phenolic acids and catechins, excluding epicatechin, analysed from pulp; ferulic acid and stilbenes were also studied. Higher contents of procyanidin B2 and gallic acid were found in the pulp as compared to those found in skins. Studies during the ripening stage showed that the higher ratio of procyanidin B2 and gallic acid concentrations in the pulp vs. skins relates to late-ripening cultivars, while for early-ripening cultivars a lower ratio was observed. Contents of phenolic acids, catechin, stilbenes, and anthocyanins were studied by means of LC-DAD; other compounds were measured by FTIR.