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The scope of the study was the employment of an innovative method beneficial to evaluate the impact of various emulsifying salts (ES) addition on selected properties of processed cheese sauces (PCS). The ES applied were disodium hydrogenphosphate (DSP), tetrasodium disphosphate (TSPP), pentasodium triphosphate (PSTP), sodium salt of polyphosphate n ˜ 20 (POLY) and trisodium citrate (TSC). Moreover, the examined effect was observed in two groups of samples, (i) PCS with non-adjusted pH and in (ii) PCS with adjusted pH. The hardness of the samples was influenced by the type of the applied ES, pH, and storage period. The PCS produced with DSP:TSPP (1:1; without pH adjustment) exhibited the higher hardness which was also confirmed by the increasing samples viscosity and storage modulus. The results obtained by the mechanical vibrations damping analysis were analogous to rheological analysis. Generally, it was found that more viscous PCS exhibited “better” vibration damping properties, which was reflected by a shift of the first resonance frequency peak position to lower frequencies. In case of all investigated samples it was verified that the increasing storage period caused increasing stiffness and led to a shift of the first resonance frequency peak position to higher frequencies.

In this study it was found that the complex microstructure of chocolate was modified by the addition of whey into original milk chocolate. A decreasing particle size diameter of the dispersed cocoa fat particles with increasing whey content followed by dynamic light scattering measurements was confirmed. Changes of the chocolate fat crystallinity through disrupting the highly ordered cocoa fat dense crystal aggregates to the less developed ones deformed by the inclusion of whey particles into the complex chocolate mass were simultaneously confirmed. These morphology changes affected the thermal and rheological behaviour of the studied samples by decreasing the melting peak temperature as well as Casson's plastic viscosity with increasing whey content. Furthermore, a gradual decrease of the hardness, thus reflecting the plasticising effect of the whey particles on the complex crystalline structure of the chocolate, was observed. The latter fact was also confirmed by the decreased acoustic emissions during chocolate breakage, thus indicating the change of the fracture process from brittle to more ductile.

The scope of this work was to evaluate the development of selected physicochemical parameters (free acidity, peroxide value and specific extinction coefficients in ultraviolet) of extra virgin olive oil, commercialized in the Czech market and stored for a time period of 5 months (at 20 ±5 °C). The tested extra virgin olive oil samples were stored under conditions simulating domestic and commercial storage environment, in which the impact of light and headspace volume were also examined. Moreover, all the analyzed samples fell within the established "extra virgin olive oil category", thus proving their legitimacy, authentication and excellent quality. Furthermore, all the monitored physicochemical parameters were affected by the progress of the storage period, the rising volume of headspace (due to more available oxygen in the container) and exposition to light, resulting in decreasing quality of the examined extra virgin olive oil samples. In addition, the storage of extra virgin olive oil samples in dark containers reported sufficient resistance to oxidation processes up to a period of 3 months, however, after this period signs of oil quality deterioration were reported. Nevertheless, if exposition to light occurred, accelerated decrease in the quality of the extra virgin olive oil samples was observed. © 2017 Potravinarstvo Slovak Journal of Food Sciences, License.

The aim of the study was to compare, within 3-week cold storage, the content of eight biogenic amines (BA) and the development of microflora in different parts of bodies (breast and thigh muscles and liver) of farm pheasants and pheasants hunted in the wild. Killed and untreated bodies of pheasants were stored hanging in an air-conditioned chamber at a cold temperature (5 ± 1 °C). The pheasant bodies were subjected to microbiological analysis and identification of isolated microorganisms whose decarboxylase activity was detected. The production of biogenic amines and polyamines was determined by means of HPLC after pre-column derivatisation with dansylchloride. The total number of microorganisms in all parts of the pheasant bodies as well as the number of psychrotrophic bacteria, enterobacteria and lactic acid bacteria was increasing during storage (P

This study focussed on the dependence on different emulsifying salt ternary mixture composition [disodium hydrogenphosphate (DSP), tetrasodium diphosphate (TSPP), sodium salt of polyphosphate (P20; number of phosphate units in the chain ≈20), trisodium citrate (TSC)] of hardness and gel strength of spreadable processed cheese (PC) manufactured from Cheddar and white brined cheeses. All PC samples were stored for 60 days (6 ± 2 °C). The hardest PC and samples with the highest gel strength were those produced from DSP and TSPP in a ratio 1:1. The hardness of all examined samples increased with the extending storage period, whilst their hardness and gel strength decreased with the rising maturity degree of the raw material utilised. Furthermore, higher values of gel strength were reported for the PC samples produced with Cheddar cheese in comparison with those made from white brined cheese.

The objective of the current study was the evaluation of 8 biogenic amines (BA) occurrence in beer samples (115 samples in total) manufactured in microbreweries of the Central Europe region in relation to the progress of the storage period (at 20 ± 2 °C). The examined beer samples were divided into 3 main groups according to their extract of original wort value (EOW): (i) Light craft beer (EOW ≤ 10; 12 samples in total), (ii) Lager craft beer (11 ≤ EOW ≤ 12; 65 samples in total), (iii) Special craft beer (EOW ≤ 13; 38 samples in total). The tested craft beer samples were analyzed immediately after purchase and at the end of the best before date. Furthermore, the most frequently detected BA was tyramine. In addition, other abundant monitored BA were putrescine and cadaverine. Moreover, concentrations of histamine above 20 mg/l were detected in lager craft beer and special craft beer samples (at the end of the best before date). On the whole, with the progress of the storage time the BA concentration increased. Thereafter, more than 30% of the tested samples presented total BA content in the range of 50–100 mg/l. However, 18% of the examined craft beer samples had a total amount of BA higher than 100 mg/l.

The scope of the study was the evaluation of Chios mastic gum (CMG) addition (0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45 and 0.50%, w/w) on the rheological, textural and meltability properties of spread-type processed cheese (PC; with 40%, w/w, dry matter and 50%, w/w, fat in dry matter) during a 60-day storage period (at 6 ± 2 °C). The hardness of the evaluated PC samples was affected by the amount of CMG applied and by the storage period. Hence, from a concentration 0.05% (w/w) of CMG up to 0.20% (w/w) the hardness of the samples decreased, followed by an increase (up to 0.40%, w/w) and a rapid decrease in hardness was again recorded. With the prolonging of the storage period the hardness of all samples increased. Furthermore, the results obtained by the rheological analysis and meltability were analogous to those of hardness analysis.

Summary The ability of typical probiotic culture of Bifidobacterium to produce biogenic amines could be considered a contrastive feature to the beneficial dietary effect on human health. The aim of this pilot study was to evaluate the decarboxylase activity of Bifidobacterium animalis subsp. lactis CCDM 239 influenced by selected factors (pH 4.5 and 5.0; the contents of NaCl 0–20.0 g L−1, glucose and lactose 0–10.0 g L−1) at in vitro conditions. The kinetics of the biogenic amine production under the above-mentioned conditions was also monitored. The biogenic amine content detection was carried out in the supernatants of inoculated broth [MRS enriched with amino acids: arginine, ornithine, lysine, tyrosine; 3 g L−1 after the cultivation (48 h, 37 ± 1 °C)]. RP-HPLC after the precolumn derivatisation with dansyl chloride was used. In most cases, the low concentrations of tyramine were monitored (

The aim of the study was to explore production of seven biogenic amines (phenylethylamine, histamine, cadaverine, tyramine, putrescine, spermine and/or spermidine) by selected staphylococci and enterococci. Thirty three enterococcal strains isolated from rabbit meat (Oryctolagus cuniculus f. domesticus) and 21 staphylococcal strains isolated from intestinal content of trout (Salmo trutta morpha fario) were tested. Production of biogenic amines was evaluated after cultivation of the tested microorganisms in the de Man, Rogosa and Sharpe Broth (enterococci) or in the Brain Heart Infusion Broth (staphylococci). Both the above cultivation media were enriched with selected amino acids (histidine, tyrosine, arginine, ornithine and lysine; 2g/L each) serving as precursors of biogenic amines. After cultivation, levels of the monitored biogenic amines in broths were analysed by a high performance liquid chromatography equipped with a UV/VIS DAD detector. Among 21 staphylococci, 18 strains produced tyramine or cadaverine, 13 strains formed putrescine or phenylethylamine and only one strain generated histamine. Two staphylococcal strains produced cadaverine levels above 1000 mg/L. Among 33 enterococcal strains, 27 formed cadaverine, 18 strains produced tyramine, 10 strains generated phenylethylamine, and 2 strains gave putrescine. Most of the tyramine producing enterococci generated more than 1000 mg/L of this biogenic amine. Production of spermine or spermidine by the studied strains was not proved.

Summary The aim was to monitor production of eight biogenic amines (BAs) (histamine, tyramine (TYR), tryptamine, putrescine, cadaverine (CAD), phenylethylamine, spermine and spermidine) by selected 81 lactic acid bacteria (LAB) strains: Lactobacillus, Lactococcus, Leuconostoc, Enterococcus, Pediococcus, Tetragenococcus and Bifidobacterium. The tested LAB and bifidobacteria were isolated from dairy products and beer. The decarboxylase activity of the micro-organisms was studied in growth medium after cultivation. The activity was monitored by HPLC after the pre-column derivatisation with dansylchloride. Fifty LAB showed decarboxylase activity. Thirty-one strains produced low concentrations of CAD (≤10 mg L−1). Almost 70% of beer isolates generated higher amounts of TYR (≤3000 mg L−1). Most of the tested LAB demonstrated decarboxylase activity. The above micro-organisms can contribute to the increase of content of BAs in dairy products or beer and thereby threaten food safety and health of consumers. Production of BAs even by the representatives of some probiotic strains (Bifidobacterium and Lactobacillus rhamnosus) was detected in this research. This study has also proved that contaminating LAB can act as sources of higher amounts of CAD and TYR in beer.

The aim of this study was to monitor the antibacterial effect of seven phosphate salts on selected strains of Gram-negative and Gram-positive bacteria, which could be considered responsible for food-borne diseases (Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Micrococcus luteus, Staphylococcus aureus, Citrobacter freundii, Escherichia coli, Proteus mirabilis, Salmonella enterica ser. Enteritidis and Pseudomonas aeruginosa). For these purposes, phosphates differing in chain length were used. The tested concentrations were in the range of 0.1-2.0% (wt v(-1)) applied at the model conditions. In the majority of cases the visible inhibitory effect on the growth of observed microorganisms could be seen. Due to the chemical structure of salts and their dissociation both the pH values of cultivation broth and similarly the growth characteristics of bacterial strains were affected. The inhibition of above mentioned bacteria was apparently supported by this dissociation. Phosphates obviously made the development of most Gram-positive bacteria impossible. Especially Micrococcus luteus was extremely sensitive to the presence of these substances. On the other hand, Gram-negative bacteria seemed to be resistant to the phosphate incidence. The exemption clause from the tested salts was represented by a high alkaline trisodium phosphate. It should be pointed out that generally the most significant antibacterial effects were shown by polyphosphates HEXA68 and HEXA70, trisodium phosphate undecahydrate, tetrasodium pyrophosphate and finally trisodium phosphate. By comparing the inhibitory effects of various phosphate salts can be concluded that the antibacterial activity was not determined only by the condensation degree but there was also proved the dependence on pH values.

Highly undesirable microbial contaminants of processed cheese are endospore-forming bacteria of the genera Bacillus and Clostridium. Survival of Bacillus subtilis, B. cereus, Clostridium butyricum and C. sporogenes was examined in model processed cheese samples supplemented with monoacylglycerols. In processed cheese samples, monoacylglycerols of undecanoic, undecenoic, lauric and adamantane-1-carboxylic acid at concentration of 0.15% w/w prevented the growth and multiplication of both Bacillus species throughout the storage period. The two species of Clostridium were less affected by monoacylglycerols in processed cheese samples and only partial inhibition was observed. The effect of milk fat content on microbial survival in processed cheese was also evaluated. The growth of Bacillus sp. was affected by the fat level of processed cheese while population levels of Clostridium sp. did not differ in processed cheese samples with 30, 40 and 50% fat in dry matter.