Evaluation of selected physicochemical parameters of extra virgin olive oil commercialized in the Czech market and stored during a period of 5 months

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

SONDEO ARQUEOLÓGICO CIERRE SUR CORTE 0 [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

The impact of different hydrocolloids on the viscoelastic properties and microstructure of processed cheese manufactured without emulsifying salts in relation to storage time

The current study was conducted to evaluate the effect of the addition of selected hydrocolloids [agar (AG), kappa-carrageenan (KC), or gelatin (PG); as a total replacement for emulsifying salts] on the viscoelastic properties and microstructure of processed cheese (PC) samples during a storage period of 60 days (at 6 +/- 2 degrees C). In general, PC viscoelastic properties and microstructure were affected by the addition of hydrocolloids and the length of storage time. The evaluated PC reported a more elastic behavior (G' > G '') over the viscous one. The highest values of viscoelastic moduli (G'; G*) were recorded for PC samples manufactured with KC addition, followed by those prepared with AG and PG. The control sample presented values of viscoelastic moduli similar to those of the PG sample. All PC samples tested had fat globule size values lower than 1 mu m. Moreover, PC with AG and KG addition presented similar microstructures and sizes of fat globules.Web of Science1122art. no. 360

Přídavek směsi rutinu/kvercetinu do taveného sýra: antioxidační a texturní vlastnosti

Spreadable processed cheese is a traditional product made from a mixture of cheese, fat, water and emulsifying salts.The aim of this research was prepared spreadable processed cheese with new functional properties. Spreadable processed cheese enriched with the mixture (1:1) of rutin and quercetin (1.0 g.100g-1) was prepared at two melting temperature 80°C and 90°C) for three holding times (1, 5 and 10 min). The effect of melting temperature and holding time on the quercetin and rutin content was assessed using liquid chromatography with UV detection after ultrasonic-assissted extraction to methanol. The corresponding antioxidant characteristics were determined using spectrophotometric assays for total phenolics (TPC) and radical scavenging activities DPPH and ABTS. The extraction yield for quercetin varied from 45.8 to 66.4% and from 12.8 to 40.8% for rutin. The level of quercetin significantly descrased with the increase of holding time, while rutin content has increased with the increase of melting temperature. TPC values ranged from 10.8. to 14.8 mg GAE·g-1 in SPC sample enriched with rutin/quercetin mixture, and the increase of melting temperature resulted in the decrease of TPC values. DPPH and ABTS assays did not reveal any statistically significant pattern using Kruskal-Wallis ANOVA. The addition of the mixture of flavonoids into the processed cheese significantly reduced the complex modulus in comparison with the control sample (without flavonoids). This indicate that the structure of enriched SPC sample was more flexible than those in control processed cheese samples. Both melting temperature and holding time increased the complex modulus. Spreadable processed cheese are scarcely used as a carrier of flavonoids in scientific researches probably due to very complex matrices. Our research proved that spreadable processed cheese containing rutin/quercetin mixture can be used as a functional food.V práci byl sledován vliv přídavku směsi rutinu/kvercetinu (1:1, w/w) do taveného sýra na jeho funkční vlastnosti v závislosti na teplotě tavení (80°C a 90°C) a času výdrže (1, 5 a 10 min). Bylo zjištěno, že obsah kvercetinu se snižoval s rostoucí teplotou tavení, zatímco obsah rutinu byl vyšší při vyšší teplotě tavení. Přídavek směsi flavonoidů významně snižoval tuhost výrobku

Influence of Heat Treatment on the Chemical, Physical, Microbiological and Sensorial Properties of Pork Liver Pâté as Affected by Fat Content

The novelty of this study is the investigation of the effect of different heat treatments and, simultaneously, the effect of different fat levels on the quality of pork liver pâtés. Hence, this study aimed to evaluate the effect of heat treatment and fat content on selected properties of pork liver pâté. For this purpose, four batches of pâtés with two different fat contents (30 and 40% (w/w)) and two different heat treatments (pasteurisation: target temperature 70 °C, holding time of 10 min; sterilisation: target temperature 122 °C, holding time of 10 min) were manufactured. Chemical (pH, dry matter, crude protein, total lipid, ammonia, and thiobarbituric acid reactive substances (TBARS)), microbiological, colour, textural, rheological, and sensory analyses were performed. Both different heat treatment and fat content affected most of the parameters observed. Sterilisation ensured the commercial sterility of the manufactured pâtés, resulting in elevated TBARS values, hardness, cohesiveness, gumminess and springiness, and increased rheological parameters (G′, G″, G*, and η*), as well as colour changes (decrease in L* and increase in a*, b*, and C* values) and deterioration of appearance, consistency, and flavour also being detected (p p < 0.05). However, the colour and sensorial parameters changed in different ways compared to the changes induced by the sterilisation effect. Overall, the observed changes might not be desirable for some consumers and further research would be appropriate to improve especially the sensorial attributes of sterilised pork liver pâtés

The effect of furcellaran or κ-carrageenan addition on the textural, rheological and mechanical vibration damping properties of restructured chicken breast ham

The aim of the study was to investigate the dependence of selected textural, rheological and mechanical vibration damping properties of restructured chicken breast ham (RCBH) on the concentration of furcellaran (FRC1 or FRC2) or kappa-carrageenan (KC) during a 14-days storage period (at 4 +/- 2 degrees C). The above-mentioned polysaccharides were used in concentrations of 0.25 g/100 g, 0.50 g/100 g, 0.75 g/100 g and 1.00 g/100 g. Control sample (CS) without any polysaccharide addition was also produced. The textural, rheological and mechanical vibration damping properties of RCBH samples were affected by the type and concentration of the polysaccharide used (p < 0.05) and the storage period (p < 0.05). Samples prepared with KC and FRC1 at a concentration level of 1.00 (g/100 g) presented the highest values of hardness, G', G '' and G*. Values of G* and delta (in all tested frequency ranges) indicated a solid-like behavior for all the samples over the experimental range. It was found that the first resonance frequency peak position increased with an increase in the RCBH stiffness leading to lower vibration damping properties of the samples (p < 0.05).Web of Science138art. no. 11062

Antioxidační vlastnosti a texturní charakteristika taveného sýra obohaceného rutinem nebo kvercetinem: vliv technologických podmínek

Spreadable processed cheese (SPC) with addition of rutin or quercetin (0.5 g/100 g) were prepared at 80 °C and 90 °C for 1, 5 and 10 min. The effect of melting temperature and holding time of melting temperature on the quercetin/rutin retention, total phenolic content (TPC) and antioxidant capacity was studied. It was found that quercetin levels significantly decreased with the increase of holding time (P&lt;0.01) while rutin degradation was more affected by melting temperature (P&lt;0.01). An increase in TPC values and a decrease in antioxidant capacity measured by ABTS assay with the increase in melting temperature were observed in SPC with quercetin. The addition of rutin or quercetin significantly decreases the gel strength of the SPC samples.Tavený sýr s přídavkem rutinu nebo kvercetinu (0,5g/100g) byl připraven tavením při 80°C a 90°C po dobu 1, 5 a 10 min. Byl studován vliv tavící teploty a její výdrže na obsah rutinu/kvercetinu, celkových fenolických látek (TPC) a antioxidační kapacitě. V rámci experimentu bylo zjištěno, že obsah kvercetinu klesal (P&lt;0,01) se vzrůstajícím časem tavení, zatímco degradace rutinu byla více ovlivněna tavící teplotou (P&lt;0,01). Zvýšení hodnot TPC a snížení antioxidační kapacity měřené metodou ABTS se zvyšující se teplotou tavení bylo zjištěno v případě taveného sýra s obsahem kvercetinu. Přídavek rutinu nebo kvercetinu významně snížilo stabilitu gelu ve vzorcích

The Impact of Different Hydrocolloids on the Viscoelastic Properties and Microstructure of Processed Cheese Manufactured without Emulsifying Salts in Relation to Storage Time

The current study was conducted to evaluate the effect of the addition of selected hydrocolloids [agar (AG), &kappa;-carrageenan (KC), or gelatin (PG); as a total replacement for emulsifying salts] on the viscoelastic properties and microstructure of processed cheese (PC) samples during a storage period of 60 days (at 6 &plusmn; 2 &deg;C). In general, PC viscoelastic properties and microstructure were affected by the addition of hydrocolloids and the length of storage time. The evaluated PC reported a more elastic behavior (G&prime; &gt; G&Prime;) over the viscous one. The highest values of viscoelastic moduli (G&prime;; G&Prime;; G*) were recorded for PC samples manufactured with KC addition, followed by those prepared with AG and PG. The control sample presented values of viscoelastic moduli similar to those of the PG sample. All PC samples tested had fat globule size values lower than 1 &mu;m. Moreover, PC with AG and KG addition presented similar microstructures and sizes of fat globules

Occurrence of Biogenic Amines in Wines from the Central European Region (Zone B) and Evaluation of Their Safety

The decarboxylation of the corresponding amino acids by microorganisms leads to the formation of biogenic amines (BAs). From a toxicological point of view, BAs can cause undesirable physiological effects in sensitive individuals, particularly if their metabolism is blocked or genetically altered. The current study aimed to monitor and evaluate the content of eight biogenic amines (BAs) in 232 samples of wines (white, rosé, red) produced in the Central European region (Zone B). White wines (180 samples), rosé wines (17 samples), and red wines (35 samples) were analyzed. High-performance liquid chromatography equipped with a ultraviolet–visible diode array detector (UV/VIS DAD) was applied to identify and quantify the BAs present in wines. In general, histamine (HIS), tyramine (TYM), putrescine (PUT), cadaverine (CAD), phenylethylamine (PEA), spermine (SPN) and spermidine (SPD) were detected in all tested wine samples. Tryptamine (TRM) was not present in any of the samples examined. In white and red wines, SPD, TYM, and PUT were most often detected. Regarding rosé wines, the three major BAs were SPN, TYM, and CAD. The BA content in red wines was generally higher than in rosé and white wines. However, HIS concentrations above the recommended limit of 10 mg/L were detected in 9% of the red wine samples. In addition, alarming levels of PUT, HIS, TYM, and PEA, with serious potential impact on consumer health, were recorded in two red wine samples. On the whole, the presence and concentrations of BAs in wine should be constantly evaluated, primarily because alcohol intensifies the hazardous effects of BAs

Changes in the Quality Attributes of Selected Long-Life Food at Four Different Temperatures over Prolonged Storage

This study reports the development of selected indicators affecting changes in food quality and safety of selected long-life canned (Szeged goulash, canned chicken meat, pork p&acirc;t&eacute;, canned tuna fish) and dehydrated (instant goulash soup) food during a two-year storage experiment at four different temperatures. The storage temperatures were selected to represent Arctic (&minus;18 &deg;C), temperate (5 &deg;C), subtropical (25 &deg;C) and tropical (40 &deg;C) climatic zones where such food is likely to be stored during, for example, humanitarian and military missions. Microorganism amounts below the detection limit (p &lt; 0.05), regardless of the storage temperature (p &ge; 0.05), were monitored in canned samples. The contents of dry matter, fat and proteins did not change during storage, regardless of the storage temperature (p &ge; 0.05). During the 24-month storage, all food showed an increase in the level of ammonia (p &lt; 0.05) and the TBARS-value (p &lt; 0.05), whereas the rate of increase in both parameters was significantly higher at higher storage temperatures (p &lt; 0.05). The losses of individual amino acids during storage ranged from 5% rel. calculated on the amino acid contents in Month &ldquo;0&rdquo; up to 15% rel. (p &lt; 0.05). With storage temperatures above the freezing point, the hardness values decreased with the increase in the storage temperature (p &lt; 0.05) and prolongation of the storage period (p &lt; 0.05). Moreover, with temperatures of &minus;18 &deg;C, the development of hardness, measured as the &ldquo;decrease rate&rdquo;, was significantly higher compared to the absolute values