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Abstract: We used regression analysis to model the influence of varying ratios of disodium hydrogenphosphate (DSP), tetrasodium diphosphate (TSPP) and sodium polyphosphate (POLY) upon the hardness, cohesiveness, and relative adhesiveness of processed cheese spread (dry matter – 40 g/100 g; fat in dry matter – 50 g/100 g) at total emulsifying salt levels of 2.0, 2.5 and 3.0 g/100 g. Specific ratios of DSP to TSPP that rapidly increased hardness and decreased cohesiveness (1:1–3:4) and relative adhesiveness (1:1–1:2) were identified. The effect of the specific ratio of DSP:TSPP on textural parameters of samples was weakening with the rising amount of POLY in the ternary mixture. With the amount of POLY above 60%, the effect of the specific ratio of DSP:TSPP on textural parameters of samples was insignificant. With an increasing concentration of emulsifying salts, the values of hardness and cohesiveness were rising while the values of relative adhesiveness of the processed cheeses were falling. However, neither the concentration of emulsifying salts nor the adjustment of pH of the samples reaching the optimal range (5.69–5.84) affected the general trend of dependence of the observed textural parameters of model processed cheeses on the changing proportion of DSP, TSPP and POLY (P ≥ 0.05). [Copyright &y& Elsevier]

Abstract: The aim of the work was to describe the development of selected biogenic amines (histamine, tyramine, putrescine and cadaverine) in 4 layers of Dutch-type cheese (Edam-cheese) depending on 3 ripening/storage regimes during a 98-day period. Biogenic amines were analysed by means of ion-exchange chromatography. A further goal was to identify microbial sources of biogenic amines in the material analysed. Phenotype characterization and repetitive sequence-based PCR fingerprinting were used to identify the isolated bacteria. The highest content of tyramine, putrescine and cadaverine was determined in cheeses stored in a ripening cellar at a temperature of 10°C during the whole observation period. Lower biogenic amines content was determined in samples which were moved into a cold storage device (5°C) after 38 days of storage in a ripening cellar (10°C). The lowest concentrations of biogenic amines were detected in cheeses which were moved into a cold storage device (5°C) after 23 days of storage in a ripening cellar (10°C). During the 98-day period, histamine was not detected in any of the regimes. Within the cheeses analysed, non-starter lactic acid bacteria Lactobacillus curvatus, Lactobacillus casei/paracasei and Lactobacillus plantarum were detected as the main producers of the biogenic amines tested. In starter bacteria Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris the decarboxylase activity tested was not detected. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to investigate the effect of selected phosphate emulsifying salts (Na3PO4, Na2HPO4, Na4P2O7, Na2H2P2O7, Na5P3O10, sodium polyphosphate) and their selected mixtures (sodium polyphosphate + Na2HPO4; sodium polyphosphate + Na4P2O7) on the viscoelastic properties of model processed cheese (dry matter – 40 g/100 g; fat in dry matter – 50 g/100 g). Viscoelastic properties of model samples stored at 6 ± 2 °C were investigated by dynamic oscillation rheometry (plate–plate geometry; frequency range 0.1–50.0 Hz; temperature 20 °C). Processed cheese manufactured with different phosphates showed various pH values and different viscoelastic properties. The firmness of samples increased due to use of particular types of tested phosphates. Their influence on cheese firmness increased in the following order: orthophosphate < polyphosphate < diphosphate < triphosphate. The increasing content of polyphosphate (up to 50%) in the binary mixture of polyphosphate and orthophosphate or polyphosphate and diphosphate caused the increase of firmness of model samples. The content of polyphosphates above 50% in the binary mixture led to decrease of firmness of model processed cheese. [Copyright &y& Elsevier]

Abstract: This work deals with hydrolysis curves for 15 amino acids (aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, isoleucine, leucine, phenylalanine, tyrosine, histidine, lysine and arginine) in bovine casein and in model-processed cheeses with 30, 45 and 60% (w/w) fat in dry matter. The effect of a different fat content on hydrolysis curves of the amino acids was observed. The hydrolysis curves were obtained by means of nonlinear regression using 13 hydrolysis intervals (range, 0–144h). The amino acid content in hydrolysates was measured using ion exchange chromatography. Correction factors were calculated with the aim of increasing the accuracy of the amino acid determinations. With the rising fat content in samples, the correction factors increased for the majority of amino acids observed. The highest correction factors were determined for threonine, serine and tyrosine. [Copyright &y& Elsevier]

One way to effectively reduce the number of biogenic amines (BAs) in food is through enzymatic reduction using bacteria, such as lactic acid bacteria. This study focuses on the ability of the bacterial strain Lacticaseibacillus casei CCDM 198 to reduce the number of three important BAs (histamine, putrescine and cadaverine) over time, depending on different conditions (temperature and pH) in vitro and for the real dairy product – skimmed milk. The obtained results show that the studied strain significantly (P < 0.05) affects the number of individual amines, and the content of all amines has a decreasing character compared to the initial relative content of BAs at time zero. Furthermore, a statistical dependence (P < 0.05) of the rate of amine degradation on the combination of investigated factors was demonstrated. The presence and the activity of multicopper oxidase enzyme was also detected in this bacterial strain. This is the first known publication demonstrating multicopper oxidase activity in Lacticaseibacillus casei CCDM 198. Moreover, the studied strain is able to reduce the tested BAs in skimmed milk and would be a good candidate for degrading these toxic compounds in other dairy products, such as cheese. These findings could significantly enhance the food safety of dairy products. • The increased presence of BAs in foods represents a health risk for consumers. • The ability of L. casei CCDM 198 to reduce BAs in MRS medium was described. • The reduction of BAs using L. casei CCDM 198 was traced also in real foods - milk. • MCO enzyme activity in L. casei was determined spectrophotometrically and in a gel. [ABSTRACT FROM AUTHOR]

Abstract 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. Highlights • Processed cheese sauces were manufactured with different emulsifying salts. • Hardest samples were produced with DSP:TSPP (1:1) and without pH adjustment. • The hardness of all samples increased with the prolonging of the storage time. • The first resonance frequency peak position depended on the storage time. [ABSTRACT FROM AUTHOR]

Abstract The objective of the study was to assess the development of the biogenic amine content in model cheese samples individually inoculated with two biogenic amine producing non-starter lactic acid bacteria strains of Lactobacillus curvatus subsp. curvatus (DEPE T3 and DEPE T36) and two biogenic amine producing non-starter lactic acid bacteria strains of Lactobacillus paracasei (DEPE T51 and DEPE T52) over the course of a 90 day storage period (10 ± 1 °C). During the entire ripening period, the dominant biogenic amine was tyramine. After just two months of ripening, tyramine concentration 167 mg/kg was detected in the model cheeses with the DEPE T3 strain (moreover a total biogenic amine concentration was 220 mg/kg), whilst in the case of the DEPE T36 strain it was even 211 mg/kg of tyramine (sum of biogenic amine was 302 mg/kg). In the samples with the added DEPE T51 and DEPE T52 strains, tyramine concentration after 90 days of ripening almost reached the level of 50 mg/kg. Highlights • The ability of NSLAB isolates to produce biogenic amine was observed in cheese. • Strains of Lb. curvatus subsp. curvatus and Lb. paracasei were tested. • Biogenic amine production by Lb. curvatus was significantly higher during ripening. • Tyramine (PubChem CID: 5610) was the most common biogenic amine. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of different melt holding time (0–20 min) at a melting temperature of 90 °C on the viscoelastic properties of full-fat (fat content in dry matter 50 g/100 g, dry matter content 35 g/100 g) processed cheeses over the course of a sixty-day storage period (6 ± 2 °C). Three various agitation speeds (1000; 1500 and 3000 rounds per min) were used. For all three monitored agitation speeds, there was a significant decrease in the firmness of the processed cheeses in the first 3 min of the holding time. The subsequent extension of the melt holding time (up to 20 min) led to the significant increase the product firmness. Over the course of a sixty-day storage period, the firmness of all the monitored processed cheeses increased. Samples produced at 3000 rpm were significantly more solid in comparison with processed cheeses produced at lower agitation speeds (1000 and 1500 rpm). [ABSTRACT FROM AUTHOR]

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 < 0.01) while rutin degradation was more affected by melting temperature (P < 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. [ABSTRACT FROM AUTHOR]

The study was focused on selected textural and viscoelastic characteristics of spreadable processed cheese (35 g/100 g dry matter; 50 g/100 g fat in dry matter) manufactured with different ternary mixtures of emulsifying salts (ES) and from Mozzarella-type cheese (MC) with different storage periods (0, 2 and 4 weeks) over the course of a 60-day storage period (6 ± 2 °C). The ES utilized consisted of disodium hydrogenphosphate (DSP), tetrasodium diphosphate (TSPP), sodium salt of polyphosphate with mean length n ≈ 20 (P20), and trisodium citrate (TSC). Furthermore, the hardest samples were those manufactured from DSP and TSPP in a ratio 1:1. This ratio resulted in processed cheese with the highest values of gel strength and interaction factor. When TSC was utilized in the mixtures, the hardness of the samples rose with the increase of P20 (≥50%). Additionally, when DSP, TSC, TSPP, and P20 were added as sole ingredients, hardness decreased in the following order: P20 > TSPP ≈ TSC > DSP. This trend was also observed with the values of gel strength and interaction factor. The hardness of all samples increased with increased storage periods. However, the hardness values dropped in relation to an increase in the storage period of the MC. [ABSTRACT FROM AUTHOR]

This study aimed to design high-quality and safe spreadable processed cheese with a prolonged shelf life appropriate for logistic support in emergency/crisis situations, foreign missions, and/or state material reserves. Samples with dry matter content (DM) of 30–55 g/100 g and fat in dry matter content (FDM) of 30–50 g/100 g were produced, hermetically sealed and sterilised at 120 °C for 40 min. The microbiological, chemical, textural, viscoelastic, and organoleptic parameters of unsterilised and sterilised processed cheese were compared. The effect of the products' dry matter and fat content on the sterilised samples' properties was also evaluated. The sterilisation regime applied was sufficient to ensure the microbiological safety of processed cheese. A significant decrease in pH values and increased rate of the complex of Maillard reactions and lipid oxidation processes (P > 0.05) was detected due to sterilisation. These processes were more intense with increasing dry matter and fat content (P > 0.05). A deterioration in the appearance, colour, and aroma of processed cheese and an increase in the firmness of the products (P > 0.05) were also observed as a result of sterilisation. For the quality and safety of sterilised processed cheese, combinations of 40 g/100 g DM and 50 g/100 g FDM were recommended for spreadable products. • Non-sterilised and sterilised processed cheeses were produced. • Sterilisation at 120 °C for 40 min was sufficient to ensure food safety. • Sterilisation process induced increased Maillard reactions intensity. • Sterilisation process increased the hardness of processed cheeses. • Optimal combination of dry matter and fat content was recommended. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare nutritional parameters (contents of fat, protein and the individual amino acids), biogenic amines (histamine, tyramine, phenylethylamine, tryptamine, putrescine, cadaverine, spermidine and spermine) content, selected functional properties (colour and textural properties) and pH values of six parts of crocodile carcass (tail dorsal – TD, tail ventral – TV, neck – N, shoulder – S, leg – L and cheek – C). The individual parts of the crocodile carcass showed different values of nutritional parameters. TD and C had the highest values of Essential Amino Acid Index (104–126). Valine, threonine and leucine were determined as limiting amino acids in individual parts of the crocodile carcass. The content of biogenic amines was very low. These results will provide crocodile meat producers as well as consumers with new and useful information about the nutritional value of this meat and its relevance for nutrition. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to compare selected properties (hardness, cohesiveness, adhesiveness, characteristics of fat globules, pH, meltability and sensory characteristics – homogeneity, rigidity and flavour) of processed cheeses (dry matter content 40 g/100 g; fat in dry matter content 50 g/100 g) made with traditional emulsifying salts (sodium salts of phosphates) and products in which the traditional emulsifying salts were replaced with 1 g/100 g κ-carrageenan. The development of the above-mentioned properties was studied in dependence on the maturity level of cheese (raw material; 1–16 weeks' maturity). The samples made without the use of traditional emulsifying salts were nearly five times as hard as the products with phosphates regardless of the maturity level of cheese. In both types of samples, hardness was decreasing and adhesiveness was rising with the increasing maturity level of cheese. Meltability of the samples without traditional emulsifying salts was very low and remained practically unchanged with the increasing maturity level of cheese. On the other hand, in the processed cheeses with phosphates, meltability was increasing with the rising maturity level of cheese. [Copyright &y& Elsevier]

Abstract: Formation of biogenic amines may occur in food due to metabolic activities of contaminating Gram-negative bacteria. Putrescine is assumed to be the major biogenic amine associated with microbial food spoilage. Gram-negative bacteria can form putrescine by three metabolic pathways that can include eight different enzymes. The objective of this study was to design new sets of primers able to detect all important enzymes involved in the production of putrescine by Gram-negative bacteria. Seven new sets of consensual primers based on gene sequences of different bacteria were designed and used for detection of the speA, adiA, adi, speB, aguA, speC, and speF genes. A newly developed touchdown polymerase chain reaction (PCR) method using these primers was successfully applied on several putrescine-producers. Selected PCR products were sequenced and high similarity of their sequences (99–91%) with known sequences of the corresponding genes confirmed high specificity of the developed sets of primers. Furthermore, all the investigated bacteria produced both putrescine and agmatine, an intermediate of putrescine production, which was confirmed by chemical analysis. The developed new touchdown PCR method could easily be used to detect potential foodborne Gram-negative producers of putrescine. The newly developed sets of primers could also be useful in further research on putrescine metabolism in contaminating microbiota. [Copyright &y& Elsevier]

The aim of the presented study was to evaluate the microbiological, chemical, physical and organoleptic properties of sugar-based foods (apricot-apple jam, flower meadow honey, sweetened hazelnut cocoa spread) stored at four different temperatures (−18, 5, 23 and 40 °C) for a period of 24 months. In addition, critical combinations of storage temperature and time were determined for maintaining food quality and food safety. Storage of all samples ≤23 °C appeared to be safe from a microbiology perspective, while in the case of storage at 40 °C it was not recommended to exceed a storage period of 6 or 12 months. The pH-values decreased and the dry matter, ammonia, TBARS content increased most intensively during the first 6 months of storage (P < 0.05). The amino acid content of sweetened hazelnut cocoa spread decreased significantly at 40 °C (P < 0.05). With the prolonged storage time, the organoleptic properties of the samples deteriorated. The changes were more intensive when an elevated storage temperature was used (P < 0.05). Moreover, under the above-mentioned conditions a marginal decrease of the total saccharide content in all samples was observed. In addition, the apparent viscosity of the honey and the firmness of the jam increased significantly at elevated temperatures of 40 °C (P < 0.05). • Quality of sugar-based foods was monitored during a storage period of 24 months. • The pH-values decreased and the dry matter, ammonia, TBARS content increased. • Decline of the amino acid content of sweetened hazelnut cocoa spread was observed. • The organoleptic properties deteriorated especially at elevated storage temperature. • Increase of the apparent viscosity (honey) and the firmness (jam) was detected. [ABSTRACT FROM AUTHOR]

The aim of the study was to reduce the concentration of biogenic amines (BAs) in Dutch-type cheese by the activity of the added culture. The reduction of BAs was caused by the use of the selected strains of Lacticaseibacillus casei and Lactiplantibacillus plantarum over a three-month period (at 12 ± 1 °C). The results indicated that the use of different microbiological strains does not have a significant influence on the basic chemical parameters of the model cheese samples. The lowest BA concentrations were determined in model cheese with Lacticaseibacillus casei CCDM 198. These samples contained fewer total BA content than the control samples: after 28 days of ripening by 32%, after 56 days by 37% and after 84 days by 32%. The adjunct culture demonstrated high efficacy of reduction of putrescine, phenylethylamine and tyramine in real conditions of the model Dutch-type cheese samples. • Dutch type cheese samples were produced with different adjunct culture. • The applied strains did not have an effect on the basic chemical parameters. • Differences between batches in concentration of free amino acids were observed. • The most effective BA reduction was caused by Lacticaseibacillus casei CCDM 198. • Reduction of phenylethylamine, putrescine and tyramine was demonstrated in cheese. [ABSTRACT FROM AUTHOR]

Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L−1 of l -tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) – even suppressing it completely in some cases – in four of the six tested tyramine producing strains. • Effect of nisin-producing lactococci and their CFSs on tyramine production was studied. • Tyramine production could be reduced by the presence of nisin-producing lactococci and their CFSs. • The level of tyramine reduction differed between tyramine producers. • Nisin-producing lactococci and their CFSs could enhance safety of fermented food. [ABSTRACT FROM AUTHOR]

The aim of the work was to compare κ-carrageenan and ι-carrageenan (in concentrations 0.025–0.150 g/100 g) application to cream desserts (dry matter content 44 g/100 g and fat content 38.5 g/100 g) and evaluate their viscoelastic properties and sensory quality. Sample properties were monitored during 28 d (6 ± 2 °C). During storage a slight decrease in the pH of the samples was monitored. Furthermore, the increasing addition of κ- and ι-carrageenan resulted in complex modulus (G*) and gel strength (A F) values increase (P < 0.05). In all samples, regardless of the type and concentration of carrageenan, a significant increase in the values of firmness was observed during storage. In general, the G* and A F were higher in the samples with κ-carrageenan compared to products to which ι-carrageenan was applied (P < 0.05). Moreover, all samples were characterised as homogenous and no water release and no off-flavour (P ≥ 0.05) were detected. The suggested concentration of both tested carrageenans in order to obtain products with desired properties lies in the range of 0.050–0.125 g/100 g. • Kappa-carrageenan was evaluated as a more effective thickening agent. • Significant increase in the firmness of cream desserts was observed during 28 d of storage. • Firmness of cream desserts was higher in products with κ-carrageenan addition. • Iota-carrageenan cream desserts presented a more viscous-like character. • Higher concentration of applied carrageenans resulted in firmer products. [ABSTRACT FROM AUTHOR]

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 κ-carrageenan (KC) during a 14-days storage period (at 4 ± 2 °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 δ (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). • Restructured chicken breast hams with κ-carrageenan and furcellaran were developed. • The hardness of the samples increased with the rising level of added polysaccharides. • The use of polysaccharides resulted in higher G* values during the cooling stage. • The samples exhibited a solid-like character over the experiment. • The polysaccharides used influenced samples displacement transmissibility and stiffness. [ABSTRACT FROM AUTHOR]

Degradation of undesirable biogenic amines (BAs) in foodstuffs by microorganisms is considered one of the most effective ways of eliminating their toxicity. In this study, we designed two sets of primers for the detection and quantification of the multicopper oxidase gene (MCO), which encodes an enzyme involved in BAs degradation, and endogenous (glyceraldehyde-3-phosphate dehydrogenase) gene (GAPDH) in Lactobacillus casei group by real-time PCR (qPCR). We tested 15 Lactobacillus strains in the screening assays (thus, MCO gene possessing assay (PCR) and monitoring of BAs degradation by HPLC-UV), in which Lactobacillus casei CCDM 198 exhibited the best degradation abilities. For this strain, we monitored the expression of the target gene (MCO) in time (qPCR), the effect of redox treatments (cysteine, ascorbic acid) on the expression of the gene, and the ability to degrade BAs not only in a modified MRS medium (MRS/2) but also in a real food sample (milk). Moreover, decarboxylase activity (ability to form BAs) of this strain was excluded. According to the results, CCDM 198 significantly (P < 0.05) reduced BAs (putrescine, histamine, tyramine, cadaverine), up to 25% decline in 48 h. The highest level of relative expression of MCO (5.21 ± 0.14) was achieved in MRS/2 media with cysteine. • High levels of BAs in fermented foodstuffs constitute a health risk for consumers. • qPCR is a key method for searching for suitable strains for starter or adjunct cultures. • We designed primers for the multicopper oxidase gene expression analysis of L. casei. • We monitored the degradation abilities of L. casei CCDM 198 used in the food industry. [ABSTRACT FROM AUTHOR]