Smoked Cheeses Research Articles

Antioxidant Activity and Peptide Levels of Water-Soluble Extracts of Feta, Metsovone and Related Cheeses

The purpose of the present study was to evaluate the antioxidant, anti-inflammatory activity and peptide levels of Feta cheese and other brined cheeses, and Metsovone cheese and other smoked cheeses. Feta, goat and cow cheeses are classified as brined. Feta cheese is made exclusively from ewe milk or ewe milk with the addition of a small amount of goat milk. Metsovone and other smoked cheeses are made from cow milk with a possible addition of small amounts of ewe and goat milk. The antioxidant activity was determined using Folin and FRAP assays, while the peptide content was determined using Bradford and Lowry assays. The anti-inflammatory activity was assessed using the lipoxygenase inhibition assay. The assays were applied in the water-soluble extract of cheeses. The results showed that Feta cheese and brined cow cheese differed in antioxidant activity. Feta cheese and brined goat cheese also differed in both antioxidant activity and peptide levels. Specifically, Feta cheese had higher antioxidant activity in comparison with both goat and cow cheeses. As for peptide content, Feta cheese had a higher peptide level compared to goat cheese. The results also showed that Metsovone cheese and other smoked cheeses exhibited significant antioxidant activity and peptide levels. Moreover, the water-soluble extracts of all cheeses showed some anti-inflammatory activity.

AN ANALYSIS OF THE CONTENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN SMOKED CHEESES

Background. Traditional cheeses, including smoked products, are one of the most recognizable products among consumers, due to their taste and relationship with regional history. However, the smoking process can be a source of cheese contamination due to the presence of some toxic compounds in smoke. The aim of the study was to analyze the content of polycyclic aromatic hydrocarbons (PAHs) in traditional smoked and non-smoked cheeses, as well as in industrial smoked cheeses (23 samples in total). The content of PAHs (18 compounds) was determined using the modified QuECHERS method with final detection by gas chromatography coupled with mass spectrometry. Results and conclusion. The total PAH content varied and ranged from 119.0 to 257.6 μg/kg in traditional non-smoked cheeses, 137.8 ÷ 625.1 μg/kg in traditional smoked cheeses and 131.8 ÷ 277.7 μg/kg in industrial smoked cheeses. Indeno[1,2,3-c,d]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene were not detected in any of the analyzed cheese samples, while naphthalene, 2-methylnaphthalene, 1-methylnaphthalene, acenaphthylene, fluorene, phenanthrene, anthracene, fluoranthene were identified in all the tested samples. Benzo[a]pyrene was identified in nine cheese samples (6/11 samples of traditional smoked cheeses, one sample of non-smoked cheese and two out of seven samples of smoked cheeses from industrial production), in the range of 1.5 ÷ 6.5 μg/kg. The occurrence of the so-called PAH markers was found in both smoked and non-smoked cheeses, which suggests that contamination with the hydrocarbons being examined might occur as early as at the raw material production stage, before the smoking process. However, no statistically significant differences were found between the three groups of cheeses, both in the total PAH and the PAH4 sum.

Evaluation of Polycyclic Aromatic Hydrocarbons in Smoked Cheeses Made in Poland by HPLC Method.

Smoked cheeses are particularly popular among consumers for their flavor and aroma. Of interest, therefore, is the health aspect related to the likelihood of polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens found in smoked products. Thus, the purpose of this study was to evaluate the occurrence of 15 polycyclic aromatic hydrocarbons (PAHs) in smoked and non-smoked cheeses purchased in Poland to monitor their safety. The level of selected PAHs in cheese samples was determined using the HPLC-DAD-FLD method. Most of the cheeses tested met the maximum level of benzo[a]pyrene (2 μg/kg) and the sum of benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene (12 μg/kg) established for these products. However, all the cheeses studied in this work had relatively low amounts of the sum of these compounds compared to the information available in the cheese literature, ranging from <LOD to 24.5 μg/kg. This amount does not pose a health risk to consumers. The predominant PAHs found were naphthalene, phenanthrene, fluorene and acenaphthene. Benzo[a]pyrene, the marker compound representing carcinogenic PAHs, was found in 100% and 0% of Polish smoked and non-smoked cheeses, respectively. Although there are currently no regulations for smoked cheeses and maximum concentrations of PAHs in this type of food product, control of PAHs content in cheeses is important due to the mutagenic and carcinogenic potential of these chemicals.

Consumer perception of smoked Cheddar cheese

Consumer perception of smoked cheese was evaluated through focus groups, surveys, and central location testing. Three focus groups (n = 29) were conducted with consumers of smoked cheese. Subsequently, 2 online surveys were conducted. The purpose of the first survey (n = 1,195) was to understand types of smoked cheeses consumed and if consumers associated specific wood smokes with smoked cheese. Next, an adaptive choice-based conjoint (n = 367) was designed to evaluate consumer perception of different attributes of smoked cheese. Maximum difference scaling and familiarity questions were also included in the adaptive choice-based conjoint survey. Following the surveys, a central location test (n = 135) was conducted with cheeses smoked with 3 different woods at a low and high intensity (6 cheeses total). Hierarchical Bayesian estimation, 1-way ANOVA, agglomerative hierarchical clustering, and 2-way ANOVA (smoke type × intensity level) were used to interpret the collected data. Results from the focus groups indicated that smoked cheese was perceived as an artisan, high-end product and that appearance and price were strong purchase factors. In general, consumers were not aware of how smoked flavor was imparted to cheese, but when informed of the processes, they preferred cold-smoked cheese to the addition of liquid smoke flavor. Results from both surveys confirmed focus group observations. Consumers perceived flavor differences among different wood smokes and smoked products. Method of smoking, smoke intensity, type of wood, and type of cheese were the most important attributes for purchase of smoked cheese. When tasting, consumers differentiated smoke aroma and flavor among cheeses and preferred cherry wood smoked cheeses over apple wood or hickory smoked cheeses. Understanding consumer perceptions of smoked cheese will give insight into the desired experience that consumers expect when purchasing smoked cheese.

Changes in Fatty Acid and Volatile Compound Profiles during Storage of Smoked Cheese Made from the Milk of Native Polish Cow Breeds Raised in the Low Beskids.

Simple SummaryCheese, due to its high nutritional value, is an important element of the daily diet of many consumers. About one third of cow milk produced globally is processed into a wide assortment of cheeses. Most of them are produced on a mass scale in industrial conditions. One factor determining cheese quality is the quality of the milk it is made from. The milk of pasture-grazed cows is known to have higher content of compounds benefiting human health. Consumers are increasingly interested in artisanal products, including cheese, manufactured directly on farms or in small, local processing facilities, regarding them as natural, less processed, and free of additives. Milk for the production of this type of cheese usually comes from cows of native breeds kept on family farms. Smoking is one of the oldest traditional methods used to prolong the shelf-life of food. It imparts a pleasant aroma to cheese and improves its palatability. The literature lacks studies on the quality of smoked cheese during storage. The aim of this study is to assess changes in chemical composition and in fatty acid and volatile compound profiles during storage of smoked cheese made from the milk of native Polish cow breeds.This study investigated changes in the proximate chemical composition and profiles of fatty acids and volatile compounds of 12 smoked cheeses made from the milk of native Polish cow breeds used in Beskid Niski. Analyses were performed during the shelf life i.e., in the 1st, 21st, 42nd and 69th day of storage. Studies have shown that thanks to smoking and vacuum-packing, the chemical composition of cheese remained stable throughout the whole shelf-life. Up until the 21st day of storage, there were no statistically significant changes in the profile of fatty acids as well as volatile compounds. Changes were observed only after the mentioned storage time. After 21 days, there was a significant (p < 0.05) and steady decrease (up to day 69) in the proportion of odd-chain (by about 36%), branched-chain (by about 17%) and unsaturated fatty acids (by slightly over 1%). Among unsaturated fatty acids (p < 0.05), however, there was a significant increase in the proportion of monounsaturated fatty acids (by 5%) and a decrease in polyunsaturated fatty acids of nearly 12%. Storage lowered (by 47% in the 69th day of storage) the content of the conjugated linoleic acids (CLA), as well as lowered the n6 to n3 fatty acids ratio. During the 69 days of storage, the content of carboxylic acids increased to more than 50%. In the period from the 42nd to 69th day of cheese storage, the content of butyric acid and hexanoic acids increased twofold, whereas that of octanoic acid increased more than tenfold. Fifty-four volatile compounds were identified in the cheese. The largest group was ketones (34%), whose level decreased during storage, with 2-butanone, 3-hydroxy- (acetoin) and 2-butanone predominating. The research found that due to their low odor threshold, carboxylic acids may have negatively affected the flavor profile of the cheese.

Quantification and risk assessment of carcinogenic polycyclic aromatic hydrocarbons in retail smoked fish and smoked cheeses

Polycyclic aromatic hydrocarbons (PAHs) are known or potential carcinogens occurring in foodstuffs during smoking processes, among others. The European Commission (EC) has defined clear limits for benzo[a]pyrene and the total concentration of benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo [a]pyrene – known as the PAH4 group – that must not be exceeded by any food product commercialized within the European Union (EC Regulation No. 835/2011). In this work, we determined the concentrations of 16 PAHs, including the PAH4 group, in 17 retail smoked fish and 11 retail smoked cheeses from four and nine producers, respectively. To this end, we first developed a gas chromatography-mass spectrometry method for identification and quantification of PAHs in smoked food matrices and validated it intra-laboratory according to the guidelines of EC Regulation No. 836/2011. For the extraction of PAHs from foodstuffs and their further clean-up, we adopted a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) protocol, based on partitioning between acetonitrile and water, followed by dispersive solid-phase extraction using commercially available QuEChERS kits. The analyses of smoked fish revealed a fairly wide range of PAH concentrations, resulting both from differences in the type of smoked fish and different producers. Smoked sprat exhibited the highest total PAH concentration (around 100 ng/g), with acenaphthylene, phenanthrene, and fluorene contributing more than half of this amount, while the lowest PAH content (about 30 ng/g) was observed in smoked trout. None of the analyzed fish samples exceeded the EC limits for either benzo [a]pyrene or PAH4 in the corresponding product categories. While no such limits exist for the smoked cheese category, it was found smoked cheeses had much lower PAH levels compared to smoked fish, around 10 ng/g for ordinary pressed cheeses and 20 ng/g for generically designated “Brădet” cheeses, irrespective of producer. The majority PAHs in all investigated cheeses were found to be phenanthrene, naphthalene, and fluorene, while PAH4 accounted for only about 10% of total PAHs. Cancer risk assessment was performed using both margin of exposure and incremental lifetime cancer risk parameter determinations and none of the samples analyzed showed significant concern.

The Levels of Polycyclic Aromatic Hydrocarbons in Traditionally Smoked Cheeses in Poland

Smoked cheeses are especially appreciated by consumers because of the unique taste and smell. The smoke used in this process is composed of a few hundred components, both favorable influencing the smoked product quality and neutral for consumers’ health, and also the ones which are questionable because of health aspects, for example, polycyclic aromatic hydrocarbons (PAHs). Even though such substances decide about the taste and smell of smoked products, they are perceived as potentially genotoxic and cancerogenic for humans. The aim of the experiment was to assess the PAHs levels in traditionally smoked cheeses in Poland. The PAHs in cheeses samples were determined by isotope dilution method with the use of HRGC-HRMS. The cheeses contained the trace amounts of benzo[a]pyrene. The except were small sheep cheeses and the Ritta goat whey cheese smoked in hot smoke in which the level of 17.0 µg/kg of benzo[a]pyrene was observed. The low levels of benzo[a]pyrene and of sum of benzo[a]pyrene, benzo[a]antracene, benzo[b]fluorantene and chrysene in the analyzed cheeses were the result of mild smoking in warm smoke. Although today, there are no regulations about smoked cheese and the maximum of PAHs concentration, the control of PAHs in the cheeses is essential due to the mutagenic and carcinogenic potential of these compounds.

Evaluation of the Microbial Quality and Total Phenolic Content of a Local Smoked Cheese

The increasing of the organic foods consumption to prevent the loss of cultural and social traditions that have survived for centuries, requires a proper assessment of the safety and quality of these products. The purpose of this study was the microbiological analysis of smoked cheese and non-smoked cheese, in order to assess the antimicrobial effect of smoke, as well as the determination of water-soluble phenolic compounds. The microbiological analyzes that were performed are: total number of aerobic mesophilic germs, coliform bacteria, coagulase-positive staphylococci, total number of yeasts and molds. The Folin–Ciocalteu test was chosen to measure total phenolic content of smoked cheese extracts. Microbial activity is reduced in smoked cheese types compared to non-smoked. The registered values were below the maximum admissible limits in the case of the total aerobic germs and shown coliform absence and inhibation in the growth of coagulase-positive staphylococci. Yeast and molds have been also inhibited through the smoking process. The total content of phenols varied from one assortment to another, with higher values in traditionally smoked cheese. The study shows that the microbiological quality of the cheese is greatly influenced by the hygienic conditions of processing and storage.

The effect of smoking on the formation of biogenic amines in Circassian cheese

In this study, the effect of smoking on the amount of biogenic amines (BA) in Circassian cheese was evaluated. The chemical and microbiological changes related to BA formation in smoked and non-smoked Circassian cheeses were evaluated after 0, 15, 30, 45, 60, and 90 days of storage. At each ending of storage time, tyramine (TYR) and histamine (HIS) could not be detected in any of the samples. Furthermore, tryptamine (TRYP) decreased significantly during storage. Also, cadaverine (CAD) in non-smoked cheese samples increased while CAD levels did not change significantly in smoked cheeses. A significant (p < 0.05) increase was observed in 2-phenylethylamine for both smoked and non-smoked Circassian cheeses while putrescine levels remained fairly the same. In conclusion, lower levels of total BA were detected in smoked samples, and smoking process improved the quality of Circassian cheeses.

Enhancement of probiotic activity by S-layer protein of Lactobacillus plantarum D6 strain in coculture with L. plantarum D13

Among numerous lactic acid bacteria strains isolated from autochthonous smoked fresh cheeses, potential probiotic strains were selected according to strict probiotic selection criteria. Further research revealed that the strain MCD6 was actually a coculture of two Lactobacillus plantarum strains which were identified as L. plantarum D13 and L. plantarum D6, where L. plantarum D6 expresses surface S-layer proteins of approximately 45 kDa. Since S-layer proteins, to our knowledge, have never been identified among representatives of L. plantarum species, it was of our great interest to further characterise and study its functional role in probiotic activity. Hence, the S-layer functional role in probiotic activity of coculture L. plantarum D6 and L. plantarum D13 through the comparison of important functional activities of probiotic strains was evaluated. Aggregation and coaggregation abilities, adhesion to intestinal epithelial cells in vitro, pathogen exclusion and survival in simulated conditions of gastrointestinal tract and during freeze drying, before and after guanidine hydrochloride extraction of S-layer proteins were examined in coculture and monocultures of L. plantarum D13 and L. plantarum D6, respectively. As a result it was established that coculture of two L. plantarum strains enhances their probiotic activity due to the S-layer protein of L. plantarum D6 strain.

The effect of natural and liquid smokes on the benzo[a] pyrene content and quality parameters of Circassian cheese

The objective of this study was to determine the effects of natural smoke and liquid smoke application methods on quality characteristics of smoked Circassian cheese. The microbial counts of liquid smoked cheeses were found to be higher than naturally smoked cheeses. It can be concluded that although natural smoke inhibited the growth of micro‐organisms more than liquid smoke application, benzo[a]pyrene, an indicator component for polycyclic aromatic hydrocarbons (PAH), was detected on the outer surface of naturally smoked cheeses. Therefore, liquid smoking could be used as an alternative method for smoked Circassian cheese production.

Microbiological Characteristics and Mineral Content of Local Smoked Cheese Produced in Yemen

This study aimed to investigate the microbiological quality and mineral content of smoked cheese collected from different retail markets from Ibb and Taiz areas in Yemen. The microorganisms were determined as follows: Mesophilic bacteria, Proteolytic, Halotolerant, Coliforms, Staphylococcus aureus, Yeast and Mold as well as the presence of Salmonella spp, Escherichia coli. Cheese made in Ibb and Taiz areas had significant differences (P <0.05) in mesophilic, proteolytic, halotolerant, Staphylococcus aureus microorganisms, yeast and mold. Salmonella spp was not detected. pH, NaCl, fat and moisture content were also analyzed There was no significant differences for chemical composition except in moisture content. Minerals including Cd, Cu, Fe, Mn and Pb were analyzed using atomic absorption spectrometry. The order levels of the metals in the Smoked cheese samples was determined to be Mn< Pb< Cd< Cu< Fe, with mean concentration 0.47, 0.53, 0.73, 1.56 and 7.84 µg/g, respectively. The investigation showed high microorganism counts, high levels of metals and poor quality of Smoked cheese, according to the Yemen Standardization (YSMO: 1556/1998).

The effect of smoking on changes in functional attributes of Mozzarella cheese

Smoking of cheeses significantly modifies not only sensory attributes, but also determines the form of their further utilisation, packaging method and shelf life. The aim of thIS study was to evaluate functional characteristics of smoked and unsmoked Mozzarella cheeses subjected to 4-week storage. It was found that smoked cheese contained 7% less water than unsmoked cheese. Meltability of smoked cheese before storage was 2 times smaller than that of unsmoked cheese, but after 4 weeks, meltability was 21% greater. Smoked cheese not subjected to storage was 2.2 times harder than unsmoked cheese. During storage, hardness of smoked cheese decreased 4.6-fold, while that of unsmoked cheese only 1.1-fold. Storage time had an increase in stretchability of unsmoked and smoked cheeses by 4.2 and 14.9%, respectively. Keywords: Mozzarella, meltability, texture

Changes in volatile, sensory and microbial profiles during preparation of smoked ewe cheese

Oscypek is a special type of Polish smoked ewe cheese with a unique flavour described as slightly sour, piquant, salted and smoked. In this study the volatile, sensory and microbial profiles of Oscypek cheese were analysed during its various preparation stages of curding, scalding, brining and smoking. The smoked ewe cheese was characterised by 54 volatile compounds belonging to nine different chemical groups (free fatty acids, esters, ketones, alcohols, aldehydes, furans/furanones, phenols, sulfur compounds, terpenes). The sensory aroma profile analysis of unsmoked and smoked cheese showed an important correlation with the analysis of volatile compounds. The microbial profile data indicated that in smoked cheese such as Oscypek the levels of selected bacteria diminished after the curding stage as a result of the subsequent scalding, brining and smoking stages. From the results it can be concluded that, although the analysed smoked cheese consisted of three groups of compounds, the first derived from biochemical reactions (free fatty acids, esters, ketones, alcohols, aldehydes, sulfur compounds), the second from smoking (furans and furanones, phenols) and the third from milk flavour (terpenes), it is the smoking process that mainly influences its typical flavour.

Headspace Solid-Phase Microextraction as a Tool to Estimate the Contamination of Smoked Cheeses by Polycyclic Aromatic Hydrocarbons

Headspace solid-phase microextraction (HS-SPME) was used to study polycyclic aromatic hydrocarbons (PAH) in smoked cheeses. Two types of fiber coatings and different extraction conditions were tested. The results reveal that the use of an 85-μm polyacrylate fiber immersed in the headspace of the samples at 70°C for 60min is suitable for the detection of PAH with no more than 4 aromatic rings. To determine if a relationship can be established between the results obtained using a solvent extraction technique and HS-SPME, 6 samples of smoked cheese previously studied by a solvent extraction method were analyzed by HS-SPME, and the results obtained by both methodologies were compared. Polycyclic aromatic hydrocarbons were identified and quantified by gas chromatography-mass spectrometry operating in selective ion monitoring mode. Among the PAH determined by the solvent extraction method, only those with 4 aromatic rings or less were detected by HS-SPME and, consequently, this technique does not allow one to determine the PAH content of smoked cheese samples under the conditions of the study. Nevertheless, the relationship between the results obtained by both techniques for some PAH revealed that HS-SPME could be useful as a screening method to distinguish among samples with different degrees of PAH contamination.

Evaluation of Color in Smoked Cheese by Sensory and Objective Methods

Surface color is one of the major attributes affecting the consumer acceptance of smoked cheeses. The colors of smoked Cheddar and Swiss cheeses were evaluated by subjective and objective methods to determine consumer perception and acceptance for surface color and to correlate consumer panel ratings with Hunter color dimensions. Hunter L, a, and b values for light to dark, red to green, and yellow to blue, respectively, correlated well with the descriptive panel perception of surface color for smoked Cheddar and smoked Swiss cheeses. Smoked Cheddar and Swiss cheeses with L values between 32 and 48 were rated more acceptable by panelists.