Lighvan Cheese Research Articles

Influence of the Blends of Sheep's and Goat's Milk on the Functional Properties and Volatile Compounds of Lighvan Cheese During Ripening: A Comparative Study

ABSTRACTIn this study, the influence of different ratios of sheep's to goat's milk (100:0, 75:25, 50:50, 25:75, and 0:100) on the content of functional metabolites and volatiles in Lighvan cheese throughout ripening was investigated. The samples were ripened under brine for 90 days and assessed in terms of variations in chemical composition, proteolysis, angiotensin‐converting enzyme, α‐amylase, and α‐glucosidase inhibitory activities, antioxidant power, total free amino acids, gamma amino butyric acid, free fatty acids, and volatile compounds. Results showed that by increasing the proportion of goat's milk, the samples exhibited higher antioxidant effect and inhibition of the angiotensin‐converting enzyme during ripening. After 90 days, an increase in α‐glucosidase and a slight decrease in α‐amylase inhibitory activities were observed in Lighvan cheese samples that were produced with 50%, 75% and 100% of goat's milk. In contrast, higher contents of sheep's milk led to a significant increase in the concentration of esters, terpenes and alcohols and a slight increase in gamma‐aminobutyric acid. The highest concentration of saturated and unsaturated fatty acids was observed in the cheese prepared with 100% raw sheep's milk after 90 days of ripening. The results revealed the possibility of making a functional white‐brined cheese by monitoring the type and ratio of the used milk and ripening time.

Influence of using different ratios of small ruminants (ovine and caprine) milk on compositional and proteolytic changes during ripening of raw milk lighvan cheese

Lighvan cheese was manufactured using different ratios of ovine and caprine milk (100:0, 75:25, 50:50, 25:75, 0:100) and ripened for 90 days. Chemical composition, proteolysis level, total and individual levels of free amino acids, texture and residual coagulant activity were analysed during ripening. Significant decreases in pH and moisture content and significant increases in texture parameters, residual coagulant activity, soluble nitrogen fractions, fat, and protein contents were determined in the cheese manufactured using higher ratios of ovine milk (P <0.05). Differences in gel electrophoresis and RP-HPLC peptide profiles of the cheeses were seen. Leu and Phe were detected as predominant free amino acids in the cheeses during ripening. In conclusion, besides the cheese manufactured using ovine milk alone, the lighvan cheeses made with ovine and caprine milk in the ratios of 75:25 and 50:50 can be introduced as the preferred cheeses because of having proper proteolysis indices and semi-hard texture.

Preparation and characterization of whey-less lighvan cheese: physicochemical, textural, fatty acid, and amino acid profile changes during ripening

Preparation and characterization of whey-less lighvan cheese: physicochemical, textural, fatty acid, and amino acid profile changes during ripening

Knowledge Transfer from a research institute to rural producers to improve the safety and health conditions of traditional dairy products; Case study - Lighvan cheese

Knowledge Transfer from a research institute to rural producers to improve the safety and health conditions of traditional dairy products; Case study - Lighvan cheese

Determination of biogenic amines in Lighvan cheese using a novel hollow‐fibre electromembrane‐microextraction coupled with gas chromatography–mass spectrometry

The fermentation process is the main formation source of biogenic amines in cheese. The other conditions, like enzymatic reaction, starter culture, temperature, period of maturation, milk treatment, the amount of proteolysis, oxygen, water activity, humidity and pH, can change the rate of the formation of biogenic amines. Tyramine has been defined as quality index for dairy products like cheese. In this work, we have successfully employed the advanced hollow‐fibre electromembrane extraction/dispersive microextraction followed by gas chromatography–mass spectrometry as a rapid and sensitive technique for the determination of biogenic amines including putrescine, tyramine, histamine and cadaverine in Lighvan cheese samples.

Comparison of the microbial, physicochemical, and sensorial properties of raw and pasteurized Lighvan cheeses during ripening time.

Traditional cheeses which are normally produced from raw milk are very popular due to their intense and unique taste and aroma. However, high microbial contamination of raw milk due to manual milking and secondary contamination may lead to many diseases in humans in Iran. Lighvan is a traditional starter‐free locally made Iranian cheese that is made from raw ewe's milk. Since the use of raw milk in the preparation of cheese produces serious health problems, due to the limited ripening period of this type of cheese, this study aimed to evaluate the feasibility of preparing Lighvan cheese from pasteurized milk. For this purpose, different characteristics of cheese prepared with pasteurized milk were compared with raw milk cheese. The results showed a reduction in the microbial population over the ripening time in both types of cheeses. However, coliforms and Escherichia coli were seen in raw milk cheeses until the last day of ripening. Regarding chemical analyses, the water‐soluble nitrogen fraction and lipolysis products increased during ripening. Moreover, the raw milk cheeses indicated a higher lipolysis index than the pasteurized ones. According to the obtained results from the sensory evaluation, the raw milk cheese indicated higher acceptability compared with the pasteurized milk cheese. However, since the presence of E. coli makes the cheese inedible, it seems that the pasteurization of milk is mandatory for the production of this type of cheese.

Phenotypic and phylogenetic characterization of Lactobacillus species isolated from traditional Lighvan cheese

Lighvan cheese (Lighvan panir) is among the most famous traditional cheese in Iran for its desired aroma and flavor. Undoubtedly, the lactic acid bacteria especially the genus Lactobacillus are the critical factors in developing the aroma, flavor, and texture in Lighvan cheese. In this study, the Lactobacillus population of the main Lighvan cheese was investigated. The Lactobacillus of the main Lighvan cheese was isolated using specific culture methods according to previously published Guidelines. Then, the phylogenetic features were investigated and the phenotypic characteristics were examined using specific culture methods. Twenty-eight Gram-positive bacterial species were identified belonged to the genus Lactobacillus. According to the same sequences as each other, three groups (A, B, and C) of isolates were categorized with a high degree of similarity to L. fermentum (100%) and L. casei group (L. casei, L. paracasei, and L. rhamnosus) (99.0 to 100%). Random amplified polymorphic DNA (RAPD) fingerprint analysis manifested the presence of three clusters that were dominant in traditional Lighvan cheese. Cluster І was divided into 4 sub-clusters. By the result of carbohydrate fermentation pattern and 16S rRNA sequencing, isolates were identified as L. rhamnosus. The isolates in clusters II and III represented L. paracasei and L. fermentum, respectively as they were identified by 16S rRNA sequencing and fermented carbohydrate patterns. Our result indicated that the specific aroma and flavor of traditional Lighvan cheese can be related to its Lactobacillus population including L. fermentum, L. casei, L. paracasei, and L. rhamnosus.Graphical abstract

Proteolysis characteristics and aroma development during ripening of functional IranianLighvancheese

Probiotic Lighvan cheese was studied during 60 days of ripening to determine microbial analysis, proteolysis characteristics, and aroma development. Viability of Bifidobacterium lactis subsp. animalis, water-soluble nitrogen (WSN), total nitrogen (TN), ripening index (RI), trichloroacetic acid-soluble nitrogen (TCA-SN), α-and β-galactosidase activities, aroma compounds, and organoleptic assessments were analyzed. After 60 days of ripening, the survival of B. lactis subsp. animalis was 6.84 log cfu/g. Values for RI and TCA-SN increased continuously throughout ripening. α-and β-galactosidase activities were markedly more pronounced in the present of B. lactis. The final concentration of volatile compounds in probiotic Lighvan cheeses was higher than traditional Lighvan cheese. Among volatile compounds, acetic acid, ethanol, and acetoin were present in the greatest quantities. B. lactis subsp. animalis did not influence sensory characteristics of cheese samples. Novelty impact statement Bifidobacterium lactis affected the proteolysis characteristics of the traditional Lighvan cheese samples; it did not alter the sensory properties of the probiotic samples. At the end of ripening, the cheeses to which bifidobacteria had been added contained significantly (p < 0.05) higher α-and β-galactosidase activity than traditionally produced Lighvan cheese. Most of the volatile compounds identified were present in all cheese samples throughout ripening, with their amounts changing significantly (p < 0.05) as ripening progressed; the final concentration of volatile compounds in most of the probiotic Lighvan cheese samples was higher than in the traditional Lighvan cheese. ​

Study of the Effect of Echinophora platyloba Ethanolic Extract on Survival of Listeria monocytogenes in Lighvan Cheese During Ripening Time

Abstract Listeria monocytogenes is one of the most frequent foodborne bacteria that can be transmitted through dairy products. The demand for replacing chemical preservatives with natural compounds has increased recently. The aim of this study was to investigate the effect of Echinophora platyloba DC ethanolic extract on the survival of L. monocytogenes in Lighvan cheese during ripening time. Three concentrations of E. platyloba ethanolic extract (0, 0.5, 1 and 1.5%) were added to raw milk at the beginning of Lighvan cheese manufacture, and the population of L. monocytogenes was counted on days 15, 30, 60 and 90. Furthermore, the pH and salt concentration of Lighvan cheese were evaluated in these periods. The results showed that an increase in the concentration of ethanolic extract, as well as the ripening time of Lighvan cheese, resulted in a significant decrease (p&lt;0.05) in the levels of L. monocytogenes (cfu/g). Moreover, the logarithm of the L. monocytogenes population (log cfu/g) was significantly decreased (p&lt;0.05) as the concentration of the added ethanolic extract was enhanced over the ripening time, but no significant changes in pH and salt concentration were observed in Lighvan cheese (p&gt;0.05). It was found that the optimal concentration of E. platyloba ethanolic extract for the complete inhibition of L. monocytogenes was 1-1.5% following 90 days of the ripening.

Behavior of Mycobacterium avium paratuberculosis in Lighvan cheese tracked by propidium monoazide qPCR and culture

Mycobacterium avium subsp. Paratuberculosis (Map) is an important animal pathogen with a worldwide distribution that may contribute to Crohn's disease in humans. This study aimed to investigate the behavior of Map in Lighvan cheese with special reference to the strains of Map, inoculum load, and storage time. One laboratory and two native strains of Map were inoculated (102 and 103Map cell/mL) to cheese milk. The behavior of Map throughout the manufacture, ripening, and storage stage of Lighvan cheese tracked using propidium monoazide (PMA) qPCR and culture examination. According to the results, PMA-qPCR showed parallel outcomes in comparison with the culture assay. Besides, in all cheese batches Map was not affected during the ripening; however, throughout the storage period Map population decreased depending on the strain of Map. Trend analysis revealed no significant difference between the persistence of sheep and goat strains, but in all cheese batches, these native strains persisted significantly (p < 0.05) longer than the laboratory strain. In all treatments, the decreasing rate of Map found independent of the initial inoculum load. Nonetheless, in the cheese batches with higher initial inoculum, Map persisted two months longer.

Profiling of bioactive metabolites during the ripening of a semi-hard non-starter culture cheese to detect functional dietary neurotransmitters

Abstract In the present study, the profile of bioactive metabolites in Lighvan cheese, a traditional Iranian semi-hard cheese produced with non-pasteurized ewes' milk and non-starter culture, was investigated during the ripening period to characterize the potential neurotransmitters. Lighvan cheese was prepared according to the local recipe and sampling was done at four stages of ripening (1, 60, 120 and 180 days). The metabolomics was monitored using gas chromatography/mass spectrometry (GC/MS) method and the obtained data were elaborated by principal component analysis (PCA). The results revealed that the content of gamma amino-butyric acid (GABA), glutamate, dopamine, and tyramine known as dietary neurotransmitters were elevated during the ripening process in Lighvan cheese mainly produced by Enterococci and Lactobacilli. Thus, the profile of metabolites of Lighvan cheese exhibited that Lighvan cheese could be a considerable source of dietary neurotransmitters. These compounds may indirectly affect human mood and health through the enteric neuron system.

Antimicrobial Effects of Zataria multiflora and Ocimum basilicum on Escherichia coli O157:H7 During Ripening of Traditional Lighvan Cheese

Background: Escherichia coli O157:H7 is one of the most common causes of contamination in Lighvan cheese processing. Using from natural antimicrobial essential oils is applied method to decrease the rate of microbial contamination of dairy products. The present investigation was done to study the antimicrobial effects of Z. multiflora and O. basilicum essential oils on survival of E. coli O157:H7 during ripening of traditional Lighvan cheese. Methods: Leaves of the Z. multiflora and O. basilicum plants were subjected to the Clevenger apparatus. Concentrations of 0, 100 and 200 ppm of the Z. multiflora and 0, 50 and 100 ppm of O. basilicum essential oils and also 103 and 105 cfu/ml numbers of E. coli O157:H7 were used. The numbers of the E. coli O157:H7 bacteria were analyzed during the days 0, 30, 60 and 90 of the ripening period. Results: Z. multiflora and O. basilicum essential oils had considerable antimicrobial effects against E. coli O157:H7. Using the essential oils caused decrease in the numbers of E. coli O157:H7 bacteria in 90th days of ripening (P &lt;0.05). Using from Z. multiflora at concentration of 200 ppm can reduce the survival of E. coli O157:H7 in Lighvan cheese. Conclusion: Using Z. multiflora and O. basilicum essential oils as good antimicrobial agents can reduce the risk of foodborne bacteria and especially E. coli O157:H7 in food products.

Production and evaluation of enzyme-modified lighvan cheese using different levels of commercial enzymes

Production and evaluation of enzyme-modified lighvan cheese using different levels of commercial enzymes

Bioactive characteristics of a semi-hard non-starter culture cheese made from raw or pasteurized sheep's milk.

In this study, the effect of pasteurization and use of starter cultures on physicochemical, microbiological and functional properties of a traditional Iranian semi-hard cheese (Lighvan cheese) was evaluated during stages of ripening (1, 60, 120days). Profiles of polar metabolites were analyzed by gas-chromatography mass-spectrometry (GC-MS). Considerable free amino acids such as gamma-aminobutyric acid (GABA) were found in samples that have higher microbial communities i.e. raw sheep's milk without use of starter cultures and pasteurized sheep's milk cheese with co-culture. However, GABA was not found in pasteurized sheep's milk cheese without starter culture during ripening. Conclusively, the application of the starter culture could reduce the ripening time of sheep's milk cheese and could be an appropriate approach to increase the functionality of the sheep's milk cheese.

Biochemical changes of Iranian probiotic Lighvan cheese

Lighvan cheese from ewe and goat milk was produced according to a traditional protocol, and with the addition of 9 log&lt;sub&gt;10&lt;/sub&gt; cfu/g fresh cells of Bifidobacterium lactis subsp. animalis. Probiotic Lighvan cheese was studied to determine the survival of B. lactis subsp. animalis and biochemical changes during 60 days of ripening of probiotic Lighvan cheese. Lipolysis level and organoleptic assessments were analysed. B. lactis subsp. animalis cells survived in cheese samples at concentrations up to 6.84 log&lt;sub&gt;10&lt;/sub&gt; cfu/g for at least 60 days of storage time. The lipolysis level increased continuously until the end of the ripening period.The ripening stage was the main factor affecting the cheese sensory properties.

Antibacterial effects of Lactococcus lactis isolated from Lighvan cheese regarding the recognition of Nisin, Lacticin and Lactococcin structural genes

The aim of this study was to evaluate the antibacterial effects of Lactococcus lactis isolated from Lighvan cheese with a focus on the recognition of Nisin, Lacticin and Lactococcin structural genes. For this purpose 1500 similar colonies from fresh grass, fresh milk, Curds, fresh cheese and ripe cheese were isolated based on morphology from 2 traditional factories in Lighvan region. After microscopic observations, 625 isolates were chosen and special biochemical experiments were carried out during which 60 suspicious isolates of Lactococcus lactis were recognized. To specify the exact species and subspecies, isolates were recognized by sequencing of 16SrRNA gene region and determined as Lactococcus lactis ssp. lactis. Antimicrobial evaluation was carried out using Agar spot and Well Diffusion techniques. Twelve isolates were positive according to antimicrobial properties and molecular experiments using specific primers. Our results showed that the frequency of antibacterial structural genes Lactococcin M, Lactococcin B, Lactococcin GQ, Lactococcin A and Nisin were 7, 6, 6, 1 and 1 out of 12 isolates, respectively.

A Preliminary study on antifungal activity of lactic acid bacteria isolated from different production stages of Lighvan cheese on Penicillium expansum and Rhodotorula mucilaginosa

Antifungal properties of 19 Lactobacillus plantarum strains isolated from Lighvan cheese during different production stages were evaluated against Penicillium expansum (ATCC 36200) and Rhodotorula mucilaginosa (ATCC 2503). To accomplish such comparison, culture-based methods including Lawn on the Spot and Well Diffusion were performed and strains with antifungal property were screened. From a pool of 19 strains, 10 of Lb. plantarum spp. exhibited antifungal activity against Pen. expansum and 11 of them against R. mucilaginosa. Thereafter the effects of pH (ranged from 2 to 7) and temperatures (80 °C for 1 h, 100 °C for 10 and 30 min, and 121 °C for 15 min) were evaluated. All Lb. plantarum spp. maintained their inhibitory effect at pH of 2 and 3, while no inhibition was observed at pH of 7. Inhibitory effect intensity decreased by increasing the temperature/time duration of heating. Lb. plantarum C28 showed the highest thermal resistance and also with inhibitory activity of 160 (AU/ml) possessed the highest anti-fungal activity using titration test. The strains LF51, C24, LF49 and LF51, C24 exhibited anti-mold and anti-yeast activity respectively after a 20-fold concentration of the cell free supernatant against Pen. expansum and R. mucilaginosa. Inhibitory effects of all isolates were lost when subjected to proteinase K which implies their proteinaceous nature.

Determination of Biogenic Amines in Cheese Using Simultaneous Derivatization and Microextraction Method Followed by Gas Chromatography–Mass Spectrometry

Microwave-assisted extraction and dispersive liquid–liquid microextraction followed by gas chromatography–mass spectrometry as a sensitive and efficient method was applied to extract and determine four biogenic amines (BAs) in Iranian Lighvan cheese samples. Carrez solutions were used for the sedimentation of proteins. Effective factors on the performance of microextraction were studied and optimized. The proposed method showed good linear ranges from 5 to 500 ng mL−1, with the coefficients of determination higher than 0.9929. Average recoveries were between 97 and 103%. Limits of detection for all analyzed BAs ranged from 5.9 to 14.0 ng g−1, and limits of quantitation ranged between 19.7 and 46.2 ng g−1. Compared with previous methods, the proposed method is simple, fast, accurate, and precise and gives low detection limits for investigating trace amounts of BAs in Iranian Lighvan cheese samples. The levels of four BAs were determined in five Lighvan cheese samples. Cadaverine was found as prevailing amine in the cheese samples. Putrescine, tyramine, and histamine were present at the second, third, and fourth highest levels, respectively.

Behaviour of Listeria monocytogenes in Lighvan cheese following artificial contamination during making, ripening and storage in different conditions

This study investigated the behaviour and fate of Listeria monocytogenes at different ripening temperatures and NaCl concentrations in traditional Lighvan cheese. L. monocytogenes was added to raw sheep's milk. After producing the cheese, they were stored in 8%, 12% and 15% NaCl at 4, 9 and 14 °C. Sampling was performed for 150 days. Different temperature and NaCl concentrations had a significant effect on the survival of L. monocytogenes (P &lt; 0.001). The lowest growth and survival rates of L. monocytogenes were in 15% NaCl at 14 °C and 12% NaCl at 14 °C, respectively. Also, the highest growth and survival rates of the bacterium were in 8% NaCl at 4 °C.

Safety Evaluation and Antibacterial Activity of Enterococci Isolated from Lighvan Cheese

AbstractTwenty three enterococci were isolated from Lighvan cheese. Enterococcal isolates identified by 16S rDNA sequencing, were evaluated for their safety and also examined for antibacterial activity and presence of the genes coding for enterocins. Four enterococcal isolates exhibited inhibitory activity against Listeria innocua and E. faecalis and harbored the bacteriocin genes (enterocins A, B, P, X and 31) too. Multiple combinations of virulence determinant genes (vanA, vanB, gelE, esp, asa1, cpd and ace) were detected in enterococcal isolates with the exception of 5 E. faecium isolates. While the isolates exhibited resistance to some antibiotics, all of them were susceptible to ampicillin and vancomycin. In conclusion, this study shows the presence of enterococci with potential biopreservative activity in Lighvan cheese; however it also warrants further research on the safety and origins of enterococci in this cheese.Practical ApplicationsLighvan is a very popular cheese in Iran with a specific texture and taste which is produced in little amount from raw sheep milk and ripened in manmade underground galleries. There are a few studies about the microflora of this cheese and the point is that enterococcus species have proven to be always dominant. Safety evaluation of these bacteria is really necessary as far as the Lighvan cheese is produced from raw milk and also the controversial viewpoint that there is about the GRAS state of enterococcus species. Recognition of the safe strains of enterococcus species isolated from the lighvan cheese would help to produce a more hygienic and safer industrial product.