Phosphotungstic Acid-soluble Nitrogen Research Articles

Proteolytic Changes During Ripening Of Kučki Cheese

Summary Production of various traditional dairy products, particularly cheese, has a long history in Montenegro. White-brined cheeses are the most well-known. One of them is Kučki cheese, with distinct flavor and higher level of proteolysis. The aim of this research was to analyze the proteolysis process during ripening of Kučki cheese. The cheese is produced using traditional technology. FTIR Spectrophotometry was used to calculate the amount of total protein in cheese (IDF141C: 2000). The degree of proteolysis was determined by SDS PAGE (Laemmli, 1970). The cheese was examined for their water-soluble nitrogen (WSN) content using Kuchroo and Fox’s method from 1982, as well as their 5% phosphotungstic acid soluble nitrogen (PTAN) content using Stadhouser’s method from 1960. The results were expressed as percentages of WSN and PTAN of the total nitrogen matter (WSN/TN and PTAN/TN), as well as PTAN as a percentage of WSN (PTAN/WSN). All analyses were done on 10th, 20th and 30th day of cheese ripening. Four samples of cheese were analyzed for each ripening period. The content of proteins increased during the ripening period. The parameters that determine the process of proteolysis increased during the first 30 days of ripening. The WSN/TN ranged from 13.33 to 44.32%. Also, PTAN/WSN varied from 3.79 to 21.57%. The initial results show that uneven ripening conditions have a direct impact on how proteolytic changes develop throughout ripening. Due to the absence of established cheese-making procedures, Kučki cheese has a considerable degree of heterogeneity in their protein content and proteolysis parameters. However, it is not possible to strictly define the optimal values of the degree of ripening for Kučki cheese. In order to reach certain conclusions, it is necessary to carry out further studies focusing on analyzing a larger number of samples.

The Impact of the Adjunct Heat-Treated Starter Culture and Lb. helveticus LH-B01 on the Proteolysis and ACE Inhibitory Activity in Dutch-Type Cheese Model during Ripening.

Simple SummaryAdjunct cultures are used in cheesemaking to improve flavour characteristics and accelerating cheese ripening. Different adjunct cultures are capable of producing enzymes with the specificity to hydrolyze caseins, leading to the release of various bioactive compounds. We studied the effect of adjunct heat-treated starter XT–312 and a cheese culture Lb. helveticus LH-B01 on selected physicochemical, microbiological properties, and on proteolysis in cheese models. Additionally, the effect of adjunct cultures on ACE inhibitory activity during ripening was determined. The application of adjunct cultures may be used as functional ingredients in Dutch-type cheese to maintain sufficient bioactive properties and improve proteolysis.Adjunct cultures are used in cheesemaking to improve the sensory characteristics of the ripened cheeses. In addition, it is known that different adjunct cultures are capable of producing enzymes with the specificity to hydrolyze caseins, leading to the release of various bioactive compounds (bioactive peptides, amino acids, etc.). The objective of this study was to evaluate the effect of adjunct heat-treated starter XT–312 and a cheese culture Lb. helveticus LH-B01 on the proteolytic activity and angiotensin converting enzymes inhibitors (ACE) in cheese models during ripening. Seven different cheese models were evaluated for: proteolytic activity using the spectrophotometric method with ortho-phthaldialdehyde (OPA), soluble nitrogen (SN), trichloroacetic acid-soluble nitrogen (TCA-SN) phosphotungstic acid-soluble nitrogen (PTA-SN), total nitrogen (TN), pH, contents of water, fat, as well as for total bacteria count (TBC), count of Lactococcus genus bacteria, count of Lb. helveticus, and number of non-starter lactic acid bacteria (NSLAB). Presence of adjunct bacterial cultures both in the form of a cheese culture LH-B01 and heat-treated XT–312 starter promoted primary and secondary proteolysis, which resulted in acceleration of the ripening process. ACE inhibitory activity and proteolytic activity was the highest throughout of ripening for cheese model with LH-B01 culture. The cheese models with the adjunct heat-treated starter were characterized by lower TBC, NSLAB and lower count of Lactococcus genus bacteria during ripening, compared to control cheeses.

DETERMINATION OF THE FACTORS THAT CAUSE BITTERNESS DURING SHELF-LIFE IN WHITE CHEESE PRODUCED USING ULTRAFILTRATED MILK

This study aimed to determine the causes of bitterness problems in white cheese produced by ultrafiltration (UF). To investigate the association between the bitterness with the enzyme use or by the starter culture, white cheese was produced using UF-pasteurized and UF-raw milk with two different coagulating enzymes and two starter cultures with different proteolytic activities. Sensory analysis, protein, water-soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen, 5% phosphotungstic acid-soluble nitrogen and acid degree values were determined on day 1, 30, 60 and 90 of the ripening periods. During the ripening process, bitterness was determined in the cheese samples due to proteolysis. The A cheese sample, which was produced using chymosin enzyme and a starter culture with high proteolytic activity, was determined to be the sample with the highest bitterness level in the sensory analyses, SDS-PAGE electrophoresis and HPLC analysis. 72.26% αs-casein hydrolysis was determined in the A cheese sample. According to HPLC results, a high hydrophobic peptide formation was determined with the increase in the area of hydrophobic peptides with a rate of 106% between 40 and 60 minutes.

Sodyum Kazeinat veya Kitosan Bazlı Yenilebilir Kaplamaların Kaşar Peynirnin Bazı Kimyasal, Yapısal ve Mikrobiyolojik, Özelliklerine Etkisi

This study aimed to evaluate the effects of the edible coatings produced from casein, casein / transglutaminase enzyme, and chitosan on certain chemical, textural, and microbiological properties of Kashar cheese over a storage period of 60 days. The use of edible coatings affected the levels of nitrogen fractions (water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, and phosphotungstic acid-soluble nitrogen) and the lipolysis level of Kashar cheese to a statistically significant extent (P<0.05 for all). The levels of nitrogen fractions and lipolysis in the uncoated control group cheeses increased significantly (P<0.05) during the storage period compared to coated cheese. Cheese samples coated with chitosan yielded significantly lower yeast-mould counts compared to samples that were uncoated or coated with sodium caseinate or sodium caseinate/transglutaminase at the end of the storage period (P<0.05). The results indicated that the edible coatings had a significant effect on the chemical, textural, and microbiological properties of Kashar cheese.

Effect of Ripening in Brine and in a Vacuum on Protein, Fatty Acid and Mineral Profiles, and Antioxidant Potential of Reduced-Fat White Cheese.

SUMMARYResearch backgroundNumerous factors affect the ripening of reduced-fat white cheese. The aim of this study is to investigate the influence of ripening environment (brine or vacuum plastic bags without brine) on the chemical composition, protein, fatty acid profile and mineral content as well as antioxidant properties of industrially produced reduced-fat white cheese.Experimental approachA low-fat white cheese was manufactured on an industrial scale from milk that remained after the production of kajmak and ripened for 60 days at 4 °C after packaging in a polystyrene container with brine containing 6% salt or in vacuum-sealed polyethylene bags. The influence of ripening environment on proteolysis was monitored by the change of soluble nitrogen fractions as well as by sodium dodecyl sulphate–polyacrylamide gel electrophoresis of tris(hydroxymethyl) aminomethane-HCl extracts of cheese proteins under non-reducing conditions and water-soluble fractions under reducing conditions. An effect that ripening environment had on fatty acid and mineral content was also monitored. The change of antioxidant potential of the investigated cheese during ripening led to the change of iron(II) chelating ability, reducing power and free-radical scavenging activity.Results and conclusionsThe ripening environment differently affected proteolysis, fatty acid composition, mineral profile and antioxidant properties of reduced-fat white cheese. White cheese ripened in brine had more intensive proteolytic changes than the cheese ripened in a vacuum, but also more intensive diffusion processes, especially between the 40th and 60th day of ripening. The brine-ripened cheese had higher values of water-soluble nitrogen content, but lower contents of trichloroacetic acid-soluble and phosphotungstic acid-soluble nitrogen than the vacuum-ripened cheese. Cheese ripened in brine had a lower content of almost all investigated macro- and microelements. After 60 days of ripening, in cheese ripened in brine only myristic (C14:0) and palmitic acid (C16:0) were detected, whereas in the vacuum-ripened cheese C10:0-C16:0 fatty acids dominated. Vacuum-ripened reduced-fat cheese had more favourable reducing power, while white brined reduced-fat cheese had better radical scavenging activity and iron(II) chelating activity.Novelty and scientific contributionThese results suggest significant influence of ripening conditions (immersion in brine or in vacuum-sealed polyethylene bags) on nutritive and functional properties of reduced-fat white cheese. Ripening in a vacuum has become a useful method for obtaining high-value reduced-fat white cheese.

Effects of different starter culture applications pre- and post-scalding on the biochemical and sensory properties of pasta filata type cheeses

In this study, three different types of starter cultures (S1, S2, and S3) were applied either before (A1) or after (A2) scalding stage in Tel Cheese production and their chemical, biochemical, electrophoretic, and sensory properties were investigated during ripening. In general, there was no significant difference between the dry matter, fat, protein and salt values of the cheese samples (P > 0.05). However, there were significant differences between the pH and titration acidity values of the samples (P < 0.05). Especially the titration acidity values of cheeses in the A2 application increased significantly until maturity. The WSN (water-soluble nitrogen), TCA-SN (trichloroacetic acid-soluble nitrogen) and PTA-SN (phosphotungstic acid-soluble nitrogen) values were significantly affected by ripening period and increased continuously (P < 0.05). These values for A2S2 and A2S3 cheeses increased more than the others suggesting better ripening characteristics. Electrophoretograms indicated that αs1-and β-casein degradation rates were the highest in A2S2 cheese. Finally, sensory scores of A1 cheeses were found to be higher than those of the A2 cheeses.

Proteolysis, lipolysis, texture and sensory properties of cheese ripened by Monascus fumeus

Monascus spp. are fungi that have been applied in food production for centuries and produce a range of bioactive metabolites. The objective of this study was to investigate the characteristics of proteolysis, lipolysis, textural and sensory properties of internal mold-ripened cheese ripened by Monascus fumeus x08. The contents of pH 4.6-soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen and 5% phosphotungstic acid-soluble nitrogen changed significantly during the ripening of the Monascus-ripened cheese. The peptides in the Monascus-ripened cheese were evaluated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and reversed-phase high-performance liquid chromatography. During ripening, many low-molecular-weight peptides (MW < 14400) were found to increase significantly and the ratio of hydrophobic to hydrophilic peptides decreased to 0.81 and 0.34 in the Red-O (outer) and Red-I (interior) parts of the cheese, respectively. The content of total free fatty acids (15 acids, C4:0–C18:3) was significantly increased and the content of unsaturated fatty acids reached 47.89 mg/g fat on day 42 of ripening. The sensory attributes of the Monascus-ripened cheese was assessed using quantitative descriptive analysis. Compared with blue cheese, purchased from a local market, the odor and taste intensity of the Monascus-ripened cheese were significantly lower, while the color intensity and overall receptivity were significantly higher. M. fumeus x08 can be used as a secondary starter to make Monascus-ripened cheese and may be particularly acceptable to consumers in China.

Evaluation of the Quality Characteristics of Siirt Herby Cheese: A Traditional Turkish Variety

Herby cheese produced in the Province of Siirt is one of the Turkish cheese varieties. The special parameters applied during the production stages give Siirt Herby cheese unique taste properties. The proteolytic, lipolytic, and electrophoretic parameters of Siirt Herby cheese samples were evaluated. The mean values of water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, and phosphotungstic acid-soluble nitrogen of Siirt Herby cheese samples were 9.49±2.66%, 6.33±2.39%, and 1.48±0.71%, respectively. The mean values of free amino group and lipolysis levels were established as 61.97±30.84 mM glycine, and 6.00±2.32 ADV, respectively. The electrophoretic analysis showed that sheep milk was more preferable for Siirt Herby cheese production.

Proteolytic Activity of Lactobacillus plantarum Strains in Cheddar Cheese as Adjunct Cultures

Microbial enzymes within adjunct cultures are important for cheese ripening. Here, survival and proteolytic function of adjunct cultures of Lactobacillus plantarum strains MU12 and S6-4 on Cheddar cheese ripening were studied. Cheeses were ripened at 4°C, and samples were collected for analysis after 1, 30, 60, and 90 days. Lactococci numbers decreased by 2 to 3 log versus control, except in a few samples exhibiting significantly elevated numbers. Lactobacilli mainly originated from adjunct cultures, with lactobacilli numbers in adjunct-treated cheese significantly exceeding control numbers after day 30. Postripening, no significant differences were observed in composition (fat, protein, and moisture) and texture among cheeses, although observed significant differences in small nitrogen-containing compound levels (water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, and phosphotungstic acid-soluble nitrogen) reflected proteolytic differences during ripening. Hydrolyzed protein, free amino acids, and volatile levels were consistently higher in adjunct-treated versus control cheeses and affected flavor. Cheddar cheeses may serve to effectively deliver beneficial organisms possessing proteolytic function.

Multiparametric analysis of cheese using single spectrum of laser-induced breakdown spectroscopy

The potential of using laser-induced breakdown spectroscopy (LIBS) for prediction of chemical quality/control parameters in a cheese matrix was investigated. Traditional methods are usually time-consuming and require complex pre-treatments, the use of toxic chemicals and laboratories and personnel equipped with these analytical skills. In this study, 11 different chemical analyses commonly performed on cheese samples were conducted using traditional methods on 82 full-fat, white pickled and ripened cheese samples. Additionally, these parameters of interest were correlated with multi-elemental spectra of LIBS using partial least squares regression. The results obtained for moisture, dry matter, salt, total ash, total protein, pH, fat, acidity, water soluble nitrogen, trichloroacetic acid soluble nitrogen, and phosphotungstic acid soluble nitrogen (Rcal2 = 0.964, 0.959, 0.970, 0.973, 0.952, 0.971, 0.733, 0.762, 0.714, 0.633, and 0.707, respectively) indicated that LIBS could be used as an alternative or complementary method in quality control of cheese.

Effects of Proteolytic and Lipolytic Enzyme Supplementations on Lipolysis and Proteolysis Characteristics of White Cheeses.

Effects of proteolytic (Neutrase, Bacillus subtilis-originate, 0.20 (P1) and 0.40 g 100 L−1 (P2)) and lipolytic (Piccantase A, Mucor miehei-originated, 0.05 (L1) and 0.10 g 100 L−1 (L2)) enzyme supplementations to cheese milk on lipolysis and proteolysis characteristics of 90-day ripened cheese samples were investigated in this study. While enzyme supplementation did not have significant effects on titratable acidity, fat and protease-peptone nitrogen ratios of cheese samples, dry matter, salt, protein, water soluble nitrogen, 12% trichloroacetic acid soluble nitrogen ratio (TCA-SN), 5% phosphotungstic acid soluble nitrogen (PTA-SN), casein nitrogen ratios, penetrometer value, total free fatty acids (TFFA) and total free amino acids (TFAA) were significantly influenced by enzyme supplementations. Individual free amino acids (15 of them) were also determined. Free amino acid contents of enzyme-supplemented cheeses were higher than the control cheese and the values increased in all cheese samples with the progress of ripening (p < 0.05). The highest amino acids in all periods of ripening were identified as glutamic acid, lysine, proline and aspartic acid. The major (Ca, P, Na, K, Mg) and minor (Zn, Fe, Cu, Mn) mineral levels of cheeses decreased with the progress of ripening and the effects of enzyme supplementations on these attributes (except for magnesium and manganese) were found to be significant (p < 0.01). As to conclude, enzyme supplementations increased proteolysis and lipolysis and accelerated ripening and thus reduced ripening durations. Especially the enzyme ratios in P1 and L1 cheeses were found to be suitable for reducing the ripening period in White cheese without any adverse effects.

Some microbiological, physicochemical and ripening properties of Erzincan Tulum cheese produced with added black cumin (Nigella sativa L.).

The effects of black cumin (BC) at 0, 1 or 2% in Erzincan Tulum cheese (Tulum cheese) on its microbiological, chemical and proteolysis properties during ripening were investigated. The addition of BC caused an increase in the dry matter, protein, ash, total nitrogen (TN), water-soluble nitrogen (WSN) (% of TN) (ripening index), 5% phosphotungstic acid soluble nitrogen (PTA-SN) (% of TN), and 12% trichloroacetic acid soluble nitrogen (TCA-SN) (% of TN) concentrations compared to BC-free (control) cheese. Additionally, the addition of BC caused a decrease in coliforms, yeasts & moulds, fat-in-dry matter (FDM), pH, and acidity. The ripening period had an increasing effect on the dry matter, protein, FDM, salt, salt-in-dry matter (SDM), ash, acidity, TN, WSN, PTA-SN and TCA-SN concentrations. In addition, the ripening period had a decreasing effect on coliforms, yeasts & moulds, and pH. The count of Staphylococcus aureus in all Tulum cheeses made of raw sheep's milk was <2 log cfu/g, ripening was faster and favourable Tulum cheese was produced. Therefore, 2months after adding 2% BC to Tulum cheese that was produced using raw sheep milk immediately after milking as the original production method, it was found that Tulum cheese can be consumed more safely than coliform bacteria and yeasts & moulds.

Influence of Lactobacillus casei LC2W on the proteolysis and aroma compounds of Cheddar cheese during ripening period

Cheddar cheeses were prepared with or without Lactobacillus casei LC2W for studying the survival of the probiotic bacteria and the influence of this strain on cheese proteolysis and aroma compounds of 180 days at 6°C. Following ripening, the probiotic bacteria counts remained about 108 cfu/g. In addition, the water-soluble nitrogen (WSN)/total nitrogen (TN) and phosphotungstic acid soluble nitrogen 5% (PTA-SN)/TN had significant differences between cheeses with and without probiotic strain at the end of ripening. Analysis of aroma compounds showed that probiotic cheese had more aroma compounds than control cheese during the ripening period, and principal components analysis (PCA) showed that the aroma profile of the two types of Cheddar cheeses belonged to different areas at the beginning of ripening, but after 180 days of ripening they were in the same area. The study demonstrated that L. casei LC2W can be used as an adjunct culture into Cheddar cheese for making a functional food.

Influence of the Probiotic Lactobacillus acidophilus NCFM and Lactobacillus rhamnosus HN001 on Proteolysis Patterns of Edam Cheese.

The objective of this study is to determine the viability of Lactobacillus acidophilus NCFM and Lactobacillus rhamnosus HN001 in Edam cheese as well as the effect of probiotic bacteria on paracasein proteolysis and changes in the water activity during ripening. The use of probiotics L. rhamnosus HN001 and L. acidophilus NCFM in Edam cheese slightly changed its chemical composition, but the change was not significant. The pH values were significantly correlated with the changes in Lactobacillus count (R=-0.807) and the level of phosphotungstic acid-soluble nitrogen compounds in total nitrogen (PTA-SN/TN) (R=0.775). After 10 weeks of ripening, the highest level of trichloroacetic acid-soluble nitrogen compounds in total nitrogen (TCA-SN/TN) was observed in the cheese containing L. rhamnosus HN001 (11.87%) and slightly lower level in the cheese containing L. acidophilus NCFM (7.60%) and control cheese (6.24%). The highest level of PTA-SN/TN fraction was noted in cheese containing L. acidophilus NCFM (3.48%) but the lowest level was observed in control cheese (2.24%) after ten weeks of ripening. The changes in the levels of PTA-SN/TN (R=-0.813) and TCA-SN/TN (R=-0.717) fractions were significantly (p<0.05) correlated with the viability of probiotic counts. Water activity (aw ) strongly correlated with the PTA-SN/TN level (R=-0.824) and bacteria viability (R=-0.728). All of the analyzed cheeses were characterized by high counts of L. rhamnosus HN001 and L. acidophilus NCFM during ten weeks of ripening.

Ripening process of Cascaval cheese: compositional and textural aspects.

Two textural characteristics, elasticity modulus and firmness, were determined during the ripening process of Cascaval cheese, using both instrumental and sensorial techniques. Uniaxial compression was used to determine the textural characteristics and the results were compared with the ones obtained by sensorial analysis, revealing a good correlation. The chemical composition of cheese was also determined, including the nitrogen fractions (total nitrogen, water soluble nitrogen, non-protein nitrogen and phosphotungstic acid soluble nitrogen). The data thus obtained were statistically processed in order to find the differences between the samples, as well as to find the correlation between the techniques of analysis. The study showed that the ripening process of the Cascaval cheese is similar to the ripening of other pasta filata cheese. The moisture content decreases during maturation as a result of water evaporation. The concentration of nitrogen fractions increases during the ripening stage, and so do the firmness and elasticity modulus. The biochemical processes that occur during maturation largely influence the textural parameters and this is proved by both instrumental and sensorial analyses.

Manufacture of Cheddar cheese using probiotic Lactobacillus plantarum K25 and its cholesterol-lowering effects in a mice model

The probiotic adjunct Lactobacillus plantarum K25 was inoculated into milk to produce probiotic cheese. The effect of Lb. plantarum K25 on cheese composition, microbiological growth and survival during the manufacturing and ripening period, primary and secondary proteolysis during cheese ripening, and the in vivo cholesterol-lowering ability of the probiotic cheese were investigated. The results showed that the use of adjunct Lb. plantarum K25 in Cheddar cheese did not affect the cheese components including moisture, protein, fat, salt content and the pH value of cheese. During the whole ripening period, the probiotic adjunct maintained its viability, suggesting the effectiveness of Cheddar cheese as a vehicle for delivery of probiotic bacteria. No significant differences were observed in water-soluble nitrogen, 70 % ethanol-soluble nitrogen, 5 % phosphotungstic acid-soluble nitrogen, free amino acids and urea-PAGE patterns between the control and probiotic cheeses. Assessment of the in vivo cholesterol-lowering property of cheese with Lb. plantarum K25 showed that the levels of serum total cholesterol, low-density lipoprotein cholesterol and triglycerides decreased significantly, and the level of serum high-density lipoprotein cholesterol increased in mice fed with the probiotic cheese. The results indicated the potential function as a dietary item of the probiotic cheese with Lb. plantarum K25 to reduce the risk of cardiovascular diseases.

Role of Streptococcus thermophilus PRI60 in histamine accumulation in cheese

The contribution of Streptococcus thermophilus to histamine formation during cheese ripening was evaluated. Cheeses were produced using, as starter cultures, histamine-producing or non-producing S. thermophilus strains (PRI60 and PRI40, respectively), in combination with a decarboxylase-negative Lactobacillus helveticus strain. Cheeses inoculated with the strain PRI40 and with cell-free extracts of PRI60 added were also produced. The different combinations of starter cultures were responsible for different proteolytic patterns as demonstrated by the behaviour of water-soluble, trichloroacetic soluble, and phosphotungstic acid soluble nitrogen. A single histaminogenic strain, present during fermentation and ripening, also in the form of a cell lysate, produced histamine up to 180 mg kg−1 in cheese. Histamine was found at a higher level in cheeses manufactured with PRI60 starter, but was also detected in cheese containing the cell-free HdcA enzyme. The problem of histamine formation by S. thermophilus in artisanal cheeses must not be overlooked, especially during typical production practices.

The role of copper in the manufacture of Finnish Emmental cheese

The effects of added copper in the manufacture of Finnish Emmental cheese were studied. Consequently, cheeses were produced with or without the copper supplement and a facultative heterofermentative strain, Lactobacillus rhamnosus Lc705, which is currently utilized as a protective culture in large-scale manufacture in Finland. Cheeses were examined at 1, 7, 30, 60, and 90 d from the microbiological, chemical, and sensory points of view. Organic acid production was affected by the presence of copper in the cheeses. The addition of copper to cheesemilk increased the level of primary proteolysis and slowed secondary proteolysis as measured by nitrogen content in different extracts after citrate fractionation of cheeses, in pH 4.4-soluble nitrogen and 5% phosphotungstic acid-soluble nitrogen, respectively. The presence of copper appears to positively regulate the sensory characteristics of the cheese produced in our conditions; in particular, consistency was affected significantly. The role of the Lb. rhamnosus Lc705 protective strain has not been shown to have important effects on most of the parameters that influence the final quality of the cheeses. Although the traditional plating systems for revealing bacterial populations during cheese manufacture did not reveal any drastic differences caused by the presence of copper, the results from chemical and sensory analyses suggest that its use plays a significant role in the regulation of bacterial physiological and biochemical activities, which in turn affect the sensory quality of Emmental cheese.

Characterisation of aroma-active compounds, chemical and sensory properties of acid-coagulated cheese: Circassian cheese

The objectives of this study were to determine basic composition, aroma and sensory characteristics of Circassian cheese. Seven Circassian cheeses were provided by local producers. Aroma compounds were extracted by using solid-phase microextraction procedure and determined by gas chromatography-olfactometry system. Water-soluble, trichloroacetic acid-soluble and phosphotungstic acid-soluble nitrogen fractions ranged between 2.30–29.35%, 2.48–9.96% and 3.33–6.26%, respectively. Diacetyl, butyric acid, 2-acetyl-1-pyrroline, 1-octen-3-one and methional were identified at high intensities in cheeses. In addition, ‘cooked’, ‘whey’, ‘creamy’ and ‘fermented’ were defined as characteristic flavour terms for Circassian cheeses.

The effect of different packaging materials on proteolysis, sensory scores and gross composition of tulum cheese

In this study, tulum cheese was manufactured using raw ewe’s milk and was ripened in goat’s skin and plastic bags. The effect of ripening materials (skin bag or plastic) on proteolysis was investigated during 120 days of ripening. In addition, sensory scores of the cheeses were assessed at the 90th and 120th days. The gross composition was also determined at the initial stage of ripening. The results showed that, some significant differences were noted between cheeses ripened in goat’s skin and plastic bags in terms of gross composition due to the porous structure of skin bag, which causes moisture loses during ripening. Significant differences were observed in proteolysis indices including water, 12% tricholoroacetic acid and 5% phosphotungstic acid-soluble nitrogen fractions among the cheese samples during ripening. Proteolysis levels were higher in tulum cheeses ripened in goat’s skin. Key words: Tulum cheese, packaging material, sensory analysis, ripening, proteolysis.