EFFECT OF HEATING AT DIFFERENT TEMPERATURES TO EXTEND THE SHELF LIFE OF VACUUM-PACKED WHITE CHEESE

The aim of this study was to determine the effects of heating applications on the shelf life of vacuum‐packed white cheese. Shelf life was evaluated for chemical, microbiological and organoleptic properties during the ripening period of 90 days. For this purpose, pickled white cheeses made with commercial starter cultures (Chr. Hansen R707 Lactococcus lactis subsp. lactis, L. lactis subsp. cremoris) were put in polyamide bags for vacuum packaging. During the ripening period, a water bath was used for heating applications at 65, 70 and 72C for 15, 10 and 5 min, respectively. In the ripening period, there were no changes in the values of dry matter in the control group. Dry matter values in control cheese were 40.02–42.09% (average value: 40.87%). Total acidity, protein (%), soluble nitrogen, ripening index (RI), tyrosine content and volatile fatty acid values all showed significant increases between the first and 90th days of the ripening period. However, in the heated cheese groups, dry matter showed no changes, but compared with the control group cheese total acidity, protein (%), soluble nitrogen, RI, tyrosine content and volatile fatty acid values increased but not as much as the control group.     

Changes in the physicochemical,microstructural and rheological properties of traditional Kope cheese during ripening

The effect of ripening time on the microstructural, physicochemical and rheological characteristics of traditional Kope cheese ripened in clay pots was investigated. The moisture content, pH and total nitrogen (TN)/dry matter (DM) of the cheese decreased, and DM, fat in DM and water‐soluble nitrogen/TN increased during this period. Storage and loss moduli increased, while loss tangent decreased; as a result, the elasticity characteristics were greater than the viscous characteristics of the samples. Microstructure images showed that the size of pores and casein network density increased significantly during ripening and, after 90 days, the structure of many pores became very similar to each other.     

Protein profiles and total antioxidant capacity of water‐soluble and water‐insoluble fractions of white brined goat cheese at different stages of ripening

This study deals with proteolysis and total antioxidant capacity of proteins of white brined cheese prepared from overheated goat milk and ripened for fifty days. Proteolytic changes were reflected through the relatively low level of soluble nitrogen (50 days ripened cheese had 15.32 g/100 g of water‐soluble nitrogen, 8.1 g/100 g of TCA‐soluble nitrogen and 2.69 g/100 g of PTA‐SN), intensive proteolysis of α_s2‐CN during initial 10 days of ripening (up to 50.70% of initial content) and its much slower degradation through further 40 days, slow but continual decrease of β‐CN content (up to 85.14% of residual content) and high level of proteolytic products tightly bounded into gel network. Total antioxidant capacity of water‐soluble and water‐insoluble fractions increased after cheese ripening. These findings could be useful for better understanding and control over the production of white brined goat cheese as highly valuable functional product.     

Effects of coagulant type on the physicochemical and organoleptic properties of Kashar cheese

Kashar cheeses were manufactured using different coagulants (calf rennet, chymosin derived by fermentation and proteases from Rhizomucor miehei and Cryphonectria parasitica) and ripened for 90 days. Use of different coagulants did not influence the dry matter, fat, protein, salt, pH, titratable acidity, total free fatty acids and texture profile analyses. The levels of water‐soluble nitrogen, 12% trichloroacetic acid‐soluble nitrogen, and for 5% phosphotungstic acid‐soluble nitrogen, the sensory properties were significantly influenced by the use of different coagulants. β‐casein was more hydrolysed in the cheese manufactured using protease from Cryphonectria parasitica than the other cheeses during 90 d of ripening.     

Volatile compounds and proteolysis in traditional Beaten (Bieno sirenje) ewe's milk cheese

Beaten ewe's milk cheese is a traditional autochthonous type of cheese manufactured in Macedonia with a relatively high nutritional value and sensory characteristics. The objective of this study was to characterise the gross composition, proteolysis and volatile profiles of the cheese that is supplied from different retails. The ranges for gross composition were from 31.53% to 42.83% (w/w) for moisture, 41.99% to 50.98% (w/w) for fat‐in‐dry matter, 2.03% to 8.25% (w/w) for salt content and 20.74% to 33.35% (w/w) for protein. Proteolysis results showed various levels of soluble nitrogen ranged from 3.15 to 33.50 for water‐soluble nitrogen (WSN) and from 1.11% to 6.79% for nitrogen soluble in 12% trichloroacetic acid (TCA‐SN). The ranges for total free amino acids were from 1.65 to 8.06 mg Leu/g. Lower proteolysis was observed in the cheese samples due to high salt contents. In total, 65 volatile compounds were identified in Beaten cheese. As a conclusion, the variation of the peptide profile, electrophoresis and volatile contents of Beaten cheeses are due to the lack of standardised manufacture protocols.     

Physicochemical differences between Croatian cheese matured in a lamb skin sack (Sir iz misine) and cheese matured in a rind throughout ripening

The aim of this study was to research differences in physicochemical parameters between Croatian cheese in a lamb skin sack (Sir iz misine) and cheese in a rind throughout ripening. Cheese in a sack had significantly (P < 0.05) lower content of total solids, fat, proteins and salt which showed the ‘protective’ effect of skin sack and higher permeability of natural rind. The water‐soluble nitrogen in the total nitrogen (%TN) and 12% trichloroacetic acid‐soluble nitrogen (%TN) at the end of ripening was significantly (P < 0.05) higher in cheese in a sack than in cheese in a rind which indicates intensive proteolysis in cheese in a sack.     

Coalho Cheese Made with Protease from Thermomucor indicae‐seudaticae N31: Technological Potential of the New Coagulant for the Production of High‐Cooked Cheese

The aim of this study was to explore the use of a new coagulant from Thermomucor indicae‐seudaticae N31 for the manufacture of a high‐cooked starter‐free cheese variety, by evaluating its physicochemical and functional characteristics in comparison to cheeses made with a traditional commercial coagulant. Coalho cheese was successfully produced with the new protease as it exhibited comparable characteristics to the one produced using the commercial enzyme: pH behavior during manufacture; cheese composition; protein and fat recovery; and cheese yield. In addition, during storage, melting was low and not affected by storage time; the increase of TCA 12% soluble nitrogen (% of total nitrogen) was lower than half of that of pH 4.6 soluble nitrogen (% of total nitrogen); concentration of β‐CN significantly decreased, whereas α_s1‐CN concentration was not affected by storage time.     

Utilization of interesterified fat in the production of Turkish white cheese

The chemical, physicochemical, proteolysis, sensory, and texture characteristics of white cheeses made from interesterified fat were examined throughout ripening for 90 days. The water-soluble nitrogen based ripening indexes of cheeses increased throughout the ripening period. However, there were not large quantitative differences between the peptide profiles of the all cheese samples. Cheeses produced by using fully interesterified fat had higher values for hardness, chewiness, and gumminess than that of control cheese (p<0.05). The polyunsaturated to saturated fatty acid ratios of cheeses were increased due to the presence of interesterified fat. The cholesterol values of cheeses decreased at the rate of between 58.83–89.04% depending on interesterified fat addition. In the sensory analysis, similar scores were obtained for both the control cheese and the other cheeses. The results showed that interesterified fat in cheese production could be used to fully or partially replace the milk fat in cheese.     

THE CONTRIBUTION OF HERBS TO THE ACCUMULATION OF HISTAMINE IN "OTLU" CHEESE

The aim of this study was to determine the effect of herbs and the use of raw milk on histamine accumulation in “Otlu” (Herby) cheese during ripening. Cow's milk was used for the cheese production. The milk was divided into two main groups: one was used raw and the other was pasteurized at 65C for 30 min. Each group was further divided into two subparts, one of which was used as control (without herbs), while 2% (w/v) of the herbs were added into the other to produce Herby cheese. All cheeses were ripened at 7C for 90 days. The cheese samples were analyzed in terms of histamine content, titratable acidity, dry matter, salt and degree of ripening on days 5, 30, 60 and 90. Total mesophilic aerobic bacteria (MAB) were also counted during ripening. The use of raw milk and the addition of herb both increased histamine formation in Otlu cheeses (P < 0.05). Moreover, higher water‐soluble nitrogen values, as degree of ripening, were obtained from both raw milk and herb‐added cheeses. The number of MAB was higher in raw cheeses (P < 0.05) and also herb‐added cheeses. The study suggests that the addition of herbs may facilitate histamine formation in Herby cheese.     

Effect of starter cultures on the physico‐chemical and biochemical features in ewe cheese made with extracts from flowers of Cynara cardunculus L

The effect of starter cultures on the physico‐chemical and biochemical features of Los Pedroches cheese made by using Cynara Cardunculus L extracts as vegetable coagulant was assessed. Specimens of cheese containing no starter (vats A and C) and others to which a lactic acid starter was added (vats B and D) were stored either under typical farmhouse ripening conditions (vats A and B) or in a controlled chamber at 14°C and 80% relative humidity (vats C and D) for 90 days. The addition of starter cultures and the ripening conditions where found to have no appreciable effect on the moisture, fat, protein, ash, NaCl, Ca and P contents of the cheese, nor on its water activity; however, it resulted in increased lactic acid contents and lower pH values relative to control specimens throughout ripening. The protein breakdown of the cheeses was assessed in terms of soluble nitrogen, non‐protein nitrogen, aminoacid nitrogen, ammonia nitrogen, soluble tyrosine and tryptophan, and urea‐PAGE. Proteolysis was generally more marked and rapid in cheese containing the lactic starter, the NPN, NH₃ ‐N and soluble Tyr and Trp contents of which were significantly higher than those of the cheese obtained with no starter. The PAGE technique revealed no appreciable differences between the four cheese batches studied; however, it showed the cheese to be more resistant to β‐CN hydrolysis than to α_s‐CN hydrolysis. In general, the flavour and aroma scores were higher in batches obtained with starter cultures and ripened under controlled conditions. © 1999 Society of Chemical Industry     

Characteristics of Miniature Cheddar‐Type Cheese Made by Microbial Rennet from Bacillus amyloliquefaciens: A Comparison with Commercial Calf Rennet

Miniature Cheddar‐type cheeses were produced using microbial rennet from Bacillus amyloliquefaciens (milk‐clotting enzyme [MCE]) or calf rennet (CAR). With the exception of pH, there were no significant differences in gross composition between MCE‐cheese (MCE‐C) and CAR‐cheese (CAR‐C). The pH value of CAR‐C was significantly higher than that of MCE‐C at 40 and 60 d of ripening. The total nitrogen content of the pH 4.6‐soluble fraction obtained from MCE‐C was higher than that obtained from CAR‐C. However, nitrogen content of the 12% TCA‐soluble fraction was similar between CAR‐C and MCE‐C. The extent of α_s1‐casein and β‐casein hydrolysis, measured by urea‐PAGE, was similar in both cheese samples. The hydrolysis of β‐casein was lower than that of α_s1‐casein. Different reverse phase‐high‐performance liquid chromatography peptide profiles of ethanol‐soluble and ethanol‐insoluble fractions were obtained from CAR‐C and MCE‐C. The peptide content in the 2 cheese samples increased throughout ripening; the ratio of hydrophobic to hydrophilic peptides was lower in MCE‐C than in CAR‐C. Compared with CAR‐C, MCE‐C was softer as a result of higher protein hydrolysis. Microbial rennet from B. amyloliquefaciens contributed to higher proteolytic rates, which reduced ripening time.     

Proteolysis,texture and colour of a raw goat milk cheese throughout the maturation

Changes on chemical and textural parameters were studied throughout maturation of PDO Ibores cheese. NCN/TN (non-casein nitrogen/total nitrogen) values were significantly modified (P < 0.001) throughout maturation, and significantly, lower values were observed at day 1 than at day 30, 60 and 90. Non-protein nitrogen/total nitrogen (NPN/TN) was not significantly changed during the ripening process (P > 0.05). Therefore, proteolysis extent (casein degradation and ‘ripening depth’) took place at initial stage and was limited throughout Ibores cheese maturation. In addition, since casein nitrogen decreased during the first month of ripening without a simultaneous increase in NPN/TN, this likely indicates that the large fragments of caseins liberated during this period are not further degraded into smaller products. Primary proteolysis (resulting from the action of endoproteases on caseins) is thus far more important than secondary proteolysis during this period. Moreover, secondary proteolysis remains limited along the 90 days. Polypeptide nitrogen significantly increased at day 30 from casein degradation compared to day 1, while free amino acids (FAA) content significantly increased during maturation process. In addition, hardness and adhesiveness values significantly increased, but cohesiveness and springiness significantly decreased up to day 60. Variables such as dry matter, NCN/TN and polypeptide nitrogen showed high correlations with textural parameters. Principal component analysis (PCA) of variables divided the Ibores cheeses according to their ripening: early, middle or late ripening.     

The effect of different packaging methods on the formation of biogenic amines and organic acids in Kashar cheese

The effects of packaging methods (nonvacuum and vacuum) on biogenic amines (cadaverine, putrescine, tyramine, tryptamine, phenylethylamine, and histamine) and organic acids (citric, lactic, formic, acetic, propionic, and butyric) during storage for 180 d at 4°C were investigated in Kashar cheese. Dry matter, titratable acidity, total nitrogen, water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, free amino group (proteolysis), pH, fat, and acid degree value were also determined. Storage period had a significant effect on all of the biogenic amines. When compared with vacuum packaging, nonvacuum packaging resulted in no large differences among the amounts of biogenic amines. Vacuum-packaged cheeses had more lactic, formic, acetic, and butyric acids than did cheeses packaged without vacuum. Water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, proteolysis, pH, and acid degree values of the cheese samples increased continuously until the end of the ripening in all the samples. No significant change was observed in total nitrogen, dry matter, or fat content within the ripening period, whereas titratable acidity values changed significantly in vacuum-packaged cheese and decreased slightly in the non-vacuum-packaged cheeses. The results of this study showed that storage period and packaging method had significant effects on the quality of Kashar cheese.     

Effects of catechin on the phenolic content and antioxidant properties of low‐fat cheese

The effect of (+)‐catechin on total phenolic content (TPC) and antioxidant properties in low‐fat hard cheese were examined over a 90‐day ripening period at 8 °C. Antioxidant activity (AA) in cheese was measured by ferric reducing antioxidant power, oxygen radical absorbance capacity (ORAC) and 2,2‐diphenyl‐1‐picrylhydrazyl assays and compared with TPC. Catechin retention coefficients in cheese curds were in the range of 0.63–0.75 and decreased the pH of cheese without affecting protein, fat or moisture content. Both TPC and AA increased during the 90‐day ripening period. Oxygen radical absorbance capacity was the most suitable technique for evaluating AA in cheese due to the high correlation with TPC and suitability in both lipophilic and hydrophilic systems.     

Biochemical changes in Picón Bejes-Tresviso cheese,a Spanish blue-veined variety,during ripening

The changes in the gross chemical composition, physico-chemical parameters, nitrogen fractions, caseins and their degradation products, and some fat characteristics were studied during the ripening process of 10 batches of Picón Bejes-Tresviso cheese, a traditional blue-veined variety made in the north of Spain. The values of the different compositional and physico-chemical parameters at the end of ripening did not differ very much from those found in other Spanish and European blue-veined cheeses. The total soluble nitrogen and the non-protein nitrogen increased by factors of 5.4 and 8, respectively, at the end of ripening compared to the values found in cheese curd after salting. The final values of all the nitrogen fractions showed that Picón Bejes-Tresviso cheese undergoes extensive and in depth proteolysis. The intense degradation of the caseins during ripening was confirmed when the caseins and their degradation products were quantified using PAGE techniques. The autooxidation of the fat does not seem very important during the ripening of this cheese. Nevertheless, lipolysis was very intense; the acidity index of the fat values (free fatty acid contents) increased by a factor of about 20 during ripening.     

Effect of some technological parameters on microbiological, chemical and sensory qualities of Civil cheese during ripening

The objective of this research was to determine the effects of different ripening methods [brine salting, dry salting, incorporating with Lor cheese (LR) and vacuum packaging] of Civil cheeses on its microbiological, chemical and sensory properties. Civil cheeses were analysed on the 2nd, 30th, 60th and 90th day of ripening. Chemical compositions of the cheeses were significantly different. While the highest dry matter and titratable acidity values were determined on dry salted cheeses, the highest fat and fat in dry matter contents were found in Civil cheese ripened together with LR. The water-soluble nitrogen and ripening index values were lower in cheese ripened incorporating with LR. Excessive proteolysis was not seen in any of cheese samples. The ripening in different methods affected microbiological and sensory properties of Civil cheese. Panellists preferred vacuum packaging and dry-salting cheeses compared to the other samples on the 90th day of ripening.     

Effects of Penicillium roqueforti and whey cheese on gross composition,microbiology and proteolysis of mould‐ripened Civil cheese during ripening

Four different types of mould‐ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as the secondary starter with and without addition of the whey cheese (Lor); in parallel, secondary starter‐free counterparts were manufactured. Chemical composition, microbiology and proteolysis were studied during the ripening. The incorporation of whey cheese in the manufacture of mould‐ripened Civil cheese altered the gross composition and adversely affected proteolysis in the cheeses. The inoculated P. roqueforti moulds appeared to grow slowly on those cheeses, and little proteolysis was evident in all cheese treatments during the first 90 days of ripening. However, sharp increases in the soluble nitrogen fractions were observed in all cheeses after 90 days. Microbiological analysis showed that the microbial counts in the cheeses were at high levels at the beginning of ripening, while their counts decreased approximately 1–2 log cfu/g towards the end of ripening.     

Accelerated ripening of Ras cheese using cell free extract,freeze- and heat-shocked Leuconostoc spp. cultures

Ras cheese was manufactured with cell free extract, freeze- and heat-shocked cultures of Leuconostoc spp. to enhance flavour development and accelerated ripening. Cheese analysis (pH, acidity, dry matter, fat, protein, soluble nitrogen, volatile acidity, free fatty acids) were carried out for 3 months. No significant differents were observed between the experiment cheeses and control, however, the cheese flavour was enhanced in cheeses with addition of heat treated Leuconostoc cells. Bitter taste was decreased in all experimental cheeses.     

The effect of mendi (Chaerophyllum sp.) on ripening of vacuum-packed herby cheese

The composition, biochemical and sensory parameters of control cheese (without herbs) and four herby cheeses at 0.5, 1, 2 and 3% herb levels (mendi, Chaerophyllum sp.) ripened at 4 ± 1°C for 90 days were compared. As herb levels increased from 0.5 to 3%, dry matter and pH value decreased significantly. However, dry matter of all cheeses showed similar changes during ripening. The salt content of samples changed from 3.44 to 5.47% during ripening. There was a tendency toward slightly higher titratable acidity in cheeses with more added herbs. Ripening index, trichloroacetic acid-soluble nitrogen/total nitrogen, phosphotungstic acid-soluble nitrogen/total nitrogen, and lipolysis values of the cheese samples were affected by adding herbs and by ripening time. The most acceptable sensory score was obtained with 1% added herbs.     

Influence of exopolysaccharide‐producing cultures on the volatile profile and sensory quality of low‐fat Tulum cheese during ripening

The objective of this investigation was to compare the composition and changes in the concentration of volatiles in low‐fat and full‐fat Tulum cheeses during ripening. Tulum cheese was manufactured from low‐ or full‐fat milk using exopolysaccharide (EPS)‐producing or non‐EPS‐producing starter cultures. A total of 82 volatile compounds were identified belonging to the following chemical groups: acids (seven), esters (21), ketones (14), aldehydes (six), alcohols (14) and miscellaneous compounds (20). The relative amounts of acids, alcohols and aldehydes increased in the cheeses made with EPS‐producing cultures during 90 days of ripening. Differences were found in the volatile profile of full‐fat Tulum cheese compared with the low‐fat variant, especially after 90 days of ripening. Exopolysaccharide‐producing cultures changed the volatile profile, and the EPS‐producing cultures including Streptococcus thermophilus + Lactobacillus delbrueckii subsp. bulgaricus + Lactobacillus helveticus (LF‐EPS2) produced cheese with higher levels of methyl ketones and aldehydes than the non‐EPS cultures. In the sensory analysis, full‐fat Tulum cheeses and the cheese produced with the EPS‐producing culture containing Lb. helveticus (LF‐EPS2) were preferred by the expert panel. It was concluded that the use of EPS‐producing starter cultures in the manufacture of low‐fat Tulum cheese had the potential to improve the flavour.