Changes of free amino acid content of Teleme cheese made with different types of milk and culture

The evolution of concentration of free amino acids in Teleme cheese made from sheep, goat or cow milk, using a thermophilic, mesophilic or a mixture of a thermophilic, a mesophilic culture throughout ripening was studied. The total free amino acid (TFAA) content increased at all stages of ripening, regardless of the milk and culture used. In general, the TFAA content was higher in cheeses made from cow’s milk than that of the cheeses made from ewe’s milk; cheese from goat’s milk ranged over intermediate levels. Also, higher concentrations of TFAA were found in cheeses made with the thermophilic than with the mesophilic culture. Cheeses made with the mixture of thermophilic–mesophilic culture ranged over intermediate levels. The results of this study have shown that Leu, Glu, Phe, Val and Lys were the major FAA of Teleme cheese at all stages of ripening, regardless of the type of milk and culture used.     

How milk type,coagulant, salting procedure and ripening time affect the profile of free amino acids in Picante da Beira Baixa cheese

The concentration of total free amino acids (FAA) in Picante cheese increased with ripening time irrespective of the particular protocol used for manufacture (ie ratio of caprine to ovine milks, animal or plant rennet and number of salting steps). The experimental cheeses manufactured with 20% (v/v) caprine milk, coagulated with animal rennet and salted only once exhibited the highest content of total FAA by 120 days of ripening. All four manufacture parameters were statistically significant on the 0.5% level of significance in terms of total concentration of FAA. The dominating free amino acids present in the various experimental cheeses throughout the ripening period were valine, leucine and phenylalanine, each one representing more than 10% (w/w) of the total concentration of FAA. All four manufacture parameters were, in general, statistically significant with respect to the content of every single FAA, with particular emphasis on salting and ripening time. © 1999 Society of Chemical Industry     

Free amino acid content of goat's milk cheese made with animal rennet and plant coagulant

BACKGROUND: Enzymes present in the flowers of Cynara cardunculus (cyprosins) are used in the production of some traditional Spanish and Portuguese cheeses, replacing animal rennet. The aim of this work was to study the changes that take place in free amino acids during the ripening of a goat's milk cheese (Murcia al Vino) manufactured with plant coagulant (PC) or animal rennet (AR). RESULTS: The total free amino acid (TFAA) concentration increased during ripening, with Ile, Val, Ala, Phe, Gaba, Arg and Lys representing more than 50% of the TFAA content at 60 days in both types of cheese. The TFAA concentration was significantly higher in cheeses made with PC (854 mg 100 g^?1 total solids (TS)) than those made with AR (735 mg 100 g^?1 TS). The concentration of most free amino acids, especially His, Ser, Gln, Thr, Ala, Met and Ile, was higher in the PC cheese. CONCLUSION: Cheese made using PC as coagulant presented higher contents of free amino acid throughout the ripening period than cheese made using AR. Therefore we can conclude that the use of PC to produce Murcia al Vino goat's cheese would accelerate the ripening process as a result of increased cyprosin proteolytic activity. Copyright © 2011 Society of Chemical Industry     

Ripening of cheese made from full concentrated milk retentate with and without peptidase addition

The aim of this study was to determine ripening of cheese made from full concentrated (FC) milk retentate with and without peptidase addition. No free amino acids (FAAs) were found in FC cheese at the end of ripening. However, added peptidase increased FAA formation. Protein and peptide profile analysis showed that FAA and small peptides increased during ripening and therefore some secondary proteolysis occurred. Added peptidase increased D‐lactic acid formation during ripening of cheeses. This kind of changes in lactose fermentation should be considered during developing the making cheese with different enzyme addition.     

Proteolysis, lipolysis, volatile compounds, texture, and flavor of Hispánico cheese made using frozen ewe milk curds pressed for different times

Hispánico cheese is manufactured in Spain from a mixture of cow and ewe milk. Production of ewe milk varies throughout the year, with a peak in spring and a valley in summer and autumn. To overcome this seasonal shortage, curd from spring ewe milk may be frozen and used for cheese manufacture some months later. In the present work, ewe milk curds pressed for 15, 60, or 120 min were held at −24°C for 4 mo, thawed, cut to 1-mm pieces, and mixed with fresh cow milk curd for the manufacture of experimental Hispánico cheeses. Control cheese was made from a mixture of pasteurized cow and ewe milk in the same (80:20) proportion. Cheeses, made in duplicate experiments, were analyzed throughout a 60-d ripening period. No significant differences between cheeses were found for lactic acid bacteria counts, dry matter content, hydrophilic peptides, 47 out of 68 vol.tile compounds, texture, and flavor characteristics. On the other hand, differences of minor practical significance between experimental and control cheeses, unrelated to the use of frozen ewe milk curd or the pressing time of ewe milk curd, were found for pH value, aminopeptidase activity, proteolysis, hydrophobic peptides, free amino acids, free fatty acids, and the remaining 21 vol.tile compounds. It may be concluded that the use of frozen ewe milk curd in the manufacture of Hispánico cheese does not alter its main characteristics.     

Free amino acid profile during ripening of ewe's milk cheese from the Croatian island Krk

The aim of this study was to determine the content of free amino acids (FAA) and their ratio in ewe's milk cheese from the island Krk during its ripening. FAA content was determined by reversed phase HPLC (RP‐HPLC) of cheese aqueous/ethanol extracts after FAA were transformed into their 6‐aminoquinolyl‐N‐hydroxysuccinimidyl carbamate derivatives. Their concentration increased during ripening, reaching the value of 5% in cheese dry matter. The dominant FAA were glutamic acid>leucine>valine>aspartic acid>phenylalanine>serine>proline, and higher content of nonessential vs essential FAA was revealed. Krk cheese has, in relation to other cheeses, higher values for glutamic acid/leucine, glutamic acid/phenylalanine, glutamic acid/proline and smaller values for leucine/aspartic acid, valine/aspartic acid, phenylalanine/aspartic acid ratios, while other ratios are comparable to those of other hard ovine cheeses.     

Evolution of free amino acid content during ripening of Mahon cheese

Evolution of free amino acids (FAA) during ripening (10–300 days) of five batches of Mahon cheese was studied; three batches were made from raw milk and two from pasteurized milk. Major FAA were GLU, VAL, LEU, LYS and PHE (43–67% of total FAA). Relative THR, SER, GLU and GLY contents significantly increased during ripening whereas LEU, PHE and ORN decreased. GLU, ILE, SER, THR, GLY and PHE varied during ripening according to a zero order reaction (r² > 0.99). Principal component analysis showed that the first principal component could be considered representative of the ripening time. The most ripened cheeses showed high GLU, GLY, SER and THR contents and the less ripened cheeses presented high ORN, LEU, PHE and ALA contents. The second component distinguished between cheeses made with pasteurized milk (with high ASN and GLN contents) and raw milk. Indigenous microflora of raw milk showed a strong influence on the proteolytic activity in Mahon cheese.     

Innovative Caciocavallo cheeses made from a mixture of cow milk with ewe or goat milk

This study assessed and compared the physicochemical, microbiological, and sensorial characteristics of Caciocavallo cheeses, made from cow milk and a mixture of cow with ewe or goat milk, during ripening. Different cheese-making trials were carried out on an industrial scale following the standard procedure of pasta filata cheeses, with some modifications. The percentage of the different added milk to cow milk influenced compositional and nutritional characteristics of the innovative products, leading to a satisfactory microbiological and sensorial quality.     

Texture and flavour development in Ras cheese made from raw and pasteurised milk

Texture, proteolysis and flavour development in Ras cheeses made from raw or pasteurised milk with two different thermophilic lactic cultures were monitored during ripening. Results showed that at day 1 of manufacture, the moisture content and pH were lower in raw milk cheese than in pasteurised milk cheeses. Levels of water-soluble nitrogen, casein breakdown, free amino groups and free fatty acids were higher in cheese made from raw milk than in that made from pasteurised milk. Textural characteristics, such as hardness, cohesiveness and chewines, increased in all treatments during the first 60 days of ripening due to the reduction in the moisture level during the second stage of salting (dry salting during the first 60 days of ripening). Cheese made from raw milk received the highest texture and flavour scores by panellists.     

Proteolysis during ripening of Manchego cheese made from raw or pasteurized ewes' milk. Seasonal variation

Changes in nitrogen compounds during ripening of 40 batches of Manchego cheese made from raw milk (24 batches) or pasteurized milk (16 batches) at five different dairies throughout the year were investigated. After ripening for six months, degradation of p-kappa- and beta-caseins was more intense in raw milk cheese and degradation of alpha(s2)-casein in pasteurized milk cheese. Milk pasteurization had no significant effect on breakdown of alpha(s1)-casein. Hydrophobic peptide content did not differ between raw and pasteurized milk cheese, whereas hydrophilic peptide content was higher in raw milk cheese. There were no significant differences between seasons for residual caseins, but hydrophobic peptides were at a higher level in cheese made in autumn and winter and hydrophilic peptides in cheese made in winter and spring. Raw milk cheese had a higher content of total free amino acids and of most individual free amino acids than pasteurized milk cheese. The relative percentages of the individual free amino acids were significantly different for raw milk and pasteurized milk cheeses. The relative percentages of Lys and lie increased, while those of Val, Leu and Phe decreased during ripening. There were also seasonal variations within the relative percentages of free amino acids. In raw milk cheeses, Asp and Cys were relatively more abundant in those made in autumn, Glu and Arg in cheeses made in winter, and Lys and Ile in cheeses made in spring and summer. Biogenic amines were detected only in raw milk cheese, with the highest levels of histamine, tryptamine and tyramine in cheeses made in spring, winter and spring, respectively.     

Volatile composition and sensory properties of industrially produced Idiazabal cheese

The volatile composition and sensory properties of industrially produced Idiazabal cheeses made from ewes’ raw milk (RM) or pasteurised milk (PM) and with addition of different starter cultures were compared. Cheeses were analysed at 90 and 180 d of ripening. Acids were the major volatile compounds in RM cheeses. Methyl ketones were the major volatile compounds in PM cheeses at 90 ripening days. However, the content of acids strongly increased with ripening whereas the content of ketones decreased in PM cheeses. The concentration of esters was higher in RM cheeses than in PM cheeses. No differences were found in the content of alcohols. Most aldehydes, hydrocarbons, terpenes and furans identified were minor volatile compounds in both RM and PM cheeses. In RM cheeses, characteristic sensory attributes for the aroma of Idiazabal cheese were present at 3 months, whereas in PM cheeses those desirable sensory attributes did not appear until 6 months of ripening.     

Specific effect of high-pressure treatment of milk on cheese proteolysis

The extent of primary and secondary proteolysis of cheeses made from raw (RA), pasteurized (PA, 72 degrees C, 15 s) or pressure-treated (PR, 500 MPa, 15 min, 20 degrees C) goats' milk was assessed. Modifications in cheese-making technology were introduced to obtain cheeses with the same moisture content, and thus studied per se the effect of milk treatment on cheese proteolysis.The PR milk cheese samples were differentiated from RA and PA milk cheeses by their elevated beta-lg content, and by the faster degradation of alphas1-, alphas2- and beta-CN throughout ripening. Non-significant differences were found in either pH 4.6 soluble-nitrogen or trichloracetic acid soluble-nitrogen contents of cheeses. However, the pasteurization of milk decreased the free amino acid production in cheese. The RA milk cheeses had the highest amount of proline and the lowest concentrations of serine, tyrosine, arginine and alpha-aminobutyric acid, whereas PR milk cheese showed higher levels of arginine.     

Changes during ripening in chemical composition,proteolysis, volatile composition and texture in Kashar cheese made using raw bovine,ovine or caprine milk

Kashar cheeses were manufactured from pure ovine (OV), bovine (BV) and caprine (CP) milk, and the chemical composition, cheese yield, proteolysis, hardness, meltability and volatile composition were studied during 90 days. Gross chemical composition, cheese yield and level of proteolysis were higher in OV cheeses than those of BV or CP cheeses. Glu, Val, Leu, Phe and Lys were the most abundant free amino acids (FAA) in the samples, and the concentrations of individual FAA were at the highest levels in OV cheeses with following BV and CP cheeses. Urea‐PAGE patterns and RP‐HPLC peptide profiles of the BV cheeses were completely different from the small ruminants’ milk cheeses (OV or CP). Higher and lower hardness and meltability values were observed in CP cheeses, respectively. OV cheeses resulted in higher levels of the major volatile compounds. In conclusion, the Kashar cheese made using OV milk can be recommended due to high meltability, proteolysis and volatiles.     

Amino acid and soluble nitrogen evolution throughout ripening of Serra da Estrela cheese

Four batches of Serra da Estrela cheese originating from as many dairy farms were sampled throughout the ripening period, and assayed for the evolution of free amino acid (FAA) content, total nitrogen content (TN), water-soluble nitrogen content (WSN), trichloroacetic acid-soluble nitrogen content (TCASN) and phosphotungstic acid-soluble nitrogen content (PTASN). The WSN content increased from 1% (on the day of manufacture) up to 43% of TN by 180 d of ripening, thus reflecting the intense proteolytic activity of the enzymes contributed by the plant coagulant utilized. The TCASN was also found to be high in this cheese by the end of ripening (16–20%), which suggests a high extent of FAA release throughout maturation. The major FAA by 180 d of ripening were Glu, Val, Leu and Lys, representing 56–70% of the total in all four dairies sampled. Cheeses produced from refrigerated milk possessed higher amounts of γ-amino-n-butyric acid (Gaba) and lower amounts of Glu when compared with those manufactured with non-refrigerated milk.     

Consumer acceptance and sensory evaluation of Monti Dauni Meridionali Caciocavallo cheese

Twelve Caciocavallo cheeses were collected from 6 factories (A, B, C, D, E, F) located in the Monti Dauni Meridionali area (Southern Italy) that adopted different protocols for cheese production. A total of 160 consumers were involved in the sensory evaluation of Caciocavallo cheese after 180 d of ripening. Cheese attributes were used to describe the flavor, texture, and appearance of cheeses. The highest scores for the shiny attribute were assigned to cheeses B, C, and E, whereas color intensity was the highest in cheeses B, D, and F. Strength, salty, and piquant attributes were higher in cheeses F and A because of the use of raw milk (F), rennet paste (A), and percentage of salt in the brine (A, F). Consumers perceived a more granular structure during the second half of chewing of Caciocavallo cheese F, as evidenced by the highest value for the grainy attribute. A positive correlation was found between overall flavor and odor intensity and water-soluble nitrogen, low molecular weight peptides, and free fatty acids and between piquant and butyric and caproic acids. A principal components analysis applied to the sensory attributes accounted for 65% of the total variance. The score plot showed that cheeses F and A were located in a well-defined zone of the plot, with cheeses in this zone displaying higher levels of strength, piquant, and salty attributes. The preference test assigned 40% of the preference to Caciocavallo cheese A, 38% to cheese F, 9% to cheese E, 8% to cheese D, and 7% to cheeses B and C. Sensory evaluation of Monti Dauni Meridionali Caciocavallo cheeses is a useful analysis to highlight the principal attributes able to influence consumers' liking that are related to biochemical features of the cheese.     

Triacylglycerol composition of protected designation of origin cheeses during ripening. Authenticity of milk fat

Triacylglycerol (TAG) composition by carbon number in 2 protected designation of origin cheeses, Mahón (cheese from cow milk) and Manchego (cheese from ewe milk) that were manufactured by 3 different producers was analyzed during cheese ripening using gas chromatography with a short capillary column. The TAG composition at different times during cheese ripening was also analyzed in cheeses from different batches produced at the same plant. Lipolysis levels in the Mahón and Manchego cheeses during ripening were low; free fatty acid values ranged from 2,500 to 4,000 ppm at the end of ripening. The TAG composition did not change significantly during ripening. The TAG values obtained from each cheese sample were substituted into the multiple regression equations that have been proposed to detect foreign fats in milk fat. The values obtained using the equations for bovine (proposed by the European Union) and ovine milk (proposed by our laboratory) were within the normal range. Accordingly, these equations can be considered useful for detecting foreign fat in these cheeses during the ripening period contemplated during this study.     

Lipolysis,proteolysis and sensory properties of ewe’s raw milk cheese (Idiazabal) made with lipase addition

In this paper, we describe the effect of the addition of pregastric lipase on the composition and sensory properties of Idiazabal cheese. Free fatty acids (FFA), partial glycerides, free amino acids (FAA), gross composition and sensory characteristics were determined at different ripening times in cheeses manufactured with three different amounts of commercial animal lipase or with lipase-containing artisanal lamb rennet paste. The addition of lipase increased the content of total FFA, particularly of short-chain FFA, and that of total partial glycerides in cheeses. Unexpectedly, lipase utilization significantly affected total FAA concentration, which decreased in cheeses elaborated with high lipase amount. In general, Val, Glu and Leu were the major FAA, and their concentrations depended, mainly, on ripening time. Lipase addition had significant influence on the sensory characteristics of the cheeses, increasing scores for most of the flavour and odour attributes of the cheese. Principal component analysis (PCA) was done including dry matter, FFA, FAA, partial glycerides and odour and flavour attributes of the cheeses. It indicated that aroma and flavour parameters of Idiazabal cheese and the content of short-chain FFA and diglycerides were highly correlated to first principal component (PC1), while texture parameters, compositional variables and FAA were correlated to the second principal component (PC2).     

Proteolytic and lipolytic changes during the ripening of León raw cow's milk cheese, a Spanish traditional variety

Proteolytic and lipolytic changes were studied throughout ripening of five batches of León cow's milk cheese, a traditional variety made in the north of Spain. Total soluble nitrogen, non-protein nitrogen, oligopeptides nitrogen, amino nitrogen and ammonia nitrogen fractions increased slightly during the ripening process. The final values of these nitrogen fractions indicate that this cheese undergoes a very slight proteolysis as much in extent as in depth. This weak protein degradation is corroborated when the caseins and their degradation products were quantified by electrophoresis. β-Casein stayed practically intact throughout the ripening process and only 10% of α_s-casein became degraded. The content of total free amino acids increased progressively but in a slightly increased way during ripening, reaching final average values of 592 mg (100 g)⁻¹ of total solids. The most abundant free amino acid at the end of ripening was lysine, followed by leucine, glutamic acid, tryptophan, valine and phenylalanine. The acidity index of the fat values increased during ripening by a factor of 4.39. The final values of this parameter are in the range of those observed in other cow's milk cheeses ripened by bacteria. The content in total free fatty acids underwent an increase throughout ripening reaching final average values of 6669 ppm. The most abundant free fatty acid at the end of ripening was oleic acid followed by butyric and palmitic acids. The high content of short-chain fatty acids is outstanding, specially that of butyric acid.     

Effects of genetic type,stage of lactation,and ripening time on Caciocavallo cheese proteolysis

The objective of this experiment was to evaluate the effects of genetic type, stage of lactation, and ripening time on proteolysis in Caciocavallo cheese. One hundred twenty Caciocavallo cheeses made from the milk of 2 breeds, Italian Brown and Italian Holstein and characterized by different stages of lactation were obtained and ripened for 1, 30, 60, 90, and 150 d. Cheese proteolysis was investigated by ripening index (ratio of water-soluble N at pH 4.6 to total protein, %) and by the study of degradation of the protein fractions (α_S1-, β-, and para-κ-casein), which was determined by densitometric analysis of isoelectric focusing results. The statistical analysis showed a significant effect of the studied factors. Ripening index was higher in Italian Brown Caciocavallo cheese and in cheeses made with early lactation milk, whereas casein solubilization was greater in the first 2 mo of ripening. Isoelectric focusing analysis of cheese samples during ripening showed extensive hydrolysis of caseins. In particular, the protein fraction that underwent major degradation by proteolytic enzymes was α_S1-casein, followed by β-casein, whereas para-κ-casein was less degraded. Italian Brown cheese showed a lower residual quantity of β- and para-κ-casein, whereas Italian Holstein cheese showed a lower residual quantity of α_S1-casein. In addition, significant interactions of both first and second order were found on both ripening index and degradation of protein fractions. This study demonstrated that the analyzed factors influenced proteolysis of Caciocavallo cheese, which forms the basis of new knowledge that could lead to the production of a pasta filata cheese with specific characteristics.     

Effect of the inclusion of artichoke silage in the ration of lactating ewes on the properties of milk and cheese characteristics during ripening

The effect of including artichoke silage in the rations of dairy ewes on milk characteristics and biochemical changes of ripened cheeses was evaluated. Four groups of lactating ewes were fed rations containing 0, 10, 20, or 30% artichoke silage on a dry matter basis. Bulk milk samples were collected 3 times during the feeding period, and semi-hard cheeses were manufactured and sampled during ripening. Milk composition and cheese yield were not affected by diet. Inclusion of 20 and 30% artichoke silage reduced the firmness of the curds at a level only detected by the Gelograph (Gelograph-NT, Gel-Instrumente, Thalwil, Switzerland) probe. Inclusion of artichoke silage in ewes’ diet decreased fat and total free fatty acids content of these cheeses and increased total free amino acids content. Despite the effect of diet on cheese ripening characteristics, the overall sensory scores for cheeses corresponding to artichoke silage diets were statistically higher than those for the control cheeses.