Influences of rennet and container types on proteolysis of traditional Kurdish cheese during the ripening (original) (raw)
Related papers
International Dairy Journal, 2004
Port Salut Argentino cheeses were studied at different ripening times (1, 6, 13, 27 and 56 days) and two sampling zones (central and external). Moisture content, salt concentration, water-insoluble fraction, water-soluble fraction, and free amino acids in the sulphosalicylic acid-soluble fraction were analysed. Moisture and salt contents at the beginning of ripening were higher in the external zone than in the central zone (51 and 46% w/w moisture, 0.95 and 0.25% w/w NaCl, respectively). Cheeses reached a uniform salt content but not a uniform moisture content during the 56 days of ripening. The hydrolysis of a s1-casein during cheese ripening was modelled using first-order kinetics. The kinetics constant of a s1-casein degradation was 0.017 day-1. Most of the watersoluble peptides increased during cheese ripening, particularly from day 13 of ripening. Free amino acids also increased from day 13 of ripening. Amino acids that characterised the ripening of Port Salut Argentino cheese were leucine, lysine, asparagine, phenylalanine, threonine, tyrosine, glutamine and valine. Proteolysis increased in both zones during ripening and there was no appreciable difference between zones using any of the methods used for investigating proteolysis.
1994
The purpose of the present study was to elaborate methods for the detailed examination of proteolysis pathways in cheese (reviewed in Chapter 1) and to demonstrate their usefulness. Many techniques, including solvent fractionation, chromatographic separation and electrophoresis have been used previously and were revisited in this study. Gel electrophoresis can be a powerful technique and was examined in detail. The methods investigated were: 1) a slab gel system using the apparatus of the E-C Apparatus Corporation and a polyacrylamide gel in a Tris-EDTA-borate buffer at alkaline pH and containing urea; 2) a mini-slab gel system using the Bio-Rad mini-Protean II apparatus, a polyacrylamide stacking and resolving gel with a discontinuous (Tris-chloride/Tris-EDTA-borate) buffer system that contained urea; 3) a mini-slab gel system using the Bio-Rad mini-Protean II apparatus, a polyacrylamide stacking and resolving gel and acetic acid-ammonium acetate buffers at acidic pH that contained urea; 4) a mini-slab gel system using the Bio-Rad mini-Protean II apparatus, a polyacrylamide gel with a stacking and resolving gel in Tris-HCl buffers containing sodium dodecyl sulphate (SDS) and a Tris-chloride-glycine electrode buffer. The mini-slab alkaline urea polyacrylamide gel electrophoresis (PAGE) method was considered to be the most suitable for monitoring the loss of intact casein during cheese ripening. However, SDS-PAGE gave good resolution of para-K-casein, ~-lactoglobulin and a-lactalbumin and it could therefore be used for the analysis of cheese in which whey proteins have been incorporated or for monitoring the brealcdown of para-K-casein (Chapter 4) in cheese. Two-dimensional PAGE revealed the presence of more bands than were visible using any single method of electrophoresis. Traces of protein were found to lie beneath the a 11-casein band and this explained why, even after considerable proteolysis, some a 11-casein appeared to remain. Storing cheese samples in such a way that there is a minimum of further change was examined using several different storage methods and temperatures, including storage as: freeze-dried powder at 4°C in the dark, frozen at-9,-16,-35,-75 and-100°C, and dissolved in 6 M urea solution and stored at 4 and-l6°C. The trial ran for 6 months and involved the multiple sampling and detailed analysis of three Cheddar cheeses by reversed phase fast protein liquid chromatography (RP-FPLC) for the water-soluble fraction (WSF) and alkaline urea-PAGE for the protein fraction.
Journal of Agricultural and Food Chemistry, 1995
The proteolytic activity of calf rennet on goat p-casein was studied under various technological parameters which affect cheese ripening (temperature, pH, salt and calf rennet concentrations). Electrophoretic studies showed that this protein hydrolyzes to give five products; P-I-P-V, in order of appearance and increasing electrophoretic mobility under alkaline conditions. In an aqueous solution, p-casein was optimally hydrolyzed to p-I at pH 6.2, p-I1 at pH 3.8, and p-I11 at pH 15.4. p-IV products were formed at all pH values, and p-V was optimally formed at pH 55.0. Both p-IV and p-V were formed in very small quantities. Proteolysis of p-casein by calf rennet is reduced by the addition of 5% NaC1, while the addition of 15% NaCl leaves only traces of ,&I. The polypeptides @-I, p-11, and p-I11 produced from caprine and bovine p-caseins gave identical results with PAGE, which suggests that the calf rennet attacks the same regions described as susceptible to bovine p-casein cleavage by chymosin.
Proteolysis in the Beyaz (White) Cheese Produced From Various Milk
Tarım Bilimleri Dergisi, 2018
The aim of this study was to investigate proteolysis development and peptide changes during the storage period of Beyaz (White) cheese which is produced from various types of milk, such as sheep, goat and cow milk. Three types of cheese were produced using goat, sheep and cow milk, and all analyses were performed in duplicate. Proteolytic changes were observed in cheese on the 1 st day, 3 rd , 6 th , and 9 th month. The total protein was investigated through using water-soluble nitrogen, soluble nitrogen in 12% Trichloroacetic acid (TCA), soluble nitrogen in 5% Phosphotungstic acid (PTA), and free amino acids. Proteolytic changes and peptide formations were observed during maturation by HPLC. While the total protein was 14.33% in sheep Beyaz cheese on the 1 st day, this value decreased during the maturation period and reduced to 6.9% in the 9 th month. These values were 13.55 and 7.95 for cow cheese and 16.30% and 7.95% for goat cheese, respectively. The water-soluble protein value increased during the maturation period. The value was 1.41% in sheep cheese on the 1 st day, and increased to 6.24% in the 9 th month. These values were 2.16% and 4.92% for goat cheese, and 1.79% and 8.53% for cow cheese, respectively. 12% TCA soluble nitrogen had been 0.211% at the beginning and was 0.51% in the 9 th month. The ripening value based on 12% TCA changed between 9.41%-47.22%. 5% PTA soluble nitrogen changed between 0.075%-0.25 %. The ripening value based on 5% PTA changed between 3.34-23.14. Changes in concentration of total free amino acids during cheese ripening were tracked. In water soluble extracts of cheese, the presence of free amino groups in all ripening stages was detected. It is observed that amino acids and smaller peptides-have concentration significantly (P<0.05) increased during ripening. The total free amino acid was found as 0.24 mg lysine g-1 in sheep cheese, 0.215 mg lysine g-1 in goat cheese and 0.208 mg lysine g-1 in cow cheese at the end of ripening period.
Proteolysis, texture and colour of a raw goat milk cheese throughout the maturation
European Food Research and Technology
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.
Evaluation of Serpa cheese proteolysis by nitrogen content and capillary zone electrophoresis
International Journal of Dairy Technology, 2003
Proteolysis of Serpa cheese produced traditionally (B) and semi-industrially (C) was evaluated for the first time by determination of nitrogen content and capillary zone electrophoresis (CZE). A citrate dispersion of cheese was fractionated to determine the nitrogen in pH 4.4, trichloroacetic and phosphotungstic acid soluble fractions respectively). The pH 4.4-SN was significantly higher for B ( P < 0.001), while TCA-SN was significantly higher for C ( P < 0.001). PTA-SN was also higher for C but at 60 days ripening no significant difference was found between B and C. Degradation of α s1 -and β -caseins evaluated by CZE was in good agreement with the maturation index (pH 4.4-SN/TN).
Proteolysis of Livanjski cheese during ripening
Journal of Central European Agriculture, 2016
Livanjski cheese belongs to the group of hard cheeses which is traditionally produced in Livno (Bosnia and Herzegovina). Proteolytic changes during the ripening of Livanjski cheese have not been investigated extensively. The aim of this paper was to determine its proteolytic changes during the different stages of ripening. Five Livanjski cheeses (from raw cow's or a mixture of sheep's and cow's milk) were observed during the ripening to evaluate its typical proteolytic profile. An electophoretic profile of Livanjski cheese was determined by Urea-polyacrylamide gel electrophoresis (urea-PAGE) and a densitometric evaluation of the urea-PAGE gels was performed using a densitometer. The water-soluble nitrogen fraction in the total nitrogen (WSN %TN) and the 12%-TCA-soluble nitrogen fraction in the total nitrogen (TCA-SN %TN) of the cheese were determined using the Kjeldahl method. Degradation of α s1-casein by chymosin caused a significant decrease (P < 0.05) of relative content of this protein in Livanjski cheese at the sixth week point of ripening. Due to the activity of chymosin on αs1-casein, αs1-I-casein and αs1-II-casein developed, which caused a significant increase (P < 0.05) of Index alpha. The relative ratio of β-casein significantly decreased (P < 0.05) during ripening leading to a significant accumulation (P < 0.05) of degraded product (sum γ 1-casein, γ 2-casein and γ 3-casein). These proteolytic changes caused a significant increase (P < 0.05) of Index betta. Accumulation of medium, small peptides and amino acids caused a significant (P < 0.05) increase of the relative content of WSN %TN and TCA-SN %TN. In general, proteolysis of Livanjski cheese during ripening was moderate probably due to the low moisture content and low water activity, although it was produced from raw milk. Taking into account that the ratio β-casein : α s1-casein at the end of ripening was 1.46, it could be concluded that degradation of α s1-casein could be the indicator of the maturity of Livanjski cheese. Due to that Livanjski cheese could be classified as "α-type of ripening" cheese.
Proteolytic Changes During Ripening Of Kučki Cheese
Contemporary Agriculture, 2023
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 10 th , 20 th and 30 th 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.