Study of the chemical composition,proteolysis, volatile compounds,and textural properties of industrial and traditional Beaten (Bieno sirenje) ewe milk cheese

The objective of this study was to determine the gross composition, proteolysis, and volatile and texture profiles during ripening of industrial (IND) and traditional (TRD) Beaten (Bieno sirenje) cheeses made by using ewe milk. In the course of the analyses, statistical differences were determined in some physicochemical parameters, nitrogen fractions, and total free amino acid levels between TRD and IND types of cheese. Higher levels of proteolysis were observed in IND cheeses than in TRD cheeses during ripening. Levels of residual β- and α_s-caseins were 72.2 and 48.7%, respectively, in 180-d-old TRD cheeses. However, the residual levels were 52.8% for β-casein and 18% for α_s-casein in IND cheeses. Similar differences were noted for the reversed-phase HPLC peptide profiles of 2 types of cheeses. Also, higher concentrations of peptides were eluted in IND cheeses than in TRD cheeses during ripening. A total of 73 volatile compounds, including alcohols (16), esters (17), acids (14), terpenes (7), ketones (5), aldehydes (4), and miscellaneous (10) were identified. The IND cheeses contained higher levels of carboxylic acids, esters, alcohols, and terpenes than the TRD cheeses; however, the same levels of methyl ketones were determined in the 2 types of cheeses at the end of ripening. These may be due to some differences (e.g., pasteurization and scalding temperature, among other factors) in the manufacture of the 2 types of Beaten cheeses. The textural profile of Beaten cheeses showed that TRD production method resulted in firmer, less fracturable, and stiffer cheeses than the IND production method. In conclusion, the results suggest that the use of industrial production method (pasteurization of cheese milk and curd scalding at 70°C) in the manufacture of Beaten ewe milk cheese enriched the volatile profile of the cheese.     

Chemical and microbiological status and volatile profiles of mouldy Civil cheese,a Turkish mould‐ripened variety

The objective of this study is to characterise the gross chemical and microbiological status and identify the volatile compounds of mouldy Civil cheeses. A total of forty‐one samples were surveyed, and gross compositional status of the cheeses was (as mean values): 6.5 for pH, 6.2% for fat‐in‐dry matter, 51.8% for moisture and 15.3% for water‐soluble nitrogen (as% of total nitrogen). Chemical composition of the cheese samples varied widely. Mouldy Civil cheese has similar pH values and moisture contents when compared with blue‐type cheeses, but it has distinct feature for fat contents. The microbiological counts of the samples were found to be high and some samples contained coliform bacteria. A total of 95 volatiles, including esters (28), acids (6), ketones (12), aldehydes (3), alcohols (15), terpenes (10), sulphur compounds (3) and miscellaneous (18), were identified in the volatile fractions of the cheeses, and principal volatile groups were esters, alcohols and ketones.     

Ripening of traditional Örgü cheese manufactured with raw or pasteurized milk: Composition and biochemical properties

The changes in composition and some biochemical properties of Örgü cheeses made from raw (RMC) and pasteurized (PMC) cow milk were investigated during a 90-day ripening period. The average contents of total solids (TS), protein, water soluble nitrogen (WSN), trichloro-acetic acid soluble nitrogen (TCA-SN) and acid degree value (ADV) were lower, while salt and salt in TS were found to be statistically higher in PMC than RMC (P < 0.05). In addition, in both RMC and PMC, the TS and protein contents were decreased as compared to an increase in salt, salt in TS, WSN and TCA-SN contents, and ADV, during ripening (P < 0.05). The evaluation of WSN, TCA-SN and ADV shows that these two experimental Örgü cheese types undergo little proteolysis and lipolysis. On the other hand, acidity development was observed to be high in both before curdling and in cheese made from raw milk during 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.     

Electrophoretic patterns and thin-layer chromatography of common cheeses in Egypt: Comparison and quantification

The extent of cheese ripening and the type of proteolysis and lipolysis of common cheeses in Egypt were measured by concentration of each of soluble tyrosine; soluble trypophan; amino N; soluble N/total N; total volatile fatty acids and free fatty acids, and by quantitative gel electrophoresis and thin-layer chromatography. The effects of concentration-related factors (e.g. moisture, salt and pH) on cheese protein and fat hydrolysis were also studied.

The results showed that, as a heterogeneous group of cheese, differences were marked in gross chemical composition and both the extent of cheese ripening and the relative proportions of protein, fat and their degradation products. Among the selected cheeses, ras cheese has higher values of ripening indices, while kariesh cheese has lower values. Increasing the salt content of mish cheese caused an inhibition in degradation of its protein and fat.

The principal protein regions in electrophoretic patterns and fractions of fat in TLC patterns were similar in number and relative mobility. In most of the cheeses, _s-casein was degraded more extensively than β-casein, while the whole of the γ-caseins were resistant to further hydrolysis. Also, there was close correlation between _s-casein and its degradation products. In spite of the absence of significant relationships between the soluble nitrogen and the relative amounts of unattached _s-, β-, and γ-caseins, the amino nitrogen and soluble tyrosine and tryptophan were in close correlation with _s- and β-caseins and their degradation products.

A positive relationship was noted between pH (from 4·40 to 5·85) and both protein and fat hydrolysis. The fat of roquefort cheese was more hydrolysed than other cheeses; however, the fat of the soft cheeses was less hydrolysed. Moreover, negative and highly significant correlations between triglycerides and their degradation by both TLC and chemical analysis were obtained.     

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.     

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.     

Effect of curd washing on cheese proteolysis,texture, volatile compounds,and sensory grading in full fat Cheddar cheese

Curd was washed to varying degrees during Cheddar cheese manufacture, by partial replacement of whey with water at the early stages of cooking, to give target levels of lactose plus lactic acid in cheese moisture of 5.3 (control), 4.5, 4.3 and 3.9% (w/w). The cheeses were matured at 8 °C for 270 days. While curd washing had little effect on composition or the mean levels of proteolysis (as measured by pH 4.6 soluble nitrogen and levels of free amino acids), it led to cheeses that were, overall, firmer and less brittle. Curd washing resulted in cheeses having lower levels of some volatile compounds, and being less acid, more buttery, sweeter, saltier and creamier than non-washed cheeses that had more 'sweaty', pungent and farmyard-like sensory notes. The results suggest that curd washing during Cheddar manufacture may be used as a means of creating variants with distinctive flavour profiles.     

Texture,flavor, and sensory quality of buffalo milk Cheddar cheese as influenced by reducing sodium salt content

The adverse health effects of dietary sodium demand the production of cheese with reduced salt content. The study was aimed to assess the effect of reducing the level of sodium chloride on the texture, flavor, and sensory qualities of Cheddar cheese. Cheddar cheese was manufactured from buffalo milk standardized at 4% fat level by adding sodium chloride at 2.5, 2.0, 1.5, 1.0, and 0.5% (wt/wt of the curd obtained). Cheese samples were ripened at 6 to 8°C for 180 d and analyzed for chemical composition after 1 wk; for texture and proteolysis after 1, 60, 120, and 180 d; and for volatile flavor compounds and sensory quality after 180 d of ripening. Decreasing the salt level significantly reduced the salt-in-moisture and pH and increased the moisture-in-nonfat-substances and water activity. Cheese hardness, toughness, and crumbliness decreased but proteolysis increased considerably on reducing the sodium content and during cheese ripening. Lowering the salt levels appreciably enhanced the concentration of volatile compounds associated with flavor but negatively affected the sensory perception. We concluded that salt level in cheese can be successfully reduced to a great extent if proteolysis and development of off-flavors resulted by the growth of starter and nonstarter bacteria can be controlled.     

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.     

Influence of ripening on proteolysis and lipolysis of Murcia al Vino cheese

The aim of this study was to evaluate the influence of five different manufacturers and two ripening periods on the proteolysis and lipolysis patterns of Murcia al Vino goat cheese. The manufacturers significantly affected the water activity (a_w), pH, dry matter and fat content, several nitrogen fractions: water soluble nitrogen (WSN), trichloroacetic acid (12% w/v) soluble nitrogen (TCASN) and phosphotungstic acid (5% w/v) soluble nitrogen (PTASN); also the free amino acid (FAA) and free fatty acid (FFA) contents, with the exception of C_4:0, C_16:0 and C_18:0. Different ripening periods significantly affected the dry matter content, WSN and PTASN and all FAA, except serine.     

Chemical composition and microbial evaluation of Argentinean Corrientes cheese

The chemical and microbial composition of an artisanal cheese made from raw cow's milk produced and consumed in the province of Corrientes (north-eastern Argentina) was evaluated using standard methods. Corrientes cheese has high moisture content (50–60%), normal protein and fat contents (21–27 and 22–26% respectively), and is low in salt (0.5–2.0% w/w). Microbial counts also varied significantly between samples (colony-forming units per gram ranges covering logs of 5–11), probably due to environmental contamination in the raw material. These results will help produce higher quality Corrientes cheeses with well-defined characteristics.     

Effect of partial substitution of NaCl with KCl on proteolysis of halloumi cheese

The effect of substitution of NaCl with Potassium chloride (KCl) in brine solution on proteolysis of halloumi cheese was investigated. Halloumi cheeses were made and kept in 4 different brine solutions (18% w/w), including only NaCl (HA; control); 3NaCl:1KCl (w/w) (HB); 1NaCl:1KCl (w/w) (HC); 1NaCl:3KCl (w/w) (HD); and stored for 56 d at 4 °C. Proteolysis was assessed using water-soluble nitrogen (WSN), trichloroacetic acid-soluble nitrogen (TCA-SN), phosphotungstic-soluble nitrogen (PTA-SN), urea polyacrylamide gel electrophoresis (urea-PAGE), and peptide patterns. WSN and TCA-SN contents were similar in all experimental cheeses. Peptide patterns of the pH 4.6 N fraction and urea-PAGE showed no significant difference between halloumi cheeses kept in various NaCl/KCl mixtures (HB, HC, HD) and control (HA). Sodium and potassium contents showed positive correlations with WSN and PTA-SN. There was an inverse correlation between calcium (Ca) contents and WSN and PTA-SN. Correlations between Ca and Na or K were negative at the same salt treatment.     

Proteolysis and textural properties of low‐fat ultrafiltered Feta cheese as influenced by maltodextrin

Maltodextrin was used as a fat replacer in low‐fat ultrafiltered cheese. Fat was replaced with 25% maltodextrin milk solution (w/w) in cheese at 15 and 50% (w/w). The chemical, rheological and sensory properties as well as the microstructure of the cheese samples were evaluated after storage for 2 months at 8 °C. Maltodextrin affected the chemical (pH, dry matter, fat, water‐soluble nitrogen to total nitrogen, nonprotein nitrogen to total nitrogen, total free amino acid) and rheological (mean relaxation time) properties, as well as the microstructure. In general, based on textural properties, sensory evaluation and economic aspects, the 50%‐fat‐reduced sample was selected as the best treatment.     

Chemometric analysis of proteolysis during ripening of Ragusano cheese

Chemometric modeling of peptide and free amino acid data was used to study proteolysis in Protected Denomination of Origin Ragusano cheese. Twelve cheeses ripened 3 to 7 mo were selected from local farmers and were analyzed in 4 layers: rind, external, middle, and internal. Proteolysis was significantly affected by cheese layer and age. Significant increases in nitrogen soluble in pH 4.6 acetate buffer and 12% trichloroacetic acid were found from rind to core and throughout ripening. Patterns of proteolysis by urea-PAGE showed that rind-to-core and age-related gradients of moisture and salt contents influenced coagulant and plasmin activities, as reflected in varying rates of hydrolysis of the caseins. Analysis of significant intercorrelations among chemical parameters revealed that moisture, more than salt content, had the largest single influence on rates of proteolysis. Lower levels of 70% ethanol-insoluble peptides coupled to higher levels of 70% ethanol-soluble peptides were found by reversed phase-HPLC in the innermost cheese layers and as the cheeses aged. Non-significant increases of individual free amino acids were found with cheese age and layer. Total free amino acids ranged from 14.3 mg/g (6.2% of total protein) at 3 mo to 22.0 mg/g (8.4% of total protein) after 7 mo. Glutamic acid had the largest concentration in all samples at each time and, jointly with lysine and leucine, accounted for 48% of total free amino acids. Principal components analysis and hierarchical cluster analysis of the data from reversed phase-HPLC chromatograms and free amino acids analysis showed that the peptide profiles were more useful in differentiating Ragusano cheese by age and farm origin than the amino acid data. Combining free amino acid and peptide data resulted in the best partial least squares regression model (R(2) = 0.976; Q(2) = 0.952) predicting cheese age, even though the peptide data alone led to a similarly precise prediction (R(2) = 0.961; Q(2) = 0.923). The most important predictors of age were soluble and insoluble peptides with medium hydrophobicity. The combined peptide data set also resulted in a 100% correct classification by partial least squares discriminant analysis of cheeses according to age and farm origin. Hydrophobic peptides were again discriminatory for distinguishing among sample classes in both cases.     

Heat-shocked lactobacilli for accelerating flavour development of ras cheese

An attempt has been made to shorten the ripening period of Ras cheese. Cheese was made from curd incorporated with a heat-shocked culture of either Lactobacillus casei or Lactobacillus helveticus at levels of 1% and 2% each. These treatments did not considerably affect the gross chemical composition of the cheese but influenced flavour intensity, body characteristics, the formation of soluble nitrogen compounds and free volatile fatty acids. Meanwhile, total proteolytic and lipolytic bacterial counts were also stimulated. Cheese with added heat-shocked lactobacilli showed desirable flavour and consistency 1–2 months earlier than control cheese made without additives.     

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.     

Proteolysis in reduced sodium Feta cheese made by partial substitution of NaCl by KCl

Feta cheeses (five trials) of different sodium content were made, using ewes’ milk, from split lots of curd by varying the salting procedure, i.e. dry salting with NaCl (control) or mixtures of NaCl/KCl (3:1 or 1:1, w/w basis) and filling the cans with brine made with NaCl or the above NaCl/KCl mixtures, respectively, in order to study the influence of the partial substitution of NaCl by KCl on the proteolysis during cheese ripening. The extent and characteristics of proteolysis in the cheeses were monitored during aging by using Kjeldahl determination of soluble nitrogen fractions (water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen), the cadmium–ninhydrin method for the determination of total free amino acids (FAA), urea–polyacrylamide gel electrophoresis of cheese proteins followed by densitometric analysis of the α_s1- and β-casein fractions, reverse-phase HPLC analysis of the water-soluble extracts of cheeses, and ion-exchange HPLC analysis of FAA. The results showed that proteolysis was similar in control and experimental cheeses at all sampling ages, indicating that the partial substitution of NaCl by KCl in the manufacture of Feta cheese had no significant effect on the extent and characteristics of proteolysis during cheese aging.     

Effect of pH on Characteristics of Low‐Moisture Mozzarella Cheese during Refrigerated Storage

ABSTRACT: This study evaluated the effect of cheese pH on proteolysis, calcium distribution, and functional characteristics of Mozzarella cheese. On 4 occasions, cultured low‐moisture part‐skim Mozzarella cheeses were obtained from a commercial producer on the day after manufacture. Cheese blocks were randomly assigned to 2 groups. One group was shredded, subdivided, and exposed to either ammonia vapor to increase the pH or HCl vapor to decrease the pH. Samples were vacuum packaged, stored at 4 °C, and analyzed for pH 4.6 and 12% TCA soluble nitrogen, apparent viscosity, free oil, and water‐soluble calcium on days 5, 12, 22, and 40. The 2nd group was sectioned into 23‐mm thick slabs and similarly exposed to either ammonia vapor to increase the pH or HCl vapor to decrease the pH. The slabs were vacuum packaged, stored at 4 °C, and analyzed for pH 4.6 and 12% TCA soluble nitrogen, TPA hardness, springiness and cohesiveness, and meltability on days 17, 29, and 41. Data were analyzed by ANOVA according to a spilt‐plot design. Experimentally induced pH differences persisted and significantly affected TPA hardness, apparent viscosity, meltability, and water‐soluble calcium throughout 40 d of storage, but did not affect soluble nitrogen changes. Thus, cheese pH affected functional characteristics and calcium distribution but did not affect proteolysis rates. Higher cheese pH resulted in a harder cheese that required longer aging to develop desirable melting characteristics, whereas cheese with lower pH developed desirable melting characteristics more quickly but had a shorter functional shelf life.     

Salting and the role of salt in cheese

Salt levels in cheese range from ∼0.7% (w/w) in Swiss-type to ∼6% (w/w) in Domiati. Salt has three major functions in cheese: it acts as a preservative, contributes directly to flavour, and is a source of dietary sodium. Together with the desired pH, water activity and redox potential, salt assists in cheese preservation by minimizing spoilage and preventing the growth of pathogens. The dietary intake of sodium in the modern western diet is generally excessive, being two to three times the level recommended for desirable physiological function (2.4 g Na, or ∼6 g NaCl per day). However, cheese generally makes a relatively small contribution to dietary sodium intake except if high quantities of high-salt cheeses such as Domiati and feta are consumed. In addition to these functions, salt level has a major effect on cheese composition, microbial growth, enzymatic activities and biochemical changes, such as glycolysis, proteolysis, lipolysis and para -casein hydration, that occur during ripening. Consequently, the salt level markedly influences cheese flavour and aroma, rheology and texture properties, cooking performance and, hence, overall quality. Many factors affect salt uptake and distribution in cheese and precise control of these factors is a vital part of the cheesemaking process to ensure consistent, optimum quality.