Physical properties of pizza Mozzarella cheese manufactured under different cheese-making conditions

The effect of manufacturing factors on the shreddability and meltability of pizza Mozzarella cheese was studied. Four experimental cheeses were produced with 2 concentrations of denatured whey protein added to milk (0 or 0.25%) and 2 renneting pH values (6.4 or 6.5). The cheeses were aged 8, 22, or 36 d before testing. Shreddability was assessed by the presence of fines, size of the shreds, and adhesion to the blade after shredding at 4, 13, or 22°C. A semi-empirical method was developed to measure the matting behavior of shreds by simulating industrial bulk packaging. Rheological measurements were performed on cheeses with and without a premelting treatment to assess melt and postmelt cheese physical properties. Lowering the pH of milk at renneting and aging the cheeses generally decreased the fines production during shredding. Adding whey protein to the cheeses also altered the fines production, but the effect varied depending on the renneting and aging conditions. The shred size distribution, adhesion to the blade, and matting behavior of the cheeses were adversely affected by increased temperature at shredding. The melting profiles obtained by rheological measurements showed that better meltability can be achieved by lowering the pH of milk at renneting or aging the cheese. The premelted cheeses were found to be softer at low temperatures (<40°C) and harder at high temperatures (>50°C) compared with the cheeses that had not undergone the premelting treatment. Understanding and controlling milk standardization, curd acidification, and cheese aging are essential for the production of Mozzarella cheese with desirable shreddability and meltability.     

Effect of ultrafiltration,fat reduction and salting on textural properties of white brined cheese

The influence of ultrafiltration of whole and skim milk on rennetability in the course of white pickled cheese manufacturing was investigated. Concentrating factors of the milk were selected as 3x, 4x, 5x and 5.5x. The renneting properties of the unconcentrated milk and the retentates (skim and whole milk ultrafiltration retentates) were explained. The white cheese produced from unconcentrated whole milk via a traditional industrial method was compared with the white cheese produced by whole milk retentate (5.5-fold). The cheeses manufactured from retentate were salted using different methods, i.e. dry salting, brine salting and salt addition before renneting. The effect of salting method on the texture of UF-cheese was determined after three months storage. It was suggested that producing of white pickled cheese from whole milk retentate (full-concentrated) was more suitable than manufacturing from skim milk retentate and was than better the conventional method which uses unconcentrated milk, actually.     

Improving the yield of Mozzarella cheese by phospholipase treatment of milk

Part-skim Mozzarella cheese was manufactured from milk hydrolyzed with fungal phospholipase A₁ prior to renneting. The phospholipase treatment reduced fat losses in whey and cooking water and increased cheese yield as a result of improved fat and moisture retention in the cheese curd. The amount of phospholipids in the whey was reduced because of improved retention of lysophospholipids in the cheese curd. Water binding in the fresh curds and young cheeses up to 3 wk of storage was investigated by a ¹H nuclear magnetic resonance spin-spin relaxation technique. In the fresh curds, 2 dominant water fractions were present, characterized by average spin-spin relaxation times (T₂) of 14 and 86 to 89 ms, respectively. These 2 fractions of low- and high-molecular-mobility water were similar in all cheeses and presumed to represent water associated with the casein matrix and water present in the pores. A few hours after manufacture, cheeses made with phospholipase showed decreased T₂ of the high-mobility fraction, indicating improved water-holding capacity. It is suggested that lysophospholipids released from the fat globule membranes act as surface-active agents in the cheese curd, helping emulsification of water and fat during processing and reducing syneresis. During 3 wk of storage after manufacture, the mobility of both water fractions increased in all cheeses, but was highest in the cheeses made with phospholipase. The increase in mobility during the first weeks of storage has earlier been ascribed to structural changes in the protein matrix, which in principle could be accelerated because of the higher moisture content. However, the microstructure of phospholipase-treated cheese was investigated by confocal laser scanning microscopy and found to be very similar to the control cheese during processing and up to 28 d of storage. In addition, flowability, stretchability, and browning were acceptable and similar in all the manufactured cheeses. Thus, phospholipase hydrolysis of cheese milk improved the cheese yield without changing the cheese microstructure, and resulted in cheese with functional properties that were identical to traditional Mozzarella cheese.     

Standardization of milk using cold ultrafiltration retentates for the manufacture of Swiss cheese: effect of altering coagulation conditions on yield and cheese quality

Fortification of cheesemilk with membrane retentates is often practiced by cheesemakers to increase yield. However, the higher casein (CN) content can alter coagulation characteristics, which may affect cheese yield and quality. The objective of this study was to evaluate the effect of using ultrafiltration (UF) retentates that were processed at low temperatures on the properties of Swiss cheese. Because of the faster clotting observed with fortified milks, we also investigated the effects of altering the coagulation conditions by reducing the renneting temperature (from 32.2 to 28.3°C) and allowing a longer renneting time before cutting (i.e., giving an extra 5 min). Milks with elevated total solids (TS; ∼13.4%) were made by blending whole milk retentates (26.5% TS, 7.7% CN, 11.5% fat) obtained by cold (<7°C) UF with part skim milk (11.4% TS, 2.5% CN, 2.6% fat) to obtain milk with CN:fat ratio of approximately 0.87. Control cheeses were made from part-skim milk (11.5% TS, 2.5% CN, 2.8% fat). Three types of UF fortified cheeses were manufactured by altering the renneting temperature and renneting time: high renneting temperature = 32.2°C (UFHT), low renneting temperature = 28.3°C (UFLT), and a low renneting temperature (28.3°C) plus longer cutting time (+5 min compared to UFLT; UFLTL). Cutting times, as selected by a Wisconsin licensed cheesemaker, were approximately 21, 31, 35, and 32 min for UFHT, UFLT, UFLTL, and control milks, respectively. Storage moduli of gels at cutting were lower for the UFHT and UFLT samples compared with UFLTL or control. Yield stress values of gels from the UF-fortified milks were higher than those of control milks, and decreasing the renneting temperature reduced the yield stress values. Increasing the cutting time for the gels made from the UF-fortified milks resulted in an increase in yield stress values. Yield strain values were significantly lower in gels made from control or UFLTL milks compared with gels made from UFHT or UFLT milks. Cheese composition did not differ except for fat content, which was lower in the control compared with the UF-fortified cheeses. No residual lactose or galactose remained in the cheeses after 2 mo of ripening. Fat recoveries were similar in control, UFHT, and UFLTL but lower in UFLT cheeses. Significantly higher N recoveries were obtained in the UF-fortified cheeses compared with control cheese. Because of higher fat and CN contents, cheese yield was significantly higher in UF-fortified cheeses (∼11.0 to 11.2%) compared with control cheese (∼8.5%). A significant reduction was observed in volume of whey produced from cheese made from UF-fortified milk and in these wheys, the protein was a higher proportion of the solids. During ripening, the pH values and 12% trichloroacetic acid-soluble N levels were similar for all cheeses. No differences were observed in the sensory properties of the cheeses. The use of UF retentates improved cheese yield with no significant effect on ripening or sensory quality. The faster coagulation and gel firming can be decreased by altering the renneting conditions.     

Effects of starter level, draining time and aging on the physicochemical, organoleptic and rheological properties of feta cheese

Feta cheese was made from ewe's milk using three different levels of starter (0.20, 0.50 and 0.75%) and two draining times (6 and 20 h). Cheese made with addition of 0.75% starter had a lower pH and moisture content than the cheeses made with 0.20 and 0.50% starter. With the increase in starter level there was also an increase in cheese fat content, although the fat in dry matter remained almost constant. The lower level of starter resulted in cheese with lower protein content, while other cheese components were not significantly affected by the starter levels used. The yield of cheese made with addition of 0.75% starter was significantly lower than the yield of cheeses made with the other levels. Also, the yield of cheeses made with 6 h drainage was greater than the yield of cheeses made with 20 h drainage. In general, the organoleptic and rheological properties of cheeses were not affected by the three levels of starter used for feta cheese manufacture.     

Free oil and rheology of Cheddar cheese containing fat globules stabilized with different proteins

Cheddar cheese was manufactured from recombined milk containing fat globules coated with alpha(s1)-CN (casein), alpha(s2)-CN, beta-CN, kappa-CN, alpha-lactalbumin, or beta-lactoglobulin. The effect of the coating on fat globule structure, free oil formation, and cheese rheology was investigated to determine if globule coating affected the physical structure of cheese. Fat globule size and shape were determined in cheese using confocal laser scanning microscopy, and the rheological properties measured by uniaxial compression after maturation for 35 and 70 d. Fat globules were elongated and clustered in the control cheese coated with native membrane material and in cheese where the globules were coated with alpha(s2)-CN, but were more circular and distinct than all others. Cheese containing globules coated with alpha(s2)-CN fractured at a lower strain and with a lower stress than other experimental cheeses. Free oil decreased in cheese as the stress at fracture of the cheese protein matrix increased. Strain at fracture increased as pH increased from 4.7 to 5.3. There was no correlation between free oil and fat globule circularity. Cheddar cheese aroma was not evident in experimental cheeses.     

Flavour-enhancement of low-fat Kashkaval cheese using heat-or freeze-shocked Lactobacillus delbrueckii var. helveticus cultures

Kashkaval cheese of different fat contents was manufactured using heat- or freeze-shocked cultures of Lactobacillus delbrueckii var. helveticus added at a level of 2% to cheese milk prior to renneting. Levels of moisture, total N, salt or titratable acidity of cheeses with different fat levels were different. Proteolysis and lipolysis in low-fat Kashkaval cheese without additives were lower than those found in full-fat cheese. Incorporation of heat- or freeze-shocked L. delbrueckii var. helveticus cultures into milk of low-fat cheese greatly enhanced proteolysis and increased slightly the levels of free fatty acids. Regular low fat cheese did not develop adequate Kashkaval cheese flavour and the cheese was firm. However, addition of heat- or freeze-shocked cultures increased the flavour intensity and improved body and texture of the resultant cheese, yielding low-fat cheese with flavour intensity and body characteristics similar to those of standard fat cheese at each stage of ripening.     

Effects of sheep alpha s1-casein CC, CD and DD genotypes on milk composition and cheesemaking properties.

The effects of sheep alpha s1-casein CC, CD and DD genotypes on milk composition and cheese yield were studied. Processed bulk milk was collected from three groups of 15 ewes, carrying alpha s1-casein CC, CD and DD genotypes. CC milk was higher in casein content than CD or DD milk (+3.5 and +8.6% respectively), and had a higher protein: fat ratio and a smaller casein micelle diameter. In addition, DD milk had a significantly lower alpha s1-casein content. The main differences were in curd formation: CC milk had better renneting properties. Cheesemaking trials, carried out in a pilot plant, showed that CC milk had better cheesemaking characteristics than DD milk, while CD milk was intermediate. Both 1 d old and fully ripened cheeses had different fat: dry matter ratios and alpha s1-I-casein electrophoretic mobilities: these were lower for DD cheese. As a consequence, these genotypes could be considered as markers of milk and/or cheese quality.     

Blue like cheese from dried milk

A trial was made to produce Blue like cheese from both whole dry milk and non fat one. The resultant cheese was kept for ripening at 5°C for two months. Cheese made from reconstituted whole dried milks were characterized with higher moisture, salt, and protein contents and acidity than the control. Protein degradation and fat hydrolysis were found to be lower in these cheeses than the control. Organoleptically, cheese made from cow's milk was found to be superior to cheeses produced from reconstituted either non fat or whole dried milk, as regards flavour, body and texture and the distribution of P. requeforti.     

The manufacture of miniature Cheddar-type cheeses from milks with different fat globule size distributions

A novel 2-stage gravity separation scheme was developed for fractionation of raw, whole bovine milk into fractions enriched in small (SFG) or large (LFG) fat globules. The volume mean diameter of fat globules in SFG, LFG or control (CTRL) milk was 3.45, 4.68 and 3.58 microm, respectively. The maximum in storage modulus (index of firmness) decreased with increasing fat globule size for rennet-induced gels formed from SFG, LFG or CTRL milks. Miniature (20 g) Cheddar cheeses were manufactured using each of the 3 milks. There were no significant (P > 0.05) differences in the pH, moisture and fat in dry matter levels between cheeses made using any of the 3 milks, however, the fat content of the cheese made using SFG milk was approximately 1% lower than that of cheese made using LFG or CTRL milk in each of the 2 trials. Image analysis of confocal scanning laser micrographs of the cheeses illustrated that the star volume of fat globules in the cheeses decreased significantly (P < or = 0.05) as the size of fat globules in the milks used for cheesemaking was reduced. This indicates that it is possible to manipulate the size distribution of fat globules in Cheddar cheese by adjusting the fat globule size distribution of the milk used for cheese-making. The concentration of free fatty acids (FFA) increased in all cheeses during ripening. At 120 d of ripening, the concentration of FFA varied significantly (P < or = 0.05 and P < or = 0.001 for trials 1 and 2, respectively) with fat globule size, with cheeses made in trial 2 from LFG, SFG or CTRL milks having total FFA levels of 3391, 2820 and 2612 mg/kg cheese, respectively.     

Effect of Guar Gum on the Physicochemical, Thermal, Rheological and Textural Properties of Green Edam Cheese

In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar gum modified cheeses were similar to those of the low-fat control. No significant differences were detected in the thermal properties (concerning the enthalpy and profile of water desorption) among all types of cheeses. The rheological behaviour of the 0.0025% modified cheese was very similar to the full-fat control. Overall, no trend was observed in the texture profile (hardness, cohesiveness, gumminess and elasticity) of the modified cheeses versus guar gum concentration, as well as in comparison with the control groups, suggesting that none of the studied polysaccharide concentrations simulated the textural functions of fat in Edam cheese.     

Influence of carboxymethylcellulose on the physicochemical,rheological and sensory attributes of a low‐fat Domiati cheese

The physicochemical, rheological and sensory attributes of a low‐fat Domiati cheese produced using carboxymethylcellulose (CMC), a hydrocolloid, at 0.4, 0.6, 0.8 and 1% (w?w) were examined during the ripening period. Results indicated that, as the carboxymethylcellulose content of cheese milk increased, cheese yield and moisture of low‐fat Domiati cheese significantly increased but the protein, salt and fat values significantly decreased. Rheological parameters were significantly lower in cheeses made with CMC. With regard to the sensory properties of the cheeses, low‐fat Domiati cheese made with 1% (w?w) CMC recorded the highest scores for sensory attributes.     

PREPARATION OF SOYBEAN CHEESE USING LACTIC STARTER ORGANISMS. Effects of Mold Ripening and Increasing Concentrations of Skim Milk Solids

SUMMARY– Soybean cheeses were prepared from blends of skim milk powder and soybean milk in which the skim milk powder contributed 0, 25, 50 and 75% of total dry weight. The amount of skim milk had little effect on the flavor of the finished cheese, due to the dominating effect of the beany flavor of the soybeans. Similarly, the skim milk had little effect on the texture of the finished cheese, indicating that only a small amount of fibrous matter from the soybeans is necessary to impart a mealy texture to the product. Mold ripening resulted in desirable changes in texture, but these were offset by the development of bitter flavors.     

Effects of Size and Stability of Native Fat Globules on the Formation of Milk Gel Induced by Rennet

Rennet‐induced gelation crucially impacts cheese structure. In this study, effects of the size and stability of native fat globules on the kinetics of rennet‐induced coagulation were revealed by determining the caseinomacropeptide release rate and rheological properties of milk. Moreover, the mobility and stability of fat globules during renneting was revealed using diffusing wave spectroscopy and confocal laser scanning microscopy. By use of a 2‐stage gravity separation combined centrifugation scheme, native fat globules were selectively separated into small (SFG, D_4,3 = 1.87 ± 0.02 μm) and large fat globules (LFG, D_4,3 = 5.65 ± 0.03 μm). The protein and fat content of SFG and LFG milk were then standardized to 3.2 g/100 mL and 1.2 g/100 mL, respectively. The milk containing different sized globules were then subjected to renneting experiments in the laboratory. Reduction of globule size accelerated the aggregation of casein micelles during renneting, giving a shorter gelation time and earlier 1/l^* change. The gel produced from LFG milk was broken due to coalescent fat globules and generated coarser gel strands compared to the finer strands formed with SFG milk. Structural differences were also confirmed with a higher final storage modulus of the curd made from SFG milk than that from the LFG. In conclusion, the size of fat globules affects the aggregation of casein micelles. Moreover, fat globule coalescence and creaming during renneting, also affects the structure of the rennet gel. A better understanding of the size of globules effect on milk gelation could lead to the development of cheese with specific properties.     

Rheological and structural properties of differently acidified and renneted milk gels

In this study we assessed the rheological and structural properties of differently acidified and renneted milk gels by controlling pH value and renneting extent. Skim milk were exactly renneted to 4 extents (20, 35, 55, and 74%) and then direct acidified to the desired pH (4.8, 5.0, 5.2, 5.5, 5.8, and 6.2), respectively. Rheological properties were assessed by dynamic rheological measurements, structural properties were studied by spontaneous whey separation and confocal laser scanning micrograph, and protein interactions were studied by dissociation test. Results showed that minimally renneted milk samples (20 and 35%) formed weak gels with low storage modulus, and the acidification range within which gels could form was narrow (pH ≤5.2). Highly renneted milk samples formed more gels with high storage modulus. The results of this study revealed that acidification determined the structural properties of highly renneted milk gels. As pH increased from 5.0 to 6.2, highly renneted milk gels had lower loss tangent, decreased spontaneous syneresis, and smaller pores. For both the low and high rennetings, divalent calcium bonds contributed less at low pH than at high pH. In conclusion, renneting increased the pH range suitable for gel formation; acidification determined the spontaneous syneresis and microstructure of highly renneted milk gels.     

Yield and sensory properties of cheese made with milk from Holstein or Montbéliarde cows milked twice or once daily

The aim of this study was to evaluate the milk properties and the yield and sensory properties of Cantal cheese made with milk from Holstein or Montbéliarde cows milked once or twice daily. Sixty-four grazing cows [32 Holstein (H) and 32 Montbéliarde (M) cows] in the declining phase of lactation (157 d in milk) were allocated to 1 of 2 equivalent groups milked once daily (ODM) or twice daily (TDM) for 7 wk. The full-fat raw milk collected during 24 h from the 4 groups of cows (M-TDM, M-ODM, H-TDM, and H-ODM) was pooled and processed into Cantal cheese 4 times during the last 4 wk of the experimental period. In all, 16 cheeses were made (2 milking frequencies × 2 breeds × 4 replicates) and analyzed after a ripening period of 15 and 28 wk. The results showed that for both breeds, the pooled milk content of fat, whey protein, casein, total protein, and phosphorus as well as rennet clotting time and curd firming time were significantly higher with ODM cows, whereas the casein-to-total protein ratio was lower, and lactose, urea, calcium, and free fatty acids contents of milk remained unchanged. The acidification and draining kinetics of the cheese as well as cheese yields and the chemical and rheological properties of the ripened cheese were not significantly modified by milking frequency. For both breeds, the cheeses derived from ODM cows had a slightly yellower coloration but the other sensory attributes, except for pepper odor, were not significantly affected by milking frequency, thereby demonstrating that ODM does not have an adverse effect on the sensory properties of Cantal cheese. Compared with that of Holstein cows, milk from Montbéliarde cows resulted in a higher cheese yield (+1.250 kg/100 kg of milk) and ripened cheeses with lower pH, dry matter, calcium, sodium chloride, and water-soluble nitrogen concentrations. These cheeses had also a less firm and more elastic texture, a more acidic taste, and a yogurt/whey aroma.     

Simultaneous use of transglutaminase and rennet in white-brined cheese production

The effects of renneting temperature (30 °C or 34 °C) on textural properties, proteolysis and yield of white-brined cheese made by simultaneous use of microbial transglutaminase (mTG) and rennet were investigated. Incorporation of mTG resulted in higher yield values for experimental cheeses than for the control cheeses at both renneting temperatures. The total solids contents of the cheeses treated with mTG were remarkably lower than the control cheeses; but the former cheeses had higher protein-in-dry matter levels. The TPA profiles of the cheeses showed that the incorporation of mTG led to modification in the textural properties. The development of proteolysis in the cheeses treated with mTG was slightly slower than the control cheeses at both coagulation temperatures. To conclude, the specific action of mTG on milk proteins could be successfully exploited to modify the textural properties and to increase the yield of white-brined cheese.     

Incorporating whey proteins into mozzarella cheese

A study was conducted to improve the yield of cheese and make reduced fat cheese by incorporating whey proteins. Whey protein dispersions were prepared by heating whey at 95°C and pH 4.6, then removing excess serum and homogenizing part of the whey protein. Cheeses were made from standardized milk and standardized milk with homogenized and non-homogenized protein dispersions. Cheeses were also made from standardized milk, reduced fat milk and reduced fat milk with homogenized protein. Adding whey proteins improved the yield, but lowered the retention of fat. Homogenization of whey proteins improved fat retention and yield. The dry matter increase was due to increased solids-non-fat. Reduced fat cheese gave lower yields, which were partially offset by adding homogenized whey proteins. Physical and sensory properties of reduced fat cheeses made with homogenized whey proteins were similar to the control.     

Proteolytic and rheological properties of aging cheddar-like caprine milk cheeses manufactured at different times during lactation

ABSTRACT:  The effects of 24 wk of aging on the proteolytic and rheological properties of cheddar-like cheese made from caprine milk collected at different lactation periods were evaluated. Cheddar cheese was made weekly using whole milk from Alpine goats and cheeses manufactured at weeks 4, 5, 12, 14, 15, 21, 22, and 23 of lactation were evaluated for proteolytic and rheological properties at 5 d after manufacture and after 8, 16, and 24 wk of aging at 4 °C. Rheology results indicated that a minimum of 8 wk of aging was needed to stabilize the texture of the cheese and that the most uniform cheeses were made from mid lactation milk. Cheeses manufactured at weeks 12 to 15 of lactation were the firmest, had the least flexible protein matrix (highest values for hardness, chewiness, and shear stress and rigidity at point of fracture), and the lowest degree of proteolysis. Understanding the factors that impact the texture of cheese, such as aging and the period of lactation that cheesemilk is obtained, will help develop guidance for maintaining the production of high quality and uniform caprine milk cheeses.     

Microstructural changes in fat during the ripening of Iranian ultrafiltered Feta cheese

In this study, fat globules in Iranian ultrafiltered Feta cheese (3 to 60 d) were directly observed during the ripening period by scanning electron microscopy. According to images of ultrafiltered Feta cheese samples obtained by scanning electron microscopy, individual fat globules and aggregates of fat were easily distinguishable on d 3 and had completely disappeared within 20 d of storage. On d 20, only the fingerprints of the fat globules and pools of free fat in the casein matrix remained. After 40 d of ripening, the texture was homogeneous and no fat globules or fat voids were detected. Chemical analysis of cheese samples showed that with an increase in the ripening period, the contents of dry matter and fat decreased significantly, whereas the pH values and salt content did not indicate any significant changes.