Physicochemical analysis of full-fat, reduced-fat, and low-fat artisan-style goat cheese

The objective of this study was to examine the physicochemical properties of cheese elaborated via traditional artisan methods using goat milk containing 5, 1.5, or 0.4% fat and ripened for 1, 7, 14, or 28 d. Seventy-two cheeses were produced (2 batches × 3 fat levels × 4 ripening times × triplicate). Proximal composition, pH, texture analysis, and color were recorded in each cheese. Protein and moisture were increased in cheese, and fat and fat in DM were decreased with decreasing fat in milk. Internal and external pH was higher in low-fat and reduced-fat cheese, and pH values decreased during the first 2 wk of ripening but increased slightly on d 28. Cheese fracturability, cohesiveness, masticability, and hardness increased with decreasing fat, whereas elasticity and adhesiveness decreased. Cheese lightness and red and yellow indexes decreased with decreasing fat content; during ripening, lightness decreased further but yellow index increased.     

Detection of milk mixtures in Halloumi cheese

A capillary electrophoresis method has been applied to the detection of illegal addition of milk from goat and/ or cow in Halloumi cheese, traditionally made with sheep milk. The electrophoretic profiles of the casein from Halloumi cheeses have revealed that caprine para-kappa-casein and bovine alphas1-casein peaks point to the presence of low percentages of goat's and/or cow's milk added to Halloumi cheese. Stepwise multiple linear regression has been used to predict these percentages with a standard error of the estimation of 2.14%. The analytical method combined with the statistical application is valid for the prediction of percentages higher than 2% of goat's and percentages of 5% of cow's milk added to the cheese either in fresh or ripened cheese. The standard error of estimation was higher for the prediction of cow's milk than for goat's milk.     

The effect of aging on low-fat, reduced-fat, and full-fat Cheddar cheese texture

This study investigated the effects of aging and fat content on the texture of Cheddar cheese, both mechanical and sensory aspects, over a 9-mo aging period. Cheeses of 6, 16, and 33% fat were tested at 0.5, 3, 6, and 9 mo of aging. Cheeses were evaluated by a trained sensory panel using an established texture lexicon as well as instrumental methods, which were used to probe cheese structure. Sensory analysis showed that low-fat cheeses were differentiated from full-fat cheeses by being more springy and firm and this difference widened as the cheeses aged. In addition, full-fat cheeses broke down more during chewing than the lower fat cheeses and the degree of breakdown increased with aging. Mechanical properties were divided by magnitude of deformation during the test and separated into 3 ranges: the linear viscoelastic region, the nonlinear region, and fracture point. These regions represent a stress/strain response from low to high magnitude, respectively. Strong relationships between sensory terms and rheological properties determined in the linear (maximum compliance) and nonlinear (critical stress and strain and a nonlinear shape factor) regions were revealed. Some correlations were seen with fracture values, but these were not as high as terms related to the nonlinear region of the cheeses. The correlations pointed to strain-weakening behavior being the critical mechanical property. This was associated with higher fat content cheeses breaking down more as strain increased up to fracture. Increased strain weakening associated with an increase in fat content was attributed to fat producing weak points in the protein network, which became initiation sites for fracture within the structure. This suggests that fat replacers need to serve this functional role.     

Detection of milk powder and caseinates in Halloumi cheese

Halloumi cheese is traditionally manufactured from fresh milk. Nevertheless, dried dairy ingredients are sometimes illegally added to increase cheese yield. Lysinoalanine and furosine are newly formed molecules generated by heating and drying milk protein components. The levels of these molecular markers in the finished Halloumi have been investigated to verify their suitability to reveal the addition of skim milk powder and calcium caseinate to cheese milk. Because of the severe heating conditions applied in curd cooking, genuine Halloumi cheeses (n = 35), representative of the Cyprus production, were characterized by levels of lysinoalanine (mean value = 8.1 mg/100 g of protein) and furosine (mean value = 123 mg/100 g of protein) unusual for natural cheeses. Despite the variability of the values, a good correlation between the 2 parameters (R = 0.975) has been found in all cheeses, considering both the fresh and mature cheeses as well as those obtained from curd submitted to a prolonged cooking following a traditional practice adopted by a very small number of manufacturers. Experimental cheeses made by adding as low as 5% of skim milk powder, or calcium caseinate, or both, to cheese milk fell outside the prediction limits at ±2 standard deviation of the above-reported correlation regardless of curd cooking conditions or ripening length. This correlation may be adopted as a reliable index of Halloumi cheese genuineness.     

Changes of organic acids,volatile aroma compounds and sensory characteristics of Halloumi cheese kept in brine

This study examines the changes in organic acids, volatile aroma compounds and sensory characteristics of ovine Halloumi cheese kept in brine (∼10% NaCl) at 4 °C for 45 days. The highest total score of the organoleptic assessment was observed at day 1, before storage in brine. During cheese storage, a large reduction of lactose was observed, especially in the first stages of storage while, concurrently, a significantly progressive increase in lactic and acetic acids was observed. Among the volatile aroma compounds determined were alcohols, aldehydes, ketones, acids, esters, hydrocarbons, sulphur compounds, as well as a variety of other compounds in very small quantities. Ethanol and acetic acid were the dominant volatile aromatic compounds and their concentrations increased during storage. The lipolysis of Halloumi cheese during storage was not excessive. The dominant free fatty acids were palmitic, oleic and acetic.     

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.     

Possible implications of milk pasteurization on the manufacture and sensory quality of ripened cheese

Cheese made from raw milk represents an important proportion of the traditional cheeses, particularly in South European countries. Besides destruction of pathogenic bacteria, the most significant changes in milk relevant to cheesemaking, which are induced by pasteurization are:

• a partial elimination of the milk microorganisms which may grow in cheese during ripening,

• a partial or total activation or inhibition of the plasmin/plasminogen complex, cathepsin D, lipoprotein lipase and alkaline phosphatase. Enzymes from psychrotrophic bacteria, acid phosphatase and xanthine oxidase, which may be active during ripening, withstand pasteurization.,

• a slight (7%) denaturation of serum proteins and little or no modification of the cheesemaking properties (coagulation, acidification by lactic acid bacteria).

From experimental work carried out on several cheese varieties, comparing pasteurized or microfiltered milk and raw milk cheeses, it was found that facultatively heterofermentative lactobacilli, Micrococcaceae, enterococci, and propionibacteria in Swiss-type cheese, are found at higher levels in raw milk cheese. The main biochemical modification of cheese during ripening concerns the nature and extent of proteolysis. Although there is no clear trend in the breakdown of _s1- and β-caseins, milk pasteurization leads to a significant decrease of the amount of small peptides and free amino acids and to different HPLC profiles. Experiments carried out with sensory analysis show that, in all cases, pasteurized or microfiltered milk cheeses have received lower flavour intensity scores than raw milk cheeses. From this review, it is concluded that the indigenous milk microflora, with its diversity of species and strains, appears to be mainly responsible of the specific sensory properties of raw milk cheeses.     

The effect of sodium chloride substitution with potassium chloride on texture profile and microstructure of Halloumi cheese

The effect of partial substitution of NaCl with KCl on texture profile and microstructure of Halloumi cheese was investigated. Four batches of Halloumi cheese were made and kept in 4 different brine solutions (18%, wt/wt), including A) NaCl only, B) 3NaCl:1KCl, C) 1NaCl:1KCl, and D) 1NaCl:3KCl and then stored at 4°C for 56 d. The texture profile was analyzed using an Instron universal machine, whereas an environmental scanning electron microscope was used to investigate the effect of NaCl substitution on the microstructure of cheeses. No significant difference was found in hardness, cohesiveness, adhesiveness, and gumminess among experimental cheeses at the same storage day. Hardness, cohesiveness, and gumminess decreased significantly during storage period with the same salt treatment, whereas adhesiveness significantly increased. Environmental scanning electron microscope micrographs showed a compact and closed texture for cheeses at the same storage period. The microstructure of all cheeses became more closed and compact with storage period. Calcium content negatively correlated with hardness and Na and K contents during storage with the same salt treatment.     

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.     

The effect of pectin concentration on viscoelastic and sensory properties of processed cheese

The effect of pectin addition on viscoelastic properties of model processed cheeses with 40% w/w dry matter and 50% w/w fat in dry matter after 42 days of storage at temperature 6 ± 2 °C has been investigated using dynamic oscillation rheometry (plate–plate geometry; frequency range 0.1–50.0 Hz; temperature 20 °C). The role of pectin concentration (0.2%, 0.4%, 0.6% and 0.8% w/w) has been studied. Also, the sensory evaluation of samples has been made to assess cheese appearance, rigidity, spreadability and flavour. All samples with the pectin addition were more rigid and less spreadable compared with processed cheeses without pectin. With the increasing concentration of pectin the storage ( G ') and loss ( G ) moduli rose at the whole tested frequency range (0.1–50.0 Hz). Growing pectin content resulted in the decrease in loss tangent (the nature of gel was changed to more elastic material). The dependence of processed cheese rigidity on pectin concentration (in range 0–0.8% w/w) was not linear. The appearance and flavour were not worse by pectin addition.     

The effect of raw milk microbial flora on the sensory characteristics of Salers-type cheeses

The sensory characteristics of Salers Protected Denomination of Origin raw-milk cheeses are linked to the biochemical composition of the raw material (milk) and to the resultant microbial community. To evaluate the influence of the microbial community on sensory characteristics, Salers-type cheeses were manufactured with the same pasteurized milk, reinoculated with 3 different microbial communities from 3 different filtrates from microfiltered milks. Each cheese was subjected to microbial counts (on selective media), biochemical tests, and volatile and sensory component analyses at different times of ripening. Adding different microbial communities to specimens of the same (biochemically identical) pasteurized milk lead to different sensory characteristics of the cheeses. Cheeses with fresh cream, hazelnut, and caramel attributes were opposed to those with fermented cream, chemical, and garlic flavors. The aromatic compounds identified (esters, acids, alcohols, and aldehydes) in these cheeses were quite similar. Nevertheless, one milk was distinguished by a higher content of acetoin, and lower 2-butanone and 3-methylpentanone concentrations. Over the production period of 1 mo, the different cheeses were characterized by the same balance of the microbial population assessed by microbial counts on different media. This was associated with the stability of some sensory attributes describing these cheeses. Nevertheless, there was no linear correlation between microbial flora data and sensory characteristics as measured in this study.     

Prediction and repeatability of milk coagulation properties and curd-firming modeling parameters of ovine milk using Fourier-transform infrared spectroscopy and Bayesian models

The aim of this study was to apply Bayesian models to the Fourier-transform infrared spectroscopy spectra of individual sheep milk samples to derive calibration equations to predict traditional and modeled milk coagulation properties (MCP), and to assess the repeatability of MCP measures and their predictions. Data consisted of 1,002 individual milk samples collected from Sarda ewes reared in 22 farms in the region of Sardinia (Italy) for which MCP and modeled curd-firming parameters were available. Two milk samples were taken from 87 ewes and analyzed with the aim of estimating repeatability, whereas a single sample was taken from the other 915 ewes. Therefore, a total of 1,089 analyses were performed. For each sample, 2 spectra in the infrared region 5,011 to 925 cm^?1 were available and averaged before data analysis. BayesB models were used to calibrate equations for each of the traits. Prediction accuracy was estimated for each trait and model using 20 replicates of a training-testing validation procedure. The repeatability of MCP measures and their predictions were also compared. The correlations between measured and predicted traits, in the external validation, were always higher than 0.5 (0.88 for rennet coagulation time). We confirmed that the most important element for finding the prediction accuracy is the repeatability of the gold standard analyses used for building calibration equations. Repeatability measures of the predicted traits were generally high (≥95%), even for those traits with moderate analytical repeatability. Our results show that Bayesian models applied to Fourier-transform infrared spectra are powerful tools for cheap and rapid prediction of important traits in ovine milk and, compared with other methods, could help in the interpretation of results.     

Effects of exopolysaccharide-producing cultures on the viscoelastic properties of reduced-fat Cheddar cheese

The objective was to study the influence of different exopolysaccharide (EPS)-producing and nonproducing lactic cultures on the viscoelastic properties of reduced-fat Cheddar cheese. Changes in the viscoelastic properties were followed over a ripening period of 6 mo. Results showed that the elastic, viscous, and complex moduli were higher in reduced-fat cheeses made with EPS-nonproducing cultures than in full-fat cheese. No differences in the viscoelastic properties were found between young reduced-fat cheese made with a ropy strain of Lactococcus lactis ssp. cremoris (JFR1) and its full-fat counterpart. Interestingly, the changes in viscoelastic moduli in both full-fat cheese and reduced-fat cheese made with JFR1 during ripening followed the same pattern. Whereas the moduli increased during the first month of ripening in those 2 cheeses, a dramatic decrease was observed in all other cheeses. Slopes of the viscoelastic moduli as a function of frequency were lower in the full-fat than in reduced-fat cheeses. The creep test showed that fresh reduced-fat cheese made with JFR1 was less rigid and more deformable than that made with EPS-nonproducing cultures. The creep and recovery properties of young reduced-fat cheese made with JFR1 and the full-fat type were similar. No differences were found in the viscoelastic properties between reduced-fat cheese made with no EPS and those made with EPS-producing adjunct cultures of Streptococcus thermophilus. After 6 mo of ripening, cheeses made with EPS-producing cultures maintained lower elastic and viscous moduli than did those made with no EPS.     

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.     

Effect of anthocyanin-absorbed whey protein microgels on physicochemical and textural properties of reduced-fat Cheddar cheese

Reduced-fat foods have become more popular due to their health benefits; however, reducing the fat content of food affects the sensory experience. Therefore, it is necessary to improve the sensory acceptance of reduced-fat foods to that of full-fat equivalents. The aim of this study was to evaluate the effect of adding whey protein microgels (WPM) with an average diameter of 4 μm, or WPM with adsorbed anthocyanins [WPM (Ant)] on the textural and sensory properties of reduced-fat Cheddar cheese (RFC). Reduced-fat Cheddar cheese was prepared in 2 ways: (1) by adding WPM, designated as RFC+M, or (2) by adding WPM (Ant), designated as RFC+M (Ant). For comparison, RFC without fat substitutes and full-fat Cheddar cheese were also prepared. We discovered that the addition of WPM and WPM (Ant) increased the moisture content, fluidity, and meltability of RFC, and reduced its hardness, springiness, and chewiness. The textural and sensory characteristics of RFC were markedly inferior to those of full-fat Cheddar cheese, whereas addition of WPM and WPM (Ant) significantly improved the sensory characteristics of RFC. The WPM and WPM (Ant) showed a high potential as fat substitutes and anthocyanin carriers to effectively improve the acceptance of reduced-fat foods.