Quality Of Cheddar Cheese Research Articles

Composition and Quality of Cheddar Cheese

Cheddar cheese samples aged 3–12 months were obtained from Ontario and Quebec cheese factories. A total of 73 samples were collected in two lots (38 samples collected in June, 1987 and 35 samples collected in July 1987), graded by an Agriculture Canada cheese grader using a 10 point scale and analyzed for pH, fat, moisture and salt contents. The second lot (35 samples) was also analyzed for calcium, phosphorus and nitrogen content. Mean compositional values (%) and their respective coefficients of variation (%) were: moisture 34.4, 4.4; fat 33.5, 4.0; protein 24.2, 3.4; salt 1.69, 10.1; calcium 0.76, 11.8; phosphorus 0.51, 7.8. Regression analysis was used to evaluate relationships between grade scores for both texture and flavour and the following parameters: cheese pH, moisture in the nonfat substance (MNFS), salt in the moisture (SM), fat in the dry matter (FDM) calcium and phosphorus. None of the models tested were useful predictors of cheese quality. There was a weak (r=0.57) but significant (p<0.001) direct relationship between texture and flavor scores. SM decreased with increasing MNFS (p<0.001), and MNFS correlated directly with FDM. Molar ratios of calcium to phosphorus were inversely related to calcium content. RésuméDes échantillons de fromage cheddar agés de 3 à 12 mois furent obtenus de fromageries de l'Ontario et du Québec. Un total de 73 échantillons furent rassemblés en deux groupes (38 échantillons recueillis en juin 1987 et 35 échantillons recueillis en juillet 1987), classes par un classificateur de fromage d'Agriculture Canada d'après une échelle de 10 points et analysés pour le pH et les teneurs en matière grasse, en humidité et en sels. Le deuxième lot (35 échantillons) fut de plus analysé pour les teneurs en calcium, en phosphore et en azote. Les valeurs de composition moyennes (%) et leurs coefficients respectifs de variation (%) furent: humidité 34.4, 4.4; matière grasse 33.5, 4.0; protéine 24.2, 3.4; sels 1.69, 10,1; calcium 0.76, 11.8; phosphore 0–51,7.8. L'analyse de régression fut utilisée pour évaluer les rapports entre les notes de classification pour la texture et la saveur et les paramètres suivants: pH du fromage, humidité de la fraction dégraissée (MNFS), sel dans l'humidité (SM), matière grasse dans la matière sèche (FDM), calcium et phosphore. Acun de ces modèles étudiés s est avéré un prédicteur utile de la qualité du fromage. Une relation directe faible (r=0.57) mais significative (p<0.001) fut observée entre la texture et la saveur. SM diminua avec l'augmentation de MNFS (p.00), et MNFS fut corrélé directement avec FDM. Les ratios mo-

Effects of Bacterial Protease on the Quality of Cheddar Cheese

A heat-stable protease secreted by Pseudomonas fluorescens T25 was used to accelerate the ripening of cheddar cheese. Additions of the bacterial protease to pasteurized milk prior to the addition of a renneting agent (porcine pepsin) in the manufacture of cheddar cheese resulted in a product which showed a higher intensity of cheddar flavour (P < 0.05) and a better preference score (P < 0.01) within six months of aging when compared to that of the control cheese not containing the bacterial protease. Neither off-flavour nor bitterness was detected in the protease-treated cheese throughout the ripening period. The results of this study indicate that protease-T25 from Ps. fluorescens T25 may be a suitable agent to accelerate the ripening of cheddar cheese and also to enhance cheddar flavour.

Yield and Quality of Cheddar Cheese from High Somatic Cell Milk Supplemented with Retentate to Varying Concentrations or Directly Ultrafiltered

High somatic cell milk with a mean cell count of 2,235,000/ml was supplemented to 1.25:1 to 1.88:1 total protein with approximately 5.5:1 low somatic cell whole milk retentate of UF. Curd formation time of cheese milk decreased with increasing concentration of SCC. Supplemented milk concentrated to 1.65: 1 and 1.88:1 total protein displayed normal curd formation times: 34 and 31min, respectively. Also, cheese made from these mixtures had normal moisture, whereas the remaining cheeses had higher than normal moisture. Supplementation to 1.65:1 and 1.88:1 total protein increased cheese yield by 9.67% and 11.38%, respectively, and produced excellent quality cheese after 2 mo at 10°C.Direct UF of high SCC milk to 1.84:1 total protein improved cheese quality and increased yield over control milk cheeses but not to the same high level attained with retentate supplementation.

Use of Recombinant Chymosin in the Manufacture of Cheddar and Colby Cheese

Recombinant chymosin purified from E. coli K12 (Genencor Inc.) was examined for its suitability to manufacture Cheddar cheese. Commercial calf rennet or recombinant chymosin with and without Bacillus subtilis cellular homogenate was used to determine if enzyme sources affected Cheddar cheese quality or yield. Cheese was evaluated at 3 and 6 mo of age. Purified enzyme was mixed with cellular extracts from B. subtilis at approximately one and four times the protein concentration in the initial homogenates. Cellular materials did not affect clot times, cheese quality, or inhibit cheese acid development. No differences were noted between the yields of Colby cheese manufactured with calf rennet and recombinant chymosin. Initial Cheddar cheese manufactured with recombinant chymosin were excessively bitter, typical of cheese retaining excessive amounts of proteases. Dilution of purified prochymosin preparations increased total enzymic activity 2.7 times. Evidently, the purified recombinant preparations contained some oligomers that became active after being incorporated into the cheese mass, causing bitter flavors to develop during aging. Diluted enzyme preparations were used successfully in the manufacture of Cheddar cheese.

A comparison of the effects of storage of raw milk at 2°C and 6°C on the yield and quality of Cheddar cheese

The advantages of storing raw milk, which is to be used for Cheddar cheese manufacture, at 2°C rather than at 6°C was examined. Storage of milk at the lower temperature effectively reduced the level of psychrotroph growth, and after 4 days the psychrotroph counts in samples stored at 2°C were 100-fold lower than those found in samples stored at 6°C. There was no advantage in terms of cheese yield in storing milks at the lower temperature, but an overall improvement in cheese quality was noted in samples produced from milk stored at 2°C.

Protein Quality of Cheddar Cheese Compared with Casein and Fabricated Cheese in the Rat

ABSTRACTThe protein quality of freeze‐dried cheddar cheese, spray‐dried cheddar cheese, freeze‐dried fabricated cheddar cheese (with casein as the main protein source), and sodium caseinate was evaluated in rats using the protein efficiency ratio (PER) assay (AOAC procedures) in two feeding experiments with casein as the control. Biological evaluation of the products showed that PER values for freeze‐dried cheddar cheese were significantly higher than casein (3.7 vs 2.5). Freeze‐dried cheddar also had a PER value significantly higher than spray‐dried cheddar cheese (3.7 vs 3.0). Freeze‐dried fabricated cheddar cheese and sodium caseinate had PER values not significantly different from the casein control.

Assessment of Cheddar Cheese Quality by Chromatographic Analysis of Free Amino Acids and Biogenic Amines

ABSTRACTThe free amino acids and biogenic amines extracted from normal and late‐gassing Cheddar cheeses were derivatized with heptafluorobutyric anhydride and trifluoroacetic anhydride, respectively, before quantification by gas‐liquid chromatography. On a microgram scale, twenty amino acids were positively identified in both types of cheese, but only high levels of γ‐amino acid butyrate (0.3 to 19.4 mg/g) and small quantities of arginate were found to be associated with “poorly aged” Cheddar cheeses. Histamine (1.54 and 1.22 mg/g) and tyramine (0.32 and 0.43 mg/g) were the bioamines present in highest concentrations in both cheeses.

Effects of variations in somatic cell count on the rennet coagulation properties of milk and on the yield, composition and quality of Cheddar cheese

SummaryCheddar cheeses were prepared from low somatic cell count (SCC) milks and from milks containing 10, 20 and 30% added high SCC milk to give modestly elevated SCC. Increased SCO in the milk were associated with a reduction in the coagulum strength and an increase in moisture content of the cheeses. Cheese texture was affected significantly as judged both by the findings of an assessment panel and by instrumental physical measurement. The panel scores for flavour were also slightly altered. It was concluded that even a small increase in SCC is detrimental to cheese composition and quality, although no significant effects on yield were detected. Relationships between cheese yield, composition and properties, coagulation properties and composition of the milk were also studied. Yield was related to the total solids and fat in the milk but not to the coagulation properties or the flavour or texture of the cheeses. Coagulum strength, cheese composition and cheese texture were strongly interrelated.

Evaluation of Yield and Quality of Cheddar Cheese Manufactured from Milk with Added Whey Protein Concentrate

Cheddar cheese was produced from whole milk with blends of whey protein concentrates added. Two whey protein concentrate powders containing 35 or 55% protein were each reconstituted to a 15% (wt/wt) suspension and heat treated at 70°C for 15min. Addition of the denatured whey protein concentrate suspension to the milk was at 5 or 10% by weight of the milk. Addition of reconstituted partially denatured whey protein concentrate increased cheese yields from 1.4 to 6.2% above those of the control on a 63% solids basis. The only significant (P<.05) increase in yield was from the 55% whey protein concentrate suspension at 10% replacement by weight of the milk. The correlation coefficient between percent denaturation in the whey protein concentrate and yield in this cheese was .62. Experimental cheese had decreased fat and total solids contents and increased total nitrogen, ash, and salt. Fat reduction varied from 4.3 to 18.2% below the control cheese, and total solids were from 1.7 to 8.9% below the control cheeses. Total nitrogen values of experimental cheese were from .73 to 5.64% above the control. Cheeses were evaluated organoleptically; more flavor defects were associated with increased whey protein concentrate in the experimental cheese. The most common criticism of the experimental cheese was an atypical (unclean) cheese flavor.

Effect of Total and Partial Substitution of Sodium Chloride on the Quality of Cheddar Cheese

Cheddar cheese was manufactured to give 1.6% residual sodium chloride or equivalent amounts (ionic strength basis) of magnesium chloride, calcium chloride, potassium chloride, or 1:1 mixtures of sodium chloride and the chloride salt of magnesium, calcium, or potassium from two split batches of curd. Sensory evaluation after 4 mo ripening at 4°C showed that cheese salted solely with magnesium chloride, calcium chloride, or potassium chloride was extremely bitter and totally unacceptable. There was extensive lipolysis (as measured by free fatty acid development) in the cheese salted with magnesium chloride, calcium chloride, or potassium chloride. Proteolysis was highest in the cheese salted with calcium chloride and magnesium chloride. These cheese gave the lowest Instron values for firmness, hardness, and cuttability. Extensive proteolysis in these cheese may be partly due to the low salt in moisture. Taste panel scores for flavor and texture of the sodium chloride/calcium chloride and sodium chloride/magnesium chloride salted cheese were significantly lower than the scores for the control cheese. Scores for flavor and texture of the potassium chloride/sodium chloride salted cheese were not significantly different from scores of the control cheese.

Effect of incorporation of denatured whey protein on the yield and quality of Cheddar cheese

Concentrated suspensions of a denatured protein‐fat complex were prepared by centrifugation of whey which had been heated in acid conditions. Significant improvements in cheese yield were obtained on adding the concentrate to milk for cheesemaking before renneting. A maximum increase in yield of 7% was attained in manufacturing Cheddar cheese which satisfied the legal requirements for moisture content. No consistent texture or flavour defects were evident in the cheese during the first jive months of maturation.

A comparison of the quality of Cheddar cheese produced from seasonal and standardized milk

The quality of Cheddar cheese made from seasonal and standardized milk has been assessed over a 12‐month period. There was a slight consumer preference for cheese made from seasonal milk, but the difference was small and unlikely to be of commercial significance. Grade scores for cheese ‘body’ were not reflected in a consumer taste panel assessment of the quality of the mature cheese.

Production and Quality of Cheddar Cheese Manufactured from Whole Milk Concentrated By Reverse Osmosis

ABSTRACTPasteurized whole milk was concentrated by reverse osmosis (RO) on a pilot plant scale. The retentate was then used to produce cheddar cheese following the traditional method but using 50% less starter and 60% less rennet. The biochemical composition of the RO cheese was close to that of ordinary cheddar. The resulting non uniformity of the fresh curd as well as the granular texture of the cheese were probably due to the high lactose content of the retentate. Contamination of the milk from bacteria already present in the reverse osmosis system caused the high coliform level of the cheese.

Effect of Sodium/Potassium (1:1) Chloride and Low Sodium Chloride Concentrations on Quality of Cheddar Cheese

Cheddar cheese samples containing either 1.25, 1.5, or 1.75% sodium chloride or 1.25 or 1.5% sodium/potassium chloride (1:1, molar basis) were manufactured from a split lot of cheese curd. Sensory analysis of the cheeses through 9 mo aging at 3°C showed that all samples were acceptable although some bitterness was observed, especially in the cheese containing 1.5% mixture. Body and texture of samples were firm, reflecting the 35% moisture content of the samples. Cheeses containing potassium chloride had higher contents of free fatty acids than those with only sodium chloride. Mean consumer preference scores showed that some consumers recognized and preferred the fuller salty taste of cheeses with higher sodium chloride concentrations over those with the small amounts or the mixture. Unsalted Cheddar cheese was disliked strongly by a laboratory panel.

Effect of Using Frozen Concentrated Direct‐to‐the‐Vat Culture on the Yield and Quality of Cheddar Cheese

ABSTRACTApproximately 53,000 liters (14,000 gal) pasteurized whole milk was used to make 16 batches of cheese, eight control batches using conventional bulk starter and eight batches using a frozen concentrated direct‐to‐the‐vat culture. The calculated yields were based on both the weight of milk and cheese, and on the weight of milk solids and cheese solids. The yields averaged, respectively, 9.517% and 48.608% with the bulk starter and 9.707% and 49.191% with the frozen concentrated culture. These differences, slightly favoring the frozen concentrated direct‐to‐the‐vat culture, can be of economic and commercial significance. The compositions of the cheeses made with the two starter cultures were very similar. Sensory evaluation did not reveal significant differences in flavor and texture of the two types of cheese when examined at 3, 6, 9 and 12 months.

Defined Single Strains of Lactic Streptococci in Bulk Culture for Cheddar and Monterey Cheese Manufacture

Acid production and Cheddar cheese quality were improved at three cheese plants when undefined commercial blends of “lactic cultures were removed and replaced with phage insensitive, single strains propagated either in pairs or in one multiple blend of five or six strains. The paired strain program worked in one plant for over 12 mo with only six strains used during the last 7 mo. Two mutants replaced parent strains. The multiple blend worked for 6 mo in two plants with only one mutant replacing a parent strain. Careful phage-activity monitoring and strain selection were necessary to assure optimal success of the programs. A refrigerated reserve culture was used to provide back-up for the primary blend in the plant using the paired strain program. Make time and final cheese pH were more uniform than when undefined culture blends were used.

Effect of proteolytic raw milk psychrotrophs on Cheddar cheese-making with stored milk

SummaryThe effect of proteolytic, psychrotrophic strains of Pseudomonas fluorescens, Ps. putida and Acinetobacter spp. on cheese-making with stored milk has been investigated. Ps. fluorescens and Ps. putida growing for 72 h in raw milk at 7·5 °C to levels of approx. 107 colony-forming units/ml caused a low degree of β- and к-casein breakdown detectable by gel electrophoresis, but this was insufficient to affect N losses in whey or cheese yields. Variations in cheese-making times with pasteurized milks were not attributable to the counts of psychrotrophs in the corresponding raw milks. The water-soluble and TCA-soluble N fractions of maturing cheeses were unaffected by psychrotroph counts in raw milks, but small differences in levels of casein fractions of cheeses made from milks stored for 72 h were detected by quantitative polyacrylamide gel electrophoresis. The incidence of casein breakdown in raw milk and subsequently in cheese were not necessarily related. None of the cheeses developed off flavour related to excessive protein breakdown but many became lipolytically rancid, despite the selection of strains with low lipolytic activity on a diagnostic medium. It is concluded that the numbers of psychrotrophic bacteria likely to occur in stored raw milk under commercial conditions are unlikely to cause significant changes in the yields or quality of Cheddar cheese through their proteolytic activity.

Lactose, lactic acid and mineral equilibria in Cheddar cheese manufacture

SummaryIn experimental small-scale manufacture of Cheddar cheese a study was made of the movement of lactose, lactic acid, calcium and phosphorus between curd and whey, and of the effect of high acidity developed in the curd before whey separation, on the pH and physical properties of the cheese. It was found that while the curd particles remain in contact with the whey, the lactose fermented in the curd is replaced by lactose diffusing from the whey. Lactic acid produced in the curd diffuses into the whey rather slowly.When a high lactic acid level is attained rapidly the curd does not cheddar well, the pH of the cheese is low, the flavour is sour and bitter, the body is crumbly and the cheese is bleached. When a high lactic acid level is reached slowly, the curd also does not cheddar properly but the pH of the cheese may be within normal limits up to 3 weeks, at which age its body is coherent and its colour is normal. However, on maturing, the cheese becomes acid, the body crumbly and liquid separation occurs even at 2 months of age. This points to a risk in grading cheese at an early age.It is suggested that the abnormal behaviour in cheddaring of ‘high-acid’ curds is connected with an excessive loss of calcium. When high acidity is developed over an extended time in the whey, the curd retains more lactose but loses more phosphorus so that its buffering capacity is reduced. Cheese made from such curd becomes highly acid at maturity and this leads to the development of a bitter flavour.It is, therefore, concluded that both the rate of development of acidity, and the time the curd is in the whey, are critical factors in controlling the quality of Cheddar cheese.

Relationship between Melting Quality and Hardness of Cheddar Cheese

Summary The relationship between melting quality, expressed as melting time, and cheese hardness was investigated. A relatively high correlation coefficient, +0.799, was found. Cheese hardness can be used as a means of predicting the melting quality of Cheddar cheese. The relationship of the fat content, the moisture content, and pH values to the melting quality and hardness of Cheddar cheese was investigated. These factors influenced hardness more than melting quality, but the effect, either separately or combined, was not strong enough to account for the wide variations found in melting quality or hardness.

Effect of Certain Chemical Factors on the Melting Quality of Process Cheese

Summary Fat and moisture contents, pH level, and free tyrosine level were not related to the melting quality of Cheddar cheese. Free tyrosine increased as the cheese aged. No relationship was noted between melting quality and fat, moisture, or pH level of process cheese, but the evidence indicated that when free tyrosine was above a given level, the melting quality was satisfactory.