Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cheese”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed2003

Evidence of a relationship between autolysis of starter bacteria and lipolysis in cheddar cheese during ripening.

Cell viability, autolysis and lipolysis were studied in Cheddar cheese made using Lactococcus lactis subsp. cremoris AM2 or Lactococcus lactis subsp. cremoris HP. Cheddar cheese was made in triplicate over a 3 month period and ripened for 238 days at 8 degrees C. Cell viability in cheese was lower for AM2 (a non-bitter strain) than for strain HP (a bitter strain). Autolysis, monitored by the level of the intracellular marker enzyme, lactate dehydrogenase (EC 1.1.1.27) in cheese 'juice' extracted by hydraulic pressure, was much greater in the cheese made using AM2 than that made with HP. Lipolysis was determined by the increase during ripening of individual free fatty acids (FFA) from butyric (C4:0) to linolenic acid (C18:3) measured using a high performance liquid chromatographic technique. Levels of individual FFA from butyric (C4:0) to linolenic (C18:3) acids increased significantly (P<0.05) during ripening in cheeses made with either starter culture. Palmitic (C16:0) and oleic (C18:1) acids were the most abundant FFA throughout ripening in all cheeses. Levels of caprylic (C8:0), myristic (C14:0), palmitic (C16:0) and stearic (C18:0) acids were significantly higher (P<0.05) in cheeses manufactured with Lc. lactis subsp. cremoris AM2 than in cheeses manufactured with Lc. lactis subsp. cremoris HP. Differences in levels of lipolysis between strains was not due to differences in the specific lipolytic or esterolytic activities in cell free extracts of the strains as measured by activity on triolein (lipase) and p-nitrophenylbutyrate (esterase) substrates. Therefore, evidence is provided for a relationship between the extent of starter cell autolysis and the level of lipolysis during Cheddar cheese ripening.

Bacteriolysis↗
PubMed2005

Specific effect of high-pressure treatment of milk on cheese proteolysis.

The extent of primary and secondary proteolysis of cheeses made from raw (RA), pasteurized (PA, 72 degrees C, 15 s) or pressure-treated (PR, 500 MPa, 15 min, 20 degrees C) goats' milk was assessed. Modifications in cheese-making technology were introduced to obtain cheeses with the same moisture content, and thus studied per se the effect of milk treatment on cheese proteolysis. The PR milk cheese samples were differentiated from RA and PA milk cheeses by their elevated beta-lg content, and by the faster degradation of alphas1-, alphas2- and beta-CN throughout ripening. Non-significant differences were found in either pH 4.6 soluble-nitrogen or trichloracetic acid soluble-nitrogen contents of cheeses. However, the pasteurization of milk decreased the free amino acid production in cheese. The RA milk cheeses had the highest amount of proline and the lowest concentrations of serine, tyrosine, arginine and alpha-aminobutyric acid, whereas PR milk cheese showed higher levels of arginine.

Amino Acids↗
PubMed1999

Influence of the composition of Alpine highland pasture on the chemical, rheological and sensory properties of cheese.

A study was undertaken to compare the chemical and sensory characteristics of Abondance cheeses made with milk from animals grazing areas within the same highland pasture, but with different predominant plants. Nine cheeses made during the last 3 d of three successive 7 d periods were evaluated. The animals grazed on the southern side of the highland pasture during the first period (15-21 June), on the northern side during the second period (22-29 June) and returned to the southern side for the third period (30 June-6 July). The gross composition of the cheeses did not vary between periods. 'North' cheeses contained more plasmin, gamma-casein, alpha s1-I-casein and water-soluble N than 'south' cheeses. Both sensory and instrumental measurements indicated that north cheeses were less firm, stickier and more easily fractured than south cheeses. North cheeses were also more salty, bitter and persistent. Their overall aroma was more intense and they had more intense sour, burnt, toasted, fermented vegetable and sweat aromas, but less intense toffee, exotic fruit and acid milk aromas. The texture differences noted between the cheeses from milk produced on the two areas may come from differences in primary proteolysis, partly due to different amounts of plasmin and plasminogen in milk and in cheeses. The aroma differences were related to differences in volatile compounds. Some compounds had a microbial origin, while some others may have come from the pasture.

Animal Feed↗
PubMed2006

Ethyl ester formation is enhanced by ethanol addition in mini Swiss cheese with and without added propionibacteria.

Esters are important contributors to cheese flavor, but their mechanisms of synthesis in cheese are largely unknown. This study aimed to determine whether ethanol concentration limits the formation of ethyl esters in cheese. Mini Swiss cheeses were manufactured with (E) or without (C) the addition of ethanol to cheese milk. Ethanol concentrations (enzymatic analysis) were 64 +/- 17 and 330 +/- 82 microg g(-1), respectively, in C and E cheeses. E cheeses also contained 5.4 +/- 2.3 times more of the five ethyl esters quantified than C cheeses, regardless of the concentrations of esters in C cheeses (range 1-128 ng g(-1)). Furthermore, the presence of propionibacteria added as acid-producing secondary starters was associated with greater concentrations of esters, due to the increase in acid concentrations that propionibacteria induced and/or to an involvement of propionibacteria enzymes in ester synthesis. This study demonstrates that ethanol is the limiting factor of ethyl ester synthesis in Swiss cheese.

Cheese↗
PubMed2000

Flavor enhancement of reduced fat cheddar cheese using an integrated culturing system.

Mild cheese flavor in reduced fat Cheddar cheese was enhanced by using an integrated starter culture system. Three cultures, Lactococcus lactis subsp. cremoris SK11, L. lactis subsp. lactis biovar. diacetylactis JVI, and Lactobacillus casei 7A, were carefully selected to obtain a nonbitter, mildly acid, buttery flavored cheese. Cheeses were produced from all possible combinations of these cultures with the constraint that L. lactis subsp. cremoris SK11 was used as the primary acid-producing culture. Cheeses made with SK11 were compared to cheeses produced using an L. lactis subsp. cremoris commercial starter culture. Cheeses were ripened for 150 days and periodically sampled for chemical, microbiological, and sensory analysis. Cheeses produced with L. lactis subsp. cremorisSK11 had substantially lower bitterness intensity than the cheeses produced with commercial starter culture. L. lactis subsp. lactis biovar. diacetylactis JVI significantly increased diacetylacetoin and acetate concentrations. Sensory results indicate that these cheeses had increased buttery (diacetyl) flavor.

Cheese↗
PubMed2000

Chemical and microbiological characteristics of ewes' milk cheese manufactured with extracts from flowers of Cynara cardunculus and Cynara humilis as coagulants.

The chemical and microbial characteristics as well as the flavor and aroma of Los Pedroches cheese made using aqueous extracts of Cynara cardunculus L. flowers were compared with those of cheeses manufactured with extracts of Cynara humilis L. throughout ripening. The two thistle species assayed were found to have no appreciable effect on the moisture, fat, protein, and NaCl contents of the cheese or on its water activity, flavor, and aroma; however, the use of C. humilis resulted in reduced lactic acid content (p < 0.001) and higher pH values (p < 0.05) relative to those of cheese specimens produced with C. cardunculus. The protein breakdown of the cheeses was assessed in terms of soluble nitrogen (SN), nonprotein nitrogen (NPN), and amino acid nitrogen (AAN). Proteolysis was more marked and rapid in cheese containing C. cardunculus as coagulant, the SN and NPN contents of which were significantly higher (p < 0. 01) than those of the cheese obtained with the species C. humilis; AAN contents were similar in both species of Cynara throughout ripening. Although total viable, coliform, and lactobacilli counts were similar in cheeses produced with both types of plant coagulant throughout ripening, enterobacteria and yeasts counts (p < 0.01) and molds counts (p < 0.05) were higher in cheese produced with C. humilis than in cheese obtained with C. cardunculus.

Animals↗
PubMed2002

The effect of vegetable oil-based cheese on serum total and lipoprotein lipids.

OBJECTIVE: To investigate the effect of rapeseed oil-based cheese (milk-fat substituted by rapeseed oil) on serum total and lipoprotein lipid concentrations and blood pressure in reference to ordinary, milk-fat-based cheese in subjects with mildly to moderately elevated serum cholesterol concentration. DESIGN: Randomized, controlled, single-blind, cross-over clinical trial. SETTINGS: Outpatient dietary intervention with free-living subjects in Eastern Finland. INTERVENTIONS: The study began with a 2 week pre-trial period followed by two 4 week intervention periods. During the intervention study subjects replaced their ordinary cheese or cold cuts with 65 g of rapeseed oil-based or milk-fat-based control cheese. The type of test cheese was switched at 4 weeks of intervention. Altogether 31 subjects completed the study. RESULTS: Compared with the control cheese period the mean serum total cholesterol concentration was 6.7% (95% Cl -9.9 to -3.5%) lower after 2 weeks and 5.0% (95% Cl -7.5 to -2.5%) lower after 4 weeks of use of rapeseed oil-based cheese. Respectively, LDL cholesterol concentration was 7.0% (95% Cl -11.7 to -2.6%) lower after 2 weeks use and 6.4% (95% Cl -10.0 to -2.8%) lower after 4 weeks' use of rapeseed oil-based cheese. CONCLUSIONS: The present study showed that the rapeseed oil-based cheese reduces serum total and LDL cholesterol concentrations in mildly to moderately hypercholesterolemic subjects when replacing ordinary milk-fat-based cheese in the diet. SPONSORSHIP: Mildola Ltd, Tuusula, Finland and Kyrönmaan Juustomestarit Ltd, lsokyrö, Finland.

Adult↗
PubMed2005

Dairy fat in cheese raises LDL cholesterol less than that in butter in mildly hypercholesterolaemic subjects.

OBJECTIVE: To determine whether dairy fat in cheese raises low-density lipoprotein (LDL) cholesterol as much as in butter, since epidemiology suggests a different impact on cardiovascular disease. DESIGN: A randomised crossover trial testing the daily consumption of 40 g dairy fat as butter or as matured cheddar cheese, each of 4 weeks duration, was preceded by and separated by 2-week periods when dietary fat was less saturated. SETTING: Free-living volunteers. SUBJECTS: A total of 14 men and five women of mean age 56+/-8 y, with mean total cholesterol of 5.6+/-0.8 mmol/l. MAIN OUTCOME MEASURES: Plasma cholesterol, LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), triacylglycerol and glucose. RESULTS: Saturated fat intake was significantly lower during the run-in than during the cheese and butter periods. Mean lipid values did not differ significantly between the cheese and run-in periods, but total cholesterol and LDL-C were significantly higher with butter: total cholesterol (mmol/l): butter 6.1+/-0.7; run-in 5.6+/-0.8 (P < 0.05; ANOVA with Bonferroni adjustment); vs cheese 5.8+/-0.6 (P > 0.05); median LDL-C (mmol/l): butter 3.9 (3.5-4.1) vs run-in 3.4 (3.0-4.1) (P < 0.05; Tukey test); vs cheese 3.7 (3.3-3.9) (P > 0.05). Among 13 subjects whose initial LDL-C was >4 mmol/l, the difference between butter (4.4+/-0.3 mmol/l) and cheese (3.9+/-0.3 mmol/l) was significant (P = 0.014). HDL-C was highest with butter and triacylglycerol with cheese (neither was significant). CONCLUSION: A total of 40 g dairy fat eaten daily for 4 weeks as butter, but not as cheese, raised total and LDL cholesterol significantly compared with a diet containing significantly less saturated fat. Dietary advice regarding cheese consumption may require modification.

Analysis of Variance↗
PubMed1996

Bioavailability of calcium of fresh cheeses, enteral food and mineral water. A study with stable calcium isotopes in young adult women.

True fractional Ca absorption from six foods was measured in twelve normal healthy women, aged 20-29 years. The tested foods were commercially available fresh cheese, fresh cheese prepared by new technology and rich in Ca, similar cheese with added Fe, enteral food, mineral water alone and combined with a spaghetti meal. The aim of the study was to investigate: (1) Ca absorption from a new Ca-rich fresh cheese and to compare it with that from the traditional commercial type of fresh cheese; (2) the effect of Fe enrichment of the new cheese on Ca absorption; (3) Ca absorption from the mineral water and the enteral product and to compare it with that from the dairy products; (4) the effect of a meal combined with the mineral water on Ca absorption. All test foods were consumed by all subjects according to a design with two Latin squares. Each treatment of 2 d was followed by a wash-out period of 2 weeks. Ca absorption was measured using a double stable-isotope (44Ca and 48Ca) extrinsic labelling technique. Mean fractional Ca absorption from the new fresh cheese was not significantly different from that from the traditional type (37.7 (SD 10.2)% v. 42.2 (SD 11.6)%). The addition of Fe to the new cheese did not significantly influence Ca absorption. Ca-absorption values from the mineral water (37.0 (SD 9.8)%) and from the enteral product (42.6 (SD 11.4)%) were not significantly different from those from the dairy products (37.7-42.2%, SD 10.2-11.6%). The co-ingestion of a spaghetti meal with the mineral water significantly enhanced Ca absorption from 37 (SD 9.8)% to 46.1 (SD 11.7)%. It is concluded that a new process leading to a fresh cheese with a higher Ca concentration does not alter Ca bioavailability compared with the standard technology and for a constant Ca supply. Thus this new fresh cheese would probably provide more Ca than the standard one. The fractional Ca-absorption values for mineral water and the enteral product indicate that these products can make an interesting contribution to Ca supply for populations with a low Ca intake and patients with specific diseases respectively.

Adult↗
PubMed1994

A study of the microbiological status of Irish farmhouse cheeses with emphasis on selected pathogenic and spoilage micro-organisms.

Ninety-six 25 g samples from 25 Irish farmhouse cheeses, two Irish non-farmhouse cheeses and four foreign cheeses were evaluated for the presence of a variety of micro-organisms, namely, coliforms, faecal streptococci, Staphylococcus aureus, yeasts, moulds, salmonellas and shigellas. Seventeen cheeses, i.e. the soft and semi-soft types, were examined for Listeria monocytogenes. Most of the farmhouse cheeses are currently manufactured from raw milk, but some producers now use heat-treated milk. The incidence of coliforms and faecal coliforms was higher in soft, semi-soft and semi-hard cheeses than in hard types. High levels of contamination by faecal streptococci and non-pathogenic (coagulase-negative) Staph. aureus prevailed in a high proportion of the cheeses. Pathogenic (coagulase-positive) staphylococci, however, were also isolated from 50% of the cheeses, some of which were manufactured from pasteurized milk. Yeasts were found mainly in unpasteurized varieties, especially in the category of soft cheeses. Moulds were isolated from five non-mould-ripened cheeses, as well as from mould-ripened varieties. Salmonellas, shigellas and Listeria monocytogenes were not detected after direct enrichment.

Cheese↗
PubMed2005

Combined effect of high-pressure treatments and bacteriocin-producing lactic acid bacteria on inactivation of Escherichia coli O157:H7 in raw-milk cheese.

The effect of high-pressure (HP) treatments combined with bacteriocins of lactic acid bacteria (LAB) produced in situ on the survival of Escherichia coli O157:H7 in cheese was investigated. Cheeses were manufactured from raw milk inoculated with E. coli O157:H7 at approximately 10(5) CFU/ml. Seven different bacteriocin-producing LAB were added at approximately 10(6) CFU/ml as adjuncts to the starter. Cheeses were pressurized on day 2 or 50 at 300 MPa for 10 min or 500 MPa for 5 min, at 10 degrees C in both cases. After 60 days, E. coli O157:H7 counts in cheeses manufactured without bacteriocin-producing LAB and not pressurized were 5.1 log CFU/g. A higher inactivation of E. coli O157:H7 was achieved in cheeses without bacteriocin-producing LAB when 300 MPa was applied on day 50 (3.8-log-unit reduction) than if applied on day 2 (1.3-log-unit reduction). Application of 500 MPa eliminated E. coli O157:H7 in 60-day-old cheeses. Cheeses made with bacteriocin-producing LAB and not pressurized showed a slight reduction of the pathogen. Pressurization at 300 MPa on day 2 and addition of lacticin 481-, nisin A-, bacteriocin TAB 57-, or enterocin AS-48-producing LAB were synergistic and reduced E. coli O157:H7 counts to levels below 2 log units in 60-day-old cheeses. Pressurization at 300 MPa on day 50 and addition of nisin A-, bacteriocin TAB 57-, enterocin I-, or enterocin AS-48-producing LAB completely inactivated E. coli O157:H7 in 60-day-old cheeses. The application of reduced pressures combined with bacteriocin-producing LAB is a feasible procedure to improve cheese safety.

Animals↗
PubMed2000

Composition of Ragusano cheese during aging.

Ragusano cheese is a brine-salted pasta filata cheese. Composition changes during 12 mo of aging were determined. Historically, Ragusano cheese has been aged in caves at 14 to 16 degrees C with about 80 to 90% relative humidity. Cheeses (n = 132) included in our study of block-to-block variation were produced by 20 farmhouse cheese makers in the Hyblean plain region of the Province of Ragusa in Sicily. Mean initial cheese block weight was about 14 kg. The freshly formed blocks of cheese before brine salting contained about 45.35% moisture, 25.3% protein, and 25.4% fat, with a pH of 5.25. As result of the brining and aging process, a natural rind forms. After 12 mo of aging, the cheese contained about 33.6% moisture, 29.2% protein, 30.0% fat, and 4.4% salt with a pH of 5.54, but block-to-block variation was large. Both soluble nitrogen content and free fatty acid (FFA) content increased with age. The pH 4.6 acetate buffer and 12% TCA-soluble nitrogen as a percentage of total nitrogen were 16 and 10.7%, respectively, whereas the FFA content was about 643 mg/100 g of cheese at 180 d. Five blocks of cheese were selected at 180 d for a study of variation within block. Composition variation within block was large; the center had higher moisture and lower salt in moisture content than did the outside. Composition variation within blocks favored more proteolysis and softer texture in the center.

Cheese↗
PubMed2000

Effect of milk preacidification on low fat mozzarella cheese. I. Composition and yield.

The effect of milk preacidification with acetic or citric acid on the composition and yield of low fat Mozzarella cheese was determined. Two cheese manufacturing trials were conducted. In trial 1, three vats (230 kg of milk per vat) of cheese were made in 1 d using no preacidification (control) and preacidification to pH 6.0 and pH 5.8 with citric acid. In trial 2, four vats (230 kg of milk per vat) of cheese were made in 1 d using no preacidification (control), preacidification to pH 6.0 and 5.8 with acetic acid, and preacidification to pH 5.8 with citric acid. Cheese manufacture was repeated on three different days in trial 1 and four different days in trial 2 using a randomized-complete block design. Preacidification to pH 5.8 with citric acid decreased cheese calcium more than preacidification to pH 5.8 with acetic acid. Preacidification with citric acid in trial 1 decreased protein recovery in the cheese, and there was a trend for decreased protein recovery in the cheese for trial 2. Differences in fat recovery due to preacidification varied, sometimes being lower than the control other times being higher than the control. The reduction in calcium and protein recovery in the cheese caused by preacidification lowered composition adjusted cheese yield and yield efficiency. Yield efficiency was reduced by about 2.5 and 5.5%, respectively, with preacidification to pH 6.0 and 5.8 with citric acid. Yield efficiency was reduced by about 2.2 and 3.4%, respectively, with preacidification to pH 6.0 and pH 5.8 with acetic acid.

Acetic Acid↗
PubMed2002

An empirical method for prediction of cheese yield.

Theoretical cheese yield can be estimated from the milk fat and casein or protein content of milk using classical formulae, such as the VanSlyke formula. These equations are reliable predictors of theoretical or actual yield based on accurately measured milk fat and casein content. Many cheese makers desire to base payment for milk to dairy farmers on the yield of cheese. In small factories, however, accurate measurement of fat and casein content of milk by either chemical methods or infrared milk analysis is too time consuming and expensive. Therefore, an empirical test to predict cheese yield was developed which uses simple equipment (i.e., clinical centrifuge, analytical balance, and forced air oven) to carry out a miniature cheese making, followed by a gravimetric measurement of dry weight yield. A linear regression of calculated theoretical versus dry weight yields for milks of known fat and casein content was calculated. A regression equation of y = 1.275x + 1.528, where y is theoretical yield and x is measured dry solids yield (r2 = 0.981), for Cheddar cheese was developed using milks with a range of theoretical yield from 7 to 11.8%. The standard deviation of the difference (SDD) between theoretical cheese yield and dry solids yield was 0.194 and the coefficient of variation (SDD/mean x 100) was 1.95% upon cross validation. For cheeses without a well-established theoretical cheese yield equation, the measured dry weight yields could be directly correlated to the observed yields in the factory; this would more accurately reflect the expected yield performance. Payments for milk based on these measurements would more accurately reflect quality and composition of the milk and the actual average recovery of fat and casein achieved under practical cheese making conditions.

Animals↗
PubMed2002

Proteolytic specificity of Lactobacillus delbrueckli subsp. bulgaricus influences functional properties of mozzarella cheese.

Low-moisture part-skim Mozzarella cheeses were manufactured from 2% fat milk and aged for 21 d. Treatments included cheeses made with one of three different strains of Lactobacillus delbrueckii ssp. bulgaricus in combination with a single strain of Streptococcus thermophilus. A fourth, control treatment consisted of cheeses made with only S. thermophilus. Although total proteolytic ability of these strains, as indicated by the o-phthaldialdehyde analysis, was similar in each of the three strains of L. bulgaricus, these strains exhibited different proteolytic specificities toward the peptide, alpha(s1)-CN (f 1-23). On the basis of their alpha(s1)-CN (f 1-23) cleavage patterns and a previously described classification, these strains were assigned to the groups I, III, and V. The objective of this study was to investigate the influence of lactobacilli proteolytic systems, based on specificity toward alpha(s1)-CN (f 1-23), on functionality of part-skim Mozzarella cheese. Moisture, fat, protein, salt-in-moisture, and moisture in nonfat substances content of cheeses made with groups I, III, and V strain were similar. Control cheese had a lower moisture content than did other treatments. Significant differences were observed in functional properties between cheeses manufactured using groups III and V strains. Cheeses made with groups I and III strains were similar in their meltability, hardness, cohesiveness, melt strength, and stretch quality. Meltability and cohesiveness increased with age, while melt strength and stretch quality decreased with age for all cheeses. Additionally, HPLC showed that total peak areas of water-soluble peptides derived from cleavage of alpha(s1)-CN (f 1-23) by different strains of lactobacilli could be highly correlated to meltability and stretch characteristics of cheeses made with those strains.

Amino Acid Sequence↗
PubMed2003

Transfer of protein from milk to cheese.

This report concerns measurement of paracasein in milk and transfer of protein from milk to cheese. In the main experiment, two vats of Cheddar cheese were made from each of 11 lots of milk from one large herd over a period of 7 mo. Exclusion of solutes from moisture in paracasein micelles in milk and cheese was central to estimation of paracasein and to the transfer of protein from milk to cheese and whey. Solute-exclusion by paracasein and its changes during cheesemaking could be visualized by considering paracasein micelles to be a very fine sponge. The sponge excludes solutes, especially the large solutes like whey proteins. The sponge shrinks during cheesemaking and expels solute-free liquid, thereby slightly diluting the whey surrounding the micelles inside the curd. Paracasein N in milk was calculated as the difference between total milk N and rennet whey N, the latter adjusted to its level in milk. Adjustment used appropriate solute-exclusion factors (h) of the protein fractions of whey and 1.08 for paracasein and associated salts. They were combined to give a factor Fpc, which adjusted the level of rennet whey N to its level in milk: 1.001 x (1 - 1.01 x FM/100 - Fpc x pc/100), where FM = fat in milk, pc = estimated paracasein, and 1.001 = dilution of milk by chymosin and CaCl2. The mean Fpc was 3.03. Differences in values were small among different procedures for calculating paracasein, but they are considered to be important because they represent biases, which, in turn, are important in analyses commercially. We conclude that solute exclusion by moisture in paracasein must have decreased during cheesemaking because the ratio of moisture to paracasein in the final cheese was 1.5, much less than the h of 2.6 for serum proteins by paracasein. Release of solute-excluding moisture from paracasein during cooking was likely the reason for lower total N in cheese whey than in the rennet whey in the paracasein analysis. Paracasein, estimated to be in cheese, curd fines, salted whey, and whey during cheddaring, was 98.21, 0.20, 0.25 and 0.19%, respectively, of the paracasein in milk for a total of 98.85% (SD of 22 vats = 0.46); the location of the missing paracasein is not known. On the other hand, recovery of milk N in cheese and wheys was 99.92% (SD = 0.37%). Nitrogen in paracasein and its hydrolysis products in cheese was estimated to be 98.51% of total cheese N. Proteose-peptone from milk appeared not to be included with the paracasein in appreciable amounts. Some was apparently included with denatured serum proteins during Rowland fractionation of whey, perhaps as a coprecipitate. Measured paracasein would include fat globule membrane proteins in milk containing fat, and denatured whey proteins in heated milks. It was concluded that the method of measurement and the associated calculations are integral parts of the definition and quantification of paracasein in milk.

Animals↗
PubMed2004

Changes in the proportions of soluble and insoluble calcium during the ripening of cheddar cheese.

In cheese, the concentration and form of residual Ca greatly influences texture. Two methods were used to determine the proportions of soluble (SOL) and insoluble (INSOL) Ca in Cheddar cheese during 4 mo of ripening. The first method was based on the acid-base buffering curves of cheese and the second was based on the extraction of the aqueous phase ("juice") of cheese under high pressure and determining the concentration of SOL Ca in the juice using atomic absorption spectroscopy. When cheese was acidified there was a strong buffering peak at pH approximately 4.8, which was due to the solubilization of residual colloidal calcium phosphate (CCP) of milk that remained in cheese as INSOL Ca phosphate. The area of this buffering peak in cheese was expressed as a percentage of the original area of this peak in milk and was used to estimate the concentration of residual INSOL Ca phosphate in cheese. There were no significant differences between the 2 methods. The proportions of INSOL Ca in cheese decreased from approximately 73 to approximately 58% between d 1 and 4 mo. These methods will be useful techniques to study the role of Ca in cheese texture and functionality.

Calcium↗
PubMed2004

Standardization of milk using cold ultrafiltration retentates for the manufacture of parmesan cheese.

The effects of using cold ultrafiltered (UF) retentates (both whole and skim milk) on the coagulation, yield, composition, and ripening of Parmesan cheese were investigated. Milks for cheese making were made by blending cold UF retentates with partially skimmed milk to obtain blends with 14.2% solids and a casein:fat ratio of 1.1. Cutting times, as selected by the cheese-maker, were approximately 15 and approximately 20 min for experimental and control milks, respectively. Storage modulus values at cutting were similar, but yield stress values were significantly higher in UF retentate standardized milks. Cheese yields were significantly higher in UF retentate standardized milks (approximately 12%) compared with control milk (cream removed) (approximately 7 to 8%). Significantly higher protein recoveries were obtained in cheeses manufactured using cold UF retentates. There were no differences in the pH and moisture contents of the cheeses prior to brining, and there was no residual lactose or galactose left in the cheeses. Using UF retentates resulted in a significant reduction in whey volume as well as a higher proportion of protein in the solids of the whey. Proteolysis, free fatty acids, and sensory properties of the cheeses were similar. The use of milk concentrated by cold UF is a promising way of improving the yield of Parmesan cheese without compromising cheese quality. The question remaining to be answered by the cheesemaker is whether it is economical to do so.

Animals↗