Nonfat Cheese Research Articles

Exopolysaccharide (EPS) Produced by Leuconostoc mesenteroides SJC113: Characterization of Functional and Technological Properties and Application in Fat-Free Cheese

A Leuconostoc mesenteroides strain (SJC113) isolated from cheese curd was found to produce large amounts of a mucoid exopolysaccharide (EPS). An analysis revealed the glucan nature of the EPS with 84.5% (1→6)-linked α-d-glucose units and 5.6% (1,3→6)-linked α-d-glucose units as branching points. The EPS showed 52% dextranase resistance and a yield of 7.4 ± 0.9 g/L from MRS medium supplemented with 10% sucrose within 48 h. Ln. mesenteroides SJC113 was also characterized and tested for the production of EPS as a fat substitute in fresh cheese. Strain SJC113 showed high tolerance to a wide range of NaCl concentrations (2, 5 and 10%), high β-galactosidase activity (2368 ± 24 Miller units), cholesterol-reducing ability (14.8 ± 4.1%), free radical scavenging activity (11.7 ± 0.7%) and hydroxyl scavenging activity (15.7 ± 0.4%). The strain had no virulence genes and was sensitive to clinically important antibiotics such as ampicillin, tetracycline and chloramphenicol. Ln. mesenteroides SJC113 produced highly viscous EPS during storage at 8 °C in skim milk with 5% sucrose. Therefore, these conditions were used for EPS production in skim milk before incorporation into fresh cheese. Four types of fresh cheese were produced: full-fat cheese (FF) made from pasteurized whole milk, non-fat cheese (NF) made from pasteurized skim milk, non-fat cheese made from skim milk fermented with Ln. mesenteroides without added sugar (NFLn0) and non-fat cheese made from skim milk fermented with Ln. mesenteroides with 5% sucrose (NFLn5). While the NF cheeses had the highest viscosity and hardness, the NFLn5 cheeses showed lower firmness and viscosity, higher water-holding capacity and lower weight loss during storage. Overall, the NFLn5 cheeses had similar rheological properties to full-fat cheeses with a low degree of syneresis. It was thus shown that the glucan-type EPS produced by Ln. mesenteroides SJC113 can successfully replace fat without altering the texture of fresh cheese.

Incorporating whey protein aggregates produced with heat and ultrasound treatment into rennet gels and model non-fat cheese systems

Native whey proteins (WP) are expulsed from cheese coagulation during syneresis. Although incorporating denatured WP aggregates into cheese gels has been previously proposed to improve the overall cheese yield, the effects of WP aggregate properties on gelation kinetics and protein retention are not yet fully understood. In this study, heat and power ultrasound were used to produce denatured whey protein aggregates with a wide range of sizes. The effects of size and hydrophobicity differences in WP aggregates produced by heat and heat coupled with ultrasound were investigated in relation to the kinetics of rennet gelation and protein retention in model non-fat cheddar cheeses. Rheological measurements showed that sufficiently large, denatured WP aggregates could avoid impairment of rennet gelation caused by native WP, irrespective of changes in the soluble calcium concentration or the surface hydrophobicity of the aggregates. WP aggregates formed by the combined heat and ultrasound treatment were more hydrophobic than the larger heat-treated aggregates and were better retained in the cheese. However, inclusion of sufficiently large aggregates in cheese milk conferred an openness to the cheese microstructure and showed promise in improving the otherwise rigid non-fat cheese.

Effect of salt concentration on acid‐ and salt‐adaptedEscherichia coliO157:H7 andListeria monocytogenesin recombined nonfat cast cheese

In Turkey, legislation reduced the salt content in fresh cheeses from 10% to 6.5% in dry matter (DM). This study investigated the effect of salt reduction on the fate of acid- and salt-adapted Escherichia coli O157:H7 and Listeria monocytogenes, as well as the textural quality of recombined nonfat cheese. The cheese was manufactured using milk protein concentrate (85% protein) and skim milk powder (35% protein). After pasteurization and addition of starter culture (0.1%), cheese milk was inoculated with acid- or salt-adapted pathogens (1 × 103 cfu/g). Following salting (4%, 6%, 8%, or 10% in DM) and fermenting (24 hr/30 °C), the microbiological and textural properties of the cheese were analyzed during 8 weeks of storage at 4 °C. Salt concentration did not affect E. coli survival during storage (p > .05). Acid-adapted L. monocytogenes and E. coli survived 1 week longer than the unadapted control. Cheese hardness was unaffected (p > .05) by the salt concentration. Practical applications The results of the present study can be used to assess the risk of survival of acid- and salt-adapted Listeria monocytogenes or Escherichia coli O157:H7 in nonfat cheese (with different salt concentration) produced from unpasteurized milk.

Shear work induced changes in the viscoelastic properties of model Mozzarella cheese

Three model Mozzarella type cheeses (full-fat, non-fat and full-fat with added tri-sodium citrate) were prepared by working cheese components together at 70 °C in a twin screw Blentech cooker. G′ at 70 °C increased with shear work input suggesting work thickening. At lower shear work inputs (<30 kJ kg−1), cheese behaved like a viscoelastic liquid exhibiting typical entangled polymer melt behaviour with moderate frequency dependence. A definite critical point for structural and viscoelastic transition was identified at higher shear work levels (∼58 kJ kg−1 at 150 rpm). Excessive shear work levels (>70 kJ kg−1) resulted in a viscoelastic solid material exhibiting low frequency dependence. Similar viscoelastic property changes occurred in non-fat cheese suggesting that major changes were taking place in the protein matrix during working. Good correlation was found between oscillatory rheological properties such as G′ and LTmax and the melting properties of test cheeses.

Effect of shear work input on steady shear rheology and melt functionality of model Mozzarella cheeses

Model Mozzarella cheeses with varied amounts of shear work input were prepared by working molten cheese mass at 70 °C in a twin screw cooker. Rheology and melt functionality were found to be strongly dependent on total shear work input. A non-linear increase in consistency coefficient (K from power law model) and apparent viscosity and decrease in flow behaviour index (n from power law model) were observed with increasing amounts of accumulated shear work, indicating work thickening behaviour. An exponential work thickening equation is proposed to describe this behaviour. Excessively worked cheese samples exhibited liquid exudation, poor melting and poor stretch. Nonfat cheese exhibited similar but smaller changes after excessive shear work input. We concluded that the dominant contributor to the changes in properties with increased shear work was shear induced structural changes to the protein matrix. A good correlation was found between the steady shear rheological properties and the melting properties of the cheeses.

Effects of reducing fat content on the proteolytic and rheological properties of Cheddar-like caprine milk cheese

High-moisture Cheddar-like cheeses made from caprine milk containing 3.6, 2.0, 1.0, and 0.1–0.5% fat were manufactured and their proteolytic and rheological properties compared after 1, 3, and 6mo of aging at 4°C. The full-fat (FF), reduced-fat (RF), low-fat (LF), and non-fat (NF) cheeses contained 48.7, 50.0, 51.5 and 55.2% moisture and 26.3, 19.0, 9.65, and 1.50% fat, respectively. Although the amount of protein in the cheese increased as fat was reduced, the FF, RF, and LF cheeses had 40–44% degradation of beta-casein over the 6mo of the study while minimal proteolysis (14%) occurred in the NF cheese. The NF cheese exhibited the highest hardness, cohesiveness, chewiness, elastic modulus, viscous modulus, and complex viscosity values due to the denser protein matrix. The FF and RF cheeses had similar rheological values. The fat content of high-moisture Cheddar-like goat cheese can be lowered to 19% without affecting its texture.

Effect of selected Hofmeister salts on textural and rheological properties of nonfat cheese

Three Hofmeister salts (HS; sodium sulfate, sodium thiocyanate, and sodium chloride) were evaluated for their effect on the textural and rheological properties of nonfat cheese. Nonfat cheese, made by direct acidification, were sliced into discs (diameter=50mm, thickness=2mm) and incubated with agitation (6h at 22°C) in 50mL of a synthetic Cheddar cheese aqueous phase buffer (pH 5.4). The 3 HS were added at 5 concentrations (0.1, 0.25, 0.5, 0.75, and 1.0M) to the buffer. Post-incubation, cheese slices were air dried and equilibrated in air-tight bags for 18h at 5°C before analysis. Small amplitude oscillatory rheology properties, including the dynamic moduli and loss tangent, were measured during heating from 5 to 85°C. Hardness was determined by texture profile analysis. Acid-base buffering was performed to observe changes in the indigenous insoluble (colloidal) calcium phosphate (CCP). Moisture content decreased with increasing HS concentration. Cheeses incubated in high concentrations of SCN− softened earlier (i.e., loss tangent=1) compared with other HS treatments. Higher melting temperature values were observed for cheeses incubated in high concentrations of SO42−. Hardness decreased in cheeses incubated in buffers with high concentrations of SCN−. The indigenous CCP profile of nonfat cheese was not greatly affected by incubation in Cl− or SCN−, whereas buffers with high concentrations of SO42− reduced the acid-base buffering contributed by CCP. The use of high concentrations (1.0M) of SCN− for incubation of cheeses resulted in a softer protein matrix at high temperatures due to the chaotropic effect of SCN−, which weakened hydrophobic interactions between CN. Cheese samples incubated in 1.0M SO42− buffers exhibited a stiffer protein matrix at high temperatures due to the kosmotropic effect of SO42−, which helped to strengthen hydrophobic interactions in the proteins during the heating step. This study showed that HS influenced the texture and rheology of nonfat cheese probably by altering the strength of hydrophobic interactions between CN.

Sensory properties and volatile composition of full and non-fat cheese produce from curd — Ripened fried acid tvarog

The study was aimed at sensory analysis and volatile content determination in fried cheese. Fried cheese was produced under commercial conditions from acid tvarog ripened and fried with no butter added (non-fat) and with an addition of butter at 4:1 (reference cheese). Cheese was evaluated immediately after production and after 6 weeks of storage at 4 °C. Total and casein nitrogen, water and fat were assayed in cheese. Sensory analyses of cheese descriptors were conducted by profiling on a 0–10 scale, while volatiles were isolated by solid phase microextraction (SPME) technique. The dominant aroma in reference cheese was cowy/phenolic and cooked, while in non-fat cheese it was cooked and free fatty acid. Sulphur aroma was least perceptible in reference and non-fat cheese. After 6-week storage the only significant changes were weakened cooked aroma in non-fat cheese and waxy/crayon aroma in reference cheese. Differences in profile analysis of full and non-fat cheese were reflected in amounts of determined volatiles, especially total sulphur compounds, acids, methyl ketones, terpenes and esters.

Influence of Emulsifying Salts on the Textural Properties of Nonfat Process Cheese Made from Direct Acid Cheese Bases

The objective of this study was to investigate the influence of several types of emulsifying salts (ES) on the texture of nonfat process cheese (NFPC). Improperly produced nonfat cheese tends to exhibit several problems upon baking including stickiness, insufficient or excessive melt, pale color upon cooling, formation of a dry skin (skinning) often leading to dark blistering, and chewy texture. These attributes are due to the strength and number of interactions between and among casein molecules. We propose to disrupt these interactions by using suitable emulsifying salts (ES). These ES chelate Ca and disperse caseins. Stirred curd cheese bases were made from skim milk using direct acidification with lactic acid to pH values 5.0, 5.2, and 5.4, and ripened for 1 d. Various levels of trisodium citrate (TSC; 0.5, 1, 1.5, 2, 2.5, 3, and 5%), disodium phosphate (DSP; 1, 2, 3, and 4%), or trisodium phosphate (TSP; 1, 2, 3, and 4%) were blended with the nonfat cheese base. Cheese, ES, and water were weighed into a steel container, which was placed in a waterbath at 98°C and then stirred using an overhead stirrer for 9min. Molten cheese was poured into plastic containers, sealed, and stored at 4°C for 7 d before analysis. Texture and melting properties were determined using texture profile analysis and the UW-Melt-profiler. The pH 5.2 and 5.4 cheese bases were sticky during manufacture and had a pale straw-like color, whereas the pH 5.0 curd was white. Total calcium contents were approximately 400, 185, and 139mg/100g for pH 5.4, 5.2, and 5.0 cheeses, respectively. Addition of DSP resulted in NFPC with the lowest extent of flow, and crystal formation was apparent at DSP levels above 2%. The NFPC manufactured from the pH 5.0 base and using TSP had reduced melt and increased stickiness, whereas melt was significantly increased and stickiness was reduced in NFPC made with pH 5.4 base and TSP. However, for NFPC made from the pH 5.4 cheese and with 1% TSP, the pH value was >6.20 and crystals were observed within a few days. Use of TSC increased extent of flow up to a maximum with the addition of 2% ES for all 3 types of cheese bases. Addition of high levels of TSC to the pH 5.2 and 5.4 cheese bases resulted in increased stickiness. Similar pH trends for attributes such as extent of flow, hardness, and adhesiveness were observed for both phosphate ES but no consistent pH trends were observed for the NFPC made with TSC. These initial trials suggest that the pH 5.0 cheese base was promising for further research and scale-up to pilot-scale process cheese making, because cheeses had a creamy color, reasonable melt, and did not have high adhesiveness when TSC was used as the ES. However, the acid whey produced from the pH 5.0 curd could be a concern.

Improving the nutritional resource environment for healthy living through community-based participatory research.

To build health promotion capacity among community residents through a community-based participatory model, and to apply this model to study the nutritional environment of an urban area to better understand the role of such resources in residents' efforts to live a healthy life. A multiphase collaborative study that inventoried selected markets in targeted areas of high African-American concentration in comparison with markets in a contrasting wealthier area with fewer African Americans. A community study set in the Los Angeles metropolitan area. African-American community organizations and community residents in the target areas. Two surveys of market inventories were conducted. The first was a single-sheet form profiling store conditions and the availability of a small selection of healthy foods. The second provided detailed information on whether the store offered fruit, vegetables, low-fat dairy products, dried goods and other items necessary for residents to consume a nutritious diet. The targeted areas were significantly less likely to have important items for living a healthier life. The variety and quality of fresh fruit and vegetable produce was significantly lower in the target areas. Such products as 1% milk, skim milk, low-fat and nonfat cheese, soy milk, tofu, whole grain pasta and breads, and low-fat meat and poultry items were significantly less available. Healthy food products were significantly less available in the target areas. The authors conclude from these results that the health disparities experienced by African-American communities have origins that extend beyond the health delivery system and individual behaviors inasmuch as adherence to the healthy lifestyle associated with low chronic disease risk is more difficult in resource-poor neighborhoods than in resource-rich ones.

Influence of Coagulant Level on Proteolysis and Functionality of Mozzarella Cheeses Made Using Direct Acidification

Nonfat (0% fat), reduced-fat (11% fat), and control (19% fat) mozzarella cheeses were made using direct acidification to test the influence of three levels (0.25X, 1X, and 4X) of coagulant concentration on proteolysis, meltability and rheological properties of cheeses during 60 d of storage at 5°C. Changes in meltability, level of intact αs1-casein and β-casein (by capillary electrophoresis), 12.5% TCA-soluble nitrogen, and complex modulus were measured. There were differences in rate of proteolysis and functional properties as a function of fat content of the cheese, but some of these differences could be attributed to differences in moisture contents of the cheeses. As fat level decreased, the percent moisture-in-nonfat-substance of the cheeses also decreased. Cheeses with the lower fat contents (and consequently the lowest moisture-in-nonfat-substance content) had slower rates of proteolysis. Fat content influenced the complex modulus of the cheese, with the biggest effect occurring when fat content was reduced from 11 to 0%. Coagulant level had only a small effect on initial modulus. Cheeses became softer during storage, and the decrease in modulus was influenced by the level of coagulant. At 0.25X, there was very little decrease in modulus after 60 d, while at 1X and 4X coagulant levels the softening of the cheese was more evident. The influence of coagulant level and fat content on cheese melting was similar to their effects on complex modulus. In general, higher fat contents promoted more melting and so did higher coagulant levels. Melting increased during storage although very little change was observed in the nonfat cheese.

Microstructure of Feta Cheese Made Using Different Cultures as Determined by Confocal Scanning Laser Microscopy

ABSTRACT: The objective of this work was to observe the microstructure of feta cheese using confocal scanning laser microscopy. Low fat cheese and cheese containing capsule‐producing cultures were made. The protein network was observed using the reflectance mode of the confocal microscope. Fat was stained by Nile red dye diluted with whey. More even distribution of fat with a larger number of smaller globules was observed in cheese made with noncapsule‐forming culture compared to that made with the capsule‐forming culture. Nonfat cheese had compact structure when made with noncapsule‐forming culture which contrasted with the open structure observed in cheese made with the capsule‐forming culture

Lien entre le niveau de lipolyse du lait de chèvre et la qualité sensorielle des fromages au lait cru ou pasteurisé

Link between goat milk lipolysis and sensorial quality of lactic goat cheeses made from raw or pasteurised milk. There is an important variability of the lipolysis level in goat milk, due to various physiological and breeding factors. The aim of this study was to evaluate the impact of these natural variations on the sensorial quality of fresh and ripened lactic goat cheeses. The effect of milk pasteurisation was also studied. The results show that the variation of the lipolysis level of goat milk do not have any significant effect on the sensorial quality of ripened cheeses. On the contrary, the sensorial quality of fresh cheeses is linked to the lipolysis level of milk. These results allowed us to recommend some means of controlling the sensorial quality of goat cheeses. For ripened cheeses, a satisfying sensorial quality could be obtained via the control of the technological parameters, notably the moisture in non-fat cheese at the demoulding. For fresh cheeses, the lipolysis level of milk should be checked before cheesemaking, and milks with high lipolysis levels should not be used. Pasteurisation of milk induced a decrease in the lipolysis level of cheeses. The use of pasteurisation led to a limitation of the appearance of organoleptic defects in rip- ened cheeses, but the overall flavour and odour of ripened cheeses made from pasteurised milk was also reduced compared to cheeses made from raw milk. goat milk / lipolysis / goat cheese / sensorial quality / pasteurisation

Low-Fat Diet Practices of Older Women: Prevalence and Implications for Dietary Assessment

Objective To evaluate the importance of information on low-fat diet practices and consumption of reduced-fat foods for accurate assessment of energy and fat intakes using a semiquantitative food frequency questionnaire (FFQ). Subjects Subjects were 7,419 women, aged 50 to 79 years, who filled out an FFQ as part of eligibility screening for a diet modification component and/or a hormone replacement trial in a multicenter study of chronic disease prevention in postmenopausal women (Women's Health Initiative). Statistical analysis For 26 FFQ questions, we receded the low-fat diet choices of participants to a high-fat counterpart and recalculated energy and fat intakes. We then determined the decrease in energy and nutrient estimates attributable to adding low-fat options to the FFQ. Results Low-fat diet practices were widespread in this population. For example, 69% of respondents rarely or never ate skin on chicken, 76% rarely or never ate fat on meat, 36% usually drank nonfat milk, 52% usually ate low-fat or fat-free mayonnaise, 59% ate low-fat chips/snacks, and 42% ate nonfat cheese. These low-fat choices had substantial effects on energy and nutrient estimates. Absolute decreases (and mean percentage decreases) for energy and nutrient measures attributable to adding low-fat diet options to the FFQ were 196 kcal (11.4%) energy, 9 percentage points in percentage energy from fat (22.3%), 23.2 g fat (29.0%), and 9.6 g saturated fat (32.5%). Black and Hispanic women and women of lower socioeconomic status reported significantly fewer low-fat diet practices than white women and women of higher socioeconomic status. Conclusion Failure to collect information on low-fat diet practices with an FFQ will result in an upward bias in estimates of energy and fat intake, and the amount of error will vary by the personal characteristics of respondents. J Am DietAssoc. 1996; 96:670-676, 679.

Effect of temperature, shearing time and rate of shear on the apparent viscosity of fresh cheeses

The apparent viscosity of market acid-type cheese samples was measured with a coaxial cylinder viscosimeter, in the temperature range 5 to 40 oC. The logarithm of the apparent viscosity was a Iinear function of the logarithm of the shear rate, of the logarithm of the shearing time and of the reciprocal absolute temperature. The activation energy of f10wwas about 13 kJ/mol for the non-fat cheese, while for the cheese containing 20% fat in dry matter and for the temperature range between 15 and 20 C, it increased to 48 kJ/mol because of solidification of the fat fraction.

VISCOSIMETRIC STUDIES ON ACID TYPE CHEESE TEXTURE

The apparent viscosities of market acid type cheese samples, containing 7.5 to 9.8% of total proteins, 12.7 to 19.9% of dry matter and 0 to 40% fat in dry matter, were measured with a coaxial cylinder viscometer, over the temperature range 5 to 40°C and the rate of strain 9 to 482 s‐1 for up to 2000 s. The logarithm of the apparent viscosity was a linear function of the logarithms of the rate of strain and of the shearing time. The activation energy of flow was about 35 to 40 kJ/mol for the nonfat cheese, while for cheese containing 30% fat in dry matter and for the temperature range between 15 and 20°C it increased to 100–130 kJ/mol. The logarithm of the apparent viscosity increased with increase of the protein content but the results were too scattered to allow prediction of the viscosity level for a single sample of known protein content.