Cheese Moisture Research Articles

Effect of an Exopolysaccharide-Producing Strain of Streptococcus Thermophilus on the Yield and Texture of Mexican Manchego-Type Cheese

An exopolysaccharide-producing strain of Streptococcus thermophilus was evaluated in the production of Mexican manchego-type cheese. This ropy strain improved water and fat retention, and significantly increased cheese yield. Furthermore, the ropy strain cheese retained more moisture than control cheese during ripening, suggesting that exopolysaccharide strongly bound water within the protein matrix of the cheese. Scanning electron microscopy confirmed that exopolysaccharide bound to the protein matrix of the cheese, producing a dense network that helped to increase water and fat retention and leading to a more open structure of the cheese that gave a softer product, as confirmed by instrumental texture profile analysis and sensory evaluation. Comparison of scanning electron microscopy micrographs of the different sections of the cheese showed higher concentration of exopolysaccharide in the centre than in the outer sections, indicating that exopolysaccharide production continued during ripening and that the environment at the centre of the cheese (moisture and/or oxygen concentration) favoured exopolysaccharide production. Instrumental texture profile analysis also demonstrated that the ropy strain cheese was more cohesive and less elastic than the control; in contrast, exopolysaccharide did not affect chewiness. The changes in texture could be correlated to composition: hardness increased as water and fat decreased, while springiness decreased with increasing fat. The interactions of exopolysaccharide with the cheese protein matrix had an affect on the increase in cohesiveness of the ropy strain cheese.

Estimating the impact of somatic cell count on the value of milk utilising parameters obtained from the published literature

The impact of mastitis on milk value per litre independent of the effect of mastitis on milk volume, was quantified for Ireland using a meta-analysis and a processing sector model. Changes in raw milk composition, cheese processing and composition associated with increased bulk milk somatic cell count (BMSCC) were incorporated into the model. Processing costs and market values were representative of current industry values. It was assumed that as BMSCC increased (i) milk fat and milk protein increased and milk lactose decreased, (ii) fat and protein recoveries decreased, (iii) cheese protein decreased and cheese moisture increased. Five BMSCC categories were examined from ⩽100000 to >400000cells/ml. The analysis showed that as BMSCC increased the production quantities reduced. An increase in BMSCC from 100000 to >400000cells/ml saw a reduction in net revenue of 3·2% per annum (€51·3million) which corresponded to a reduction in the value of raw milk of €0·0096cents/l.

Lactose and galactose content in cheese results in overestimation of moisture by vacuum oven and microwave methods

Moisture determination in cheese is a critical test for regulatory compliance, functionality, and economic reasons. Common methods for moisture determination in cheese rely upon the thermal volatilization of water from cheese and calculation of moisture content based on the resulting loss of mass. Residual sugars, such as lactose and galactose, are commonly present in cheeses at levels ranging from trace amounts to 5%. These sugars are capable of reacting with other compounds in cheese, especially under the thermal conditions required for moisture determination, to yield volatile reaction products. The hypothesis of this work is that residual sugars in cheese will be converted into volatile compounds over the course of moisture determination at a level sufficient to result in overestimated cheese moisture. A full-factorial statistical design was used to evaluate the effects of cheese type, sugar type, sugar level, method type, and all interactions. Cheddar and low-moisture, part-skim (LMPS) Mozzarella cheeses were prepared with 1, 3, and 5% added lactose or galactose, and subjected to either vacuum oven or microwave-based moisture determination methods. Browning index and colorimetry were measured to characterize the color and extent of browning. Volatile analyses were performed to provide chemical evidence of the reactions proposed. The presence of residual sugars altered moisture calculations as a function of cheese type, sugar type, sugar level, method type, and numerous interactions. At higher concentrations of residual sugar, the percentage moisture determinations were increased by values of up to 1.8. Measures of browning reactions, including browning index, colorimetry, and volatile profiles demonstrate that the proposed browning reactions played a causative role. This work establishes the need to consider cheese type, sugar type, sugar levels, and method type as a means of more accurately determining moisture levels.

Influence of starter culture, temperature and processing technology on the quality of Macedonian white brined cheese

The effect of the starter culture, temperature of curdling and processing technology on the composition, cheese yield and process optimization of Macedonian White cheese (MWC) was studied during 60 days of ripening in brine. Three treatments of cheese were made using current technological process and yogurt as starter-culture gained along processing of previous day (MWCK), freeze dried culture of L?ctobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus 3:1; F-DVS YF-3331 Yo-Flex version: 2 PI-EU-EN (MWC?1), and (MWC?2) with same starter culture as previous but whith 5 minute earlier processing of curd and temperature of curdling at 39?C. As ripening progressed, titratable acidity (?SH), salt and protein contents of the (MWC?2) treatment continuously increased, whereas their fat-in-dry-matter and lactose contents decreased. In same production conditions depending on the used temperature. Way of processing and starter cultures the cheese from (MWC?2) treatment was with highest acidity of 66.63 + 2.73oSH until the end of ripening of the cheese. Moisture of cheeses remained stable during ripening. The pH of cheese at the 1 day of ripening, which decreased by increasing the temperature of curdling (5.03, 5.11 and 5.00 for MWCK, MWC?1 and MWC?2, respectively), significantly (P < 0.05) affected most of the chemical characteristics of cheese. The content of salt at the end of storage at (?1) and (?2) variant is 5.23 + 0.31 and 5.52 + 0.31 respectively. Higher temperature of curdling decreased moisture and pH, whereas cheese protein content increased. The consumption of milk for production of a 1 kilogram of cheese ranged from 7.8 to 8.3 liters of milk. It was concluded that starter cultures have possstively influenced and improved the quality of white cheese.

Controlled transglutaminase treatment in Edam cheese-making

Transglutaminase (TG) has been widely used in the dairy industry to increase product yield. However, it has not been used in the production of ripened cheeses because of the difficulty of controlling TG activity. It was observed that cross-linking of TG in ultrafiltration retentate could be controlled using a protein standardisation step. TG increased the cheese yield 4%, due to an increase in the moisture content of the cheeses. Traditionally, increased cheese moisture reduces hardness of cheese, but this was not observed in the cheese from TG-treated milk. Furthermore, the organoleptic properties of the TG-cheeses did not differ significantly from those of the control cheeses. No differences were observed in the protein profile of the whey fraction as a result of the TG treatment. The protein standardisation process thus makes it possible to use TG in the production of Edam cheese.

Effect of curd washing on cheese proteolysis, texture, volatile compounds, and sensory grading in full fat Cheddar cheese

Curd was washed to varying degrees during Cheddar cheese manufacture, by partial replacement of whey with water at the early stages of cooking, to give target levels of lactose plus lactic acid in cheese moisture of 5.3 (control), 4.5, 4.3 and 3.9% (w/w). The cheeses were matured at 8 °C for 270 days. While curd washing had little effect on composition or the mean levels of proteolysis (as measured by pH 4.6 soluble nitrogen and levels of free amino acids), it led to cheeses that were, overall, firmer and less brittle. Curd washing resulted in cheeses having lower levels of some volatile compounds, and being less acid, more buttery, sweeter, saltier and creamier than non-washed cheeses that had more 'sweaty', pungent and farmyard-like sensory notes. The results suggest that curd washing during Cheddar manufacture may be used as a means of creating variants with distinctive flavour profiles.

Determination of fat, protein and moisture in ricotta cheese by near infrared spectroscopy and multivariate calibration.

Near-infrared reflectance spectroscopy (NIRS) with partial least squares regression (PLSR) was used to determine levels of fat, protein and moisture in ricotta cheese without complex sample preparation. Spectra of 19 conventional and low-fat ricotta samples from different manufacturers were collected in duplicate, with 33 of the 38 spectra used as a calibration set and the remaining 5 spectra used as an external validation set. The best results were obtained by processing the spectral region between 1,100 and 2,500nm. Multivariate models with six latent variables (LVs) showed good prediction capability for fat and protein determinations, with average relative errors (Er) of 6.37% and 5.95%, respectively. For moisture, a more robust model was obtained with 4 LVs, showing better prevision capacity and Er of 1.91%.

Production and characterization of Cheddar-type cheese enriched with green tea extract

Green tea polyphenols are known for their antioxidant properties. They also interact with milk proteins, suggesting good retention in the cheese matrix. The objective of this study was to evaluate the effect of green tea extract (GTE) enrichment on the organoleptic and physicochemical properties of Cheddar-type cheese during storage. GTE was added to milk at concentrations of 0, 1, and 2 g.kg−1 and cheeses were produced on a pilot scale. An average polyphenol retention coefficient of 0.63 was obtained in cheese. Total protein, fat, micellar calcium content, and yield of cheese were not significantly affected by GTE addition (P > 0.05). However, cheese moisture decreased by 1.9% with the addition of GTE at a concentration of 2 g.kg−1 of milk. Enrichment with GTE significantly affected the color of Cheddar-type cheese (P ≤ 0.05). A loss of lightness (L* value) and an increase in redness (a* value) and yellowness (b* value) were observed. Cheeses enriched with GTE showed higher hardness and a loss of cohesiveness and springiness, which is indicative of alteration of the paracasein matrix. Cheese sensory properties were evaluated by trained panelists using a ranking test. A decrease in the typical Cheddar flavor and an increase in the overall flavor intensity and the astringency of cheese were observed with the addition of GTE. The addition of GTE at a concentration of 1 or 2 g.kg−1 of milk increased the antiradical activity of cheese by 25 and 44%, respectively (P ≤ 0.05). GTE enrichment of Cheddar-type cheese could result in new products with increased health benefits.

Usefulness of a large field of view sensor for physicochemical, textural, and yield predictions under industrial goat cheese (Murcia al Vino) manufacturing conditions

The applicability of a light backscatter sensor with a large field of view was tested for on-line monitoring of coagulation and syneresis in a goat cheese (Murcia al Vino) manufactured under industrial conditions. Cheesemaking was carried out concurrently in a 12-L pilot vat and a 10,000-L industrial vat following the normal cheesemaking protocol. Cheese moisture, whey fat content, hardness, springiness, and adhesiveness were measured during syneresis. The results obtained show that cutting time is best predicted by considering the coagulation ratio at the inflection point and the percentage increase in the ratio during coagulation, with no need for the first derivative. The large field of view reflectance ratio provided good results for the prediction of moisture content, yield, hardness, springiness, and adhesiveness of the final cheese.

Effect of curd washing on composition, lactose metabolism, pH, and the growth of non-starter lactic acid bacteria in full-fat Cheddar cheese

Cheddar cheese was manufactured in triplicate from mid-lactation milk and analysed over a 270-day ripening period. The curd was washed in the cheese vat to give target levels of lactose plus lactic acid in cheese moisture (LLAMc) in the final cheese of 5.3 (control), 4.5, 4.3 and 3.9% (w/w); these values correspond to the expected LLAMc levels in non-washed cheeses made from milk with lactose levels of 4.8 (control), 4.6, 4.3 and 3.8% (w/w), respectively. Increasing curd washing from 0 to 33% of milk volume significantly reduced mean levels of total lactate and LLAMc over the ripening period. Conversely, it increased the mean cheese pH by ∼0.3–0.4 at times≥90 days. The LLAMc was ∼1.0–1.6 units lower than predicted based on levels of milk lactose and curd washing. Otherwise, alteration of curd washing generally did not affect gross composition or microbiology of the cheese.

Effect of specialized combined strains on reconstituted milk reduced-fat cheese

The reduced-fat cheese using reconstituted milk powder (CRMP) has the problems of texture and flavor because of heating and drying treatments of milk. The application of an exopolysaccharide (EPS)-producing strain, as well as an adjunct strain in CRMP was investigated to address these quality issues. Volatiles of these cheeses were determined by solid phase microextraction-gas chromatography-mass spectrometry and texture by the textural profile analysis. The EPS-producing strain could hold moisture and result in cheese with higher yield compared to the non EPS-producing strain. Meanwhile, the cheese made with the EPS-producing Streptococcus thermophilus TM11 had a lower hardness, springiness, chewiness, gumminess, resilience and a higher adhesiveness and cohesiveness than the cheese made with non EPS-producing S. thermophilus SP1.1. These changes were attributed to the differences of protein matrix according to observation of scanning electron microscopy. On the other hand, results of the main flavor compounds in CRMP indicated that combination of the EPS-producing S. thermophilus TM11 and an adjunct Lactococcus lactis ssp. lactis could provide CRMP with novel and proper flavor properties while improving the textural characteristics.

Evaluation of quality of grated cheese to protect public health

By definition Grated cheese, is the product obtained by crumbling or grating cheese of low humidity suitable for human consumption. It is a food widely consumed by the population, however it can offers some risks to public health when it is contaminated with a pathogen. The Foodborne Diseases (FBD) are caused by ingestion of food or drink that contains pathogens and/or toxins produced by them in quantities that affect the health of consumers. Among the microorganisms that cause FBD of importance in cheese stand out, Staphylococcus aureus, Salmonella sp. e Escherichia coli . The related legislation in Brazil, the RDC no 12 and the Ordinance no 357 regulates the microbiological standards for foods. This study evaluated the quality of samples of grated cheese marketed in the city of Juiz de Fora , MG. Twenty samples were analyzed. Forty percent were rejected for the counting of molds and yeasts and 15% had counts close to the acceptation limit for these microorganisms. Concerning to moisture analyses, 20% of the samples were in disagreement with the limit established by legislation to low moisture cheeses. These results show that grated cheese industries should be better monitored by health authorities, so that the final product has quality and safety guaranteed.

High‐Pressure Effects on the Microstructure, Texture, and Color of White‐Brined Cheese

White-brined cheeses were subjected to high-pressure processing (HPP) at 50, 100, 200, and 400 MPa at 22 °C for 5 and 15 min and ripened in brine for 60 d. The effects of pressure treatment on the chemical, textural, microstructural, and color were determined. HPP did not affect moisture, protein, and fat contents of cheeses. Similar microstructures were obtained for unpressurized cheese and pressurized cheeses at 50 and 100 MPa, whereas a denser and continuous structure was obtained for pressurized cheeses at 200 and 400 MPa. These microstructural changes exhibited a good correlation with textural changes. The 200 and 400 MPa treatments resulted in significantly softer, less springy, less gummy, and less chewy cheese. Finally, marked differences were obtained in a* and b* values at higher pressure levels for longer pressure-holding time and were also supported by ΔE* values. The cheese became more greenish and yellowish with the increase in pressure level. The quality of cheese is the very important to the consumers. This study documented the pressure-induced changes in selected quality attributes of semisoft and brine-salted cheese. The results can help the food processors to have knowledge of the process parameters resulting in quality changes and to identify optimal process parameters for preserving pressure-treated cheeses.

Comparison of free fatty acid composition between low-fat and full-fat goat milk cheeses stored for 3 months under refrigeration

Differences in free fatty acid (FFA) compositions between low-fat (LF) and full-fat (FF: whole milk) goat cheeses were evaluated during 3 months at 4oC refrigeration. The two types of cheeses were manufactured using a bulk milk from the mixed herd of Saanen, Alpine, and Nubian goat breeds. LF cheeses were made using LF milk after cream separation. FFAs of all cheeses were extracted in diisoprophyl ether using polypropylene chromatography column, and FFA concentrations were quantified using a gas chromatograph equipped with a fused silica capillary column. Moisture, fat, protein contents (%) and pH of fresh LF and FF cheeses were: 55.1, 52.3; 1.30, 25.6; 35.7, 22.5; 5.40, 5.42, respectively. The FFA contents (mg/g cheese) of fresh FF and LF cheeses prior to storage treatments for C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, C18:1, and C18:2 were: 0.020, 0.072; 0.070, 0.035; 0.061, 0.055; 0.181, 0.167; 0.073, 0.047; 0.174, 0.112; 0.579, 0.152; 0.308, 0.202; 0.521, 0.174; and 0.057, 0.026, respectively. The respective FFA to total fatty acid ratios for 0, 1 and 3 months aged FF and LF cheeses were 8.44, 12.4; 6.31, 16.91; 12.03, 14.19. The LF cheeses generated more FFA than FF cheeses, while actual FFA content in FF cheese was significantly higher than in LF cheese. The FFA contents of LF cheese at 0, 1 and 3 months storage were 48.0, 96.8 and 36.4% of those of FF cheese, respectively. It was concluded LF cheese generated higher amount of FFA than FF cheese, although total FFA content was significantly (P<0.05) lower in LF cheese than in FF cheese.

EFFECT OF STARTER CULTURE ON THE QUALITY AND YIELD OF KARISH CHEESE MADE FROM BUFFALO’S MILK

Karish cheese was made from fresh buffaloes' skim milk (0.5% fat) using a commercial starter culture DOM 1® (Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris (1:1)) and with natural starter from good quality karish cheese. Four treatments were made by using 1 & 2% natural starter culture (YS-1 and YS-2, respectively) and with 1 & 2% of DOM 1® starter culture (DS-1 and DS-2, respectively). Yield of the resultant cheeses were calculated. Chemical, microbiological and sensory characteristics of cheeses were monitored when fresh and during 60 days of storage at 5±2°C. Gross composition of all resultant cheeses was within the Egyptian legal limits for Karish cheese. The highest cheese yield (25.4%) was obtained when 2% of DOM 1® starter culture was added (DS-2). This increase in the cheese yield of DS-2 was associated with an increase in the cheese moisture content by 2.7% compared with YS-1 and 1.1% compared with YS-2 treatments. The pH values were decreased during storage period, but both YS-1 and YS-2 treatments had lower pH-values than DS-1 and DS-2 treatments. The highest values of SN and SN/TN were observed in the DS-2 cheese treatment. This could be an indication of more proteolysis occurred when 2% of the DOM 1® starter culture was used. DS-1 and DS-2 treatments showed a reduction in the losses of TS and TN contents in the pickling solution during storage compared with YS-1 and YS-2 treatments. It was also observed that YS-1 and YS-2 treatments had higher total viable bacterial and mold & yeast counts than that in DS-1 and DS-2 treatments. On the other hand, there was a slight increase in the total sensory score of the DS-2 treatment. It can be concluded that manufacture of karish cheese by using 2% DOM 1® improved cheese yield, organoleptic properties and decreased losses of cheese components in pickling solution.

Influence of high-pressure processing (HPP) on physico-chemical properties of fresh cheese

Freshly prepared rennet-coagulated soft cheese was high-pressure (HP) treated at up to 291 MPa and 29 min and using a full 2-factor central composite design of experiment, its physico-chemical properties (colour, fat, lipid oxidation, moisture and protein content, pH, and texture) were examined. HP treatment influenced significantly (p<0.05) the colour, fat, moisture, lipid oxidation, hardness and adhesiveness of the fresh cheese. Fat content increased apparently as moisture decreased significantly after HP treatment of above 100 MPa. Increased pressures reduced lipid oxidation but increased yellowness although the latter showed more effect over redness in the HP-treated fresh cheese. Also, increased pressures increased hardness, decreased acidity and adhesiveness in HP-treated fresh cheese although increased exposure was found to increase acidity. Industrial relevance: High isostatic pressure for processing fresh cheese is yet to be adopted on an industrial scale. There is a need for research to provide evidence that improved properties of fresh cheese can be realized. The effects of HPP on rennet-coagulated soft Scottish cheese are investigated and the data from this study have provided points where optimized characteristic properties of HPP fresh cheese can be attained, which can serve as a lead for HPP users on fresh cheese

Influence of brine concentration and temperature on composition, microstructure, and yield of feta cheese

The protein matrix of cheese undergoes changes immediately following cheesemaking in response to salting and cooling. Normally, such changes are limited by the amount of water entrapped in the cheese at the time of block formation but for brined cheeses such as feta cheese brine acts as a reservoir of additional water. Our objective was to determine the extent to which the protein matrix of cheese expands or contracts as a function of salt concentration and temperature, and whether such changes are reversible. Blocks of feta cheese made with overnight fermentation at 20 and 31°C yielded cheese of pH 4.92 and pH 4.83 with 50.8 and 48.9g/100g of moisture, respectively. These cheeses were then cut into 100-g pieces and placed in plastic bags containing 100g of whey brine solutions of 6.5, 8.0, and 9.5% salt, and stored at 3, 6, 10, and 22°C for 10 d. After brining, cheese and whey were reweighed, whey volume measured, and cheese salt, moisture, and pH determined. A second set of cheeses were similarly placed in brine (n=9) and stored for 10 d at 3°C, followed by 10 d at 22°C, followed by 10 d at 3°C, or the complementary treatments starting at 22°C. Cheese weight and whey volume (n=3) were measured at 10, 20, and 30 d of brining. Cheese structure was examined using laser scanning confocal microscopy. Brining temperature had the greatest influence on cheese composition (except for salt content), cheese weight, and cheese volume. Salt-in-moisture content of the cheeses approached expected levels based on brine concentration and ratio of brine to cheese (i.e., 4.6, 5.7 and 6.7%). Brining at 3°C increased cheese moisture, especially for cheese with an initial pH of 4.92, producing cheese with moisture up to 58g/100g. Cheese weight increased after brining at 3, 6, or 10°C. Cold storage also prevented further fermentation and the pH remained constant, whereas at 22°C the pH dropped as low as pH 4.1. At 3°C, the cheese matrix expanded (20 to 30%), whereas at 22°C there was a contraction and a 13 to 18g/100g loss in weight. Expansion of the protein matrix at 3°C was reversed by changing to 22°C. However, contraction of the protein matrix was not reversed by changing to 3°C, and the cheese volume remained less than what it was initially.

Use of milk protein concentrate to standardize milk composition in Italian citric Mozzarella cheese making

To better exploit manufacturing facilities and standardize cheese quality, milk composition could be standardized by fortifying its protein content with a milk protein concentrate (MPC) addition so avoiding partially skimming the milk. With this aim Mozzarella cheese was obtained adding citric acid into milk standardized at 4% protein and a fat to protein ratio of 1.0. Protein fortification was obtained adding MPC produced by ultrafiltration. Milk, whey, curd, cheese and stretching water were weighed and analysed for total solid, fat and protein content, to measure component recovery and yield. Yield increase (from 13.8% to 16.7%) was due to the higher recovery of the milk total solids and proteins in MPC cheese (48.2 and 78.3%, respectively) and to the slightly higher cheese moisture, obtained with a little modification of the cheese technology when adding MPC. Milk fat in cheese was lower than that reported in literature. Hot water stretching of the curd resulted in very low losses (1%) of protein and considerable losses (14%) of fat for both control and MPC cheeses. The likely reasons of this low recovery are discussed and it can be supposed that a further cheese yield increase is possible by changing the curd stretching procedures.

Influence of backslopping on the acidifications curves of “Tomme” type cheeses made during 10 successive days

The use of natural whey starter (NWS), also named “backslopping”, is still widespread for several cheesemaking processes. This practice plays a decisive role in the cheese typicity but can also lead to technological defects. A lack of knowledge exists concerning these problems. In this research, “Tomme” cheese variety is used as a model to study backslopping. A starter made of three characterized lactic acid bacteria (LAB) strains was used on day one. During the 10 following days, the whey was used from one day to the other as NWS. The milk used was pasteurized and re-seeded with identified strains of LAB to mimic the contribution of the raw milk flora. As expected, the pH evolution during molding changed from day to day. The analysis of the compositional data, and among them, moisture in non fat cheese and calcium on non fat dry matter, and the use of a statistical PLS approach allowed to prove that pH fluctuations were simply explained by the evolution of the composition of NWS. These results reinforced the accuracy of the model to study backslopping.

Use of NIRS technology with a remote reflectance fibre-optic probe for predicting major components in cheese

In the present work the potential of near infra-red spectroscopy technology (NIRS) together with the use of a remote reflectance fibre-optic probe for the analysis of fat, moisture, protein and chlorides contents of commercial cheeses elaborated with mixtures of cow's, ewe's and goat's milk and with different curing times was examined. The probe was applied directly, with no previous sample treatment. The regression method employed was modified partial least squares (MPLS). The equations developed for the cheese samples afforded fat, moisture, protein, and chloride contents in the range 13–52%, 10–62%, 20–30%, and 0.7–2.9%, respectively. The multiple correlation coefficients (RSQ) and prediction corrected standard errors (SEP (C)) obtained were respectively 0.97 and 0.995% for fat; 0.96% and 1.640% for moisture; 0.78% and 0.760% for protein, and 0.89% and 0.112% for chlorides.