Systematic approach to study temperature and time effects on yield of pasta filata cheese

A batch cooker‐stretcher for pasta filata cheese production was developed based on the kitchen machine ‘Thermomix’. With this batch model system, the effect of kneading time (180, 420 and 600 s) and temperature (55, 60 and 70 °C) on the chemical composition of the pasta filata cheese and the yield was investigated. An increase in temperature from 55 to 70 °C reduced the yield of the pasta filata cheese production from 0.88 to 0.59 g/g, compared to initial curd weight. A correlation between process temperature and the water‐holding properties of protein (casein micelles) is proposed.     

凝乳工艺对功能性低脂干酪中活菌数的影响

活菌数是功能性低脂干酪的重要指标,本文就凝乳工艺过程对功能性低脂干酪活菌数的影响进行了研究,旨在通过控制凝乳工艺过程参数而使干酪最终活菌数达到功能性食品的标准。通过对单因素实验和正交实验研究与分析,结果表明:凝乳酶添加量0.01%,凝乳温度35℃,凝乳pH值为6.2,CaCl2添加量0.03%,干酪活菌数均能达到107mL-1,符合功能性低脂干酪的活菌数要求,能够获得较为理想的实验效果。     

Galactose concentration in pizza cheese prepared by three different culture techniques

A study was conducted to determine the most suitable lactic culture combinations and the techniques for the preparation of low moisture part skim (LMPS) mozzarella cheese (pizza cheese) with a low level of galactose. The cheesemaking time tested for all 12 culture combinations was less than 3 h and hence was found suitable for pizza cheesemaking. The initial accumulated galactose concentration was lower in unstretched curd followed by no-brine curd and stretched curd in ascending order. During storage of the cheese for 7 days, the galactose percentage in the cheeses prepared using cultures comprising galactose-fermenting strains of Lactobacillus helveticus and Streptococcus thermophilus was 0.30 in stretched curd, 0.04 in unstretched curd and 0.03 in no-brine curd. The degree of reduction in the level of galactose in pizza cheese during storage was maximum with the no-brine curd technique followed by the unstretched and stretched curd techniques in that order. This study provides information regarding selection of starter culture combinations and techniques for pizza cheesemaking based on consumer preference for low or moderate browning mozzarella cheese as a result of its galactose concentration.     

Effect of homogenisation of cheese milk and high‐shear mixing of the curd during cream cheese manufacture

The role of the homogenisation pressure of cheese milk (0, 25, 100 MPa) and high‐shear mixing of cheese curd at different speeds (750, 1500, and 3000 r.p.m.) and times (2 and 4 min) in improving the texture of medium‐fat cream cheese was investigated independently. Homogenisation resulted in small fat globules and firmer texture, while increasing speed and mixing times resulted in a decrease in curd particle size and an increase in the spreadability of the cheese. All curd samples from both the trials exhibited shear‐thinning behaviour. Unhomogenised milk and high‐shear mixing of the curd showed a low coefficient of friction (better lubrication property).     

Segmentation of Parmigiano Reggiano dairies according to cheese-making technology and relationships with the aspect of the cheese curd surface at the moment of its extraction from the cheese vat

Parmigiano Reggiano cheese dairies develop specific cheese-making strategies to adapt the variable characteristics of raw, not standardized milk to the final goal of obtaining cheese consistent with the standard. Analyzing 1,175 cheese-making reports from 30 out of 383 dairies associated with the Parmigiano Reggiano Consortium in 2010 and 2011, 4 groups of Parmigiano Reggiano dairies using specific cheese-making technologies were discriminated by means of multiple linear discriminant analysis. Cheese makers manage cheese-making practices to obtain curd with different roughness properties, classified according to jargon words such as “rigata” and “giusta” or synonyms, because they believe that the roughness of the cheese curd surface immediately after the extraction from the vat is associated with different whey-draining properties and to the final outcome of the cheese. The aspect of the surfaces of the curds produced by the 4 groups of dairies was different according to the technology applied by each group. Cutting of the coagulum when it is still soft for a longer time and faster cooking of the cheese curd grains were associated with a less rough appearance of the surface of the curd, whereas under the opposite conditions, cutting the coagulum when it is firm for a shorter time, led to a curd with a rougher surface. These findings partially support the traditional feeling of Parmigiano Reggiano cheese makers, who consider the curd surface aspect one of the main drivers for their technological choices; to date, however, no data are provided about correlation between the aspect of the curd and the quality of the ripened cheese. If a sufficiently strong correlation could be demonstrated by the future development of the research, the operational effectiveness of Parmigiano Reggiano dairies will be able to largely benefit from the availability of sound and early process markers.     

Effect of post-cheddaring manufacturing parameters on the meltability and free oil of mozzarella cheese

The effect of reducing the salt content on the meltability and free oil of mozzarella cheese was studied. In addition, the alternative use of a twin-screw extruder is proposed for the stretching of the curd. It was found that by reducing the salt content the meltability and the free oil are slightly decreased. On the other hand, the cheese produced from the twin-screw extruder (fed with chilled curd) had lower meltability but no free oil at all compared with that from a conventional stretcher.     

Effect of goat milk composition on cheesemaking traits and daily cheese production

Cheese yield is strongly influenced by the composition of milk, especially fat and protein contents, and by the efficiency of the recovery of each milk component in the curd. The real effect of milk composition on cheesemaking ability of goat milk is still unknown. The aims of this study were to quantify the effects of milk composition; namely, fat, protein, and casein contents, on milk nutrient recovery in the curd, cheese yield, and average daily yield. Individual milk samples were collected from 560 goats of 6 different breeds. Each sample was analyzed in duplicate using the 9-laboratory milk cheesemaking assessment, a laboratory method that mimicked cheesemaking procedures, with milk heating, rennet addition, coagulation, curd cutting, and draining. Data were submitted to statistical analysis; results showed that the increase of milk fat content was associated with a large improvement of cheese yield because of the higher recovery of all milk nutrients in the curd, and thus a higher individual daily cheese yield. The increase of milk protein content affected the recovery of fat, total solids, and energy in the curd. Casein number, calculated as casein-to-protein ratio, did not affect protein recovery but strongly influenced the recovery of fat, showing a curvilinear pattern and the most favorable data for the intermediate values of casein number. In conclusion, increased fat and protein contents in the milk had an effect on cheese yield not only for the greater quantity of nutrients available but also for the improved efficiency of the recovery in the curd of all nutrients. These results are useful to improve knowledge on cheesemaking processes in the caprine dairy industry.     

Effect of rennet coagulation time on composition, yield, and quality of reduced-fat cheddar cheese

This study compared the effect of coagulum firmness at cutting on composition of 50% reduced-fat Cheddar cheese. Coagulum firmness was determined by subjective evaluation by the cheese maker. Three firmness levels were tested, and these corresponded to average times of coagulant addition to cutting the curd of 25, 48, and 65 min. A slow acid-producing culture was used, and ripening times were altered to give similar curd pH values throughout cheese making. A longer rennet coagulation time (firmer coagulum at cutting) resulted in an increase in cheese moisture as well as an increase in cheese yield. The percentages of fat recovered in the cheese decreased with increasing curd firmness. The percentage of nitrogen recovered in the cheese was similar among the treatments. The amount of whey collected from the curd after milling increased as the coagulum firmness at cutting increased. Higher moisture content and lower pH of cheese made from the firmer curd at cutting contributed to softer, smoother-bodied cheeses, but the Cheddar flavor intensity was not affected.     

霉菌成熟软质干酪工艺参数优化的研究

对影响霉菌成熟软质干酪加工关键因素进行了研究。结果表明,发酵剂添加量为0.01%效果较好,CaCl2添加量为0.02%为宜,凝块切割大小为15mm3效果较好,装模pH值为5.4效果较好,加盐量为1.5%为宜,霉菌添加量为0.005%可得较好的产品品质。     

A new type of semi-hard cheese from recombined milk

Technological aspects for achieving a suitable technique for making a new semi-hard cheese from pasteurized recombined milk were studied. The manufacturing procedure was basically set on setting temperature of 35°C, rennet powder quantity of 8 g/100 kg milk, curd cubes size of 11/4 in, scalding for 1.5 min at 40°C and pressing at 1.50 lb/in2 for 3 hr. The resulting cheese is named 'Ain Shams' and is characterized by a mild and slightly acidic flavour, tender body and very slightly open texture. The new cheese contains 40% moisture and 40% fat/dry matter.     

Effects of indirect indicators of udder health on nutrient recovery and cheese yield traits in goat milk

In dairy goats, very little is known about the effect of the 2 most important indirect indicators of udder health [somatic cell count (SCC) and total bacterial count (TBC)] on milk composition and cheese yield, and no information is available regarding the effects of lactose levels, pH, and NaCl content on the recovery of nutrients in the curd, cheese yield traits, and daily cheese yields. Because large differences exist among dairy species, conclusions from the most studied species (i.e., bovine) cannot be drawn for all types of dairy-producing animals. The aims of this study were to quantify, using milk samples from 560 dairy goats, the contemporary effects of a pool of udder health indirect indicators (lactose level, pH, SCC, TBC, and NaCl content) on the recovery of nutrients in the curd (%REC), cheese yield (%CY), and daily cheese yields (dCY). Cheese-making traits were analyzed using a mixed model, with parity, days in milk (DIM), lactose level, pH, SCC, TBC, and NaCl content as fixed effects, and farm, breed, glass tube, and animal as random effects. Results indicated that high levels of milk lactose were associated with reduced total solids recovery in the curd and lower cheese yields, because of the lower milk fat and protein contents in samples rich in lactose. Higher pH correlated with higher recovery of nutrients in the curd and higher cheese yield traits. These results may be explained by the positive correlation between pH and milk fat, protein, and casein in goat milk. High SCC were associated with higher recovery of solids and energy in the curd but lower recovery of protein. The higher cheese yield obtained from milk with high SCC was due to both increased recovery of lactose in the curd and water retention. Bacterial count proved to be the least important factor affecting cheese-making traits, but it decreased daily cheese yields, suggesting that, even if below the legal limits, TBC should be considered in order to monitor flock management and avoid economic losses. The effect of NaCl content on milk composition was linked with lower recovery of all nutrients in the curd during cheese-making. In addition, high milk NaCl content led to reductions in fresh cheese yield and cheese solids. The indirect indicators of the present study significantly affected the cheese-making process. Such information should be considered, to adjust the milk-to-cheese economic value and the milk payment system.     

Mozzarella干酪的研制

以新鲜牛乳为主要原料,通过干酪制造条件的优化研究,确定了制造Mozzarella干酪的工艺流程及主要参数,实验表明,新鲜牛乳经标准化使得酪蛋白与脂肪之比为0．84,然后加入发酵剂和凝乳酶,凝乳形成后,经切割,排乳清,并在热水中拉伸,盐渍即到成品,产品的平均脂肪和水分的含量分别为22．82％和50．74％,达到了Mozzarella干酪的质量要求。     

Relationships between cheese-processing conditions and curd and cheese properties to improve the yield of Idiazabal cheese made in small artisan dairies: A multivariate approach

Very diverse cutting and cooking intensity processes are currently used in small artisan dairies to manufacture Idiazabal cheese. The combination of the technical settings used during cheese manufacturing is known to affect cheese composition and yield, as well as whey losses. However, the information regarding the effect on microstructure and texture of cheese is scarce, especially in commercial productions. Therefore, the effect of moderate- and high-intensity cutting and cooking processes on whey losses, curd-grain characteristics, microstructure and cheese properties, and yield were analyzed. Three trials were monitored in each of 2 different small dairies during the cheesemaking of Idiazabal cheese, which is a semihard cheese made from raw sheep milk. The role and know-how of the cheesemakers are crucial in these productions because they determine the cutting point and handle semi-automatic vats. The 2 dairies studied used the following settings: dairy A used moderate-intensity cutting and cooking conditions, and dairy B used high-intensity cutting and cooking settings. Multiple relationships between cheese-processing conditions and curd, whey, and cheese properties as well as yield were obtained from a partial least square regression analysis. An increased amount of fat and casein losses were generated due to a combination of an excessively firm gel at cutting point together with high-intensity cutting and cooking processes. The microstructural analysis revealed that the porosity of the protein matrix of curd grains after cooking and cheese after pressing was the main feature affected, developing a less porous structure with a more intense process. Moderate-intensity cutting and cooking processes were associated with a higher cheese yield, regardless of the longer pressing process applied. No significant differences were observed in cheese composition. After 1 mo of ripening, however, the cheese was more brittle and adhesive when the high-intensity cutting and cooking process was applied. This could be associated with the composition, characteristics, and size distribution of curd grains due to differences in the compaction degree during pressing. These results could help to modify specific conditions used in cheesemaking, especially improving the process in those small dairies where the role of the cheesemaker is crucial.     

Effect of polyphenolic ingredients on physical characteristics of cheese

A novel cheese product developed based on the incorporation of various polyphenolic compounds was evaluated for its texture characteristics. Single phenolic compounds including catechin, epigallocatechin gallate (EGCG), tannic acid, homovanillic acid, hesperetin and flavone, along with natural crude compounds such as grape extract, green tea extract and dehydrated cranberry powder, were added as functional ingredients during the cheese-making process. Cheese curds containing polyphenolic compounds at a concentration of 0.5 mg/mL showed a decrease of curd moisture content (CMC) while the gel strength (GS) was not affected. Structural differences were observed when crude polyphenolic compounds were added to the cheese, resulting in rough and granular structures. Physical properties of the cheese product were evaluated after adding bioactive phenolic compounds to the cheese curd. We fully expect to apply this approach to other dairy products in the future.     

An attempt to produce low fat cephalotyre (Ras) cheese of acceptable quality

Two trials were carried out to produce low fat Ras cheese with acceptable organoleptic properties. In the first trial, cheese milk containing 1%, 1·5% or 2% fat and including CMC or carrageenan at levels of 0·1% and 0·02%, respectively, was used in cheese making. Control cheese was also made from milk containing 4% fat. Cheese without added stabilizers and containing lower fat levels than the control cheese had a flat flavour and tough rubbery body throughout ripening. The addition of both stabilizers improved the body characteristics of low fat cheese but did not affect flavour development in cheeses made from 1% and 1·5% fat milk and only slightly enhanced flavour intensity in cheese made from 2% fat milk.In the second trial, cheese milk of 1% or 1·5% fat with added 0·02% carrageenan was used for the preparation of Ras cheese curd. The resultant curd was then mixed with 2% of a starter culture containing S. diacetylactis and L. casei with 10 ml of 0·05% MnCl₂ solution for each kilogram of curd or reduced glutathione at a level of 100 mg/kg curd. The additives enhanced flavour intensity, improved body characteristics and accelerated the formation of both soluble nitrogenous compounds and Free Volatile Fatty Acids.     

Determination of microbial contamination sources for use in quality management of cheese industry: “Dil” cheese as an example

The microbiological quality, safety and shelf-life of cheeses depend on manufacture and handling in an environment that meets basic standards for hygiene and the management of hygiene in the process. In this research contamination sources of “Dil” cheese during production in a local dairy plant in Bursa, Turkey were determined. Eighteen different control points (raw milk, pasteurized milk, heated curd, molded cheese before kneading, kneaded cheese, brine solution for kneading, thermophilic culture, rennet, calcium chloride solution, brine solution for cheese, cheese vat, workers hands, production room air, production room floor, production room wall, packaging material and packaged cheese) have been examined for the enumeration of total aerobic mesophilic bacteria, Staphylococci, Enterobacteriaceae, Salmonella spp., Escherichia coli, lactic acid bacteria, Pseudomonas spp. and yeast-moulds. It was determined that viability of lactic acid bacteria in thermophilic culture was not in high numbers and some contaminations to “Dil” cheese were detected from the starter culture. Brine solutions and rennet were contaminated with Staphylococci. Yeast and moulds in production room air were the major sources of contamination. Pasteurization and kneading in hot brine solution can eliminate some of the microorganisms but that was not sufficient in the production of Dil cheese. Finish cheese should meet specific hygienic standards, with respect to regulations post-contaminations to the cheese must be inhibited and a HACCP plan should be established during production.     

Quality and ripening changes of Ras cheese made by direct acidification

Trials were carried out to produce Ras cheese of good quality without the use of starter. Cheese was made from pasteurized cow's milk acidified with lactic acid or citric acid to pH 5.8 alone or coupled with mixing the curd with glucono δ lactone (4.5 g/kg curd). Control cheese was made from milk ripened with a starter culture of S. lactis. Resultant cheeses showed poor body and texture, weak flavour intensity and low levels of soluble nitrogen compounds and free volatile fatty acids. Incorporation into the cheese curd of mixtures containing Fromase 100 (fungal protease) and Piccantase B (fungal lipase) or Fromase 100 and Capalase K (animal lipase) enhanced flavour intensity, improved body characteristics and accelerated the formation of both soluble nitrogen compounds and free volatile fatty acids. The organoleptic properties of the experimental cheeses with added enzymes were comparable to those of the control cheese.     

凝乳酶对超滤浓缩乳生产Quark干酪的影响

采用每100g超滤乳中添加0、50、100、150、200、250μL六个水平的凝乳酶.研究了不同的凝乳酶添加量对Quark干酪组成、凝乳硬度、贮藏期产品感官品质和干酪中水溶性氮含量的影响.结果表明,当凝乳酶的添加量从0μL/100g增大到250μL/100g时,产品的水分含量上升了1.49%,粗产率和校正产率分别上升了1.42%和0.99%,固形物的回收率下降了3.5%,凝乳硬度从16,83g增大到40.84g.但干酪的苦味和水溶性氮含量,随着贮存期的延长和凝乳酶用量的增加而增大.     

Effect of high pressure homogenisation of milk on cheese yield and microbiology, lipolysis and proteolysis during ripening of Caciotta cheese

The principal aim of this work was to compare Caciotta cheeses obtained from cow milk previously subjected to high pressure homogenisation (HPH) at 100 MPa with those produced from raw (R) or heat-treated (P) cow milk. HPH had both direct and indirect effects on cheese characteristics and their evolution during ripening. In particular, HPH treatment of milk induced a significant increase of the cheese yield; moreover, it affected the microbial ecology of both curd and cheese. Compared with the thermal treatment, the HPH treatment resulted in a decrease of about one log cfu/g of yeast and lactobacilli cell loads of the curd. The initial milk treatment also affected the evolution over time and the levels attained at the end of ripening of all the microbial groups studied. In fact, lactobacilli, microstaphylococci and yeast cell loads remained at lower levels in the cheeses obtained from HPH milk with respect to the other cheese types over the whole ripening period. Moreover, HPH of milk induced marked and extensive lipolysis. Cheeses from HPH milk showed the presence of high amounts of free fatty acids immediately after brining. The electrophoretic patterns of the different cheese types showed that Caciotta made from HPH-treated milk was characterized by a more extensive and faster proteolysis as well as a significant modification of its volatile molecule profile. The results obtained and the sensory analysis indicated that HPH treatment of milk was able to differentiate Caciotta cheese or to modify its ripening patterns.