Establishment of Enabling Technology for Manufacture of Selected Types of Continental and Speciality Cheeses

End of Project ReportThe objectives in the project were the development of the science and technology for speciality cheese manufacture, identification and overcoming of the technical constraints to the manufacture of soft speciality cheeses in Ireland and the development of Moorepark Technology Limited (MTL) pilot plant as an integrated, flexible pre-commercial manufacturing platform with which to evaluate the market for speciality cheese.Department of Agriculture, Food and the Marin

Impact of freezing on the physicochemical and functional properties of low–moisture part–skim mozzarella

peer-reviewedLow–moisture part–skim (LMPS) mozzarella cheeses were held at 4 °C for 0, 2 or 8 d before freezing to −20 °C. The cheeses were frozen at a rate of 0.6, 2.0 or 8.0 °C h−1 and held frozen at −20 °C for 1, 6, 12 or 44 weeks. After freezing, cheeses were stored at 4 °C for 16–37 d, resulting in a total storage time at 4 °C (before and after freezing) of 24–37 d (frozen–thawed mozzarella). Control mozzarella was stored at 4 °C for 25–37 d. The control and frozen–thawed cheeses were assayed for composition, primary proteolysis, moisture distribution, texture profile analysis and melting characteristics after similar storage times at 4 °C. Freezing under the evaluated conditions resulted in reduced firmness of the unheated cheese but did not significantly affect the properties of the heated cheese. The results suggest that freezing may be effectively applied to control or extend the functional shelf–life of LMPS mozzarella shipped to long–distance markets.Flanders' FOO

Establishment of Enabling Technology for Manufacture of Selected Types of Continental and Speciality Cheeses

End of Project ReportThe objectives in the project were the development of the science and technology for speciality cheese manufacture, identification and overcoming of the technical constraints to the manufacture of soft speciality cheeses in Ireland and the development of Moorepark Technology Limited (MTL) pilot plant as an integrated, flexible pre-commercial manufacturing platform with which to evaluate the market for speciality cheese.Department of Agriculture, Food and the Marin

Effects of milk pre-acidification using CO2 or lactic acid on the storage-related properties of low-moisture part-skim mozzarella

Ca solubilization plays a crucial role in regulating the functional properties of low-moisture part-skim (LMPS) mozzarella. In order to control the extent of Ca solubilization during cheese-making, commercial manufacturers may use direct acidification techniques to lower the pH of the starting milk. Research to date on the properties of LMPS mozzarella has mainly reported on the effects of milk pre-acidification using liquid or powdered acidulants. To our knowledge ,the use of a gaseous acidulant has not yet been investigated. Our study evaluates the effects of milk pre-acidification to pH 6.2 using CO2 on the functional properties of LMPS mozzarella after 2, 4, 8, 15 or 30 d of storage at 4°C, and compares the findings with both control cheeses and cheeses produced from milk pre-acidified to pH 6.2 or pH 5.8 using lactic acid. The cheeses were assayed for composition, primary proteolysis, and functional characteristics. Milk pre-acidification with CO2 resulted in reduced Ca-cheeses with similar dry matter and fat-in-dry matter to those of the control. In contrast, cheeses produced from milk pre-acidified with lactic acid had the lowest contents of dry matter or Ca, and exhibited the largest improvement in functional quality. A linear model, however, revealed that the melting and extensibility characteristics of the cheese were predominantly affected by changes in Ca. Overall, cheeses produced from pre-acidified milk were lower in Ca, exhibited a reduced melting point, and required less work to extend to a height of 38 cm after heating when compared to the control. The results therefore suggest that commercial manufacturers may consider milk pre-acidification using CO2 in order to produce mozzarella with different points of variation

Variations in the biochemical and functional properties of industrial low-moisture part-skim mozzarella during 4 months of storage at 4°C

The functional properties of low-moisture part-skim (LMPS) mozzarella are pivotal for its commercial application, e.g. as pizza topping. We previously investigated the variations in the functional properties of LMPS mozzarella manufactured on different days using a standardized procedure during 1 month of storage at 4°C. However, we did not investigate the variations in the functional quality of LMPS mozzarella stored for more than 1 month at 4°C. The time allocated to transport, processing and storage of the cheese may be longer than 1 month. Moreover, we did not investigate the influence of other sources of process-related variability, such as the use of alternating cultures, coagulants, or other adjustments to the cheese manufacturing procedure. The current study therefore investigates the variability in LMPS mozzarella characteristics sampled at monthly intervals over a 1-year period from an industrial cheese plant during 4 months of storage at 4°C. One hundred-and-fifty cheese blocks were procured from 50 vats, held at 4°C for 0.5, 2, 3 or 4 months and assayed for composition, primary proteolysis, texture profile analysis, heat-induced changes in viscoelastic behavior, cheese extensibility and flow. The results revealed differences in the functional quality between cheeses obtained on different sampling occasions after 0.5, 2 or 3 months of storage. A linear model revealed that the variability in the functional performance was not only affected by storage time, but also by differences in cheese composition, and by several interaction effects. The results further demonstrated that the impact of process-related variations in cheese composition on the solubilization of colloidal Ca or the flow of the heated cheese outweighed that of storage time after 14 d. This study may therefore offer commercial manufacturers with clearer insights in the quality consistency of their cheese after its release into the market

Effect of varying the salt and fat content in Cheddar cheese on aspects of the performance of a commercial starter culture preparation during ripening

peer-reviewedProduction of healthier reduced-fat and reduced-salt cheeses requires careful selection of starter bacteria, as any substantial alterations to cheese composition may prompt changes in the overall performance of starters during cheese ripening. Therefore, it is important to assess the effect of compositional alterations on the individual strain response during cheese ripening for each optimised cheese matrix. In the current study, the effect of varying fat and salt levels in Cheddar cheese on the performance of a commercial Lactococcus lactis culture preparation, containing one L. lactis subsp. lactis strain and one L. lactis subsp. cremoris strain was investigated. Compositional variations in fat or salt levels did not affect overall starter viability, yet reduction of fat by 50% significantly delayed non-starter lactic acid bacteria (NSLAB) populations at the initial ripening period. In comparison to starter viability, starter autolysis, as measured by release of intracellular lactate dehydrogenase (LDH) or post-proline dipeptidyl aminopeptidase (Pep X) into cheese juices, decreased significantly with lower salt addition levels in full-fat Cheddar. Conversely, reducing fat content of cheese resulted in a significantly higher release of intracellular Pep X, and to a lesser extent intracellular LDH, into juices over ripening. Flow cytometry (FCM) indicated that the permeabilised and dead cell sub-populations were generally lower in juices from cheeses with reduced salt content, however no significant differences were observed between different salt and fat treatments. Interestingly, fat reductions by 30 and 50% in cheeses with reduced or half added salt contents appeared to balance out the effect of salt, and enhanced cell permeabilisation, cell death, and also cell autolysis in these variants.Overall, this study has highlighted that alterations in both salt and fat levels in cheese influence certain aspects of starter performance during ripening, including autolysis, permeabilisation, and intracellular enzyme release. However, it may be possible to reduce the fat and salt content of Cheddar cheese by 30 or 50%, respectively, without largely altering permeabilised and dead cell sub-populations and, in turn, the amount of released intracellular Pep X activity, such that these performance parameters are similar to those observed for control full-fat, full-salt Cheddar cheese