Moisture cheese

A food system can experience rather large fluctuations in temperature during its lifetime, depending on a variety of factors, such as the location and time of year the product is manufactured and the conditions of distribution, storage, and display. For example, if a food product, such as an intermediate moisture cheese, is manufactured and packaged with an aw] equal to 0.66 at... 

The strength of the rennet-induced gel is also adversely affected by heat treatment of the milk, again presumably because the whey protein-coated micelles are unable to participate properly in the gel network. Gels from severely heat-treated milk have poor syneresis properties, resulting in high-moisture cheese which does not ripen properly. Syneresis is undesirable in fermented milks, e.g. yoghurt, the milk for which is severely heat-treated (e.g. 90°C x 10 min) to reduce the risk of syneresis. 

Pigmentation Rhodotorula glutinis. Sporobolomyces spp. Carotenoids (pink, red) Rhodotorula ghitmis causes pink sauerkraut and discolors the surface of high-moisture cheeses. 

Temperature also has a similar effect on the dielectric properties of cheese. The effect of temperature, however, depends on the moisture content of the cheese being processed. Medium-moisture content cheese exhibits a decrease in e for temperatures between 5°C and 55°C. Further increase in processing temperature results in an increase in e. The increase in e value reversed again at 65°C. The decrease in s value between 65°C and 85°C is common for both medium- and low-moisture cheese. The dielectric property changes at higher temperatures are similar to that of soy protein. Higher processing temperatures result in protein denaturation. 

The loss factor (s") for higher- and medium-moisture content cheese increases gradually with temperature (5°C-85°C). The trend is opposite for low-moisture cheese. The increase in s" for high- and medium-moisture cheese could be attributed to ionic conduction. It was reported that the effect of temperature was more pronounced at lower frequencies than at higher frequencies (above 1 GHz) (Nelson and Bartley, 2000). Models were also developed to predict the effects of moisture and salt content. These models can provide the effects of frequency, temperature, and compositions on microwave processing of cheese. 

The water content of an 875.4-mg sample of cheese was determined with a moisture analyzer. What is the %w/w H2O in the cheese if the final mass was found to be 545.8 mg ... 

Cott lge Cheese. Cottage cheese is made from skimmed milk. As compared to most other cheeses, cottage cheese has a short shelf-life and must be refrigerated to maintain quaHty, usually <4.4° C to provide a shelf-life of three weeks or more. Cottage cheese is a soft uncured cheese which contains not more than 80% moisture. 

Proposed IDE standards for caseiaate are hsted ia Table 4. la most cases the sodium salt is preferred for emulsificatioa the calcium salt is preferred for imitation cheese. Caseia and caseiaates must be stored carefliUy and evaluated for flavor before use ia products. Improperly manufactured or stored caseia—caseiaate has a very stroag, musty off-flavor. Excessive fat coateat, high lactose and moisture contents, and high storage temperatures contribute to undesirable flavor development. 

Any material used for packaging natural cheeses must prevent moisture loss, maintain good product appearance, protect against microorganisms, and act as an oxygen barrier. Aluminum foil laminates provide this type of protection for cheese. Cream cheese is packed in lami-... 

Calcium caseinate and butter oil have been extruded directly at 50-60% moisture levels to obtain a cheese analog with no surface water or fat (Cheftel et ah, 1992). The fat emulsification and melting ability increased with screw speed or barrel temperature. The texture of the extmded analogs was similar to those obtained by batch cooking and was affected by pH (Cheftel et ah, 1992) and emulsifying salts (Cavalier-Salou and Cheftel, 1991). The product can be used as adjimcts for hamburger, pizza, and sauces. 

Typically, sorption isotherms are constructed for a single food ingredient or food system. An alternative approach is to plot the moisture content versus water activity (or relative vapor pressure) values for a variety of as is food ingredients and food systems. The result is a composite food isotherm (Figure 17). The composite isotherm fits the typical shape observed for a sorption isotherm for an individual food system, with a few products falling above or below the isotherm curve (chewing gum, honey, raisins, bread, and colby and cheddar cheeses). Slade and Levine (1991) were the first to construct such a plot using moisture content and aw values from van den... 

In agriculture and food, NIR has been a powerful tool for decades. All shipments of grain leaving US ports are analyzed for moisture, fat, protein, and starch via NIR. Processed foods are also a prime venue for NIR percent of fat in cheese spread, hardness of wheat, and freshness of meats are just some of the applications in food. 

Finally, a food processor presented 11 samples for a feasibility study on cheese powder to indicate its usefulness in quantifying caloric content as well as such constituents as moisture, protein, fat, ash, and carbohydrate. The composite absorbance tracings of Figure 11 produced a 3-wavelength equation, the results of which are shown in Table III. The... 

For certain foodstuffs, aw may be estimated from chemical compostion. A nomograph relating the aw of freshly made cheese to its content of moisture and NaCi is shown in Figure 7.9. Likewise, various equations relating the aw of cheese to [NaCi], [ash], [12% trichloroacetic acid-soluble N] and pH have been developed (see Marcos, 1993). 

Gel strength (curd tension). The gel network continues to develop for a considerable period after visible coagulation (Figure 10.8). The strength of the gel formed, which is very important from the viewpoints of syneresis (and hence moisture control) and cheese yield, is affected by several factors - the principal ones are summarized in Figure 10.9. 

Syneresis. Renneted milk gels are quite stable if undisturbed but synerese (contract), following first-order kinetics, when cut or broken. By controlling the extent of syneresis, the cheesemaker can control the moisture content of cheese curd and hence the rate and extent of ripening and the stability of the cheese - the higher the moisture content, the faster the cheese will ripen... 

All cheeses are salted, either by mixing dry salt with the drained curd (confined largely to English varieties), rubbing dry salt on the surface of the pressed cheese (e.g. Romano or Blue cheeses), or by immersion of the pressed cheeses in brine (most varieties). Salt concentration varies from c. 0.7% (c. 2% salt-in-moisture) in Emmental to 7-8% (c. 15% salt-inmoisture) in Domiati. 

Salting promotes syneresis and hence reduces the moisture content of cheese about 2 kg of water are lost for each kilogram of salt absorbed. 

Coagulant. Most of the coagulant is lost in the whey but some is retained in the curd. Approximately 6% of added chymosin is normally retained in Cheddar and similar varieties, including Dutch types the amount of rennet retained increases as the pH at whey drainage is reduced. As much as 20% of added chymosin is retained in high-moisture, low-pH cheese, e.g. Camembert. Only about 3% of microbial rennet substitutes is retained in the curd and the level retained is independent of pH. 

Properly made cheese is quite a hostile environment for bacteria due to a low pH, moderate-to-high salt in the moisture phase, anaerobic conditions (except at the surface), lack of a fermentable carbohydrate and the production of bacteriocins by the starter. Consequently, cheese is a very selective environment and its internal non-starter microflora is dominated by lactic acid bacteria, especially mesophilic lactobacilli, and perhaps some Micrococcus and Pediococcus. 

Since the ripening of cheese, especially low moisture varieties, is a slow... 

Exogenous enzymes, usually proteinases and/or peptidases. For several reasons, this approach has had limited success, except for enzyme-modified cheeses (EMC). These are usually high-moisture products which are used as ingredients for processed cheese, cheese spreads, cheese dips or cheese flavourings. 

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