Homogenization, cheese

The technical demands for a cheese coating are very comprehensive since it has to fulfill a large number of functions [132,135]. First of all, it has to offer both mechanical and hygienic protection over a long period of time. Therefore, the coating should be homogeneous and crack free and adhere well to the wet... 

Small foam pieces are impregnated with chicken, duck or turkey offal homogenate at the rate of 12.5 parts medium to one part foam by weight. A wide mouthed Erlenmeyer flask of 500 ml capacity is filled with this foam homogenate mixture to the 250-300 ml mark (about 100 g). The mouth of the flask is wiped, plugged with cotton, wrapped with cheese muslin cloth and autoclaved at 121°C for 20 min. 

Emulsifying salt Substance which converts proteins contained in cheese into a dispersed form and thereby brings about homogenous distribution of fat and other components... 

For cheese sample Ultraturrax homogenization (two cycles) with H2O, centrifugation (for skimming), acidification at pH 4.2. 6 (for casein precipitation), centrifugation, filtration For cheese sample extraction with H2O (sonication) for milk centrifugation, acidification (pH 4.6) to precipitate caseins, centrifugation, filtration... 

A cheese-like spread, which is similar to processed cheese spread, is prepared by combining hydrolyzed Swiss-or Cheddar-whey protein and cultured cream. The whey protein is precipitated by heat and acid. The granular, chalky precipitate then acquires a smooth texture by enzymatic hydrolysis with Rhozyme P-11 at 39.5 to 40.5 °C for 30 min. The product is heated to 85 °C for 15 min to inactivate the enzymes then it is homogenized and blended with an equal quantity of 45° cream culture containing Lactobacillus casei (Webb and Whittier 1970). 

Prior to cheesemaking, milk is generally clarified and may or may not be homogenized or pasteurized, depending on the type of cheese. The first step in the actual cheesemaking process is the formation of the... 

The use of homogenized milk for cheesemaking has been reviewed by Peters (1964). The advantages of homogenized milk in the manufacture and ripening of cheese are (1) lower fat losses in whey and therefore a higher yield, (2) reduced fat leakage of cheese at room temperatures, and (3) increased rate of fat hydrolysis and, therefore, desired flavor production in blue cheese. 

Homogenized milk is generally not used for cheesemaking because of the cost and potential increase in hydrolytic rancidity in cheese. There are a few major exceptions cheese spreads, cream, Neufch tel, and blue cheese (Kosikowski 1977). 

A higher yield of cheese is obtained when homogenized milk is used for cheesemaking. This is due to increased fat and moisture retention of the curd. However, the fat in the whey cannot be recovered by centrifugal processes because of the failure of homogenized fat globules to cluster. 

Emmons, D. B., Kalab, M., Larmond, E. and Lowrie, R. J. 1980. Milk gel structure. X. Texture and microstructure in Cheddar cheese made from whole milk and from homogenized low-fat milk. J. Texture Studies 11, 15-34. 

Extraction is an essential step when analyzing solid samples. In some cases homogenization with a solvent suffices, but in others the sample must first be coimninuted. Water, solutions of acetic acid or sodium chloride, or more complex saline solutions are used as solvents. Mixtures of water and methanol or water and ethanol are also employed. The choice of solvent depends on the degree of selectivity desired in the extraction and whether the extraction yield is intended for quantitative analysis. Optimization of the extraction procedure is required in all cases, to fit the nature of the sample to be analyzed and the range of molecular weights of the peptides to be separated. For example, water has been used as the extraction solvent for cheese (33) and legumes (34). Saline solutions have been utilized to extract peptides from meat (35-38) and flour (39,40). Benedito de Barber et al. (41) examined differences in the extractability of amino acids and short peptides in various solvents (1M acetic acid, 70% ethanol, and distilled water) they concluded that extraction with 1M acetic acid yielded the maximum amino acid and peptide contents. 

The Extrelut cleanup method is suitable for most foodstuffs, such as cheese, yogurt, and other samples that tend to form emulsions during extraction. The prepacked or refilled Extrelut column in a plastic tube consists of a wide-pore kieselgel column. A sample is homogenized in 0.5 N sulfuric acid, diluted with water, and applied onto the Extrelut column for at least 15 min. The absorbed preservatives are eluted with a chloroform - isopropanol (9 1) mixture, and the elu-ate is collected and evaporated carefully nearly to dryness. The last few milliliters of solvent are removed with a gentle flow of nitrogen to prevent substantial losses of BA and SA, which have relatively high vapor pressures. The residue is transferred with methanol into a 10-ml volumetric flask and diluted to volume with methanol. To speed up the dissolution, the use of an ultrasonic bath is recommended. The filtered extract is analyzed on a /zBondaPak Cl8 column, with a... 

The same derivatization was applied to the HPLC determination of STR and DHS in milk. The comparison of HPLC and ELISA methods was also performed for DIHS. After removal of fat by extracting a milk sample with oxalic acid and centrifuging, proteins were precipitated with TCA. The supernatant was treated by SPE on a Cl8 column. The cartridge was washed with water, and the analytes were eluted with ion-pair in MeCN. The eluate was reconcentrated by evaporating and dissolving in water. Postcolumn reaction took place at 65°C. Recoveries were dependent on the concentration level and the batch of SPE columns used, and independent of the fat content and homogenization. The sample cleanup was not sufficient for the analysis of cheese. The DIHS concentrations of incurred samples determined by ELISA were higher than those obtained by the LC method (107). 

His Tyr Ion-pair HPLC of PA derivatives and fluorimetric detection at 425 nm (Aex = 338 nm). Nova-Pak C-l 8 stationary phase. Mobile phase MeOH, hydrogen-phosphate, heptanesul-fonic acid, pH = 3.0. 1-5 mg/L in cheese Dairy products, infant formulae, yogurt, cheese found in cheese 25-223 mg/L Homogenization with MeOH at T = 60°C, cooling, MeOH addition, filtration. 159... 

Camembert cheese HC104 and CH2C12 addition, 66 homogenization. NaOH addition, dilution, 0.45-/xm filtration. 

External Characters.—The cheese is struck with the knuckle or with a small hammer on the rind to ascertain if it gives a clear, sharp sound (sound cheese) or if there is discontinuity (blisters, honey-combing, fissures). The interior is examined to ascertain if this is homogeneous, and in the case of a cheese with cavities, if these are uniform to determine if the odour is agreeable and piquant (sound cheese) or repulsive (altered), if the taste is that characteristic of the particular cheese and if the colour is uniform or if red, black or bluish spots are present. 

These approaches have been reviewed extensively (Jameson, 1990 Ardo, 1997 Fenelon and Guinee, 1997 Fenelon, 2000). Various recommendations for the manufacture of reduced-fat cheeses with improved sensory and textural properties (Mistry et al., 1996 Johnson et al., 1998), (e.g., half-fat Cheddar prepared by homogenization of cream used to standardize the cheese milk) (Nair et al., 2000) the combined effects of increases in milk pasteurization temperature and pH at curd milling, and the use of selected starters and starter culture adjuncts (Guinee et al., 1999 Fenelon et al., 2002) ... 

Table 11.2. Effect of Homogenization or Microfluidization of Milk, or Cream, on the Composition of Cheese... 

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