Meat freezing

AFRC, Meat Freezing- Why and How, AFRC Institute ofFood Research, Bristol Laboratory, 1974... 

In the case of meat and most vegetables, phase changes induced by freezing temperatures are easily reversed with melting or thawing. The liquids and solids in meat freeze and melt without much noticeable affect on taste. Likewise, the liquids and solids in most vegetables can freeze and melt without trouble. But fruit is another story. 

A. Calvelo, Recent studies on meat freezing. In Developments in Meat Science, R. Lawrie (ed.), Vol. 2, Applied Science Publishers, London, 1981, pp. 125-158. 

Meat Freezing-thawing Magnetization transfer imaging... 

Citric acid is used in carbonated beverages to provide tartness, modify and enhance flavors, and chelate trace metals. It is often added to jams and jellies to control pH and provide tartness. It is used in cured and freeze-dried meat products to protect the amino acids (qv) and improve water retention. Bakers use it to improve the flavor of fmit fillings in baked goods. Because citric acid is a good chelator for trace metals, it is used as an antioxidant synergist in fats and oils, and as a preservative in frozen fish and shellfish (7) (see Antioxidaisits). 

The lambda type is nongelling, and functions as a thickner. Iota-carrageenan has been recommended (45) for use in formulating low fat ground beef due to its abihty to retain moisture, especially through a freeze—thaw cycle which is typical for ground beef patties. Oat bran and oat fiber can also be used to improve moisture retention and mouth feel. Modified starches can be used as binders to maintain juiciness and tenderness in low fat meat products. Maltodextrins (dextrose equivalent less than 20) may be used as binders up to 3.5% in finished meat products. Other carbohydrates such as konjac flour, alginate, microcrystalline cellulose, methylceUulose, and carboxymethylceUulose have also been used in low fat meat products (see CELLULOSE ETHERs). 

A lot of meat is now boned or produced as the final cuts, in the factory. For this, the meat needs to be at 0°C or just below, i.e. just above the temperature at which it starts to freeze hard. 

To produce Fusarium sp. for meat substitutes the aseptic system must be operated with recovery by filtration followed by deep-freezing. The cost is thus 0.649 + 0.04 + 0.001 + 0.04 = 0.730 per kg biomass. 

TAPPEL A L (1956) Freeze-dried meat. 2. The mechanism of oxidative deterioration of freeze-dried beef, Food Res, 21, 195-206. 

The nature of the bonds between an oxygen atom and two atoms of hydrogen has an enormous impact on how our planet works. Because of the highly polar covalent bond, salt dissolves in water, which enabled our ancestors to preserve meat. It also produces the hydrogen bonds that make our lakes freeze from the top down, per-... 

Table 1.6 Size and number of pores in chicken meat as a function of freezing rate.

Figure 2.3 illustrates a process in which the outer layer of a product is quickly frozen as a congealed crust. These CRUSToFREEZE plants have a capacity between 1500 and 5000 kg/h and require 0.5 to 0.8 kg LN2 pro kg of product, which has to be frozen totally on a conveyor belt. Figure 2.4 shows the product exit of the plant in Fig. 2.3. The freeze drying of coffee and tea extracts, fruit pulps or small pieces of meat require a multi- stage pretreatment. The granulated end product from coffee and tea extracts should have a defined grain size, a desired color, and a predetermined density. Fruit pulps should become granulated, with the appearance of fruit pieces, while meat pieces should not stick together like a small meat ball, but be recognized as single pieces when presented in a meal.

The color of the end product is influenced by the freezing speed (fine crystals show a lighter color). Furthermore, the color is influenced by the structure of the foam and the surface of the dried product. To freeze meat in single pieces, special temperatures have to be used during cutting and preparation of each type of meat. 

Lime [4.15] described the freeze drying of avocado salad (88.7 % avocado-meat, 4.6 % lemon juice, 0.7 % onion powder, 1.43 % NaCl, and 5.0 % cracker powder) ending with a... 

Tofu can be kept frozen or freeze-dried to prevent microbial deterioration. However intemolecular interactions occur during frozen storage. As a result, the texture of tofu is changed from soft, smooth to sponge-like with a meat-like chewiness. 

Continuous freeze-drying equipment has been developed(60), and chopped meat and vegetables may be dried in a rotating steam-jacketed tube enclosed in the vacuum chamber. A model of the freeze-drying process has been presented by Dyer and Sunderland191 , and further details are given in Section 15.8 on freeze crystallisation. 

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