Meat, dehydration

Weight losses during the heating process are caused through exudative and/or evaporative moisture losses. Prevention of the cooking loss is a major concern in heat processing of meat. In meat dehydration, however, the weight lost by evaporation must be effectively achieved, but solid losses should be avoided (Sebranek, 1988). 

Studies of autoxidation and rancidity in relation to off-flavour production in foods cannot be overemphasized. Rancidity development in food products such as milk, meat, dehydrated food, potato chips, fruits and vegetables is a prime concern of food chemists. The process of autoxidation and rancidity not only involves cis to trans isomerization but also production of many other compounds, such as peroxides and hydroperoxides. IR spectroscopy has been used sucessfully to follow the autoxidation process qualitatively and quantitatively. Bands at 2.93, 3.2, 5.72 and 10 to 11 have been associated quantitatively with hydroperoxides, free acid, C=0, and cis to trans isomerization, respectively. Analysis by IR absorption was found to be more sensitive to changes than a qualified taste panel and considerably more sensitive than determination of peroxide values (O Connor, 1956). 

Your freezer can have the conditions necessary for the sublimation of ice or the deposition of water vapor. Ice cubes left in the freezer after a period of time shrink. Ice crystals formed on meat (even in air-tight containers) provide an example of deposition. The crystals are a product of the deposition of the water vapor in the meat to ice, leaving the meat dehydrated. 

Food processing firms producing heat-preserved, frozen, dehydrated, or chemically preserved foods may be classified by their finished products. Companies may be further grouped based on whether they process raw materials into ingredients, such as in poultry and meat processing plants, or whether they take these ingredients and convert them to ready-to-eat consumer products. 

Symps of 25—30 DE are used as spray-drying aids in products such as coffee. High conversion symp, maltose symp, and 42-DE symp are used in jams and jeUies. Com symp is also used in table symps, baby food, meat packing, breakfast foods, salad dressing, pickles, dehydrated powdered foods, medicinal symps, textile flirnishings, adhesives, and numerous other products and processes. 

Unsealed products will be affected by low humidity of the air in the cooled space and may suffer dehydration. Conversely, some food products such as fresh meat will deteriorate in high humidities. Since the dewpoint of the air approaches the fm surface temperature of the evaporator (see also Chapter 24), the inside humidity is a function of the coil AT. That is to say, the colder the fin surface, the... 

Clarification, decrease foaming, promote malo-lactic fermentation Soy sauce, fish sauce, bouillon, dehydrated soups, gravy powders, processed meats, special diets Tenderization, recover proteins from bones... 

Amines react with nitrous acid (formed by the reaction NaN02 + H HNO2) to give a variety of products. The nitrous acid isn t very stable, so generating it in place from sodium nitrite is necessary. (Sodium nitrite is a meat preservative and a color enhancer.) Under acidic conditions, nitrous acid dehydrates to produce the nitrosonium ion, NO. The NO ion is a weak electrophile that s resonance stabilized. (See Chapter 7.) Figure 13-22 illustrates the dehydration of nitrous acid. 

Sodium acetate is a mordant in dyeing. Other applications are in photography, as an additive to food, in purification of glucose, in preservation of meat, in tanning, and as a dehydrating agent. In analytical chemistry it is used to prepare buffer solution. 

The routes involved in the formation of the various furan sulphides and disulphides involve the interaction of hydrogen sulphide with dicarbonyls, furanones and furfurals. Possible pathways are shown in Scheme 12.8. Furanthiols have been found in heated model systems containing hydrogen sulphide or cysteine with pentoses [56-58]. 2-Methyl-3-furanthiol has also been found as a major product in the reaction of 4-hydroxy-5-methyl-3(2H)-furanone with hydrogen sulphide or cysteine [21, 59]. This furanone is formed in the Maillard reaction of pentoses alternatively it has been suggested that it may be produced by the dephosphorylation and dehydration of ribose phosphate, and that this may be a route to its formation in cooked meat [21, 60]. 

Aside from actual incorporation of this substance into foods, benefits may be derived in other ways. For example, one such suggested use76 is for the formation of a coating on meats, fruits, and vegetables, in conjunction with antimold substances, for protecting the foodstuffs from bacteria and molds. It is also noteworthy that the addition of carboxymethylcellulose to foods, prior to dehydration, is said to improve the retention of natural flavors. 

Hodge et al. (45) discussed mechanisms for formation of methyl furanones and related substances from Amadori compounds. They have been produced by heating D-ribose and D-ribose phosphate with ammonia (46 47). Hicks and Feather (48) demonstrated that the Amadori compound 1-benzylamino-l-deoxy-D-threo-pentulose dehydrates to 4-hy-droxy-5-methyl-3(2H)-furanone and it has also been identified as a degradation product of L-ascorbic acid. This compound is believed to be formed from ribose-5-phosphate, and gained prominence when it was isolated from beef by Tonsbeck et al. (49). It became more apparent as a precursor of meat flavor when Van den Ouweland and Peer (50) reacted it and its thio analog with HaS to produce a number of sulfur compounds, some of which had meaty odors. 

Furfural identified in beef diffusate appears to be a prominent meat flavor intermediate. It is a dehydration product of pentoses similar to formation of hydroxy methyl furfural from hex-oses. These compounds are formed by dehydration of 1,2-enediols derived from deamination of Amadori compounds (51). 

Ancient peoples are known to have had dried fruits, vegetables, and meats. The pemmican of Native Americans and the jerky consumed by present-day campers and hikers are both prepared by drying. The drying process can include smoking, which may actually add antibacterial agents. The processes of dehydration and freeze-drying, used today to produce such foods as powdered coffee and soup, are variations of drying. 

The loss of glycogen by degradation to reducing sugar is higher in pork than in beef and hence the former browns more. Cooked meat is more stable than uncooked meat on dehydration, because the amylolytic activity is inactivated. 

Widely used on fresh and fix)zen meat and fish to prevent superficial dehydration (Shaw et al. 1980X sausage casing (Macquarrie 2002), granulation-coated powder, dry solids foods, oily foods (Ninomiya et al. 1997), soft nongelatine capsules (Bartkowiak and Himkeler 2001 Fonkwe et al. 2003 Tanner et al. 2002) Arabic gum limitation of flavour evaporation (Nisperos-Carriedo 1994)... 

Bakery products/Meat products/Spices/Cereals/Dehydrated... 

Par-fried products, such as batter-coated fish, chicken, meat patties, and so on the surface coating is dehydrated, whereas the interior is not. For chicken and meat, it is important for the center of the food to reach certain temperature (discussed later) for food safely, whereas the fish remains frozen inside the fried crust. It is important to retain most of the moisture in these products to maximize the yield and reduce the dryness of the product for the subsequent frying process. 

Application of natural aqueous smoke flavourings to meat is done in large part for the purpose of producing smoked colour. Smoke solutions are applied to the surface of meat where smoked product colour is desired. The carbonyls are known to be the initiators of a brown smoked colour. While aqueous smoke solutions are innately a reddish brown colour, virtually none of this colour is imparted to the product through a staining effect. Rather, carbonyls first react with amines to produce Schiff bases which eventually end up as mealnoidins through complex, multiple-step reactions which are driven by heat and dehydration. 

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