Dehydrated beef

Wehhng, R. L., Froning, G. W., Cuppet, S. L., and Niemann, L., Extraction of cholesterol and other lipids from dehydrated beef using supercritical carbon dioxide, J. Agric. Food Chem., 40 1204 (1992)... 

Dehydrated beef [12] and chicken [13], which are used extensively in a variety of convenience products, were extracted since extraction of intact muscle presents difficulties due to its fibrous structure and high moisture. Lipid and cholesterol r uction of 95 and 89%, respectively, was achieved at 38.6 MPa/55°C with chicken chunks [13]. Lipids were more easily extracted from beef and chicken chunks than powders. Even though dehydrated chicken products (2.89 and 4.4% moisture in powder and chunks, respectively) were used, there was a further reduction in moisture content following extraction. Lighter color products with less redness were reported for chicken and beef [12, 13], which was due to extraction of pigments with SC-CO2. 

Surface basicity can also be examined by indicator dyes, but there has beef much less study of surface basicity than of surface acidity. Phenolphthalein, bromothymol blue and various nitro-analines have been used to assess the effect of dehydration on the basicity of alkaline earth oxides or hydroxides, using benzoic... 

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). 

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. 

FIGURE 1.11 Electron micrographs of negatively stained crystals of (a) pig pancreatic a amylase, and (b) beef liver catalase. The dark areas represent solvent filled areas in the crystal, which are replaced by dense heavy metal stain the light areas correspond to protein molecules where the stain is excluded. The underlying periodicity of the crystals is evident here, even after dehydration and staining. 

A wide range of flavouring substances is used in powdery or pasty convenience foods. Reaction flavours based on hydrolysed plant proteins, natural flavours, artificial flavours and meat, vegetable, yeast and spice extracts are added to the products to generate the desired flavour profile. The most common savoury flavour types used for dehydrated convenience foods are chicken, beef and vegetable flavours. However various other flavour types are used while formulating dehydrated convenience foods. Amongst them are mutton, crawfish, fish, wine and various spice and herb flavours. 

The beef heart enzyme (M, = 80,000) (117) is a component of the citric acid cycle. Its active form contains one [4Fe-4S] cluster. Although such a cluster is normally associated with electron transfer, the enzyme catalyzes the nonredox reaction of citrate-isocitrate interconversion via a dehydration-hydration pathway. The current state of understanding of cluster structures and reactions of beef heart aconitase has been thoroughly reviewed by Emptage (130). When isolated aerobically, aconitase is inactive and contains one [3Fe-4S] cluster. Upon incubation of the reduced protein with Fe(ll), the fully active enzyme is generated. When a 3-Fe center is reduced to [3Fe-4S]°, Reaction 10 builds a 4-Fe cluster in a nonredox process. The Mossbauer spectra in Fig. 8 address the question of subsite specificity in this reaction of aconitase (124). If the externally supplied iron is Fe, the resultant spectrum reveals the intrinsic (original) Fe atoms... 

In another process described by Leistner (1987) and Buckle et al (1988), the whole muscle is boiled for 40-45 min, after which it is cut into cubes or pieces (5 x 5 X 10 cm). Although beef is preferred because of its fibrous nature, pork and chicken are sometimes used (Lo, 1980). The cubes are added to the cure in a steam kettle and cooked until nearly all of the cure has evaporated. The meat is removed from the steam kettle and dried in a hot air dehydrator. The final a , is about 0.69. Leistner (1987) concluded that an a < 0.69 is critical for Chinese dried meats, although Ho and Koh (1984) suggested that an a, < 0. 61 is needed to prevent mold growth. 

Jones, S. B. (1977). Ultrastructure characteristics of beef muscle. Food Technol. 31(4), 82. Judge, M. D., Okos, M. R., Baker, T. G., Potthast, K., and Hamm, R. (1981). Energy requirements and processing costs for freeze-dehydration of prerigor meat. Food Technol. 35(4), 61. 

The present results appear to be inconsistent with the results of others vho have reported lew mutagenicity of lew-fat meat (j ). liewever/ the present study was carried out with reconstituted samples from totally dehydrated and defatted meat. The consistency of the reconstituted samples was similar to, but certainly different from/ the oonsisteney of ground beef. These physical effects of total dehydration and defatting may contribute to the differences in the observed results using reconstituted and normal lew-fat ground beef. 

In a number of other studies, GC-MS of DMOX derivatives has been utilized to determine the CLA isomer distribution from a variety of sources. The structures of pure isomers of 9c,llt-18 2 and 10f,12c-18 2, isolated by crystallization of a CLA mixture prepared by alkali-isomerization of linoleate, were confirmed (67). The presence of 9c,llt-18 2 was established in chocolate (49). In conjunction with GC-FTIR, all possible geometrical isomers of 9,11-18 2 (c,i > t,t > c,c and t,c) were detected in human adipose tissue (10). In dehydrated castor oil, although the 9,11 isomers (c/i, c,c and t,t) appeared to be the most abundant, 7,9- and 8,10-18 2 (c/t and but not c,c) were also detected with the aid of SPA (46). The presence of It, 9c-18 2 (as well as lower levels of 7c,9c-, lt,9t- and possibly 7c,9f-18 2) was confirmed in cow s milk, cheese, beef, and human milk and adipose tissue (9). Together with silver-ion HPLC, the isomer distribution in different tissues of pigs fed commercial CLA was determined (2). The CLA content of lactic acid bacteria (44), and the nature of the CLA isomers formed as a result of add-catalyzed methylation of allylic hydroxy oleates (secondary hpid autoxidation products) (47) were also established. 

The extraction of cholesterol from beef and chicken was investigated by Wehling (1992). The meat was dehydrated prior to extraction. Extractions were carried out at 45°C (299 atmospheres) and 55°C (381 atmospheres). The cholesterol content of both meats could be reduced by between 80 and 90% for either meat. Extraction was possible on dehydrated chunks as well as with powdered samples. 

Dehydration of 1-deoxy-l-dibenzylamino-D-fructuronic acid at 100 " C and pH 7 yielded 4-hydroxy-5-methyl-3(2/f)-furanone, a flavouring component of beef. The mechanism of formation of the product was examined using labelled substrates and deuterium oxide. 

Fnir Mwicw-AMEados, bananas, beef and veal, breads, cheese, chkfken, com, commeaL dates, dehydrated fruit fish atd seatoads, lamb, liver, olives, pork, raspberries, rice, turkey, most green leafy vegetables. 

Various methods of processing cause considerable destruction of vitamin E. Dehydration causes 35 to 45% loss of alpha-tocopherol in chicken and beef, but little or none in pork. Canning causes losses of 41 to 55% of the alpha- tocopherol content of meats and vegetables. An 80% destruction occurs during the roasting of nuts. 

We tested this reaction scheme in meat. Ten percent D-glucose was added to a beef extract and the pH was adjusted widi a 6 N hydrochloric acid or sodium hydroxide solution. Figure 4 shows the pH-dependence of M-1 and M-3 after 15 min heating at 121°C. As expected, 1,2-enolization and M-3 formation predominates below pH 4. Above pH 5 there is little M-3 formation, which explains why we never observed M-3 from heated meats (pH 5.4). There is a sharp decline in the M-1 yield above pH 10. This observation is consistent with the base-catalyzed fructose dehydration Shaw et al. investigated at pH 11.5 (45). They reported that M-1 was not formed at pH 11.5 however, if the alkalinity was not constantly maintained, M-1 was formed as the pH decreased. Similarly, when 1% D-ribose was added to the beef extract, formation of 2-furaldehyde dominated at low pH and M-2 formation became more impotant at pH above 4.5, which again explains why 2-furaldehyde was never observed in heated meats. The general reaction pathways for formation of the markers are summarized in Figure 5. 

Using a eontaet-dehydration sheet, a paekage system has been developed to transport bloeks of meat such as beef and pork in a chilled condition without losing the Ireshness and appearance (see Fig. 4). While the excess water is actively absorbed by the contact dehydration sheet, thus prevent-... 

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