Analysis frozen meat

A HS gas analysis method for the determination of volatile hydrocarbons in sealed containers was described by Loliger (1990). The experimental setup consists of a gas chromatograph equipped with a gas sampling valve, a vacuum pump and a manometer. The sampling system is evacuated to c. 1 mbar, the tin is punctured by a stainless steel plunger, the gas is left to reach equilibrium and a HS sample is subsequently transferred by means of the valve to a column packed with activated alumina. This system allows estimation of Ci-C6 hydrocarbons, which represents final and stable secondary oxidation products, and was applied to various food systems ranging from oils and emulsions to frozen meats and dehydrated cereals, potatoes and milk. 

Most of the studies indicate that denaturation of muscle proteins plays the dominant role in the quality changes of the frozen stored meats. The muscle proteins of fish and other aquatic animals have been found to be much less stable than those of beef animals, pigs and poultry (1 ). The present paper will be limited primarily to fish muscle as one representative of vertebrate muscle and it will also deal primarily with the behavior of fish proteins at sub-zero temperatures. In order to do a thorough analysis within the space limit permitted, focus will be on the changes of the proteins per se leaving peripheral problems to other reviews (2-18). 

Example 2 Experiments have shown that fish meat frozen directly after capture contains sufficient amounts of DNA for analysis in about 100 mg of sample. But after thawing and refreezing, 1 to 2 g of fish is needed to obtain sufficient amounts of DNA analysis with only 100 mg could fail. However, for meat from mammals, the influence is not that strong. 

Samples of meat and fish must be refrigerated for prompt analysis or frozen for extended storage. Fish and other small animals may be dissected promptly after collection or just before analysis. Samples should be weighed when fresh, dried, and ashed as needed for the specified purpose in reporting radionuclide concentrations. 

Equipment used for sample preparation must be dry and clean and may be cooled or chilled. Speedy sample preparation is required to reduce heating and consequent evaporation of water, which would affect the determination of moisture content. Blades must be sharp to achieve consistent and fast comminution. Samples (preferably well chilled or slightly frozen) may be prepared by passing through a meat chopper or mincer multiple (3 x ) times, often using plates of decreasing size where the sample is very large. Often, quite small samples are received for analysis and a bottom-driven bowl cutter may be more appropriate. 

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