Quality Improvements by Thawing Treatments on Frozen Lamb Ribs in Refrigerated Storage

Objective Effects of thawing frozen lamb ribs in refrigerated storage on quality deteriorations, such as discoloration, nutrient oxidation, and dehydration, of the meat were studied.

Methods A film-wrapping or a pretreatment, in comparison to no treatment CK, on raw Tan lamb ribs for thawing while in refrigerated storage was applied to determine its effectiveness in preserving the quality of frozen-thawed meat. The frozen ribs were either wrapped in a plastic barrier film or pre-sprayed with a mixture of anti-osmosis water, NaOH solution, and pH 10 alkaline electrolyzed water in a modified atmosphere package prior to storage. Discoloration, oxidation degree, and water binding state of the meat in 0-6d in storage were monitored. Meat color was measured using a colorimeter, lipid and protein oxidation by chemical analysis, and water binding by low-field nuclear magnetic resonance (NMR).

Results Both treatments on the frozen lamb ribs significantly ameliorated declining a* of red color measurement immediately after the refrigerated storage at 4^oC. In 6d. The meat a* rose to 1.40-fold and the lipid and protein oxidation decreased to 1.54-fold of those of CK in that period. The NMR distinguished the bound, imbibed, and free water in the muscle tissue showing a significantly reduced proportion of bound water with an increased imbibed water of the total moisture content.

Conclusion By simply wrapping the ribs with a protective film or pre-spraying them with an alkaline dehydration-preventing solution before packaging, thawing the frozen product in refrigerated storage significantly avoided the undesirable browning discoloration and nutrient degradation of the ribs. Presumably, similar treatments could extend the shelf-life of most prepacked raw red meats as well.