Abstract:

【Objective】 The effects of freeze-thawing cycles on pork quality properties and microstructure were investigated. The purpose of this study was to provide a scientific basis for meat preservation. 【Method】 The porcine longissimus dorsi (LD) were frozen for 7 d under -26℃, then thaw by lotic water (room temperature, 18℃). The effects of freeze-thawing cycles on thawing loss (TL), cooling loss (CL), cutting force (CF), microstructure, color (L*, a*, and b*-values), TBARS (thiobarbituric acid-reactive substances) of pork were studied. 【Result】 The results showed that freeze-thawing cycles significantly increased the TL, CL, TBARS, L*-values and b*-values, and decreased a*-values (P＜0.05). The scanning electron micrograph of pork muscle showed that freeze–thawing cycles increased the space between fiber, torn and confused muscle fiber bundles, and breakdown muscle endometrial. The pork CF subjected one freeze-thawing cycle was significantly higher than that of fresh pork, and was gradually lower after multiple freeze-thawing cycles. 【Conclusion】 The results demonstrated that freeze-thawing cycles seriously damaged microstructure of muscle and declined the quality properties of pork.

Key words: freeze-thawing cycle, pork, microstructure, quality properties