Effects of radio frequency, air and water tempering, and different end-point tempering temperatures on pork quality

摘要

To explore the effects of different tempering methods and end-tempering temperature on pork quality, 1 kg frozen lean pork samples in cuboid shapes were treated under radio frequency tempering (3 kW, 27.12 MHz), water tempering, and air tempering from -22 degrees C to -1 degrees C and -4 degrees C, respectively. Tempering time, temperature distribution, drip loss, cook loss, pH, color, thiobarbituric acid reactive substances (TBARS) value, total volatile base nitrogen (TVBN) value of tempered samples were evaluated for comparison. Results showed both tempering methods and tempering temperature had significant (p 0.05) effects on pork quality. The tempering time needed for water and air tempering were about 9 and 17 times longer than radio frequency tempering to reach -1 degrees C, respectively (p 0.05). From the tempering temperature point of view, when tempered to -1 degrees C, no significant effect was found on physical and chemical properties of pork samples than tempered to -4 degrees C (p 0.05) expect for the increased drip loss, cook loss and the decreased pH (p 0.05). From the tempering method point of view, air tempering retains the most physiochemical properties of fresh pork samples except for a higher cook loss, and a lower pH when tempering to -1 degrees C (p 0.05). The cook loss, TVBN and b* values were significantly higher, and the pH and L* values were lower (p 0.05) in water immersion tempering to -1 degrees C than those of fresh samples. Meanwhile, the cook loss, TVBN and b* was higher, and pH was lower than those of fresh values (p 0.05) after radio frequency tempering to -1 degrees C. In general, air tempering retained the best quality of pork samples, and radio frequency tempering showed the fastest tempering rate while also resulted in an acceptable meat quality, which has the potential of being further applied to meat industry. Practical application Results in this study provide sufficient data to the meat industry for selecting appropriate tempering method and target tempering temperature based on specific requirements. Results reveal that radio frequency tempering was fast and relatively uniform, which had the capability of defrosting meat blocks in the desired short time with acceptable physiochemical properties. However, radio frequency tempering also showed its limitation on non-uniform heating especially at targeting temperature of -1 degrees C. This reminds the meat industry to carefully design tempering protocols with appropriate tempering rate and endpoint temperature when applying radio frequency technology.