Mary-Grace C. Danao
Joe Baumert & Gary Sullivan
Date of this Version
Alqaraghuli, A. 2019. HIGH PRESSURE THAWING OF RAW POULTRY MEATS. MS Thesis. Department of Food science and technology, University of Nebraska-Lincoln.
The melting temperature of water reaches its minimum when pressurized from 0 °C at atmospheric pressure down to -22 °C at 220 MPa, showing that frozen products at atmospheric pressure (0.1 MPa) can be thawed rapidly by simply increasing the pressure to 210-250 MPa. High pressure thawing (HPT) of poultry meats (ground chicken, chicken breast, thigh, liver, gizzard, and heart) commonly used in the raw pet food industry was evaluated at 240 MPa, two processing fluid temperatures (refrigerated, 0-10 °C and room, 20-30 °C), and four holding times (1, 180, 360, and 540 s). Changes in color via * * * measurements ( ), core temperature ( ), thawed percentage ( , % w/w), and thawing rate ( , % per min) were measured. Results showed that no significant color change was detected with HPT treatment at 240 MPa across holding times tested. Core temperatures of -2 to -5 °C were achieved, meaning all meat types were tempered during HPT. In fact, on average, 46.7-80.7 % (w/w) of the meat was thawed after HPT treatment for 180-540 s. Compared to thawing in air and water, or using a microwave, discoloration of thawed raw meats was highest after microwave thawing ( = 11.5) and lowest with HPT treatment ( = 1.27 and 1.39 at refrigerated and room temperatures, respectively). Average core temperatures were highest with HPT ( = -2.21 °C and -3.52 °C at room and refrigerated temperatures, respectively), followed by microwave thawing ( = -3.58 °C), and thawing in either air or water ( ranged from -4.16 to -4.43 °C). Microwave thawing delivered the highest average thawed percentage ( = 84.5 % w/w) and thawing rate ( = 29.6 % min-1), followed by HPT at room temperatures ( = 74.0 % w/w and = 13.9 % min-1), HPT at refrigerated temperatures ( = 65.8 % w/w and = 12.0 % min-1). Thawing in still air and still water resulted in the lowest thawed percentages ( = 44.1-55.1 % w/w) and thawing rates ( = 0.30-2.00 % w/w). HPT thawing rates were half as fast as that of microwave thawing, 10 times faster than thawing in still water, and 22-45 times faster than thawing in still air. Only HPT could thaw raw poultry meats at a fast rate with minimum change in color. Results from this study are useful to meat processors interested in reducing thawing time while maintaining raw quality of the meat during tempering.
Advisor: Mary-Grace C. Danao