Oxidative stability of frozen pork patties: Effect of fluctuating temperature on lipid oxidation

The mobility of solutes in fat from pork belly, in lean pork belly and in lean pork longissimus dorsi, containing 1% NaCl was characterized by the ESR spin probe technique using the nitroxyl spin probes TEMPO and TEMPOL. The mobility of TEMPO in fat increased for temperature above −60 °C and the mobility of TEMPOL in lean meat increased for temperature above −40 °C. Temperatures for studying the effect of fluctuating temperatures during frozen storage of meat were selected based on the ESR characterization of the mobility of solutes. The oxidative stability of pork patties during frozen storage was measured as thiobarbituric acid reactive substances (TBARS), during storage at −10, −23 and −40 °C and with fluctuations between these temperatures, of pork patties made from pork loin (low fat 1.8%) or pork belly (high fat 22.7%). Lower storage temperatures resulted in less lipid oxidation, and temperature fluctuations between −40 and −23 °C and fluctuations between −23 and −10 °C resulted in oxidation intermediate to oxidation in samples stored at constant low or high temperatures of the fluctuation interval. The level of α-tocopherol was unaffected by the extent of oxidation in the frozen samples, an observation which is discussed in relation to differences in molecular mobility between oxygen and α-tocopherol.