Effect of illumination and temperature on initial oxidation of yak fat

The thiobarbituric acid reactive substances(TBARS) was used as an oxidation index,and the influence of different light and temperature on initial oxidation of yak fat was studied.The results indicated that the initial stage of oxidation occurred during the first 25 days storage at the storage temperature of(15±1)℃.Importantly,during this stage,the change of TBARS treated with 20 lx illumination(opaque packaging material) was significantly less than that of 964 lx(semi transparent packaging material) and 1 550 lx(transparent packaging material),and about 15 days lag,which indicated that TBARS was impacted heavier by non-light than light;the change of TBARS at(4±1)℃ significantly lagged than that at(15±1)℃,and the lag period was 10 days,which reflected the lower temperature could inhibit peroxide formation and postpone fat oxidation.The change of TBARS at(9±1)℃ was between that at(4±1)℃ and(15±1)℃,which reflected the change of fat oxidation caused by the temperature was moderate and uniform.