Pentane Production as an Index Of. Rancidity in Freeze‐dried Pork

Levels of hydrocarbon in the headspace over freeze‐dried pork was measured to evaluate rancidity. At the same time, the pork was given to a sensory panel to describe the degree of rancid odor. When the pentane level in the headspace reached about 0.05 μ1, 100% of the. panel described the pork as rancid. In the early stage of rancidity, the pentane production levels were not correlated with the rancid odor scores. However, overall pattern of the pentane production was significantly correlated with that of the rancid scores. The correlation coefficient (0.88) was significant at the 99% level. Serum rubber caps used for sealing the sample containers to facilitate headspace gas sampling absorbed hydiocarbons significantly. The extent of the hydrocarbon absorption increased with increasing chain length of the hydrocarbons, i.e., hexane > pentane > butane > propane. Teflon tape‐covered silicone rubber septa could alleviate this problem.