After heated and boiled for 5 min, hot waterwas used towash the acticarbon.
The filtratewas respectively detected for the free amino acid contents of the samples, including non-fermented pork jerky, fermented pork jerky, remaining fermented medium, and the medium before fermentation using the colorimetric method of ninhydrin (Wu, Li, & Ma, 2006).
Accordingly,ninhydrin was added to the samples under acidic conditions and the absorbance of the solution was ascertained at 570 nm.