Quality Comparison of Pepper Oleoresins from Different Geographical Origins by Multi-instrumental Analysis Combined with Chemometrics

To establish chemical fingerprints of pepper oleoresins from different geographical origins and comprehensively analyze and compare their quality characteristics.

The compositions of piperines, chemical elements and volatile flavor compounds in pepper oleoresins from Indonesia, Sri Lanka and Vietnam were quantitatively analyzed by high performance liquid chromatography-ultraviolet detection (HPLC-UVD), inductively coupled plasma-mass spectrometry (ICP-MS) and gas chromatography-ion mobility spectrometry (GC-IMS), respectively. Furthermore, chemometrics was applied to identify the potential chemical markers to discriminate geographical origins of pepper oleoresin.

Sample Ⅱ from Sri Lanka contained significantly higher levels of piperine (31.57%) and piperonylic acid (0.72%) than the other samples, whereas sample Ⅰ from Indonesia showed significantly higher contents of piperonol (1.88%) and piperlongumine (1.89%) than the other samples. A total of 54 chemical elements were simultaneously quantified in pepper oleoresin. Among them, 13 were determined as major differential elements, including Cs, Na, Cu, Rb, Ru, P, Mg, Sn, Ag, K, Mo, Cr and Co. The abundance of elements decreased in the order of Vietnam > Indonesia > Sri Lanka. Altogether, 90 volatile compounds were identified. Vietnam samples had the strongest aroma, followed by Indonesian samples. The significantly differential volatiles identified were n-pentane cyanide, 1-cyanopropene, linalool, 2-ethylpyrazine, ethyl valerate, valeraldehyde, n-caproic acid, 2-ethylfuran, isobutyraldehyde and limonene. In conclusion, there are significant differences in the chemical fingerprints of pepper oleoresin from different geographical origins. Overall, pepper oleoresin from Vietnam exhibits superior quality to those from the other two countries.