Rapid headspace analysis of commercial spearmint and peppermint teas using volatile ‘fingerprints’ and an electronic nose

Authors: Siderhurst, Matthew; BARTEL, WILLIAM - Eastern Mennonite University; HOOVER, ANNA - Eastern Mennonite University; LACKS, SKYLAR - Eastern Mennonite University; LEHMAN, MEREDITH - Eastern Mennonite University

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2024
Publication Date: 9/27/2024
Citation: Siderhurst, M.S., Bartel, W.D., Hoover, A.G., Lacks, S., Lehman, M.G. 2024. Rapid headspace analysis of commercial spearmint and peppermint teas using volatile ‘fingerprints’ and an electronic nose. Journal of the Science of Food and Agriculture. 105(2):1365-1374. https://doi.org/10.1002/jsfa.13926.
DOI: https://doi.org/10.1002/jsfa.13926

Interpretive Summary: Mint teas, such as spearmint and peppermint, are widely consumed around the world due to both their flavor and therapeutic properties. There is increasing concern about the authenticity or adulteration of foods and beverages. When questions arise about whether a food or beverage product is what it claims to be, it is helpful to have analytical methods to resolve these issues. This work demonstrates the ability of two different techniques to differentiate spearmint teas from peppermint teas (dry samples, unbrewed). During the testing, two outlier samples were detected, one of which might represent a peppermint tea mislabeled as a spearmint tea. With specific volatile profiles identified for each tea, unknown samples could be rapidly tested in the lab, or potentially on farms or along the supply chain, to confirm the provenance and authenticity of mint food or beverage commodities.

Technical Abstract: BACKGROUND: Spearmint, Mentha spicata L., and peppermint, Mentha X piperita L., teas are widely consumed around the world for their flavor and therapeutic properties. Dynamic headspace sampling (HS) coupled to gas chromatography/mass spectrometry (GC-MS) with principal component analysis (PCA) of ‘fingerprint’ volatile profiles were used to investigate twenty-seven spearmint and peppermint teas. Additionally, comparisons between mint teas were undertaken with an electronic nose (enose). RESULTS: Twenty compounds, all previously known in the literature, were identified using HS-GC-MS. PCA found distinct differences between the fingerprint volatile profiles of spearmint, peppermint, and spearmint/peppermint combo teas. HS-GC-MS analysis performed with an achiral column allowed faster processing time and yielded tighter clustering of PCA tea groups than the analysis which used a chiral column. Two spearmint outliers were detected. One showed a high degree of variation in volatile composition and a second wholly overlapped with the peppermint PCA grouping. Enose analysis separated all treatments with no overlaps. CONCLUSION: Characterizing the volatile fingerprints of mint teas is critical to quality control for this valuable agricultural product. The results of this study show that fingerprint volatile profiles and enose analysis of mint teas are distinctive and could be used to rapidly identify unknown samples. With specific volatile profiles identified for each tea, samples could be tested in the lab, or potentially on farm or along the supply chain, to confirm the provenance and authenticity of mint food or beverage commodities.