Quality control of mint species based on UV-VIS and FTIR spectral data supported by chemometric tools

Mints are valued for their specific essential oil used in food, pharmaceutical and cosmetic industry. Chemical compounds differing between species, cause changes in medicinal/pharmacological properties, antioxidant activities or smell sensations. For this reason fast procedure for quality control of at least two most popular mint species, peppermint and spearmint, is the issue at hand. UV-VIS spectrophotometry and FTIR-ATR spectroscopy were used for recording the spectral fingerprints of a collection of more than 20 mint varieties harvested in three periods. Two-step chemometric approach for mints quality control involved SIMCA (Soft Independent Modeling of Class Analogy) to filter out species other than peppermint and spearmint. The samples suspected to be either peppermint or spearmint underwent final discrimination using adequate discrimination tools PLS-DA (Partial Least Squares-Discriminant Analysis) or SVM (Support Vector Machines). The model performance ranged between 60 and 80% depending on spectroscopic data used for model training and the harvest season.