Infrared spectroscopy-based rapid determination of adulteration in commercial sheep's milk cheese via n-hexane and ethanolic extraction

Abstract

This study aimed to authenticate a commercial cheese using FT-IR spectroscopy combined with chemometrics via ethanol and n-hexane extraction. Erzincan Tulum cheese (ETC) is one of the most produced and consumed cheeses in Türkiye. With an increase in production and consumption, adulteration has become a concern. Authentic ETC (n = 24) and non-authentic cheese samples (n = 22) were purchased from local markets. Ethanol and n-hexane extracts of the ETC were used for FT-IR analysis. Aliquots of the extracts were placed on a zinc selenide crystal, dried, and scanned in the mid-infrared region (4000–650 cm−1). Partial least squares-discriminant analysis (PLS-DA), soft independent modelling of class analogy (SIMCA), and conditional entropy (CE) were used as chemometric tools. PLS-DA and SIMCA provided 99% accuracy, followed by CE as low as 93.5%. Despite some disadvantages, overall, FT-IR spectroscopy with chemometrics is simple, rapid, and an inexpensive tool to detect cheese adulteration.