Detection and Quantification of Patulin in Apple Juice Using Fourier Transform Infrared Spectroscopy

Patulin is a dangerous mycotoxin and is relatively stable to heat treatment and thus difficult to inactivate. Its presence in juice is necessary to detect before sale. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy with chemometrics showed potential for its detection in apple juice by modulating pH. Spectra (4000–500 cm−1) of patulin spiked (25, 50 75 ppb) apple juice (pH 4, 6, 8) revealed distinct variations specifically in 1605–1543 cm−1 range. Absorption peak for all the spiked sample having pH 8 were higher than those of spiked samples maintained at pH 6–4. Principal component analysis showed concentration based sample clustering (p ≤ 0.05) at pH 8. Developed models successfully classified different levels of patulin into their respective classes using soft independent modeling of class analogy. Patulin in apple juice was best predicted in wave number range of 1605–1543 and 3049–2975 cm−1, using partial least square regression with coefficient of determination of 0.92–0.88 for calibration and validation, respectively. Current study demonstrated that patulin-contaminated (50 ppb; permissible limit set by FSSAI) juice sample and uncontaminated juice samples could be effectively discriminated using ATR-FTIR spectroscopy by modulating pH of apple juice.