The FTIR‐ATR Spectroscopy as a Biosensing Strategy for Thermal Effects in Permissibility Verification of Lard‐Adulterated Palm Oil

ABSTRACT Ensuring authenticity of edible oils is vital for consumer trust, regulatory compliance and permissibility assurance, particularly for Muslim consumers. This study introduces a spectral biosensing strategy using Fourier transform infrared spectroscopy coupled with attenuated total reflectance (FTIR‐ATR) and chemometric modelling to detect lard adulteration in palm oil (PO) under thermal stress. PO samples spiked with 1%–50% v/v lard were heated from 25°C to 200°C for 30 min, simulating industrial and culinary conditions. FTIR‐ATR spectra showed distinct shifts in carbonyl and fingerprint regions due to lard incorporation and heat‐induced lipid degradation. Discriminant analysis (DA) achieved 100% classification accuracy across the full spectrum (4000–650 cm −1 ), demonstrating strong discriminatory power. Partial least squares–discriminant analysis (PLS‐DA) identified the fingerprint region (1000–650 cm −1 ) as most diagnostic, yielding robust performance with R 2 Y = 0.895, R 2 X = 1.000, Q 2 = 0.893 and 100% correct classification in both training and validation datasets. Principal component analysis (PCA) revealed clear clustering of pure and adulterated samples, even under severe thermal conditions. Moreover, using the optimised FTIR‐ATR/PLS model, the lard adulteration in thermally treated PO could be reliably detected at levels as low as 1% v/v with LOD and LOQ ranges of 0.01%–1.14% and 0.02%–3.34% v/v, respectively. These findings position FTIR‐ATR with multivariate chemometrics as a rapid, nondestructive and thermally resilient platform for lard detection in PO. The approach extends to broader food quality and safety monitoring in real‐world processing scenarios.