Pathlength effects on NIR Transflectance performance for polar and apolar liquid food analysis.

Near-infrared (NIR) transflectance spectroscopy is widely used across various applications, including food analysis, yet the effect of accessory pathlength on spectral quality and subsequent chemometric performance has not been systematically assessed. This study evaluates how pathlengths (1, 2, 4, and 6 mm) influence spectral characteristics and partial least squares regression (PLSR) accuracy in two contrasting liquid food systems: an apolar matrix-tree-picked olive oil (TPOO) adulterated with ground-picked olive oil (GPOO)-and a polar matrix-vodka spiked with methanol. Spectra were acquired using both a benchtop FT-NIR spectrometer (10,000-4000 cm-1) and a handheld NIR device (7407-3921 cm-1). In the apolar oil system, longer pathlengths (4-6 mm) enhanced CH overtone bands, with the 6 mm pathlength delivering the highest prediction accuracy among those evaluated (1-6 mm) for %GPOO (SEP = 0.56 %, r = 1.000, RPD = 52.6). In the polar methanol-vodka system, strong OH absorption caused early saturation, making the 1 mm pathlength optimal within the tested pathlength range of 1-6 mm; removing the 5300-5000 cm-1 region improved model accuracy (SEP = 0.036 %, r = 0.999, RPD = 47.2). While handheld NIR measurements followed the same pathlength trends, their predictive performance was lower due to narrower spectral range, lower resolution, and reduced signal-to-noise ratio. These findings offer practical guidance within the tested interval: in lipid-rich, apolar matrices, intermediate-to-long pathlengths (4-6 mm) maximize informative signal capture, whereas in water-rich, polar matrices, short pathlengths (1 mm) prevent spectral saturation and preserve detail, ensuring robust chemometric models.

• Publication year

  2025

• Venue

  Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy

• Publication date

  2025-11-19

• Fields of study

  Agricultural and Food Sciences, Medicine, Chemistry, Environmental Science

• Identifiers
  DOI 10.1016/j.saa.2025.127225PMID 41273857
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

• The Quality Prediction of Olive and Sunflower Oils Using NIR Spectroscopy and Chemometrics: A Sustainable Approach

  2025cited by this paper
• Rapid Assessment of Taste Indicators in Orange Juice Using a Handheld Near-infrared Scanner in Transflectance Mode

  2025cited by this paper
• The Role of Near-Infrared Spectroscopy in Food Quality Assurance: A Review of the Past Two Decades

  2024cited by this paper
• Evaluation of Near-Infrared Reflectance and Transflectance Sensing System for Predicting Manure Nutrients

  2022cited by this paper
• Building robust models for identification of adulteration in olive oil using FT-NIR, PLS-DA and variable selection.

  2020cited by this paper
• Invited review: Use of infrared technologies for the assessment of dairy products-Applications and perspectives.

  2018cited by this paper
• Classification and quantification of palm oil adulteration via portable NIR spectroscopy.

  2017cited by this paper
• Optical path length and wavelength selection using Vis/NIR spectroscopy for olive oil's free acidity determination

  2015cited by this paper
• Infrared, Raman, and Fluorescence Spectroscopies: Methodologies and Applications

  2013cited by this paper
• Evaluating the Transferability of FT-NIR Calibration Models for Fatty Acid Determination of Edible Fats and Oils Among Five Same-make Spectrometers Using Transmission or Transflection Modes with Different Pathlengths

  2012cited by this paper
• Quantitative Determination of Quality Parameters and Authentication of Vodka Using near Infrared Spectroscopy

  2010cited by this paper
• Mid-infrared spectroscopy coupled with chemometrics: a tool for the analysis of intact food systems and the exploration of their molecular structure-quality relationships - a review.

  2010cited by this paper
• Fatty Acid-derived signals in plant defense.

  2009cited by this paper
• Functional characterization of two 13-lipoxygenase genes from olive fruit in relation to the biosynthesis of volatile compounds of virgin olive oil.

  2009cited by this paper
• Near Infrared Spectroscopy: fundamentals, practical aspects and analytical applications

  2003cited by this paper
• Near infrared transflectance spectroscopy: determination of dexketoprofen in a hydrogel.

  2002cited by this paper
• Near Infrared Reflectance Spectroscopy for Online Particle Size Analysis of Powders and Ground Materials

  2001cited by this paper
• Infrared and Raman Spectroscopy

  2000cited by this paper
• Lipoxygenase activity in olive (Olea europaea) fruit

  1999cited by this paper
• Analysis of air pollution plant exposure data: The soft independent modelling of class analogy (SIMCA) and partial least squares modelling with latent variable (PLS) approaches.

  1988cited by this paper

• No citing papers are available for this paper.