Rapid and Simultaneous Determination of the Iodine Value and Saponification Number of Edible Oils by FTIR Spectroscopy

Abstract

A rapid method is developed to facilitate the Fourier transform infrared (FTIR) spectroscopy analysis of edible oils using disposable polyethylene (PE) films as sample support for the determination of the iodine value (IV) and saponification number (SN). For direct IV analysis, quantification is achieved using the cis and trans double band region (3206–2992 cm−1) by a partial least squares calibration model, whereas, SN is directly determined using the area in carbon chain skeleton vibration absorption region (781–650 cm−1). The proposed method is applicable to various edible oils ranging in IV from 7.0 to 190.0 g 100 g−1 and SN from 162.7 to 222.0 mg g−1 with good precision and accuracy (relative standard deviations 0.39 and 0.32%, respectively) relative to the AOCS standard methods but with markedly less sample preparation and analytical effort. Practical Applications: Standard titration methods for determining the IV and SN of edible oils are labor intensive and require complex solvents and reagents. The PE‐film‐based FTIR method is more sensitive than attenuated total reflectance‐FTIR method and free from problems associated with the viscosity of oils, which is practical and easy to operate. The method can further simplify and facilitate simultaneous FTIR IV and SN analyses and is applicable to various edible oils over a wide range. A PE‐film‐based FTIR method is developed to determine the iodine value (IV) and saponification number (SN) of edible oils. The regions 3206–2992 cm−1 and 781–650 cm−1 are selected for IV and SN analysis, respectively. In the graphical abstract the IV and SN calibration and validation figures are presented.

Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) Coupled with Chemometrics, to Control the Botanical Authenticity and Quality of Cold-Pressed Functional Oils Commercialized in Romania

“…Over the past few decades, Fourier transform infrared (FTIR) spectroscopy had provided a reliable analytical tool in the fat and oil industries and become an attractive alternative to traditional methods, being a rapid and easy-to-use technique to evaluate qualitatively or even quantitatively the oils' edibility, their intrinsic quality parameters, safety, as well as authenticity, traceability and adulteration [1][2][3][4][5][6][7]. Moreover, the determination of edible oil authenticity, compared with the more accurate but time-consuming, laborious, and expensive chromatography-based method is advantageous as a more rapid and cheaper solution.…”

Caryocar brasiliense Cambess. Pulp Oil Supplementation Reduces Total Cholesterol, LDL-c, and Non-HDL-c in Animals

“…The saponification index is related to its molecular weight or chain length of triglycerides that compose the oil [ 32 ]. The reported result presented a low value (136.5 mg KOH g −1 ), near the recommended level for olive oil (184–196 mg KOH/g) and palm oil (190–209 mg KOH/g) [ 4 , 33 ], with characteristics similar to C. brasiliense .…”

Rapid Determination of Acid Value of Edible Oils via FTIR Spectroscopy Using Infrared Quartz Cuvette

“…A number of quantitative calibration technique based on FTIR has been proposed and provided analysts with precision and accuracy. Numerous quality parameters, such peroxide value 30 , trans fatty acid 31 , iodine value and saponification number 32 , could be predicted by models established through the relationship between the chemical parameters and spectral data of oils, using a variety of chemometric methods. These detection methods relied on spectral acquisition accessory, such as ATR and PE film, to collect the sample spectra.…”