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Pulassery S, Abraham B, Ajikumar N, Munnilath A, Yoosaf K. Rapid Iodine Value Estimation Using a Handheld Raman Spectrometer for On-Site, Reagent-Free Authentication of Edible Oils. ACS Omega 2022; 7:9164-9171. [PMID: 35350360 PMCID: PMC8945061 DOI: 10.1021/acsomega.1c05123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/10/2022] [Indexed: 05/15/2023]
Abstract
Edible oil adulteration is a common and serious issue faced by human societies across the world. Iodine value (IV), the total unsaturation measure, is an authentication tool used by food safety officers and industries for edible oils. Current wet titrimetric methods (e.g., Wijs method) employed for IV estimation use dangerous chemicals and elaborate procedures for analysis. Alternate approaches for oil analysis require sophisticated and costly equipment such as gas chromatography (GC), liquid chromatography, high-performance liquid chromatography, mass spectrometry (MS), UV-Visible, and nuclear magnetic resonance spectroscopies. Mass screening of the samples from the market and industrial environment requires a greener, fast, and more robust technique and is an unmet need. Herein, we present a handheld Raman spectrometer-based methodology for fast IV estimation. We conducted a detailed Raman spectroscopic investigation of coconut oil, sunflower oil, and intentionally adulterated mixtures with a handheld device having a 785 nm excitation source. The obtained data were analyzed in conjunction with the GC-MS results and the conventional wet Wijs titrimetric estimated IVs. Based on these studies, a specific equation for IV estimation is derived from the intensity of identified Raman spectral bands. Further, an algorithm is designed to automate the signal processing and IV estimation, and a stand-alone graphical user interface is created in user-friendly LabVIEW software. The data acquisition and analysis require < 2 minutes, and the estimated statistical parameters such as the R 2 value (0.9), root-mean-square error of calibration (1.3), and root-mean-square error of prediction (0.9) indicate that the demonstrated method has a high precision level. Also, the limit of detection and the limit of quantification for IV estimation through the current approach is ∼1 and ∼3 gI2/100 g oil, respectively. The IVs of different oils, including hydrogenated vegetable oils, were evaluated, and the results show an excellent correlation between the estimated and reported ones.
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Affiliation(s)
- Sanoop Pulassery
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science
and Technology, Thiruvananthapuram 695019 Kerala, India
- Research
Centre, University of Kerala, Thiruvananthapuram 695034, Kerala, India
| | - Bini Abraham
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science
and Technology, Thiruvananthapuram 695019 Kerala, India
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Nandu Ajikumar
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science
and Technology, Thiruvananthapuram 695019 Kerala, India
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Arun Munnilath
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science
and Technology, Thiruvananthapuram 695019 Kerala, India
| | - Karuvath Yoosaf
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science
and Technology, Thiruvananthapuram 695019 Kerala, India
- Academy
of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Research
Centre, University of Kerala, Thiruvananthapuram 695034, Kerala, India
- . Phone: 0091-471-2515477
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