Molecules, Vol. 27, Pages 4724: Quantitative Raman Analysis of Carotenoid Protein Complexes in Aqueous Solution

Molecules, Vol. 27, Pages 4724: Quantitative Raman Analysis of Carotenoid Protein Complexes in Aqueous Solution Molecules doi: 10.3390/molecules27154724 Authors: Joy Udensi Ekaterina Loskutova James Loughman Hugh J. Byrne Carotenoids are naturally abundant, fat-soluble pigmented compounds with dietary, antioxidant and vision protection advantages. The dietary carotenoids, Beta Carotene, Lutein, and Zeaxanthin, complexed with in bovine serum albumin (BSA) in aqueous solution, were explored using Raman spectroscopy to differentiate and quantify their spectral signatures. UV visible absorption spectroscopy was employed to confirm the linearity of responses over the concentration range employed (0.05–1 mg/mL) and, of the 4 Raman source wavelengths (785 nm, 660 nm, 532 nm, 473 nm), 532 nm was chosen to provide the optimal response. After preprocessing to remove water and BSA contributions, and correct for self-absorption, a partial least squares model with R2 of 0.9995, resulted in an accuracy of the Root Mean Squared Error of Prediction for Beta Carotene of 0.0032 mg/mL and Limit of Detection 0.0106 mg/mL. Principal Components Analysis clearly differentiated solutions of the three carotenoids, based primarily on small shifts of the main peak at ~1520 cm−1. Least squares fitting analysis of the spectra of admixtures of the carotenoid:protein complexes showed reasonable correlation between norminal% and fitted%, yielding 100% contribution w...
Source: Molecules - Category: Chemistry Authors: Tags: Article Source Type: research