Quantitative Raman Analysis of Carotenoid Protein Complexes in Aqueous Solution

Abstract

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 when fitted with individual carotenoid complexes and variable contributions with multiple ratios of admixtures. The results indicate the technique can potentially be used to quantify the carotenoid content of human serum and to identify their differential contributions for application in clinical analysis.

Antimicrobial Potential of an Actinomycete Gordonia terrae JSN1.9-Derived Orange Pigment Extract

“…Based on the maximum adsorption results (Figure 3), it is assumed that the pigment produced by G. terrae JSN1.9 belongs to the carotenoid group, which typically exhibits colors ranging from yellow to orange. Carotenoids absorb light in the visible region of 400-500 nm (Udensi et al 2022). Supporting this finding, Loh et This study investigated the antimicrobial activity of the pigment extract from G. terrae JSN1.9 against various microbes, showing stronger effects on B. subtilis, S. aureus, and C. albicans (Table 1).…”

Technofunctional Properties and Rheological Behavior of Quinoa, Kiwicha, Wheat Flours and Their Mixtures

“…Raman analysis is a vibration-based spectroscopy technique that identifies the components of multicomponent samples without the need to separate the elements individually [ 42 , 43 ]; it is suitable for the qualitative analysis of solid products [ 44 , 45 , 46 ]. However, it can be affected by interferences such as background fluorescence, which affects detection, in addition to the analysis problem and difficult quantitative analyses due to non-linear bias [ 47 ].…”

Surface-Enhanced Raman Analysis of Uric Acid and Hypoxanthine Analysis in Fractionated Bodily Fluids

“…Linear correlations were calculated for the maximum peak intensity of SERSs spectra and the concentrations of uric acid, hypoxanthine determined by HPLC for three bodily fluids. The Wilcoxon signed-rank test was applied to the comparison of two repeated or correlated data whose measurements were at least ordinal [ 34 ].…”