Two-trace two-dimensional (2T2D) correlation infrared spectral analysis of Spirulina platensis and its commercial food products coupled with chemometric analysis

Application of electrospinning to fabricate phycocyanin- and Spirulina extract-loaded gliadin fibers for active food packaging

This study explored the active food packaging application of phycocyanin- and Spirulina extract-loaded gliadin electrospun fibers (GPhy and GSPE5%). SEM findings confirmed that the morphology of fibers was tubular, showing the GPhy and GSPE5% as the optimum fibers. The loading efficiencies of GPhy and GSPE5% were also around 90%, which proved the well-incorporated compounds within the fibers. Simulation results of α-gliadin dissolved in acetic acid illustrated the denaturation of the protein. FTIR and TGA confirmed that after electrospinning the chemical/structural changes and enhanced thermostabilities occurred, respectively. Antibacterial and antioxidant tests detected higher bactericidal and antioxidative effects of GSPE5% than GPhy. In the application part, it was found that GPhy and GSPE5% were able to decrease PV and TBA values as the indications of walnut kernels' protection from lipid oxidation. This work shows a facile and an efficient way to fabricate active food packaging materials using electrospinning and natural compounds.

Novel Developments and Progress in Two-Dimensional Correlation Spectroscopy (2D-COS)

This first of the two-part series of the comprehensive survey review on the progress of the two-dimensional correlation spectroscopy (2D-COS) field during the period 2021-2022, covers books, reviews, tutorials, novel concepts and theories, and patent applications that appeared in the last two years, as well as some inappropriate use or citations of 2D-COS. The overall trend clearly shows that 2D-COS is continually growing and evolving with notable new developments. The technique is well recognized as a powerful analytical tool that provides deep insights into systems in many science fields.

Diverse Applications of Two-Dimensional Correlation Spectroscopy (2D-COS)

This second of the two-part series of a comprehensive survey review provides the diverse applications of two-dimensional correlation spectroscopy (2D-COS) covering different probes, perturbations, and systems in the last two years. Infrared spectroscopy has maintained its top popularity in 2D-COS over the past two years. Fluorescence spectroscopy is the second most frequently used analytical method, which has been heavily applied to the analysis of heavy metal binding, environmental, and solution systems. Various other analytical methods including laser-induced breakdown spectroscopy, dynamic mechanical analysis, differential scanning calorimetry, capillary electrophoresis, seismologic, and so on, have also been reported. In the last two years, concentration, composition, and pH are the main effects of perturbation used in the 2D-COS fields, as well as temperature. Environmental science is especially heavily studied using 2D-COS. This comprehensive survey review shows that 2D-COS undergoes continuous evolution and growth, marked by novel developments and successful applications across diverse scientific fields.

Two-trace two-dimensional correlation spectra (2T2D-COS) analysis using FTIR spectra to monitor the immune response by COVID-19

There is a growing trend in using saliva for SARS-CoV-2 detection with reasonable accuracy. We have studied the responses of IgA, IgG, and IgM in human saliva by directly comparing disease with control analyzing two-trace two-dimensional correlation spectra (2T2D-COS) employing Fourier transform infrared (FTIR) spectra. It explores the molecular-level variation between control and COVID-19 saliva samples. The advantage of 2T2D spectra is that it helps in discriminating remarkably subtle features between two simple pairs of spectra. It gives spectral information from highly overlapped bands associated with different systems. The clinical findings from 2T2D show the decrease of IgG and IgM salivary antibodies in the 50, 60, 65, and 75-years COVID-19 samples. Among the various COVID-19 populations studied the female 30-years group reveals defense mechanisms exhibited by IgM and IgA. Lipids and fatty acids decrease, resulting in lipid oxidation due to the SARS-CoV-2 in the samples studied. Study shows salivary thiocyanate plays defense against SARS-CoV-2 in the male population in 25 and 35 age groups. The receiver operation characteristics statistical method shows a sensitivity of 98% and a specificity of 94% for the samples studied. The measure of accuracy computed as F score and G score has a high value, supporting our study's validation. Thus, 2T2D-COS analysis can potentially monitor the progression of immunoglobulin's response function to COVID-19 with reasonable accuracy, which could help diagnose clinical trials. KEY MESSAGES: The molecular profile of salivary antibodies is well resolved and identified from 2T2D-COS FTIR spectra. The IgG antibody plays a significant role in the defense mechanism against SARS-CoV-2 in 25-40 years. 2T2D-COS reveals the absence of salivary thiocyanate in the 40-75 years COVID-19 population. The receiver operation characteristic (ROC) analysis validates our study with high sensitivity and specificity.

Biosorption and bioreduction of aqueous chromium (VI) by different Spirulina strains

Spirulina has emerged as a promising microorganism for the treatment of industrial heavy metal ions in wastewater due to their simplicity of cultivation and harvesting, rich functional binding groups, and high bioreductive activity during the uptake process. While the capacities of biosorption and bioreduction for heavy metal ions differ significantly among various algal strains. Therefore, the physiological characteristics were investigated to identify the different Spirulina strains, and the chromium (VI) adsorption capacities of the algal strains were also evaluated. In this study, it was found that algal strains YCX2643 and CLQ1848 performed higher removal efficiency (86.5% and 83.7%) than the other four Spirulina strains (59.4%, 56.3%, 65.6%, and 66.5%, respectively). Moreover, the mechanisms of chromium (VI) ions binding and biotransformation in the Spirulina cell were scrutinized by FTIR (Fourier transform infrared) spectroscopy and scanning electron microscopy (SEM), and it indicated that the varieties of cellular components involved in high binding affinity may cause the higher biosorption and bioreduction of aqueous chromium (VI) in algal strains YCX2643 and CLQ1848, which could be used as promising biosorbents in the removing heavy metal pollutants from wastewaters.

Exploring the use of infrared absorption spectroscopy and two-trace two-dimensional correlation analysis for the resolution of multi-component drug mixtures

Community drug checking provides an essential service that responds to the unpredictable and variable supply of illicit drugs. Point of care detection of trace components using portable infrared spectrometers is a harm reduction measure to prevent overdose. This study investigates the ability of weighted subtraction and two-trace two-dimensional (2T2D) correlation analysis to reveal the presence of heroin in an opioid mixture that contains heroin and fentanyl mixed with caffeine as a cutting agent. In both methods, a spectral trace was identified that provided reasonably high correlation scores to heroin when compared to entries in drug libraries. The two-trace correlation analysis produced a higher match score, suggesting that future improvements in spectral unmixing methods may enhance the reliability of detecting trace components in drugs.

Infrared spectrochemical findings on intermittent fasting-associated gross molecular modifications in rat myocardium

Cardiovascular diseases are among the primary life-threatening conditions affecting human society. Intermittent fasting is shown to be functional in the prevention of cardiovascular diseases, however, the information on fasting-associated modifications in myocardial biomolecules is limited. This study aimed to determine the impact of 18-h intermittent fasting administered for five weeks on 12 months-old rats using supervised linear discriminant analysis and support vector machine algorithms constructed on spectrochemical data obtained from myocardial tissues. These algorithms revealed gross biomolecular modifications, while quantitative analyses demonstrated higher amounts of saturated lipids (19%), triglycerides (11%), and lipids (56%), in addition to enhancement in membrane dynamics (18%). The concentrations of nucleic acids and glucose are increased by 52%, while the glycogen content is diminished by 61%. The protein carbonylation/oxidation is reduced by 38%, whereas a 35% increase in protein content was measured. Phosphorylated proteins have been calculated to be at higher concentrations in the 13-62% range. The study findings demonstrated significant molecular changes in the myocardium of rats subjected to intermittent fasting.

Screening of Spirulina strains for high copper adsorption capacity through Fourier transform infrared spectroscopy

Microalgae have emerged as promising biosorbents for the removal of toxic metals from industrial effluents due to the presence of various free functional groups. While the constitutes are distinct among different algal strains, it needs to screen the algae with high adsorption capacities for heavy metal ions by analyzing the algal components. In this study, a rapid and nondestructive Fourier transform infrared (FTIR) method combined PCA algorithm was used to discriminate algal strains according to their cellular components. With FTIR spectroscopy, we have found that the algal strains for high copper adsorption capacity (RH44, XS58, AH53, and RZ22) can be well differentiated from other strains via assessing the components involved in the biosorption of copper ions at the spectral window range of 1,200–900 cm⁻¹ mainly attributed to polysaccharides. Correspondingly, the copper removal efficiency by different Spirulina strains was also measured by biochemical assay and scanning electron microscopy (SEM) in order to confirm the screening result. Compared with the chemical measurement, the assessment based on spectral features appears fairly good in the evaluation and differentiation of copper adsorption capacity in various Spirulina strains. This study illustrates that FTIR spectroscopy may serve as a fast and effective tool to investigate the functional groups for copper ions binding in the Spirulina cell and it even offers a useful and accurate new approach to rapidly assess potential adsorbents for the high capacity of copper adsorption.

Discrimination of Adulterated Ginkgo Biloba Products Based on 2T2D Correlation Spectroscopy in UV-Vis Range

Ginkgo biloba is a popular medicinal plant widely used in numerous herbal products, including food supplements. Due to its popularity and growing economic value, G. biloba leaf extract has become the target of economically motivated adulterations. There are many reports about the poor quality of ginkgo products and their adulteration, mainly by adding flavonols, flavonol glycosides, or extracts from other plants. In this work, we developed an approach using two-trace two-dimensional correlation spectroscopy (2T2D COS) in UV-Vis range combined with multilinear principal component analysis (MPCA) to detect potential adulteration of twenty G. biloba food supplements. UV-Vis spectral data are obtained for 80% methanol and aqueous extracts in the range of 245–410 nm. Three series of two-dimensional correlation spectra were interpreted by visual inspection and using MPCA. The proposed relatively quick and straightforward approach successfully differentiated supplements adulterated with rutin or those lacking ginkgo leaf extract. Supporting information about adulteration was obtained from the difference between the DPPH radical scavenging capacity of both extracts and from chromatographic (HPLC-DAD) fingerprints of methanolic samples.