The FTIR-ATR method coupled with the multivariate analysis of specific spectral areas of samples was developed to characterize two white grape varieties (Sauvignon Blanc and Hibernal) and two blue grape varieties (André and Cabernet Moravia) of wine planted and harvested in the Moravia region, Czech Republic. Principal component analysis and hierarchical cluster analysis were performed using fingerprint regions of FTIR spectra for all wines. The results obtained by principal component analysis in combination with linear discriminant analysis (PCA-LDA) scores yielded clear separation between the four classes of samples and showed very good discrimination between the wine samples, with a 91.7% overall classification rate for the samples. The conducted FTIR spectroscopy studies coupled with chemometrics allowed for the swift analysis of multiple wine components with minimal sample preparation. These methods can be used in research to improve specific properties of these wines, which will undoubtedly enhance the quality of the final wine samples obtained.
4-[5-(Naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol (NTBD) was extensively studied through stationary UV–vis absorption and fluorescence measurements in various solvents and solvent mixtures and by first-principles quantum chemical calculations. It was observed that while in polar solvents (e.g., methanol) only a single emission band emerged; the analyzed 1,3,4-thiadiazole derivative was capable of producing dual fluorescence signals in low polarity solvents (e.g., n-hexane) and certain solvent mixtures (e.g., methanol/water). As clearly follows from the experimental spectroscopic studies and theoretical modeling, the specific emission characteristic of NTBD is triggered by the effect of enol → keto excited-state intramolecular proton transfer (ESIPT) that in the case of solvent mixture is reinforced by aggregation of thiadiazole molecules. Specifically, the restriction of intramolecular rotation (RIR) due to environmental hindrance suppresses the formation of non-emissive twisted intramolecular charge transfer (TICT) excited keto* states. As a result, this particular thiadiazole derivative is capable of simultaneously producing both ESIPT and aggregation-induced emission (AIE).
Flower petals, as byproducts, provide significant health benefits and can be used in food production. In this study, the impact of the micronization process using a ball mill on the properties of micronized powders derived from wild rose petals of the rugosa variety (Rosa rugosa Thunb.) was examined. The micronized rose powders were subjected to an investigation regarding their particle size, color, molecular characterization (FTIR), electronic nose procedure and antioxidant potential. The study found that micronization considerably reduced d50 particle dimensions from 98.6 µm to 39.9 µm. An FTIR analysis revealed the presence of characteristic (2980, 1340, and 1225 cm−1) bands. The hydrolysable tannins are the most abundant polyphenolic chemicals in rose powders, followed by anthocyanins. Rose powders are an extremely valuable antioxidant raw material due to their high total phenol content (71.8 mg GAE/g), which increased by approximately 26% after micronization. The antioxidant activity, as determined by ABTS•+, DPPH• and FRAP, is likewise very high. The intensity of volatile chemicals decreased in powders after micronization.
Lignin obtained in acidic conditions is a waste product in various technological processes like sulfite pulping, organosolv pulping, or bioethanol production. Knowing the structure of the lignin enables its use in high-value-added applications. In this paper, the lignin structure isolated from Pinus sylvestris L. and Populus deltoides × maximowiczii wood in acidic conditions was investigated. Two methods of lignin isolation (Klason method and a method using a sulfuric and phosphoric acid mixture) were compared. Additionally, lignin acetylation was performed. The lignin samples were analyzed using different instrumental techniques, such as size exclusion chromatography (SEC), attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). Based on the studies carried out, it was found out that the lignin isolated from pine and poplar wood in acidic conditions had a highly condensed structure. This was evidenced by the high-weight average molar mass of lignin (up to 118,700 g/mol) and the precipitates, aggregates, and agglomerates on its surface. Moreover, the characteristic signals of condensed lignin in ATR-FTIR analysis (band with wavenumber of 767 cm−1) and their decrease/disappearance (band that usually occurs with a wavenumber of about 814 cm−1) were observed. Lignin acetylation and analysis in the 0.5% LiCl/DMAc system have proven particularly effective in the case of the condensed poplar lignin. The beneficial effect of lignin acetylation was confirmed by SEM analysis. The high-molecular-weight condensed lignin, despite some of its problematic properties connected mainly with solubility, is a valuable substance that can be used for different applications (carbon fibers or as an additive for thermoplastic blends), which was confirmed by the studies in this paper and the findings of other scientists.
The purpose of this study was to investigate the effect of micronization on the characteristics of black cumin pressing waste material. The basic composition, amino acid, and fatty acid content of the raw material—specifically, black cumin pressing waste material—were determined. The samples were micronized in a planetary ball mill for periods ranging from 0 to 20 min. The particle sizes of micronized samples of black cumin pressing waste material were then examined using a laser analyzer, the Mastersizer 3000. The structures of the produced micronized powders was examined by X-ray diffraction. Additionally, the FTIR (Fourier-transform infrared) spectra of the micronized samples were recorded. The measurement of phenolic and antiradical properties was conducted both before and after in vitro digestion, and the evaluation of protein digestibility and trypsin inhibition was also conducted. The test results, including material properties, suggest that micronization for 10 min dramatically reduced particle diameters (d50) from 374.7 to 88.7 µm, whereas after 20 min, d50 decreased to only 64.5 µm. The results obtained using FTIR spectroscopy revealed alterations, especially in terms of intensity and, to a lesser extent, the shapes of the bands, indicating a significant impact on the molecular properties of the tested samples. X-ray diffraction profiles revealed that the internal structures of all powders are amorphous, and micronization methods have no effect on the internal structures of powders derived from black cumin pressing waste. Biochemical analyses revealed the viability of utilizing micronized powders from black cumin pressing waste materials as beneficial food additives, since micronization increased total phenolic extraction and antiradical activity.
Climate change forces agriculture to face the rapidly growing virulence of biotrophic fungal pathogens, which in turn drives researchers to seek new ways of combatting or limiting the spread of diseases caused by the same. While the use of agrochemicals may be the most efficient strategy in this context, it is important to ensure that such chemicals are safe for the natural environment. Heterocyclic compounds have enormous biological potential. A series of heterocyclic scaffolds (1,3,4-thiadiazole, 1,3-thiazole, 1,2,4-triazole, benzothiazine, benzothiadiazine, and quinazoline) containing 2,4-dihydroxylaryl substituents were investigated for their ability to inhibit the growth and development of biotrophic fungal pathogens associated with several important cereal diseases. Of the 33 analysed compounds, 3 were identified as having high inhibitory potential against Blumeria and Puccinia fungi. The conducted research indicated that the analysed compounds can be used to reduce the incidence of fungal diseases in cereals; however, further thorough research is required to investigate their effects on plant–pathogen systems, including molecular studies to determine the exact mechanism of their activity.