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Plant-based beverages (PBs) are currently gaining interest among consumers who are seeking alternative sustainable options to traditional dairy drinks. The study aimed to obtain powdered plant beverages without the addition of carriers by spray drying method to implement them in the future as an alternative to the liquid form of dairy drinks. Some of the most well-known commercial beverages sources like soy, almond, rice and oat were analyzed in this work. The effect of different treatments (concentration, addition of oat fiber) and two approaches od spray drying (conventional high temperature spray drying—SD, and dehumidified air spray drying at low temperature—DASD) were presented. Moreover, moisture content, water activity, particle morphology and size of obtained powders were analyzed. It was possible to obtain PBs without the addition of carriers, although the drying yield of four basic beverages was low (16.1–37.4%). The treatments and change in spray drying approach enhanced the drying yield, especially for the concentrated beverage dried using DASD (59.2%). Additionally, Fourier Transform Infrared (FTIR) spectroscopy was applied to evaluate the differences in chemical composition of powdered PBs. FTIR analysis revealed differences in the range of the absorption frequency of amide I, amide II (1700–1500 cm−1) and carbohydrate region (1200–900 cm−1). Principal component analysis (PCA) was carried out to study the relationship between spray dried plant beverages samples based on the fingerprint region of FTIR spectra, as well as the physical characteristics. Additionally, hierarchical cluster analysis (HCA) was employed to explore the clustering of the powders. [ABSTRACT FROM AUTHOR]

In the presented study, advanced experimental techniques, including electronic absorption and fluorescence spectroscopies [with Resonance Light Scattering (RLS)], measurements of fluorescence lifetimes in the frequency domain, calculations of dipole moment fluctuations, quantum yields, and radiative and non-radiative transfer constants, were used to characterize a selected analogue from the group of 1,3,4-thiadiazole, namely: 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol (NTBD), intrinsically capable to demonstrate enol → keto excited-states intramolecular proton transfer (ESIPT) effects. The results of spectroscopic analyses conducted in solvent media as well as selected mixtures were complemented by considering biological properties of the derivative in question, particularly in terms of its potential microbiological activity. The compound demonstrated a dual fluorescence effect in non-polar solvents, e.g. chloroform and DMSO/H2O mixtures, while in polar solvents only a single emission maximum was detected. In the studied systems, ESIPT effects were indeed observed, as was the associated phenomenon of dual fluorescence, and, as demonstrated for the DMSO: H2O mixtures, the same could be relatively easily induced by aggregation effects related to aggregation-induced emission (AIE). Subsequently conducted quantum-chemical (TD-)DFT calculations supported further possibility of ESIPT effects. The following article provides a comprehensive description of the spectroscopic and biological properties of the analyzed 1,3,4-thiadiazole derivatives, highlighting its potential applicability as a very good fluorescence probes as well as a compound capable of high microbiological activity. [ABSTRACT FROM AUTHOR]

This work reports on biophysical insights into the excited state intramolecular proton transfer (ESIPT) processes taking place in three 1,3,4-thiadiazole derivatives that served as model compounds, on which electronic absorption, fluorescence, Fourier-transform infrared spectroscopy (FTIR), surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS) studies were performed. The fluorescence spectra recorded in various solvents revealed an interesting dual fluorescence effect. In molecules in their monomeric form, the effect is associated with the ESIPT phenomenon, and may be further enhanced by aggregation-related effects, such as aggregation-induced emissions. Other spectroscopic studies on the selected molecules in a liposomal medium as a model revealed that, in a biomimetic environment, they can exist in both monomeric and aggregated forms. In both cases, however, the effects observed are closely related to the lipid's main phase transition temperature and the structure of the molecule. Introduction of specific substituents to the phenyl moiety either allows or prevents proton transfer from occurring in the excited state. The hydrophobicity changes in a lipid environment may result in an emergence of specific molecular forms and therefore either facilitate or hinder ESIPT processes. SPR and EIS confirmed the significant hydrophobicity changes in the model lipid systems, while FTIR measurements revealed a notable influence of 1,3,4-thiadiazoles on the fluidity of liposomal membranes. The results obtained clearly show that the thiadiazole derivatives are very good model molecules for studying hydrophobic-hydrophilic environments, and particularly with polymers or liposomes used as drug delivery systems. [ABSTRACT FROM AUTHOR]