Manuka honey plays a significant role in modern medical applications as an antibacterial, antiviral, and antibiotic agent. However, although the importance of manuka honey is well documented in the literature, information regarding its physicochemical characteristics remains limited. Moreover, so far, only a few papers address this issue in conjunction with the examination of the pollen composition of manuka honey samples. Therefore, in this study, two parameters crucial for honey quality control—the diastase number (DN) and the hydroxymethylfurfural (HMF) content—as well as the melissopalynological analysis of manuka honey, were examined. The research found a large variation in the percentage of Leptospermum scoparium pollen in honeys labeled and sold as manuka honeys. Furthermore, a significant proportion of these honeys was characterized by a low DN. However, since low diastase activity was not associated with low HMF content, manuka honey should not be considered as a honey with naturally low enzymatic activity. Overall, the DN and HMF content results indicate that the quality of commercially available manuka honey is questionable.

Zeaxanthin and lutein are xanthophyll pigments present in the human retina and particularly concentrated in its center referred to as the yellow spot (macula lutea). The fact that zeaxanthin, including its isomer meso-zeaxanthin, is concentrated in the central part of the retina, in contrast to lutein also present in the peripheral regions, raises questions about the possible physiological significance of such a heterogeneous distribution of macular xanthophylls. Here, we attempt to address this problem using resonance Raman spectroscopy and confocal imaging, with different laser lines selected to effectively distinguish the spectral contribution of lutein and zeaxanthin. Additionally, fluorescence lifetime imaging microscopy (FLIM) is used to solve the problem of xanthophyll localization in the axon membranes. The obtained results allow us to conclude that one of the key advantages of a particularly high concentration of zeaxanthin in the central part of the retina is the high efficiency of this pigment in the dynamic filtration of light with excessive intensity, potentially harmful for the photoreceptors.

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C₁-C₂ alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni²⁺/Ni³⁺, Cr²⁺/Cr³⁺, Mn²⁺/Mn³⁺, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr³⁺/Cr⁴⁺) and Mn (Mn³⁺/Mn⁴⁺) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

Since the imbalance between free radicals and antioxidants in the body plays a significant role in the physiology of common, often dangerous diseases, an emphasis is placed on enriching the daily diet with compounds characterized by antioxidant activity. Good sources of natural antioxidants are bee products such as honey, bee pollen, bee bread and propolis, and the best path for introducing the latter products into the diet is mixing them with honey. However, the characteristics of bee product mixtures are not yet fully understood. Therefore, the aim of this study is to verify the health-promoting properties of a mixture of honeydew honey and multifloral bee bread. The profile of phenolic compounds, radical scavenging activity, total phenolic content, diastase number, and also proline and HMF content were determined. The obtained results indicated the improved health-promoting value of this mixture, as increases in radical scavenging activity (from 82.7 to 88.4%), in the total content of phenolic compounds (from 74.6 to 118.8 mg·100 g⁻¹), and also in the proline content (from 64.0 to 95.5 mg·100 g⁻¹) and diastase activity (from 22.6 to 38.8 Schade units) were observed when 5% of bee bread (w/w) was added. Moreover, the bee bread addition provided two important flavonoids to the honeydew honey, i.e., rutin and kaempferol.