Propolis, a complex bee product, is a source of numerous bioactive principles, beneficial for human health, therefore it is intensively studied. In the present work, extracts of propolis from Bihor Romanian County were studied to identify the relationship between the polyphenolic derivatives profile and their antioxidant and antimicrobial activity. Extracts were obtained using water and 25%, 50%, and 70% ethanolic solutions (w/w), at 2:1, 4:1, and 6:1 liquid: solid ratios (w/w). 21 polyphenolic derivatives were quantified by UHPLC-MS, proving that the extracts composition strongly depends on the solvent. The sum of quantified polyphenolics extracted varied between 1.5 and 91.2 mg/g propolis. The antioxidant capacity was evaluated using the free radicals 2,2’-azino-bis (3-ethylbenzothiazoline-6 sulfonic acid) diammonium salt (ABTS) and 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging methods. Antimicrobial efficiency was tested against Gram-positive (B. subtilis), Gram-negative bacteria (E. coli), and fungi (C. albicans) by disc-diffusion method. All extracts, even the aqueous ones, demonstrated antibacterial and antifungal activity. Chemometric methods (partial least squares) and a saturation-type model were used to evaluate the contribution of various bioactive principles in building the antioxidant capacity of extracts. Both experimental and modelling results show that 50% ethanolic extracts provide a rich polyphenolics profile and ensure a good antioxidant capacity.

Any change in the composition or physicochemical parameters of honey outside the standardized intervals may be deemed fraud, irrespective of direct introduction of certain substances or feeding honeybees with syrups. Simple and rapid tools along with more sophisticated ones are required to monitor fraudulent practices in the honey trade. In this work, UV–Vis spectroscopy was used to identify and quantify six Romanian honey types (five monofloral and one polyfloral) mixed with commercially available corn syrup, corn syrup with plant extracts, inverted syrup, and fruit syrup at different concentrations (5%, 10%, 20%, 30%, 40%, and 50%). Relevant spectral features were used to develop a neural model, which was able to pinpoint adulteration, regardless of the honey and adulterant type. The proposed model was able to detect adulteration levels higher than 10%, thereby serving as a cost-effective and reliable tool to monitor honey quality.

The 4000–400 cm⁻¹ spectral information obtained by FTIR-ATR for bee pollen samples of different floral origin from various Romanian counties were used to formulate a method for rapid classification using principal component analysis (PCA) and linear discriminant analysis (LDA) as multivariate statistics tools. Entire IR range spectra were used as input data in both techniques. PCA reduced the problem dimensionality and put in evidence the presence of outliers. LDA, applied for samples characterized by the first 11 principal components (PCA-LDA), clearly separated 10 groups according to botanical and geographical origin, thus representing a base for developing an identification tool of the new pollen samples origin. Furthermore, spectral information and previously determined properties (polyphenols, flavonoids, sugars, proteins) were tested for identifying polynomial correlations using partial least squares (PLS) technique. The good correlation coefficients, R² > 0.97, and low mean errors in both training and testing stages proved that a FTIR-ATR spectrum provides key information for rapid screening of bee pollen in terms of the parameters significant for its nutritional labelling.

• UAE changes polyphenolic acids and flavonoids profiles compared to maceration. • Solvent is the key operational parameter setting up extracted polyphenolics profile. • 50% ethanol & UAE boost yield, antioxidant capacity and antimicrobial activity.

Romanian Honey: Characterization and Classification | InTechOpen, Published on: 2017-03-15. Authors: Raluca Daniela Isopescu, Ana Maria Josceanu, Teodora Colta, et

: We identified and quantified by LC-MS/MS 11 (quercetin, galangin, pinocembrin, kaempferol, vanillin, chrysin, gallic acid, p-coumaric acid, trans-ferulic acid, caffeic acid, and caffeic acid phenethyl ester) out of the 21 polyphenolic compounds we looked for in ethanolic (25% and 50%) and aqueous propolis extracts by comparison with standards and literature data.