ABSTRACT
Research background: Coastal region of Croatia is rich in autochthonous grape varieties. Many of them have been almost abandoned, such as the autochthonous varieties of Kastav (Croatia), used for the production of the Kastavska Belica wine. Therefore, the rationale of the presented study is to characterize autochthonous grape varieties Verdic, Mejsko belo, Jarbola, Divjaka and Brajkovac. In addition, we performed a molecular characterization of the corresponding Belica wines. Experimental approach: Firstly, the genetic origin and ampelographic and economic characteristics of five autochthonous grape varieties were determined. Standard physicochemical profiles and phenolic components of 12 wines from different producers were determined by liquid chromatography coupled to triple quadrupole mass spectrometer (LC-QQQ-MS). Fourier-transform infrared spectroscopy (FTIR) was used for determination of standard physicochemical parameters. Results and conclusions: Ampelographic analysis, which includes the data on producing characteristics and cluster and berry composition of the varieties, revealed significant differences between the analysed grape varieties. Results of the physicochemical analysis of the Belica wine showed that all wines met the requirements needed for the production of quality and top quality wines labelled with protected designation of origin (PDO) in Croatian coastal region. The LC-QQQ-MS analysis confirmed the presence of different phenolic components in the Belica wines, where the most prominent phenols were flavonoids from the flavan-3-ol group. Overall, these results showed that autochthonous grapes from the Kastav region can be used for production of wines with added market value due to a growing demand for autochthonous products on the global market. Novelty and scientific contribution: The presented results give scientific insight and a basis for further determination of the optimal cultivation technology aimed to take advantage of the best characteristics of each variety for production of a wine with desirable features.
ABSTRACT
Honey is a natural food consisting mainly of sugars, enzymes, amino acids, organic acids, vitamins, minerals and aromatic substances. In addition to specific organoleptic properties, honey also has other components that contribute to its nutritional and health value. Proteins, vitamins, minerals, organic acids and phenolic compounds, the most variable components of honey, are predominantly responsible for its strong bioactive effect. Honeydew honey is a less known type of honey with outstanding antimicrobial and antioxidant properties that also demonstrates prebiotic effects and can promote the growth of probiotic bacteria. Foodborne illnesses can be prevented by using probiotic strains in combination with prebiotics. The aim of this study was for the first time to determine potential synergistic antimicrobial effect of fir (Abies alba Mill.) honeydew honey (HS) and probiotic bacteria Lactiplantibacillus plantarum on Salmonella enterica serotype Typhimurium, a primary cause of foodborne illnesses. The effect of three different samples of fir honeydew honey on the growth of L. plantarum in de Man, Rogosa and Sharpe (MRS) medium and the potential synergistic effect of HSs and L. plantarum on the growth of S. Typhimurium in the Brain Heart Infusion (BHI) medium were examined. The results indicate that concentrations of 1 and 5% of all three HS samples stimulate the growth and metabolic activity of L. plantarum, while a concentration of 10% inhibits the growth of L. plantarum. The concentration of 5% of all three HS and L. plantarum combined inhibits the growth of S. Typhimurium in BHI broth. Fir honeydew honey showed potential prebiotic properties and antimicrobial activity, both of which can synergistically enhance the probiotic efficacy of L. plantarum against S. Typhimurium To conclude, the combination of fir honeydew honey and L. plantarum represents a successful combination against S. Typhimurium and additional experiments are necessary regarding the mechanisms of their combined effect.
ABSTRACT
Research background: The composition of honey is influenced by the botanical source and geographical area of the nectar from which it is derived. Unifloral honeys reach higher market value than multifloral honeys due to their specific aromas, which result from volatile and phenolic compounds. Experimental approach: The aim of our study is to characterize the phenolic composition of a rare unifloral variety of honey - mint (Mentha spp.) honey. For this purpose, we performed standard physicochemical analyses, pollen analysis, determined total phenolic and flavonoid content, analysed antioxidant activity and performed qualitative and quantitative analyses of phenolic compounds for five mint honeys. Results and conclusions: Our results indicate that mint honey samples have high phenolic content, expressed in gallic acid equivalents, from (76.7±0.6) to (90.1±1.1) mg/100 g, and flavonoid content, expressed as quercetin equivalents, from (6.7±0.6) to (12.5±0.8) mg/100 g. These honey samples also exhibit strong antioxidant activity, expressed as Trolox equivalents, from (33.6±2.8) to (51.3±1.2) mg/100 g and from (14.4±0.8) to (55.1±2.4) mg/100 g when analysed with DPPH and ABTS assays, respectively. Quantitative LC-MS/MS analysis revealed that the most abundant phenols in all samples were chrysin, apigenin and p-coumaric acid. Qualitative LC-MS/MS analysis identified the presence of kaempferide, diosmetin, acacetin and several caffeic acid derivatives. Novelty and scientific contribution: Our study indicates that mint honey contains unique phenolic profiles, which likely contribute to its distinctive aroma and strong antioxidant activity. A detailed description of the rare honey varieties gives beekeepers greater visibility and easier access to the demanding natural product market.
ABSTRACT
Propolis is a complex biological matrix consisting mostly of plant resins and waxes, and in a small proportion of the herbal secondary metabolites, phenols. Phenols are components that are responsible for biological activities of propolis, however, their qualitative and quantitative composition is strongly influenced by climate and vegetation. Although studies on profiling of propolis samples from different countries have been carried out for some time propolis from Croatia is still not characterized till now. Targeted liquid chromatography coupled to triple quadrupole (LC-QQQ), untargeted liquid chromatography coupled to quadrupole time-of-flight (LC-QTOF) and direct injection QTOF methods were developed and 56 propolis samples from different geographical regions of Croatia were analyzed. Results revealed that there is not only one expected type of propolis in the territory of Croatia; i.e. beside expected European "poplar" propolis another type can be distinguished. Principal component analysis (PCA) and Partial least squares Discriminant Analysis (PLS-DA) indicated that the phenolic content of propolis samples significantly changes under the influence of the Mediterranean, so the "European" propolis type mixes with the Mediterranean type on the Croatian coast, especially on the islands. For fast screening of propolis type, direct injection QTOF analysis demonstrated to be fast and reliable method, but for unambiguous identification of phenolic compounds, chromatographic separation is indispensable. This paper presents the findings from the first research on phenolic profiling of propolis from Croatia.
