Carmen Pop

Antibacterial activity and interactions of plant essential oil combinations against Gram-positive and Gram-negative bacteria

The aim of this study was to compare the antibacterial effects of several essential oils (EOs) alone and in combination against different Gram-positive and Gram-negative bacteria associated with food products. Parsley, lovage, basil, and thyme EOs, as well as their mixtures (1:1, v/v), were tested against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella typhimurium. The inhibitory effects ranged from strong (thyme EO against E. coli) to no inhibition (parsley EO against P. aeruginosa). Thyme EO exhibited strong (against E. coli), moderate (against S. typhimurium and B. cereus), or mild inhibitory effects (against P. aeruginosa and S. aureus), and basil EO showed mild (against E. coli and B. cereus) or no inhibitory effects (against S. typhimurium, P. aeruginosa, and S. aureus). Parsley and lovage EOs revealed no inhibitory effects against all tested strains. Combinations of lovage/thyme and basil/thyme EOs displayed antagonistic effects against all bacteria, parsley/thyme EOs against B. cereus, S. aureus, P. aeruginosa, and E. coli, and lovage/basil EOs against B. cereus and E. coli. Combinations of parsley/lovage and parsley/basil EOs exhibited indifferent effects against all bacteria. The combination of lovage/basil EO showed indifferent effect against S. aureus, P. aeruginosa, and S. typhimurium, and the combination parsley/thyme EO against S. typhimurium. Thyme EO has the highest percentage yield and antibacterial potential from all tested formulations; its combination with parsley, lovage, and basil EOs determines a reduction of its antibacterial activity. Hence, it is recommended to be used alone as the antibacterial agent.

Characterisation of Hop Varieties Grown in Romania Based on their Contents of Bitter Acids by HPLC in Combination with Chemometrics Approach

Salanţă L.C., Tofană M., Socaci S., Mudura E., Fărcas A., Pop C., Pop A., Odagiu A. (2015): Characterisation of hop varieties grown in Romania based on their contents of bitter acids by HPLC in combination with chemometrics approach. Czech J. Food Sci., 33: 148–155. Reverse-phase high performance liquid chromatography technique was used for studying the evolution of bitter acids from three varieties of hop growing in Romania during the development of hop cones and the pelletisation process in order to provide the information on the bitter acids profile of each cultivar. Chemometrics methods were applied for highlighting the statistical correlations existing between the genotype (variety), chemotype (composition), and phenotype (phenophase of cone development) with respect to the classes of biologically active compounds investigated (bitter acids). The bitter acid content of each hop cultivar was not only significantly dependent on the phenophases of the cones, but was also influenced by the harvest year. The variations in the α/β ratio as well as cohumulone and colupulone contents were low in both experimental years and the cohumulone/∑α did fraction not exceed 30% in any of the three varieties.

Determination of Volatiles in Hops from Romania by Solid Phase Fiber Microextraction and Gas Chromatography–Mass Spectrometry

ABSTRACT The main objective of this study was to evaluate the variability of the essential oils of hops harvested in two consecutive years using in-tube extraction with gas chromatography–mass spectrometry. The second objective was to assess the possibility of using the volatile profile to characterize and discriminate hop cultivars based on a chemometric approach. Three hop varieties from Transylvania, Romania were studied. Principal component analysis and cluster analysis were used to differentiate hop varieties and to identify discriminant varietal markers. Forty-nine volatiles were separated from hop cultivars, with forty-seven identified. The main components of hop essential oils included monoterpenes (β-myrcene) and sesquiterpenes (β-caryophyllene and α-humulene). The results indicated that even though the composition of hop essential oil may be influenced by environmental factors, volatile profiles may be employed to identify cultivars.

Characterization of pine bud syrup and its effect on physicochemical and sensory properties of kefir

This study aimed to develop a value-added kefir by the addition of pine bud syrup. For this purpose, different concentrations of pine bud syrup [2, 4, 6, 8, and 10% (w/w)] were added to kefir formulation after the fermentation. The pine bud syrup used for kefir fortification is rich in polyphenols and terpenes and has a high antioxidant activity. The study was designed to evaluate the influence of pine bud syrup on the physicochemical and sensory properties of kefir. The addition of pine bud syrup resulted in an increase in total solids and a decrease in fat content, proteins, and pH. The kefir sample with 10% pine bud syrup was the most appreciated by sensory panelists. Its overall acceptability score was higher (6.71 points) than regular kefir (5.57 points). The addition of 10% pine bud syrup improved the texture and consistency of regular kefir.

Synthesis, lipophilicity and antimicrobial activity evaluation of some new thiazolyl-oxadiazolines

Background and aims Synthesis of new potential antimicrobial agents and evaluation of their lipophilicity. Methods Ten new thiazolyl-oxadiazoline derivatives were synthesized and their structures were validated by 1H-NMR and mass spectrometry. The lipophilicity of the compounds was evaluated using the principal component analysis (PCA) method. The necessary data for applying this method were obtained by reverse-phase thin-layer chromatography (RP-TLC). The antimicrobial activities were tested in vitro against four bacterial strains and one fungal strain. Results The lipophilicity varied with the structure but could not be correlated with the antimicrobial activity, since this was modest. Conclusions We have synthesized ten new heterocyclic compounds. After their physical and chemical characterization, we determined their lipophilicity and screened their antimicrobial activity.

Risk Factors Associated with Alcohol Consumption Among Romanian University Students- Preliminary Research

Young people’s consumption of alcohol is an ongoing problem. Many young adults binge-drink alcohol excessively, with serious negative consequences thereafter. This preliminary research assessed risk factors associated with alcohol consumption, drinking problems and related consequences among university students. The study was carried out on a total of 1056 students from UASVM Cluj-Napoca, Romania. University students claimed altered states of health after drinking episodes: vomiting, abdominal pain, headache, dizziness (43.1%), forgetfulness after drinking (3.1%). Furthermore, students who drank over the limit reported physical and violence-related problems (2.7%) and were more likely to develop risky behaviors, like driving under the influence of alcohol (13.9%) or car accidents (0.2%). The participants in the study were not heavy social drinkers, 50.9% of the respondents reported no consequences after drinking alcohol.

The Evaluation of the Sensory and Microbiological Properties of the Yogurt Supplemented with Achillea melifolium and Solanum muricatum

This research explored the sensory characteristics and consumer acceptance of novel yogurt. The study aimed to develop a new type of yogurt through addition of microcapsules with Achillea melifolium infusion and jelly from the pepino fruit. The effect of yogurt supplementation with four different levels (0%,1%,3%,5%) of microcapsules with Achillea melifolium infusion (MI) and four levels (0%,3%,7%,11%) of pepino juice jelly (PJ) on sensory properties and the viability of lactic acid bacteria in yogurts during storage (21 days) at 4°C was evaluated. The yogurt supplementation with 3% microcapsules and 7% jelly significantly improves the stability of the lactic acid bacteria, that contained the recommended levels of 108 cfu/g lactic acid bacteria at the end of 21-days shelf life. All the yogurt samples, however, contained the recommended levels of (106–107 cfu/g) lactic acid bacteria at the end of 21-day shelf life.The yogurt with 3% microcapsules and 7% jelly was the most appreciated (6.78 points), followed by the classic yogurt (5.98 points). Total phenols content was 251 mg GAE/g for A. millefolium infusion and 117 mg GAE/g for pepino juice. The radical scavenging activity of A. millefolium infusion was 78% and for pepino extract 56.30%.