Studii privind viabilitatea şi capacitatea de germinare a polenului unor soiuri Vitis vinifera L.

Pollen quality is an important indicator in the estimation of grape production, being analysed based on its germination capacity. Thus, viability and germination potential of pollen from six Vitisvinifera L. varieties, grownin the climatic area of the Iasi vineyard,were analysed. To perform the determinations, were used comparatively three methods for observingthe viable cells, by treating them with tetrazolium chloride (TTC), Lugol solution (IKI) and methylene blue (AM) solution. The germinating potential was analysed in vitro, the culture being performed on agar medium with added sucrose (0 to 20%). The viable cells weremore clearly highlighted using the AM method, but the TTC method was more accurate in indicating the percentage of pollen viability. The highest pollen germination rate was observed in the 15% added sucrose variant

Analiza activităţii fotosintetice şi transpiraţiei la pomii de păr în dependenţă de acţiunea substanţelor biologic active

Research to elucidate the effectiveness of photosynthesis and transpiration intensity in depending on the donor –acceptor process in pear plants has been carried out. The obtained results have shown that the physiological state of the plants during the active of the vegetation period can be characterized depending on the season and the specificity of the vegetation period performance in dynamic of the photosynthesis efficacy and transpiration activity . It has been established that in the spring, during the vegetation period, the pear trees with the increase of the intensity of the photosynthesis and transpiration activity

Activitatea antimicrobiană a unui bioprodus biologic activ obţinut din seminţele de struguri

At the Research Station for Viticulture and Enology Iasi, a polymeric condensed proanthocyanidins was obtained from Fetească neagră grape seeds, through a phase preparation, which under determined conditions with hydrogen peroxide, led to the production of a water-soluble bio product with antibacterial, antifungal and antioxidant properties. Evaluation of the antimicrobial activity of the bio product was performed by determining minimum inhibitory concentration (MIC) and minimal bactericidal concentration (CMB) against Staphylococcus aureus and Escherichia coli. From the analysis of the obtained data it was found that the bio product reacted differently from the tested species, being more active against Staphylococcus aureus (G +). The determined MIC was 1.5 mg/mL and the CMB 2.0 mg / mL. In the case of the Escherichia coli (G-) test, the MIC and CMB values were equal but increased to 3.0 mg/mL

Valorificarea reziduului vegetal de seminţe de struguri rezultat din procesele extractive ale compuşilor fenolici

The stepwise extraction process of phenolic compounds from grape seeds ultimately leads to the production of a residue rich in protein, cellulose and substances without nitrogen which can be biodegraded in nature by microorganisms from the soil. The purpose of this research was to verify whether the vegetable residue of grape seeds, resulting from the extraction of polymerized proanthocyanidins can be used as an organic fertilizer in the soil. The soil biodegradation process was assessed by microbiological analysis and analysis of current and potential dehydrogenase activity. The results obtained showed that the vegetal residue led to the increaseof the number of soil microorganisms involved in the nitrogen circuit and carbon, as a result of the triggering of the biodegradation process as well as its non-polluting effect supported by current and potential dehydrogenase activity determined in dynamicsover a year in experimental plots

Assessment of the technological performance of some Saccharomyces and non-Saccharomyces indigenous yeast strains

The study aimed to assess the technological potential of four indigenous Saccharomyces cerevisiae strains (S. cer. 4.1.11, S. cer. 4.3, S. cer. 4.6 and S. cer. 4.10), as possible sources for starter cultures. The experiments were carried out at micropilot level on the natural must of 'Fetească albă' cultivar. The evaluation of the yeasts was carried out according to the chemical parameters and volatile compounds analysed in the obtained wines compared to the wine obtained with a commercial starter culture (CSC). The values of the main physico-chemical parameters analyzed in the obtained wines were similar to those determined in the control wine. The average values of the volatile compounds with positive impact on the wine aroma ranged within the interval 177.46 - 217.81 mg/L, a higher value compared to the control wine, respectively 166.33 mg/L. The use of the indigenous strain Torulospora delbrueckii (T.d 10) in association with the strains S. cer. 4.1.11 or S. cer. 4.10 led to an increase of 12.56%, respectively 8.30% in glycerol concentrations, as well as an increase of 11.94% to 14.49% in the average concentration of volatile compounds. Harnessing the oenological potential of the yeasts tested in sequential fermentations proved dependent on the time allowed for the development of the strain T.d 10, namely 24 and 48 hours, as well as on the yeasts used. Thus, in the wines obtained by the association T.d 10/ S. cer. 4.10, in which the development of the culture T.d 10 was carried out for 48 hours, we noticed an increase of 12.52% and, respectively 32.95%, in the average of volatile compounds, compared to the monoculture wine for the same S. cer. 4.10 strain and to the control wine (CSC)

Separarea şi caracterizarea principalelor fracţiuni de proantocianidine din seminţele de struguri

Grape seeds, as waste products of the winemaking industry, contain large amounts of monomers, oligomers and more highly polymerised proanthocyanidins (PA), being a good source of phytochemicals for the production of antioxidative dietary supplements. PA from defatted grape seeds were extracted by precipitation with diethyl ether from the crude alcoholic extract and fractionated into monomers (FI), oligomers (FII) and polymers (FIII) of flavan-3-ols by their separation on C18 Sep-Pak cartridges. FIII was the predominant class of proanthocyanidins (82.22%), while monomeric PA has only 5.71% of total. The ratio PA (by vanillin assay) / tannins (Bate-Smith assay) indicates the highest degree of polymerisation (DP) in FIII fraction (1.28). Thin layer chromatography (TLC) confirmed the presence of monomers in FI, the DP increasing significantly for the next two fractions. Oligomeric and polymeric PA showed the highest antioxidant activity (% scavenged DPPH), but the synergic antioxidant effect of PA classes was also observed