Ettore Barone

Candida zemplinina for production of wines with less alcohol and more glycerol

We developed a new protocol for winery mixed fermentations, using the selected Candida zemplinina yeast strain Cz3. The results of a two-year study, in which red musts (Merlot in 2010; Merlot, Nero d’Avola and Frappato in 2011) were inoculated with Cz3, is discussed. These wines were compared with wines obtained by inoculation with commercial Saccharomyces cerevisiae yeast strains (NDA21 and AR06 in 2010; NDA21 in 2011), or with those obtained by spontaneous fermentation (only in 2011). The inoculation of Cz3 always resulted in a two-phase fermentation: the first phase was driven by the C. zemplinina strain, while the second was dominated by the indigenous S. cerevisiae yeasts coming from the grapes and/or the winery. In both years the Cz3 wines contained less alcohol and more glycerol than those made with the commercial yeast strains or those obtained by spontaneous fermentation. Triangle tests showed that a sensorial difference between wines could only be achieved through the utilisation of Cz3.

Toward the definition of a carbon budget model: seasonal variation and temperature effect on respiration rate of vegetative and reproductive organs of pistachio trees (Pistacia vera)

This study, as a preliminary step toward the definition of a carbon budget model for pistachio trees (Pistacia vera L.), aimed at estimating and evaluating the dynamics of respiration of vegetative and reproductive organs of pistachio tree. Trials were performed in 2005 in a commercial orchard located in Sicily (370 m a.s.l.) on five bearing 20-year-old pistachio trees of cv. Bianca grafted onto Pistachio terebinthus L. Growth analyses and respiration measurements were done on vegetative (leaf) and reproductive (infructescence) organs during the entire growing season (April-September) at biweekly intervals. Results suggested that the respiration rates of pistachio reproductive and vegetative organs were related to their developmental stage. Both for leaf and for infructescence, the highest values were observed during the earlier stages of growth corresponding to the phases of most intense organ growth. The sensitivity of respiration activity to temperature changes, measured by Q(10), showed an increase throughout the transition from immature to mature leaves, as well as during fruit development. The data collected were also used to estimate the seasonal carbon loss by respiration activity for a single leaf and a single infructescence. The amount of carbon lost by respiration was affected by short-term temperature patterns, organ developmental stage and tissue function.

Isolation, identification and oenological characterization of non-Saccharomyces yeasts in a Mediterranean island

We isolated, identified and characterized yeast strains from grapes, and their fermented musts, sampled in the small island of Linosa, where there are no wineries and therefore the possibility of territory contamination by industrial strains is minimal. By traditional culture‐dependent methods, we isolated 3805 colonies, distinguished by molecular methods in 17 different species. Five hundred and forty‐four isolates were analysed for the main oenological characteristics such as fermentative vigour with and without sulphites, sugar consumption and production of alcohol, volatile acidity, hydrogen sulphide, glycerol and β‐glucosidase. This analysis identified Kluyveromyces marxianus (seldomly used in winemaking) as the most interesting candidate yeast for the production of innovative wines.

Seasonal effects on mortality rates and resprouting of stems treated with glyphosate in the invasive tree of heaven (Ailanthus altissima (Mill.) Swingle)

Tree of heaven (Ailanthus altissima) is regarded as invasive within urban and natural areas worldwide. Efficient methods to control it are significantly needed if we are to limit its well-known environmental and economic impacts. Up to now the use of herbicides has proven necessary since following mechanical damage, Ailanthus vigorously resprouts. However, the seasonal response of Ailanthus stems, treated with herbicides, has never been assessed. We compared the control efficacy recorded in autumn, winter and summer in an abandoned suburban citrus grove in Sicily, under Mediterranean-climate conditions. Glyphosate was injected within drill holes made in knee-high cut trees. Tree mortality and the resprouting ability of treated stems were significantly affected by the application timing and by diameter class of stems. Mortality was significantly lower in winter treatments within the smaller diameter class. Within the larger diameter class, only autumn treatments showed a notably higher mortality rate and a significantly lower growth of sprouts. Hence, autumn interventions are strongly recommended to effectively treat Ailanthus. Mortality was notably higher in the smaller diameter class. Our results confirm the importance of early intervention to control Ailanthus, also showing that the choice of the season is crucial to obtaining satisfactory control of its resprouting ability.