Mara Rossoni

Proteome changes in the skin of the grape cultivar Barbera among different stages of ripening

BackgroundGrape ripening represents the third phase of the double sigmoidal curve of berry development and is characterized by deep changes in the organoleptic characteristics. In this process, the skin plays a central role in the synthesis of many compounds of interest (e.g. anthocyanins and aroma volatiles) and represents a fundamental protective barrier against damage by physical injuries and pathogen attacks. In order to improve the knowledge on the role of this tissue during ripening, changes in the protein expression in the skin of the red cultivar Barbera at five different stages from véraison to full maturation were studied by performing a comparative 2-DE analysis.ResultsThe proteomic analysis revealed that 80 spots were differentially expressed throughout berry ripening. Applying a two-way hierarchical clustering analysis to these variations, a clear difference between the first two samplings (up to 14 days after véraison) and the following three (from 28 to 49 days after véraison) emerged, thus suggesting that the most relevant changes in protein expression occurred in the first weeks of ripening. By means of LC-ESI-MS/MS analysis, 69 proteins were characterized. Many of these variations were related to proteins involved in responses to stress (38%), glycolysis and gluconeogenesis (13%), C-compounds and carbohydrate metabolism (13%) and amino acid metabolism (10%).ConclusionThese results give new insights to the skin proteome evolution during ripening, thus underlining some interesting traits of this tissue. In this view, we observed the ripening-related induction of many enzymes involved in primary metabolism, including those of the last five steps of the glycolytic pathway, which had been described as down-regulated in previous studies performed on whole fruit. Moreover, these data emphasize the relevance of this tissue as a physical barrier exerting an important part in berry protection. In fact, the level of many proteins involved in (a)biotic stress responses remarkably changed through the five stages taken into consideration, thus suggesting that their expression may be developmentally regulated.

An integrated biorefinery concept for olive mill waste management: supercritical CO2 extraction and energy recovery

Commercial production of olive oil generates four times the amount of waste as it does oil, along with a number of environmental issues. We propose an integrated biorefinery concept for the management of pomace, i.e. solid Olive Mill Waste (OMW), that utilizes supercritical carbon dioxide (SCO2), coupled with a polar co-solvent (Ethanol), for extracting value-added polyphenols and mono/poly-unsaturated fatty acids (MUFA/PUFA), followed by thermochemical (oxidation or pyrolysis) recovery of energy, biofuels and materials. The SCO2 + EtOH extraction recovered 77.6 g of freeze-dried extract per kg of raw OMW, with relatively high concentrations in polyphenols (10.9 g kg−1 of which 60.1% of di-hydroxytyrosol), PUFA (20 g kg−1), MUFA (601 g kg−1) and other valuable compounds, such as squalene (10 g kg−1). All these substances are of extreme interest in pharmaceutical and nutraceutical market, for their antioxidant, anti-cancer, functional, anti-bacterial and nutritional properties. The SCO2 + EtOH flux acted as physical/chemical carrier for over 85% of humidity, leaving the exhaust OMW almost dry, with evident advantages for downstream. Using nonisothermal thermogravimetric analysis, the apparent activation energies required to pyrolyze OMW to produce fuel and biochar ranged from 20 to 140 kJ mol−1 depending on heating ramp rate and temperature regime. BET analysis of unactivated biochars show increased (+25%) mesopore surface areas after SCO2 extractions (up to 500 m2 g−1). A more in-depth view on the proposed biorefinery is needed, to consider the overall energy balance, as well as possible market values of the obtained extract, and evaluate the real feasibility of the proposed concept.

Study of intra-varietal diversity in biotypes of Aglianico and Muscat of Alexandria (Vitis vinifera L.) cultivars

Background and Aims Somatic mutations are the major source of intra-varietal variability in some species such as grapevine (Vitis vinifera L.) that are propagated vegetatively. Aglianico and Muscat of Alexandria are two cultivars mostly cultivated in the south of Italy, showing great intra-varietal diversity. The variability of 15 clones of Aglianico belonging to three biotypes, Taburno, Taurasi and Vulture, and 21 clones of Muscat of Alexandria, coming from France, Greece, Italy and Spain, was investigated. Methods and Results The intra-varietal diversity was investigated by ampelographic and eno-carpological (berry characteristics of oenological interest) methods (nine OIV descriptors, related to bunch and berry morphology, sugar content, total acid content and pH of must), chemical (anthocyanins, aromatic compounds and phenolic substances) and genetic analysis [18 K SNPs, single nucleotide polymorphisms (SNP)]. Intra-varietal diversity has been detected in both cultivars, mainly based on differences in the accumulation of secondary metabolites. The Taurasi biotype was discriminated by linear discrimination analysis mainly for the proportion of malvidin-3-O-glucoside acetate and methoxylated anthocyanins, while the Spanish Muscat biotype was discriminated based on the proportion of flavanols and hydroxycinnamic acids. Conclusions Ampelography and the concentration of secondary metabolites have proved to be the best tools for the characterisation of the intra-varietal variability of grapevine germplasm. The high-throughput genetic analysis based on 18 K SNP loci did not highlight a polymorphism sufficient to distinguish among biotypes of the same cultivar, suggesting that a different molecular approach has to be adopted. Significance of the Study This study confirms that intra-varietal diversity is better examined with a multidisciplinary approach.