Influence of Different Modalities of Grape Withering on Volatile Compounds of Young and Aged Corvina Wines.

Withering is a practice traditionally used in various regions to produce sweet or dry wines. During withering there is an increase in sugar content but also a modification in volatile compound profiles. Controlling metabolic changes through the dehydration process to obtain wines with desired characteristics is therefore a challenging opportunity. The effects of two different withering technologies, post-harvest or on-vine with blocked sap vessel flow, on the volatile profile of young and aged Corvina red wines was investigated. The results showed that modulation of wine aroma due to the withering process is associated with fermentative metabolites, such as esters, higher alcohols, and acids, as well as grape-related compounds such as C6 alcohols, terpenes and norisoprenoids. Significant differences were also found by comparing the two withering techniques. Post-harvest in a traditional "fruttaio" warehouse wines showed higher content of ethyl acetate, ethyl butanoate, ß-citronellol and 3-oxo-α-ionol, whereas post-harvest withering on-vine increased ß-damascenone in wines. The type of withering technique has an influence on the evolution of some aroma compounds during the aging of wine, among them linalool, (E)-1-(2,3,6-trimethylphenyl)buta-1,3-diene (TPB), n-hexyl acetate, ethyl acetate, ethyl 3-methylbutanoate, 3-oxo-α-ionol and ß-damascenone.

Targeted delivery of photosensitizers: efficacy and selectivity issues revealed by multifunctional ORMOSIL nanovectors in cellular systems.

PEGylated and non-PEGylated ORMOSIL nanoparticles prepared by microemulsion condensation of vinyltriethoxy-silane (VTES) were investigated in detail for their micro-structure and ability to deliver photoactive agents. With respect to pure silica nanoparticles, organic modification substantially changes the microstructure and the surface properties. This in turn leads to a modulation of both the photophysical properties of embedded photosensitizers and the interaction of the nanoparticles with biological entities such as serum proteins. The flexibility of the synthetic procedure allows the rapid preparation and screening of multifunctional nanosystems for photodynamic therapy (PDT). Selective targeting of model cancer cells was tested by using folate, an integrin specific RGD peptide and anti-EGFR antibodies. Data suggest the interference of the stealth-conferring layer (PEG) with small targeting agents, but not with bulky antibodies. Moreover, we showed that selective photokilling of tumour cells may be limited even in the case of efficient targeting because of intrinsic transport limitations of active cellular uptake mechanisms or suboptimum localization.