Tommaso Ugolini

Olive tree leaf is a phenol-rich, high-potential-value biomass that can be used to formulate food additives and supplements. Leaf phenolic content varies depending on numerous factors, like cultivar, geographical origin, year, and season of harvest. The aim of this research was to evaluate the variations in phenolic profile of four major Tuscan cultivars (Frantoio, Leccio del Corno, Leccino, and Moraiolo) over four different phenological phases and across two years. All 96 olive leaf samples were harvested from trees grown in the same orchard located in Florence. After drying, their phenolic profile was characterized using HPLC-DAD-MS, and the obtained data were processed by ANOVA, GA-LDA, and RF methods. A total of 25 phenolic derivatives were analyzed, with total contents ranging 16,674.0–50,594.3 mg/kg and oleuropein (4570.0–27,547.7 mg/kg) being the predominant compound regardless of cultivar, year, and season of harvest. Oleuropein and hydroxytyrosol glucoside showed inverse proportionality and similar behavior across years in all cultivars, and therefore were highlighted as main phenolic compounds correlated with the seasonal variability in studied cultivars. Interesting behavior was also pointed out for apigenin rutinoside. Application of GA-LDA and RF methods allowed pointing out the excellent performance of leaf phenols in discriminating samples based on cultivar, harvest year, and harvesting season.

Consumers are increasingly willing to pay a premium for high-quality extra virgin olive oils (HQ-EVOOs) with specific sensory or nutraceutical properties, and originating from particular botanical or geographical origins. Regarding geographic origin, Italy is one of the main producers, with many local production areas, each characterized by its own distinctive typicity. The aim of this study is the chemical, sensory, and nutraceutical profiling of HQ-EVOO produced over two production years in Montespertoli (province of Florence) by 12 producers involved in the “MontEspertOlio” project, funded by the Tuscan Region. Oils were produced based on a production process previously defined and specifically applied to this territory. The shelf-life of the oil was also evaluated over a 12-month period. Legal quality parameters were analyzed according to EU regulation. Phenolic compounds, tocopherols, fatty acid composition, and volatile compounds were analyzed using HPLC-DAD, HPLC-FLD, HS-SPME-GC-MS, and GC-FID, respectively. Finally, sensory analysis was conducted using the Panel Test method. Results showed that Montespertoli HQ-EVOO is characterized by distinctive sensory and chemical traits that fully match consumer preferences, even across two production years characterized by different growing conditions. The shelf-life performance was excellent over 12 months, also showing a protective effect of greater bottle sizes against oxidation.

Several chemical analytical methods were applied to characterize the chemical structure of polysaccharides extracted from discarded apples and pomegranate peels using hydrodynamic cavitation methods in a circular economy perspective. In particular, the purity of the polysaccharides and the degrees of acetylation and methylation were evaluated by proton Nuclear Magnetic Resonance (¹H-NMR) analysis; simple sugars and galacturonic acid were analyzed simultaneously by High-Performance Anion Exchange Chromatography—Pulsed Amperometric Detector (HPAEC-PAD); the molecular weight of the extracted polysaccharides was determined by High-Performance Size Exclusion Chromatography-Refractive Index Detector (HPSEC-RID). The results showed a negligible presence of co-precipitated proteins/tannins, easily removed by dialysis, as well as other co-precipitated molecules such as monosaccharides and organic acids. Polysaccharides from apples consisted mainly of pectic material with a prevalence of homogalacturonans. Polysaccharides from pomegranate peels showed greater compositional variability with significant amounts of arabinose and galactose, a lower content of pectin, and the presence of rhamnogalacturonans I. Both polysaccharides were highly methylated and differed in the degree of acetylation, which could lead to different properties. Polysaccharides from apples presented two main molecular weights (>805 kDa and 348–805 kDa, respectively), while those from pomegranate peel showed a major fraction at 348 kDa and minor fractions < 23 kDa. In conclusion, the research tools proposed by this study have allowed defining the macrostructure of polysaccharides in a quick and efficient way to valorize these food by-products.