A Mathematical Model to Evaluate the Kinetics of D-glucose and D-fructose Fermentations by Saccharomyces bayanus at Increasing Ethanol Concentration

In the cellar, slow and stuck fermentations occurring during winemaking are often successfully solved by the addition of yeast strains like Saccharomyces bayanus. The kinetic behaviour shown by S. bayanus during alcoholic fermentation was investigated using a mathematical model previously tested for S. cerevisiae, in order to show which of the six functional parameters of the model differed significantly with the yeast population. Although some parameters (hexose fractions converted to ethanol and glycerol) did not change, the kinetic constant related to the inactivation rate of the yeast population showed by S. cerevisiae assumed a value significantly higher (approximately 50-fold) than that observed for S. bayanus, while this latter population was ten times less affected by ethanol than S. cerevisiae. Although no remarkable differences could be found between the ability shown by the two yeast populations to convert hexoses (D-glucose and D-fructose), the tolerance for ethanol accumulation changed strongly. The conversion rate of these two hexoses by S. bayanus was affected less (about ten thousand-fold) by ethanol than that of S. cerevisiae

Nutraceutical Oils Produced by Olives and Citrus Peel of Tuscany Varieties as Sources of Functional Ingredients

The essential oils extracted from the peels of two Tuscany Citrus of the Massa province have been characterised. Moreover, the flavedo of these species has been used in the production of two Citrus olive oils (COOs) obtained with an innovative method in which the citrus peels are cryomacerated and then pressed with the olives. The presence of functional compounds, such as carotenoids, naringenin and minor phenolics, classifies these COOs as nutraceuticals with the potential to develop enriched foods able to promote a healthy diet. Moreover, the increased presence of tyrosol and hydroxytyrosol, compared to the unflavoured oil, further highlights the nutritional value to the two COOs, being these phenolic compounds recognized as good possible therapeutic candidates for the inhibition of neurodegenerative diseases as the Parkinson's disease. In this perspective, the citrus peels, rich in bioactive compounds, have been valued transforming their waste nature in an innovative resource

The effects of packaging and storage temperature on the shelf-life of extra virgin olive oil

This research aimed to study the effects of packaging and storage temperature on the shelf-life of an extra virgin olive oil (EVOO) as it can occur in most points of sale. The evolution of the chemical and sensory characteristics of an EVOO, initially stored in stainless steel silos under nitrogen at 12–18 °C, was evaluated after packaging. Tinplate tin (TT) and greenish glass (GG), the most used packaging containers, and temperatures of 6 and 26 °C were taken into consideration. After 125 days from packaging all the samples maintained clearness, green and yellow reflections and the positive sensory notes of bitterness and pungency of the starting EVOO. Shelf-life of EVOO was significantly affected by different storage conditions: oil samples stored in GG at 6 °C preserved for the most part the positive attributes, whereas those stored in TT at 26 °C showed a significant presence of the rancid flavor due to oxidative processes. Moreover, samples stored in GG at 6 °C maintained the highest bitterness intensity and did not show defects at the end of the storage period. The results suggest that storage in GG at a low temperature could represent a promising storage condition to slow-down the oil degradation during market storage

Metabolismo degli acidi grassi

Il volume, promosso dalla Società Italiana di Chimica Agraria, rappresenta l’opportunità di offrire agli studenti, in particolare dei corsi di studio triennali dell’area agraria e forestale, uno strumento didattico capace di fornire le basi necessarie per la comprensione delle trasformazioni biochimiche che la materia subisce all’interno degli organismi viventi, delle relazioni tra queste trasformazioni e gli aspetti quali-quantitativi e tecnologici delle produzioni agrarie. Le trasformazioni biochimiche: la catalisi enzimatica - vista d’insieme del metabolismo cellulare - le membrane biologiche e il trasporto di soluti - il metabolismo glucidico: i carboidrati - la glicolisi - il ciclo di Krebs e la fosforilazione ossidativa - la fotosintesi: la conversione dell’energia luminosa in energia chimica - utilizzo dell’energia e biosintesi dei carboidrati - il metabolismo lipidico: i lipidi - metabolismo degli acidi grassi - il metabolismo azotato: acquisizione e assimilazione dell’azoto - i nucleotidi e gli acidi nucleici: aspetti strutturali e funzionali degli acidi nucleici - la sintesi delle proteine - I metaboliti secondari delle piante: ruolo dei metaboliti secondari nelle piante - la nutrizione minerale delle piante e i rapporti con il suolo: i principi della nutrizione delle piante e il sistema suolo-pianta - indice analitico

Reactive Oxygen Species and Photosynthetic Functioning: Past and Present

The present chapter begins by presenting the basic introduction to Reactive Oxygen Species (ROS), then detailng the current knowledge in ROS research. In particular, Electron Paramagnetic Resonance (EPR) technique applicability in photosynthesis research was considered. Kinetics of superoxide formation by illuminated thylakoids was shown. The progress of the knowledge on the different sites of photosynthetic membranes involved in ROS formation was reported and the main defense mechanisms occurring in the chloroplast to detoxify from ROS were decribed

Chelate-assisted phytoextraction of Cd by Brassica juncea: the role of phenolic acids in metal tolerance

14th FESPB Congres

Impact of leaf removal on phenolics and antioxidant activity of Trebbiano berries (Vitis vinifera L.)

Leaf removal is a canopy management practice widely applied in viticulture to enhance the phenol composition and concentration of grapes, which then results in improved wine quality. Many studies were carried out on red berried varieties, but information on white ones is scanty. The aim of the study was to assess the effect of basal leaf defoliation in post fruit set on the phenol composition, ascorbate level and antioxidant activity of Trebbiano grapes. Electron paramagnetic resonance was also employed to monitor the decay kinetics of 1,1-diphenyl-2-picrylhydrazyl which allowed the identification of antioxidants with different action rates. The results show that defoliation caused an increase in the phenolic acid (hydroxycinnamic and hydroxybenzoic acids) and flavonol concentrations of berries without changes in the composition. Both ascorbate and antioxidant activity were also enhanced in the berries from defoliated vines. Besides increasing the number of fast-rate antioxidants, leaf removal resulted in the formation of intermediate-rate ones. In the Trebbiano variety, leaf removal in the post fruit set may represent an effective strategy to enhance the phenolic composition and the antioxidant defense system of berries

I lipidi

Il volume, promosso dalla Società Italiana di Chimica Agraria, rappresenta l’opportunità di offrire agli studenti, in particolare dei corsi di studio triennali dell’area agraria e forestale, uno strumento didattico capace di fornire le basi necessarie per la comprensione delle trasformazioni biochimiche che la materia subisce all’interno degli organismi viventi, delle relazioni tra queste trasformazioni e gli aspetti quali-quantitativi e tecnologici delle produzioni agrarie. Le trasformazioni biochimiche: la catalisi enzimatica - vista d’insieme del metabolismo cellulare - le membrane biologiche e il trasporto di soluti - il metabolismo glucidico: i carboidrati - la glicolisi - il ciclo di Krebs e la fosforilazione ossidativa - la fotosintesi: la conversione dell’energia luminosa in energia chimica - utilizzo dell’energia e biosintesi dei carboidrati - il metabolismo lipidico: i lipidi - metabolismo degli acidi grassi - il metabolismo azotato: acquisizione e assimilazione dell’azoto - i nucleotidi e gli acidi nucleici: aspetti strutturali e funzionali degli acidi nucleici - la sintesi delle proteine - I metaboliti secondari delle piante: ruolo dei metaboliti secondari nelle piante - la nutrizione minerale delle piante e i rapporti con il suolo: i principi della nutrizione delle piante e il sistema suolo-pianta - indice analitico