Gavina Manca

Analytical Characterisation of Myrtle Berries, partially Processed Products ans Commercially Available Liqueurs.

Characterisation of the chemical and technological variables of the liqueur “Mirto di Sardegna Tradizionale” revealed the complexity of the product. The study concerned the berries, the partially processed product and the commercially available liqueur. The following parameters were analysed: alcohol content, net dry matter, total sugars, reducing sugars, total acidity, ash, total polyphenols, vanillin index, proanthocyanidins, free anthocyanins, flavonols, organic acids, cations, anions, myo-inositol, volatile compounds, the 13 C/ 12 C isotopic ratio in some constituents, amino acids and total nitrogen. Particular attention was paid to: method of extraction of the main components of the raw material (berries gathered exclusively from plants growing wild in Sardinia), depending on the different technical procedures employed by the most important distillers in Sardinia; chemical changes brought about by the preliminary stages such as dilution to reach the desired alcohol content, filtration, addition of sugar; characterisation of the finished product and differences in composition compared with other products made from aromatic compounds with the possible addition of other substances. The results of the study were used to draw up a set of production regulations to safeguard the authenticity of this typical traditional Sardinian product, with proposals for a series of indicators to be used in routinary or detailed inspections.

Comparison of γ-Aminobutyric Acid and Biogenic Amine Content of Different types of Ewe's Milk Cheese Produced in Sardinia, Italy.

The bioactive compounds γ-aminobutyric acid (GABA) and biogenic amines (BA), together with protein-free amino acids, were measured by high-performance liquid chromatography in ewe’s milk cheeses produced in Sardinia with different technological traits. The study included three types of cheese: Pecorino Sardo PDO, Pecorino and Casu Marzu. Farmhouse Casu Marzu and Pecorino showed GABA content (maximum levels: 1001.3 and 378.1 mg 100 g–1 respectively) that had never been found so high in cheese before, suggesting that these types of cheese present ideal conditions to produce GABA. These two types of cheese also showed high levels of BA (their total maximum levels were 1035.7 and 288.0 mg 100 g–1 respectively). Pearson correlation analysis detected significant correlation between GABA and the main BA present in the cheeses (tyramine, cadaverine and putrescine), suggesting that the factors affecting the production of GABA are the same as those influencing BA formation.

Level of «cis-» and «trans-» resveratrol and their glucosides as a function of different cultivar of red wines

Variability of trans - and cis -resveratrol and their glucosides in red wines, coming from 13 different species of vine grown on two parallel plots of land, different for pedo-climatic conditions, during three different vintages, was determined by HPLC. The data obtained were elaborated by multivariate statistical analyses (Principal Component Analysis and Discriminant Analysis). The results showed that trans - and cis -resveratrol are more correlated than transand cis -glucoside, due to the uniformity of vinification treatments. Furthermore, Principal Component Analysis pointed out a good separation among five types of wine (Pinot noir, Malbeck, Gaglioppo, Refosco and Ciliegiolo), coming from the same cultivars, which are also discriminated in the Discriminant Analysis as a function of resveratrol content. This would underline that the cultivar variable, almost for the five above mentioned cultivars, has a higher influence than the other factors in wine characterisation with respect to their content of resveratrol.

Variability of trans and cis resveratrol and their glucosides in red wines produced in Sardinia and Corsica.

Variability of trans - and cis -resveratrol and their glucosides in red wines produced in Sardinia and Corsica was determined by HPLC. The data obtained were elaborated by multivariate statistical analysis (Principal Component Analysis). The results showed a higher average total stilbene content in Corsican samples than in Sardinian samples, due to the aglycons content. Furthermore, PCA pointed out a good separation between the two groups which seems to be related to the samples origin. Lastly, the Cagnulari, which is a particular Sardinian cultivar, showed high values of total stilbenes, related to the glucoside content, as did three Corsican samples.

Effects of Some Yeast on Resveratrol Content During Alcoholic Fermentation

The variability of the content of four monomeric forms of resveratrol (3, 5,4’-trihydroxystilbene): trans and cis -resveratrol, , trans and cis -β-Dglucopyranoside in musts of Cagnulari grapes grown in northwest Sardinia, using different strains of the yeast Saccharomyces cerevisiae , was determined by HPLC at different stages of vinification. The first sample was taken after three days, the second 10 days after inoculation of the yeasts and the third after the samples had been stored for two months at 10°C. The data were elaborated by multivariate statistical analysis, considering the variability of the concentrations of the four stilbene forms at different times. The results showed that from the beginning of sampling the form of resveratrol present in the highest amounts was the glucosylated form, but this had already decreased significantly in the second sample. The decrease in the glucosylated forms was not, however, accompanied by a proportional increase in the free forms. In addition, some yeast strains were identified that do not substantially change the total content of the four monomeric forms of resveratol.

Content of Resveratrols as a Function of Red Wine Cultivar and of the Year Production (2000-2001-2002)

As a continuation of a previous research project, the variability of trans - and cis -resveratrol and their glucosides in red wines, from 14 different species of vine, was determined. The wine came from grapes grown on two plots of land at two separate locations differing in pedo-climatic conditions. The content of total resveratrol is between 1.55 and 16.76 mg/L with an average value of 6.71 mg/L. Moreover the results showed that trans - and cis -resveratrol are more correlated (r = 0.83) than trans - and cis -glucoside (r = 0.72), due to the uniformity of vinification treatments. The species of vine, having a higher mean content of total resveratrol, are: Refosco, Pinot Nero, Ciliegiolo, Montepulciano e Gaglioppo. The data, elaborated by multivariate statistical analyses (Principal Component Analysis and Discriminant Analysis), pointed out a good separation between the three vintages as a function of resveratrol content.

Energy as a determining variable in the production of goods in Sardinia

The evolutionary phase of advanced economic systems is characterised by the progressive substitution of material inputs, including energy, by immaterial inputs. Among these the availability and adaptability of technological innovation, services and the information transfer technology are of particular importance. Innovation processes and technological transformation are among the factors that dominate the evolution of industrial energy consumption. These require programming and continuity in the economic system. The relationship between output and the elements that make up input allow the construction of indices which can accurately describe static and dynamic phenomena of the particular economic system.

The Role of the Free Amino Acids Profile in Characterising "Pecorino Sardo" Cheese

In this paper the results of the analysis by HPLC of the free amino acids content of 40 samples of “Pecorino Sardo” cheese at different stages of maturity, taken from 18 Sardinian cheese factories are presented. Statistical analysis was used to identify the free amino acids and the ratios between them which best correlated to ripening stages of the cheese, with the aim of establishing a predictive model of its age. Among the amino acids analysed, the regression line based on the valine content was best able to describe the stage of ripening of the cheese. In addition an attempt was made to discover which of the variables examined was capable of describing the particular characteristics of this cheese.