A preliminary investigation on 20 Aglianico del Vulture commercial wines from the Basilicata region proved the existence of a significant variability in total antioxidant capacity which can exert a potential impact on wine quality. Nineteen Saccharomyces cerevisiae strains were tested in Aglianico del Vulture on pilot scale fermentation and the experimental wines obtained were evaluated for the antioxidant capacity, ethanol and total polyphenols. At the ninth day of fermentation the experimental wines had an antioxidant capacity, measured by photochemiluminescence, between 2.88 and 6.25 mM of ascorbic acid equivalent, ethanol concentration, measured by GC, between 5.49% and 10.99% and total polyphenols, determined by Folin Ciocalteau reagent, from 1153 to 1867 mg catechins/l. After 12 days the total antioxidant capacity was increased in most wines but decreased in some wines. These results, statistically analysed by principal component analysis, revealed a significant influence of S. cerevisiae strain on total antioxidant capacity and total polyphenols content of wine.

Among the non-Saccharomyces yeasts which dominate the early fermentation stages, Hanseniaspora uvarum represents the prevalent species, due to its wide diffusion on the grapes and in grape must just pressed. Few years ago strains of this species were considered as spoilage species exhibiting undesirable oenological traits, while recently numerous studies have demonstrated the existence of a significant biodiversity also in H. uvarum population for technological traits. During the last ten years numerous H. uvarum wild strains, isolated and identified at the species level by molecular techniques, have been included in the collection of Wine Microbiology Laboratory of Basilicata University. They have been analyzed to evaluate their genetic and technological variability. For the genetic characterization, the strains were submitted to RAPD-PCR analysis by using the primer P80 (5CGCGTGCCCA3) and M13 and the results obtained emphasized the existence of a significant genetic polymorphism among the strains. The H. uvarum strains were characterized for parameters of technological interest in oenology, such as the evaluation of enzymatic activities influencing wine quality (beta-glucosidase and beta-xylosidase activities), as well as for the capacity to form by-products, such as higher alcohols, acetic acid, acetaldehyde, acetoin, during grape must fermentation. The evaluation of technological parameters revealed the existence of a wide phenotypic biodiversity, correspondent to the genetic polymorphism.

Few studies have been performed on the characterization of yeasts involved in the production of agave distilled beverages and their individual fermentation properties. In this study, a comparison and evaluation of yeasts of different origins in the tequila and wine industries were carried out for technological traits. Fermentations were carried out in high (300 g l(-1)) and low (30 g l(-1)) sugar concentrations of Agave tequilana juice, in musts obtained from Fiano (white) and Aglianico (red) grapes and in YPD medium (with 270 g l(-1) of glucose added) as a control. Grape yeasts exhibited a reduced performance in high-sugar agave fermentation, while both agave and grape yeasts showed similar fermentation behaviour in grape musts. Production levels of volatile compounds by grape and agave yeasts differed in both fermentations.

In Mexico there are different alcoholic beverages produced from agave juices from different agave plants, which are cooked, fermented and distilled. For tequila production only Agave tequilana is allowed. In this study we compared yeast strains of different species from different origin (agave and grape juice) for parameters of technological interest, such as SO2 and copper resistance, ethanol tolerance and enzymatic activities. All agave strains were found to be more resistant to SO2 and agave non-Saccharomyces yeasts were more tolerant to ethanol, whereas grape strains exhibited positive results for β-glucosidase and β-xylosidase activities. As regards fermentations of Agave tequilana juice with ethanol added at different concentrations, only agave Saccharomyces strains were more tolerant to ethanol than grape strains.

Aims: The characterization by molecular and physiological methods of wild apiculate strains, isolated from 'Aglianico del Vulture' grape must.Methods and Results: The restriction analysis of 18S rDNA allowed the identification of strains at the species level, which were predominantly Hanseniaspora uvarum. The RAPD analysis and the evaluation of technological traits, such as the metabolic and enzymatic activities, were useful to evaluate the polymorphism of this species.Conclusions: The RAPD analysis clustered the wild H. uvarum strains in four main genetic groups and a very high phenotypic variability confirmed this genetic polymorphism. The technological variables, which determined the strain biodiversity differed significantly, demonstrating that these technological traits are strain dependent. A certain correlation was found between the strain behaviour and its isolation zone, indicating the influence of the environment on the genetic patrimony of the population.Significance and Impact of the Study: The genetic and technological biodiversity recorded among H. uvarum wild strains represents the basis for organizing a collection of apiculate strains exhibiting oenological characteristics at different levels, such as high/low production of secondary compounds, and, therefore, potentially useful for a selection programme.

In this study 80 wine strains of Saccharomyces cerevisiae were characterized for the production of acetic acid. A significant variability in the production levels was determined among the strains, which produced from a few mg/l to more than 1 g/l. Fifteen strains, differing in acetic acid production, were tested in fermentation of grape musts of different varieties (Aglianico Basilicata, Aglianico Apulia, Cannonau, Bombino nero, Nero d'Avola, Vermentino, Fiano). The results emphasized a great strain variability, but the best strain behaviour was strictly related to the must composition, which is a determinant factor on the expression of the best strain potentiality. Therefore, this study, confirming the high/low production of acetic acid as a strain characteristic, demonstrated also that the inoculated fermentation becomes more advantageous when the starter culture is chosen in relation to the interaction of yeast strain/vine variety.

The isomers of 2,3-butanediol [R,R; S,S; R,S (meso-form)] and of acetoin (R,S) were determined in laboratory wine fermentations carried out by 50 yeast strains, 10 for each of the following species, Saccharomyces cerevisiae, Kloeckera apiculata, Candida stellata, Metschnikowia pulcherrima and Brettanomyces bruxellensis, in order to evaluate if such parameters might be used to differentiate wines obtained with different yeast species. According to analysis of variance (ANOVA), the strains of the same species behaved similarly, whereas the five yeast species behaved differently so that species-specific profiles were recognized. Moreover, the discriminant analysis grouped the wines into five groups, each including the 10 wines obtained by the 10 yeast strains of the same species. Trials were also included where musts partially fermented by non-Saccharomyces species were inoculated with a selected strain of S. cerevisiae to complete fermentation, and the content in 2,3-butanediol and acetoin isomers was again determined and statistical analysis was performed. Although the final values of these parameters resembled those obtained in pure fermentation with S. cerevisiae, statistical analysis discriminated wines according to the yeast species performing the first fermentation phase.

The diversity and the composition of the yeast micropopulation significantly contribute to the sensory characteristics of wine. The growth of each wine yeast species is characterized by a specific metabolic activity, which determines concentrations of flavour compounds in the final wine. However, it must be underlined that, within each species, significant strain variability has been recorded. The wide use of starter cultures, mainly applied to reduce the risk of spoilage and unpredictable changes of wine flavour, can ensure a balanced wine flavour, but it may also cause a loss of characteristic aroma and flavour determinants. Thus, the beneficial contribution from the yeast increases when starter cultures for winemaking are selected on the basis of scientifically verified characteristics and are able to complement and optimise grape quality and individual characteristics. Here we report the characterization of a large number of strains of different wine yeast species, isolated from spontaneous wine fermentations and included in the culture collection of the Basilicata University.

One hundred and fifteen Saccharomyces cerevisiae strains from Aglianico del Vulture, a red wine produced in Southern Italy, were characterized for the production of some secondary compounds involved in the aroma and taste of alcoholic beverages. The strains exhibited a uniform behaviour in the production levels of n -propanol, active amyl alcohol and ethyl acetate, whereas isobutanol, isoamyl alcohol and acetaldehyde were formed with a wide variability. Only five strains produced wines close to the reference Aglianico del Vulture wine for the traits considered. Of these, two strains were selected, underwent to tetrad analysis and the single spore cultures were tested in grape must fermentation. The progeny of one strain showed a significant metabolic variability, confirming the necessity to test starter cultures for the segregation of traits of technological interest. Our findings suggest the selection of specific strains for specific fermentations as a function of the vine variety characteristics in order to take the major advantage from the combination grape must/ S. cerevisiae strain.

This work deals with biogenic amine production by yeast strains isolated from grapes and wines. A total of 50 strains were tested for their capacity to produce biogenic amines in wine. In general, all the species produced very low or non-detectable amounts of histamine, whereas methylamine and agmatine were formed by all the species considered. The highest concentration of total biogenic amines was formed by Brettanomyces bruxellensis, with an average value of 15 mg/l, followed by Saccharomyces cerevisiae with an average of 12.14 mg/l. The other species formed less than 10 mg of total biogenic amines per litre. Wines fermented with the most fermentative strains of S. cerevisiae species had the highest contents of ethanolamine, from 2.3 to 16 mg/l, and of agmatine, from 3.1 to 7.5 mg/l. The strains of the other species, which exhibited a low fermentative ability, Kloeckera apiculata, B. bruxellensis and Metschnikowia pulcherrima, varied in the production of agmatine and phenylethylamine. A significant variability in the production of cadaverine was characteristic of Candida stellata strains, which varied also in ethanolamine production. Our results emphasize the importance of using selected strains of S. cerevisiae, not only for the expression of desirable technological traits, but also to avoid potentially negative effects on human health. Therefore, the characterization of strains of S. cerevisiae for the 'production of biogenic amines' becomes of applicative interest.

The ability to degrade tyramine and histamine in 26 strains of Staphylococcus xylosus, isolated from craftmade fermented sausages produced in Basilicata region, was investigated. In these sausages a general decease of total amine amounts during the first 7 days was observed. Twenty-one oxidase positive strains of S. xylosus were detected: seventeen oxidized both the amines, even if with different percentages of degradation; three of them (S28,S47 and S78) showed only histamine oxidase activity; the strains S80 degraded only tyramine.The greatest monoaminooxidase activity was observed for the strains S81 and S206, that caused 100 and 93% histamine decrease respectively.

Forty-nine strains of Kloeckera apiculata , isolated from the Friuli region in Italy, were differentiated on the basis of fermentation behaviour and production of secondary compounds in two different grape musts at 18 °C. The isolates exhibited a controlled production of acetic acid, only in a few cases more that 1 g/l. In Moscato grape must the strains exhibited a more uniform behaviour for the production of higher alcohols, ethyl acetate and acetoin than in red grapes. In general, higher levels of ethanol, glycerol and acetic acid were produced in red grape must fermentation. Apiculate strains behaved differently in the two musts, with different metabolic phenotypes dominating the fermentation process. The existence of different metabolic phenotypes correlated with the must composition underlines the need to perform a selection of indigenous apiculate yeasts to obtain the desired consistent products.

The ability to degrade tyramine and histamine in 26 strains of Staphylococcus xylosus, isolated from craftmade fermented sausages produced in Basilicata region, was investigated. In these sausages a general decrease of total amine amounts during the first 7 days was observed. Twenty-one oxidase positive strains of 5. xylosus were detected: seventeen oxidized both the amines, even if with different percentages of degradation; three of them (S28, S47 and S78) showed only histamine oxidase activity, the strains S80 degraded only tyramine. The greatest monoaminooxidase activity was observed for the strains S81 and S206, that caused 100 and 93% histamine decrease respectively.

The aim of this work was to produce good-quality "salsiccia sotto sugna" salami which pose no health risk to consumers. A mixture of L. sakei and Kocuria varians, isolated from artisanal salami of Basilicata region, was added in the manufacture of salami from two different producers. The effects of the temperature and R.H. conditions were evaluated on the quality of the final products.The starter cultures influenced the growth of spoilage microorganism and reduced biogenic amine content. The ripening according to the traditional processes resulted more efficient on the organoleptic quality of salami than that performed according to industrial techniques.

The aim of this work was to produce good-quality salsiccia sotto sugna salami which pose no health risk to consumers. A mixture of L. sakei and Kocuria varians, isolated from artisanal salami of Basilicata region, was added in the manufacture of salami from two different producers. The effects of the temperature and R.H. conditions were evaluated on the quality of the final products. The starter cultures influenced the growth of spoilage microorganism and reduced biogenic amine content. The ripening according to the traditional processes resulted more efficient on the organoleptic quality of salami than that performed according to industrial techniques.

Artisanal manufactured sausage "salsiccia sotto sugna", produced according to traditional receipts, has been analysed in some areas of Basilicata region. During sausages making and ripening they have been drawn samples. For some products the microbiological analysis showed the potentiality for the selection of lactic acid bacteria and micrococci starters in order to improve the product (avoiding defects in consistence and flavour but keeping its tradition and tipicity). The study of the techniques used and the sensorial evaluation allowed to say that the production technique "a punta di coltello" and drying and ripening for three weeks at 12 degrees-15 degrees C and RU 75% are the best conditions to obtain "saisiccia sotto sugna" of excellent quality.

Artisanal manufactured sausage salsiccia sottosugna, produced according to traditional receipts, has been analysed in some areas of Basilicata region. During sausages making and ripening they have been drawn samples. For some products the microbiological analysis showed the potentiality for the selection of lactic acid bacteria and micrococci starters in order to improve the product (avoiding defects in consistence and flavour but keeping its tradition and tipicity). The study of the techniques used and the sensorial evaluation allowed to say that the production technique a punta di coltello and drying and ripening for three weeks at 12°-15°C and RU 75% are the best conditions to obtain salsiccia sotto sugna of excellent quality.

Sixty-six yeasts were isolated from seven samples of water-buffalo Mozzarella cheese. The yeast population ranged from 2x10(5) to 1x10(6) cfu/g. Among isolates, strains belonging to non-fermenting Candida spp., Saccharomyces cerevisiae and Kluyveromyces marxianus var. marxianus and var. lactis together with their anascosporogenous forms were identified. The dominant fermenting species were examined for production of secondary metabolites in synthetic medium and in milk. The fermenting yeasts were able to produce aromatic compounds other than ethanol, in particular ethyl acetate, which contributed significantly to the organoleptic characteristics of the cheese. In addition, the presence of non-lactose, but galactose fermenting S. cerevisiae can be useful in the reduction of residual sugars for the manufacture of low browning Mozzarella cheese.