Molecular and enological characterization of autochthonous <i>Saccharomyces cerevisiae</i> strains isolated from grape-musts and wines Cannonau

Fermentation by autochthonous yeasts may produce wines with enological properties that are unique of a specific area or variety of grape must. In order to identify yeast starter strains for the production of the Sardinian wine Cannonau DOC, 66 Saccharomyces cerevisiae strains, isolated from musts and wines Cannonau of six vitivinicole areas in Sardinia, were subjected to enological characterization and molecular identification. The RFLP-PCR fingerprinting of the ITS region of rRNA (ITS1-5,8S- ITS2) as well as ethanol, foam, and H2S production were analysed

I Lieviti delle salamoie delle olive da mensa

Pickled table-olives (Tonda variety) were obtained from Dolianova Cooperative (CA). From 11 samples examined, 110 yeast strains were isolated as follows: 65 of Candida boidinii (90,91 % frequency); 2 of Candida diddensiae (9,10% frequency); 30 of Candida krusei (72,73% frequency); 1 of Cryptococcus infirmo-miniatus (9,10% frequency); 1 of Hansenula anomala (9,10% frequency); 6 of Saccharomyces cerevisiae var. cerevisiae (9,10% frequency); 3 of Saccharomyces cerevisiae var oleaceus (18,18% frequency); 2 of Saccharomyces cerevisiae var. uvarum (9,10% frequency). Since all the species found, except Cryptococcus infirmo-miniatus, are capable of fermenting at least glucose, they are probably involved in the pickle microfloral complex responsible for the table-olive fermentation

L'Invecchiamento biologico del Cannonau di Oliena

Accelerated ageing trials were carried out on « Cannonau di Oliena» under production conditions. Yeast «Flor» strains of the species Saccharomyces prostoserdovii were used as ageing agents. Results showed that wines produced using these yeasts were superior to those produced normally specially when Sacch. Prostoserdovii was added to the musts as «pied de cuve», thus reducing maturing times considerably

Produzione di anidride solforosa da parte dei lieviti nel corso della fermentazione alcolica

SO2 production by yeast during alcoholic fermentation. Determinations were made of SO2 produced during must fermentation by 29 strains of Saccharomyces cerevisiae. After 2 days of fermentation, only 4 reached a 50 - 70 mg/l SO2 production; on the 4th day only 2; and on the 7th day only 1. All proved to belong to the low SO2 producer category

Influenza di alcuni interventi tecnologici nella trasformazione al naturale di olive da mensa

Sardinia table olives are chiefly obtained with the natural style, processing green fruits. Lack of scientific data sometimes results in low quality products. The present study was aimed to verify the effectiveness of some technological steps – such as brine acidification and sugar or microbial starter addition – on main chemical- physical parameters of “Manna” cultivar. Results clearly show beneficial effects of starter inoculation and acidification on the sensorial and safety characteristics. La produzione di olive da mensa in Sardegna è condotta quasi esclusivamente con il metodo al naturale su olive verdi. Tale tecnologia, vista anche la scarsità di documentazione scientifica al riguardo, porta spesso all’ottenimento di un prodotto scadente. Con il presente lavoro si è verificata l’efficacia di alcuni interventi tecnologici, quali l’acidificazione della salamoia e l’aggiunta di substrato fermentescibile o di starter microbici, sui principali parametri chimico- fisici delle olive della varietà “Manna”. I risultati ottenuti evidenziano gli effetti positivi, dal punto di vista sensoriale e igienico- sanitario, dello starter e dell’acidificazione

Influenza dei lieviti «flor» sull'evoluzione delle caratteristiche cromatiche durante la maturazione della Vernaccia di Oristano

The Authors have studied the «flor» yeasts influence on the chromatic characteristics of the «Vernaccia» wine. The wine, wich is not treated with select yeasts, drows a marked tendency to darkening. The wine, inoculated with some strains of «flor» yeasts belonging to Sacch. prostoserdovii, Sacch. bayanus and less Sacch. aceti species does not present this phenomenon or does in a very attenuate way

Aerobic and anaerobic spore-forming bacteria in Sardinian honey.

Apart from an ubiquitous microflora, this investigation into 52 samples of honey revealed some undesirable spore-forming bacteria, Bacillus alvei and B. larvae which are bee pathogens. Bacillus cereus can cause spoilage and food poisoning. It is, therefore, considered essential that every country includes microbiological standards in its Food Safety Regulations for honey, so that the consumer is guaranteed as to the wholesomeness as well as the quality of the product

I Lieviti del tubo digerente dell'<i>Apis inellifica ligustica</i> Spinola

The results of microbiological surveis of apis mellifica lingustica Spinola intestinal tacts are givenhere. From 100 samples 54 yeast strains were isolated. The yeast specie identified are: H. anomala var. schneggii, C. guilliermondii var. guilliermondii, T. apicola, T. candida, T. glabrata, T. haemulonii. The yeast species isolated were not so different from those discovered by other authors in similar environments

Fungicidal activity of some o-nitrophenyl-hydrazones

The antimycotic activity of 16 o-nitrophenylhydrazones against strains of Hansenula anomala, Saccharomyces cerevisiae, Candida parapsyliosis, and Cryptococcus albidus was tested. All 16 compounds inhibited growth of the yeast strains. The inhibitory activity of the 4 methyl-derivatives substituted on the aromatic nucleus was particularly significant

Prove di tossicità da S C P nell'ovino: nota 7.: rilievi sul comportamento della microflora ruminale

During chronic and acute toxicity trials on ovines, fed with an alkanegrown SCP, observations were also made on the behaviour of the ruminaI microflora. The different diet supplied to both experimental and control groups of animals, did not seem to have affected the total count and the total numbers of Starch digesters, Cellulose digesters and Proteolytic bacteria. During the chronic toxicity test, 194 strains of yeast were identified belonging to the following species: Candida boidinii, Candida slooffii, Candida tropicalis, Cryptococcus albidus var. albidus, Cryptococcus albidus var. diffluens, Cryptococcus dimennae, Cryptococcus kuetzingii, Rhodotorula glutinis var. dairenensis, Rhodotorula glutinis var. glutinis, Rhodotorula graminis, Rhodotorula pallida, Rhodotorula rubra, Torulopsis versatilis, Trichosporon cutaneum, Debaryomyces hansenii, Debaryomyces phaffi, Debaryomyces tamarii, Saccharomyces vafer . The yeast species that were isolated were not so different from those discovered by other authors in similar researches, carried cut, however, in animals fed differently. A marked diffusion of the genus Debaryomyces was to be observed, together with a notable lipolytic and caseinolytic activity in most of the strains isolated. At first the introduction of SCP in the diet at concentrations of 15% and 40% seemed to favour the multiplication of the yeasts in the rumen fluid, but their numbers diminished towards the end of both test in all groups under observation. The type of protein given, does not seem to have affected even the species of yeasts that are usually lodged in the animals rumen. Screening of the isolated strains is now in course for the SCP production on glucose, lactose, xylose, starch, fruit and citrus pulps, and other conventional substrata