Papers by Agostino Cavazza
The environmental adaptibility of clones: influence of the yeast strains and must clarifying in the modification of wine quality
South African Journal of Enology & Viticulture, 2016
) is a biological process that contributes to wine quality,but it is frequently affected by vario... more ) is a biological process that contributes to wine quality,but it is frequently affected by various vinification conditions. Resistance to four wine-limiting factors was studied with respect to 10 Oenococcus oeni strains in order to select a suitable strain for performing reliable MLF in difficult wines. Resistance to low fermentation temperature, high SO2 and/or ethanol concentration, and low pH were assayed in laboratory tests. A pool of the most resistant strains was used in a set of laboratory MLFs. At the end of fermentation, the dominant strains were identified by RAPD-PCR. The PN4 strain was found to be dominant in the majority of cases and under the most detrimental wine conditions, and it was therefore chosen as the single-strain inoculum for the subsequent MLF trials, The effectiveness of the PN4 strain was confirmed in a series of MLFs carried out in three different countries under experimental and industrial conditions. It accomplished MLF in wines with up to 15.8% ethanol, pH as low as 3.0,60 mg/L of free SO2, and in fermentation temperatures below 17°C. Our findings indicate that the 0. oeni PN4 strain could be an effective starter, guaranteeing regular and reliable MLF fermentation.
Microbial Biotechnology, 2016
SummaryVino Santo is a sweet wine produced from late harvesting and pressing of Nosiola grapes in... more SummaryVino Santo is a sweet wine produced from late harvesting and pressing of Nosiola grapes in a small, well‐defined geographical area in the Italian Alps. We used metagenomics to characterize the dynamics of microbial communities in the products of three wineries, resulting from spontaneous fermentation with almost the same timing and procedure. Comparing fermentation dynamics and grape microbial composition, we show a rapid increase in a small number of wine yeast species, with a parallel decrease in complexity. Despite the application of similar protocols, slight changes in the procedures led to significant differences in the microbiota in the three cases of fermentation: (i) fungal content of the must varied significantly in the different wineries, (ii) Pichia membranifaciens persisted in only one of the wineries, (iii) one fermentation was characterized by the balanced presence of Saccharomyces cerevisiae and Hanseniaspora osmophila during the later phases. We suggest the ex...
BioMed research international, 2015
Nostrano-cheeses" are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige,... more Nostrano-cheeses" are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of "Nostrano-cheeses" and evaluated their potential to produce 𝛾-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (𝑛 = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0 ± 2.7 mg/kg) was a Sc. thermophilus.
Regulatory aspects of lipid synthesis in a yeast frequently associated with grape sour rot
Etude de divers parametres lies aux conditions de culture et influencant les mecanismes de la bio... more Etude de divers parametres lies aux conditions de culture et influencant les mecanismes de la biosynthese des acides gras chez Candida steatolytica
Progetto Food quality: giudizio mediamente positivo
Biodiversità microbica dei latti trentini destinati alla produzione dei formaggi nostrani
Formaggi di qualità con il minicaseificio
Genotypic characterization of enterococci isolated from Puzzone di Moena cheese
Microorganisms immobilization in silica/alginate sistem
Immobilisierung von Weinmikroorganismen in Sylice/Alginate Systeme
Washing the grapes before crushing: effects on contaminants and fermentation
ABSTRACT The effect of grape washing was evaluated at winery scale in two premium white and red v... more ABSTRACT The effect of grape washing was evaluated at winery scale in two premium white and red vinifications in Trentino (Italy). White and red grapes were washed in winery scale with 1 % citric acid solution, and the compositions of the musts were compared with that of the untreated controls. The metal and pesticide content of musts were well different if grape contamination was detectable. The yeast content of musts was also reduced by the washing procedure. The fermentation rate was measured in musts inoculated with native yeast (spontaneous fermentation) and with two differently prepared starter cultures. In all cases the fermentation rate was higher with washed grapes. Introduction Grapes to be used in winemaking are maybe the only raw material that is not washed before processing. This is probably due to avoid risks of sophistication or adulteration of wines with water addition, but in this way everything that is present on grape skins, like chemicals and microorganisms, but also leaves, parts of stems and sometimes of soil, can contaminate the musts. A reduction of these external abiotic contaminants, by washing the grapes before their crushing, could reduce the stress of yeast during fermentation. Moreover some pesticides (i.e. copper) can delay the yeast growth and lead to stuck or sluggish fermentations (Regueiro et al. 1993). The grapes are also a primary source of yeasts and the species that starts the natural fermentation are those predominant on grapes at the time of harvest. Even if Active Dry Yeasts (ADY) are added, the growth of indigenous non-Saccharomyces yeasts will also contribute to the overall fermentation (Heard and Fleet, 1985; Fleet et al. 1993; Beltran et al. 2002, Pretorius 2000), usually in a negative way. Thus, with the aim to reduce external contaminants (chemical and microbial) but without removing totally the natural grape microbiota, we checked the effect of a grape washing system (CLU® Grape Cleaning Unit – Tecnicapompe Zanin srl -Fara Vicentino – Italy) that uses a citrate solution to remove contaminants and complex metals. In the present work, we investigated the dynamics of yeast populations and the fermentation kinetics in musts produced with washed grapes, when fermentation was carried on by native yeasts (spontaneous fermentation), or by a Natural Starter Culture (NSC) or Active Dry Yeasts (ADY).
Microbiological aspects of raw milk used for Grana Trentino cheese production and stored under different thermal conditions
NUOVA PAC Una carta da giocare 8 ALIMENTAZIONE Come mangiano i trentini? 31 SPECIALE Trentingrana... more NUOVA PAC Una carta da giocare 8 ALIMENTAZIONE Come mangiano i trentini? 31 SPECIALE Trentingrana 85 anni in forma 52 TECNICA Reti antigrandine alla prova PROVINCIA AUTONOMA DI TRENTO AssessoRATo pRovinCiAle All'AgRiColTURA foResTe, TURismo e pRomozione N. 5 anno LVI t erra t rentina www.trentinoagricoltura.net periodico di economia e tecnica per un'agricoltura moderna al servizio del consumatore e dell'ambiente MONDO CONTADINO A Roncone un Festival anche per l'agricoltura PRIMO PIANO NUOVA PAC, UNA CARTA DA GIOCARE il "riconoscimento" della montagna c'è, ci saranno anche le risorse? Dipenderà dalla regionalizzazione degli aiuti. Uno su tre è in sovrappeso, e la metà non lo sa. ma ora arrivano le linee guida: prodotti locali e a basso impatto ambientale nella ristorazione collettiva Lorenzo Rotondi, Federico Bigaran periodico di economia e tecnica dell'agricoltura. organo dell'Assessorato provinciale all'agricoltura, foreste, turismo e promozione
Alcoholic Fermentation with Saccharomyces cerevisiae Trapped in SiO2 Films
Eurogel '91, 1992
Abstract Viable Saccharomyces cerevisiae cells can be trapped in SiO2 films on glass sheets. The ... more Abstract Viable Saccharomyces cerevisiae cells can be trapped in SiO2 films on glass sheets. The morphology of the matrix and occluded cells is studied by SEM. The catalyst activity was tested in sucrose fermentation. Results indicate cells to survive the deposition process, as shown by their reproduction and improved specific catalytic activity.
Temperatura e modalità di conferimento del latte al caseificio: effetti sulla carica psicotrofa e non solo
… del Grana Trentino: …, 2011
Citation: Poznanski, E., Franciosi, E., Cologna, N., Settanni, L., De Sabbata, G., Gardini, F., e... more Citation: Poznanski, E., Franciosi, E., Cologna, N., Settanni, L., De Sabbata, G., Gardini, F., et al.(2011). Temperatura e modalità di conferimento del latte al caseificio: effetti sulla carica psicotrofa e non solo. In Atti del convegno La filiera del Grana Trentino: approcci ...
World Journal of Microbiology and Biotechnology, 2010
Raw milk used to produce Grana cheese was subjected to several treatment regimes, including varyi... more Raw milk used to produce Grana cheese was subjected to several treatment regimes, including varying temperatures and storage times. Milk from morning and evening milking were transferred to a dairy factory separately (double delivery) or together (single delivery), after storage at the farm for 12 h; in the former case, milk was stored at 12 or 8°C, whereas, in the latter, it was kept at ambient temperature or 18°C. Values of pH of the vat milk were lower for milk samples kept at room temperature, while other physico-chemical parameters and rheological characteristics tested did not show significant differences linked to the different storage temperatures of milk used for ''Grana Trentino'' cheese production. Total microorganisms and several microbial groups (psychrotrophic bacteria, coliforms, mesophilic and termophilic lactic acid bacteria, including enterococci, pseudomonads and clostridia) were detected and quantified by classical (plate count and most probable number) techniques, after each technological treatment for a total of 212 milk and cream samples. The application of a culture-independent microbiological strategy, consisting of denaturing gradient gel electrophoresis, allowed the recognition of several bacterial genera and species.
Immobilization of yeast and bacteria cells in alginate microbeads coated with silica membranes: procedures, physico-chemical features and bioactivity
Journal of Materials Chemistry, 2008
ABSTRACT Salt alginate beads are used to entrap yeast or bacteria cells and exploited as protecti... more ABSTRACT Salt alginate beads are used to entrap yeast or bacteria cells and exploited as protective environment for deposition of silica gel membranes. This inorganic layer is obtained through different methods: by dipping the beads in a silica sol (method A), by further consolidating them with tetraethoxysilane in an apolar solvent (method B), and by coating the beads with methyltriethoxysilane in the gas phase (method C). Physical–chemical and biological features are investigated. The pyrolysis study elucidates the features of the polymeric organic layer. Elemental analysis and 29 Si solid state NMR prove the presence and the condensation degrees of the silica membranes. The bioactivity is studied by evaluating both glucose (Saccharomyces cerevisiae) and L-malic acid (Oenococcus oeni) fermentations. The fermentation performance is discussed considering possible limitations of mass transport across the silica gel layer. Method A produces an inorganic layer made by of 57.3% Si(OSi^) 4 and 42.7% HO–Si(OSi^) 3 units). In this case a linear relation is found among different contact times between silica sol and beads and both silica amount and average thickness. Method B appears to be successful in building up the layer, but it is also detrimental to cell viability. Method C is very efficient in terms of mass deposit, cell viability maintenance and leakage reduction. In this case the membrane is constituted by H 3 C–Si(OSi^) 2 OH and H 3 C–Si(OSi^) 3 units in an almost 1 : 1 ratio.
Journal of Food Processing and Preservation, 2009
Raw cow's milk and cheese samples collected from factories producing "Puzzone di Moena" located i... more Raw cow's milk and cheese samples collected from factories producing "Puzzone di Moena" located in the alpine province of Trento (northern Italy), were analyzed for their enterococcal content. Presumptive enterococci (Gram positive, catalase negative, coccal shaped and positive for growth on kanamycin aesculin azide) were isolated, verified for their growth in presence of 6.5% NaCl, 40% bile salts and esculin hydrolysis, and analyzed by a genetic polyphasic approach consisting of intergenic spacer (ITS)-polymerase chain reaction (PCR) between the 16S and 23S rRNA genes, denaturing gradient gel electrophoresis (DGGE) of the V3 region of the 16S rRNA gene and a sodA gene-based multiplex PCR. Results showed the presence of Enterococcus faecalis as the main species found in milk and cheese. Enterococcus casseliflavus and Enterococcus durans were also detected in raw milk. In order to exclude clonal relatedness, the isolates were subjected to randomly amplified polymorphic DNA-PCR (RAPD-PCR). Winter cheese was characterized by a higher biodiversity than summer production, both in terms of Enterococcus species and number of strains. No strain was found positive for vancomycin resistance as determined by vanAand vanB-specific PCR. Two strains were shown to be characterized by an anti-Listeria behavior due to bacteriocin-like inhibitory substances (BLIS) production. BLIS producer strains persisted during the ripening of cheese.
Italian Journal of Animal Science, 2010
A study was conducted to monitor raw milk hygiene, and to understand the relationship between dif... more A study was conducted to monitor raw milk hygiene, and to understand the relationship between different bacterial groups found in raw milk collected from stables in the Trentingrana area. Twenty stables in Trento province were sampled. Each farmer provided one milk sample every 2 months for 8 months. The milk samples were examined for total bacterial count, coliforms, enterococci, psycrotrophic, acidificant and proteolytic microflora. The bacterial counts of four milk samples for each stable, examined over an 8-months period were averaged and expressed as mean bacterial count per milliliter. In most samples, coliforms and enterococci were below 2Log cfu/ml; this suggests that herds and milking hygiene were well controlled by all farmers. The milk refrigeration practice seems to have no influence on the growth of its microflora but to affect that of acidifying and proteolytic bacteria.
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Papers by Agostino Cavazza