Inactivation of Brettanomyces bruxellensis by High Hydrostatic Pressure technology

The aim of the research was to investigate a potential application of high hydrostatic pressure (HHP) for reduction/elimination of Brettanomyces bruxellensis and Saccharomyces cerevisiae in wines. Dry red wine was inoculated with B. bruxellensis and sweet white wine was inoculated with S. cerevisiae yeast. Both wines were treated by HHP under 100 and 200 MPa for 1, 3, 5, 15 and 25 min. The culturability was determined immediately after the treatment and again after 30, 60 and 90 days of storage. The phenolic content and chromatic characteristics were evaluated spectrophotometrically immediately after the treatment and after 90 days of storage. The culturability of B. bruxellensis was not confirmed immediately after the most invasive treatment (200 MPa for 15 and 25 min). With the same parameters, only a decrease in the culturability of S. cerevisiae was observed. During storage, opposing results were observed for two yeasts treated with 200 MPa for 15 and 25 min: there was a complete reduction of S. cerevisiae in the wine treated, but the culturability of B. bruxellensis completely recovered in all wines, implying that B. bruxellensis yeast entered a viable but not culturable (VBNC) state after HHP exposure. Regarding the chemical analyses, applied process parameters induced a slight decrease of anthocyanins in red wine, while changes of total phenolics and total colour difference value were negligible. In conclusion, HHP could potentially be successful for microbial stabilisation of sweet wines and consequently assure a lower use of sulphur dioxide, while inactivation of B. bruxellensis could only be successful in the early stages of wine contamination.

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Survival of mouse blastocysts after low-temperature preservation under high pressure

Acta Veterinaria Hungarica ◽

10.1556/avet.52.2004.4.10 ◽

2004 ◽

Vol 52 (4) ◽

pp. 479-487 ◽

Cited By ~ 7

Author(s):

Cs. Pribenszky ◽

M. Molnár ◽

S. Cseh ◽

L. Solti

Keyword(s):

Phase Transition ◽

Hydrostatic Pressure ◽

Low Temperature ◽

High Hydrostatic Pressure ◽

Room Temperature ◽

Freezing Point ◽

Significant Loss ◽

Embryo Cryopreservation ◽

Subzero Temperatures ◽

Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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