WINETECH Technical Yearbook 2021

APPLICATION IN THE WINERY The ZYMAFLORE ® products can be added to the harvest and winery equipment to ensure continuous colonisation of contact surfaces for the duration of harvest. This will prevent accumulation of the unwanted microorganisms such as acetic acid bacteria which tend to flourish during this busy time in the cellar. The products can also be add- ed directly to the must or juice during any of the pre-fermentative stages for better microbial control. FIELD TRIALS Several field trials were conducted during Bordeaux’s 2020 harvest season to test the effectiveness of the ZYMAFLORE ® products. Some of the main findings are summarised below: Harvester trial The harvester and the winery receiving bin were sprayed with ZYMAFLORE ® ÉGIDE TDMP before contact with the grapes/ must, as well as after each unloading. Must samples were taken at the beginning of the day, halfway through the harvest and at the end of the day and analysed using quantitative polymerase chain reaction (qPCR) technology, as well as plated onto culture media, to assess microbial growth. Results showed that in the absence of bioprotection, mould and indigenous

CONCLUSION Results from the ZYMAFLORE ® trials are promising as the use of the products was accompanied by a limited growth of spoilage microbiota. Bioprotection could therefore be used as a tool to successfully manage microbial populations on the winery equip- ment and in the musts, possibly serving as a credible alternative to sulphites. SUMMARY During harvest, microorganisms naturally present on the grapes can rapidly multiply increasing the risk of premature fermentation, spoilage and the formation of undesirable compounds. Certain pre- fermentative processes such as cold soaking will support the growth of unwanted microbial populations. Bioprotection is a natural method to inhibit undesirable indigenous microorganisms present on the grapes or in the must. By adding living organisms specifically chosen for certain properties, the matrix can be colonised in a controlled manner and limit the predominance of the unwanted microflora. REFERENCES Sipiczki, M., 2006. Metschnikowia strains isolated from botrytized grapes antagonize fungal and bacterial growth by iron depletion. Applied and Environmental Microbiology 72(10), 6716-6724.

yeast species flourished, while the must sample from the ZYMAFLORE ® treatment showed a dramatically reduced population of undesirable moulds and yeasts while established T. delbruekii and M. pul­ cherrima populations were evident. Rinse water trial Harvest bins were rinsedwith ZYMAFLORE ® ÉGIDE TDMP inoculated water after each un- loading. Water samples were collected after rinsing and analysed using media plating and qPCR technology. In the absence of ZY- MAFLORE ® ÉGIDE TDMP mould and non- Sac­ charomyces yeast species were present, while the treated water was populated with only the two species present in the product. Stabulation trial Juice was kept on the lees for 10 days at 4°C with the aim to maximise the extraction of beneficial compounds and aromatic pre - cursors located in the solids. For this appli- cation, ZYMAFLORE ® KHIO MP was tested and compared to a treatment to which no bioprotection was added. Results showed that 36% of yeast species in the ZYMA - FLORE ® KHIO MP -treated juice consisted of S. cerevisiae , while the remainder was M. pulcherrima. The population composition of the control sample (no bioprotection) showed that around 90% of the microflora present at the end of stabulation were in- digenous S. cerevisiae species.

Morata, A., Loira, I., Escott, C., del Fresno, J.M., Bañuelos, M.A. & Suárez-Lepe, J.A., 2019. Applications of Metschnikowia pul - cherrima in wine biotechnology. Fermenta­ tion 5(3), 63. Coulon, J., Nazaris, B. & Seabrook, A., 2019. Low SO 2 winemaking: Bio-protection for microbial control pre-fermentation. Wine and Viticulture Journal 34(3), 23-26. Csutak, O., Vassu, T., Avram, I., Stoica, I. & Cornea, C.P., 2013. Antagonistic activity of three newly isolated yeast strains from the surface of fruits. Food Technology and Biotechnology. Renault, P., Coulon, J., Moine, V., Thibon, C. & Bely, M., 2016. Enhanced 3-sulfanylhexan-1-Ol production in sequential mixed fermentation with Torulaspora delbrueckii/Saccharomyces cerevisiae reveals a situation of synergistic interaction between two industrial strains. Frontiers in Microbiology 7 (Mar), 1-10. Parapouli, M., Hatziloukas, E., Drainas, C. & Perisynakis, A., 2009. The effect of Debina grapevine indigenous yeast strains of Metschnikowia and Saccharomyces on wine flavour. Journal of Industrial Microbiology and Biotechnology 37(1), 85.

For more information, contact Morné Kemp at morne.kemp@laffort.com.

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