Ana Boban, mag.chem., research assistant, has successfully defended her doctoral thesis titled “Impact of indigenous non-Saccharomyces yeasts on the aroma profile of young wine from ‘Maraština’ cv. (Vitis vinifera L.)”. The thesis was prepared following the Scandinavian model as part of the research projects IP-2020-02-1872 “Impact of native non-Saccharomyces wine yeast on wine aromas“ and DOK-2021-02 “Young Researchers’ Career Development Project-Training New Doctoral Students”. The thesis was awarded the distinction summa cum laude.

The public defense of the doctoral thesis was held on July 23, 2025, at the Faculty of Food Technology and Biotechnology, University of Zagreb, before the Thesis Defense Committee consisting of:

• Karin Kovačević Ganić, Ph.D., Full professor, Faculty of Food Technology and Biotechnology (chair)
• Jasenka Gajdoš Kljusurić, Ph.D., Full professor, Faculty of Food Technology and Biotechnology (member)
• Vesna Milanović, Ph.D., Associate professor; Università Politecnica delle Marche, Ancona, Italy (member)

Supervisor: Irena Budić-Leto, Ph.D., scientific advisor with tenure

We sincerely congratulate Ana and wish her continued success in her future research work!

The full doctoral thesis is available in the Dabar repository.

The successful publication of scientific papers resulting from the WINE AROMAS project continues with the release of a new article titled “Unlocking the potential of indigenous Saccharomyces cerevisiae from Maraština grapes for use as starter cultures in the winemaking process”, published in the journal Applied Food Research (Elsevier, IF = 6.2).

This latest scientific paper presents the results of molecular identification and detailed analysis of 117 indigenous strains of Saccharomyces cerevisiae isolated from spontaneous fermentations of Maraština grape must, collected from three winegrowing subregions of Dalmatia.

Key research findings:

• Strains from Central and Southern Dalmatia (CSD) demonstrated high resistance to sulfur dioxide and elevated sugar levels, along with reduced production of undesirable compounds such as H₂S and acetic acid.
• Strains from Northern Dalmatia (ND) showed better tolerance to higher alcohol concentrations but exhibited lower aromatic potential.
• Eleven of the most promising isolates were selected for further testing – all successfully completed fermentation within 15 days.
• A comparison with the commercial strain EC 1118 revealed that indigenous strains produced a more complex aroma profile, particularly due to increased ester production (fruity and floral notes).

More details are available at the following link: https://www.sciencedirect.com/science/article/pii/S2772502225004500

The WINE AROMAS project team has published another scientific paper resulting from the recently completed project. The paper was published in the journal European Food Research and Technology, by Springer.

Key findings from the paper:

• The research examined the impact of indigenous non-Saccharomyces yeasts on the early metabolite profile of wine using sterile grape must from the Maraština variety.
• Indigenous yeasts contribute to regional wine identity and shape the early fermentation profile of Maraština wines.
• The species M. sinensis/shanxiensis and M. chrysoperlae were studied for the first time in winemaking, and during the early fermentation phase, they produced lower concentrations of acetic acid and acetaldehyde compared to control fermentations with commercial Metschnikowia and Lachancea yeasts.
• These yeasts enhance wine aroma by increasing the concentration of compounds such as linalool, α-terpineol, and β-damascenone, which impart floral, sweet, and fruity aromas.

More details can be found at the following link: https://doi.org/10.1007/s00217-025-04732-y

Using a targeted metabolomic approach with UHPLC-MS/MS, we investigated the impact of native non-Saccharomyces yeasts on the lipid profile of Maraština wine produced through monoculture and sequential fermentations. Certain components exhibited opposite trends (increase or decrease) in sequential fermentation compared to monoculture and the initial must. Metschnikowia chrysoperlae and Metschnikowia pulcherrima produced more total free fatty acids and their esters in monoculture, while Metschnikowia sinensis/shanxiensis generated more free fatty acid esters in sequential fermentation with S. cerevisiae. The Hanseniaspora genus was the least affected by inoculation treatments, with most lipid compounds following the same trend. Exceptions included oleanolic and stearic acid for H. uvarum, and palmitoleic acid for H. guilliermondii. Hierarchical cluster analysis grouped native yeasts based on their influence on the synthesis or degradation of lipid compounds. The most significant impact observed in this study was on the biosynthesis of unsaturated fatty acids.

More details can be found at the following link: https://www.mdpi.com/2304-8158/14/2/269

On November 20, 2024, the final workshop of the research project “Impact of native non-Saccharomyces wine yeast on wine aromas” was held at the Institute for Adriatic Crops and Karst Reclamation. The results of the project, funded by the Croatian Science Foundation, were presented to interested participiants.

The project results were presented by:

• Dr. Irena Budić-Leto, project leader, on the topic:
  “Presentation of Research Project Results IP-2020-02-1872: The Influence of Indigenous Non-Saccharomyces Yeasts on Wine Aroma – WINE AROMAS”
• Ana Boban, mag.chem., PhD student, on the topic:
  “The Potential of Indigenous Non-Saccharomyces Yeasts to Enhance the Aroma of Maraština Wine”

With this workshop, we have achieved all the objectives of the research project “Impact of native non-Saccharomyces wine yeast on wine aromas” and successfully brought the project to its conclusion. 🎉

We presented part of the results of our research project at the scientific and professional conference on viticulture and winemaking, organized by the Faculty of Agriculture, University of Zagreb held during the 34^th International Meeting of Winegrowers and Winemakers – Sabatina 2024.

Sabatina took place in Mali Lošinj from November 14–17, 2024, organized by the Cooperative Union of Dalmatia and the Croatian Association of Wine Cities. The event brought together numerous participants, including representatives from the wine sector.

A lecture titled “The influence of indigenous non-Saccharomyces yeasts on the aromas of the Maraština wine” was presented by PhD student Ana Boban.

At the Biotechnical Faculty of the University of Ljubljana, Department of Biology, the final conference and Management Committee meeting of the COST Action CA 19116 PLANTMETALS was held from September 17 to 20, 2024. Dr. Irena Budić-Leto participated as a member of the Action’s Management Committee. At the gathering, we presented preliminary research results related to the metabolism of certain non-Saccharomyces yeast isolates and the concentration of metal ions and antioxidant activity in the wine of the Maraština grape variety.

Book of abstracts is available on the link: https://plantmetals.eu/PLANTMETALS2024_Book-of-Abstracts_25092024_print_final.pdf

This study examined the impact of indigenous non-Saccharomyces yeasts on wine aroma through monoculture and sequential fermentations with Saccharomyces cerevisiae. The primary metabolites and volatile profiles of Maraština wine were modified solely by the tested yeasts, as the research was conducted on sterilized must of the Maraština variety.

This is the first comprehensive study on the yeast strains Metschnikowia chrysoperlae, M. sinensis/shanxiensis, Hypopichia pseudoburtonii, and Starmerella apicola in wine technology research. In monoculture, fermentations with the M. pulcherrima isolate resulted in the lowest ethanol concentration and higher total terpene concentrations. Pichia kluyveri produced a high level of thiols and esters, while Hanseniaspora guilliermondii increased the total concentration of C13-norisoprenoids.

Seven sequential fermentations revealed interactions between indigenous non-Saccharomyces yeasts and commercial S. cerevisiae yeast. P. kluyveri – S. cerevisiae fermentations had the most distinctive volatile profiles compared to controls, especially in C13-norisoprenoid and ester concentrations. M. pulcherrima in sequential fermentation reduced the production of volatile phenols. The isolates did not affect wine color and produced lower polyphenol concentrations than S. cerevisiae. These results highlight different volatile profiles under the same winemaking conditions, emphasizing the biochemical role of each isolate in fermentation. This study represents a first step in understanding the positive roles of non-Saccharomyces yeasts in winemaking.

More details can be found at the following link:  https://www.sciencedirect.com/science/article/pii/S2772502224001641?via%3Dihub

We’re sharing with you the atmosphere from this year’s Researchers’ Night.

The event took place on September 27, 2024, as part of the Reconnect Science with the Blue Society 2.0 project, aimed at popularizing science.

See you next year!

Photo: Cropix and Wine Aromas

https://www.facebook.com/profile.php?id=61552472441834

A targeted metabolomic UHPLC-MS/MS approach was used to investigate the influence of H. uvarum, H. guilliermondii, L. thermotolerans, M. pulcherrima, and P. kluyveri isolates, as well as two yeast species not previously studied in wine-M. chrysoperlae and M. sinensis/shanxiensis-on the metabolism of aromatic amino acids during monoculture and sequential fermentations with S. cerevisiae. The results were compared with fermentations using commercially available strains of M. pulcherrima, L. thermotolerans, and S. cerevisiae.

The results demonstrate the impact of individual yeast strains in different fermentations. These findings will enhance the understanding of tryptophan, phenylalanine, and tyrosine metabolism, through which indigenous non-Saccharomyces yeast contribute to the aroma of wine.

More details can be found at the following link: https://www.mdpi.com/2304-8158/13/18/2939.