Bioprotective effect of non-Saccharomyces yeasts in wines made without SO2
Rocio Escribano Viana - ICVV, Instituto de Ciencias de la Vid y el Vino (University of La Rioja, La Rioja Government, CSIC). Finca La Grajera, Ctra. LO-20- salida 13, 26071 Logroño, Spain
Mª del Patrocinio Garijo - ICVV, Instituto de Ciencias de la Vid y el Vino (University of La Rioja, La Rioja Government, CSIC). Finca La Grajera, Ctra. LO-20- salida 13, 26071 Logroño, Spain
Rosa López - ICVV, Instituto de Ciencias de la Vid y el Vino (University of La Rioja, La Rioja Government, CSIC). Finca La Grajera, Ctra. LO-20- salida 13, 26071 Logroño, Spain
Pilar Santamaría- ICVV, Instituto de Ciencias de la Vid y el Vino (University of La Rioja, La Rioja Government, CSIC). Finca La Grajera, Ctra. LO-20- salida 13, 26071 Logroño, Spain
Ana Rosa Gutiérrez- ICVV, Instituto de Ciencias de la Vid y el Vino (University of La Rioja, La Rioja Government, CSIC). Finca La Grajera, Ctra. LO-20- salida 13, 26071 Logroño, Spain
Lucía González Arenzana- ICVV, Instituto de Ciencias de la Vid y el Vino (University of La Rioja, La Rioja Government, CSIC). Finca La Grajera, Ctra. LO-20- salida 13, 26071 Logroño, Spain
Email contact: rocio.escribano[@]icvv.es
The sulphur dioxide (SO2) is the most widely used additive in the wine industry because of its preservative action. However, in recent years the number of wineries that produce wines without SO2 has increased significantly because its allergenic character. The production of SO2-free wines may lead to the development of different spoiling microorganisms, which could lead to wine deterioration. One of the strategies suggested to avoid wine spoilage, is the non-Saccharomyces yeast inoculation, which prevent bacteria development.
The objective of this work was to evaluate the bioprotective effect of a mixed inoculum of non-Saccharomyces yeasts (Torulaspora delbrueckii and Lachancea thermotolerans 70/30) in two consecutive vintages (2018 and 2019). Three strategies were carried out in triplicate: spontaneous fermentation in sulphited must, spontaneous fermentation in non sulphited must and inoculated fermentation (non-Saccharomyces mixed inoculum) in non sulphited must. In all cases, after 72 hours of fermentation the vats were seeded with a commercial Saccharomyces cerevisiae yeast. The presence in the medium of lactic and acetic bacteria and the chemical composition of the wines were evaluated.
The obtained results indicated that the bioprotective effect of non-Saccharomyces yeasts inoculation was determined by the success of the implantation. Only in 2019 assays the inoculum was successfully implanted, and therefore, the bioprotective effect was like the observed for sulphited samples, since it limited the lactic and acetic bacteria population. This inoculation also modulated the physicochemical composition of the resulting wines. However, in 2018 the inoculum was not implanted and differences were not detected, neither in wines composition nor in the detected bacteria.
Effect of environmentally friendly vineyard protection strategies on yeast ecology during fermentation
Vasileios ENGLEZOS, Ilario FERROCINO, Simone GIACOSA, Susana RIO SEGADE, Jatziri MOTA-GUTIERREZ, Luca COCOLIN, Luca ROLLE, Kalliopi RANTSIOU
University of Turin, DISAFA, Italy
Email contact: firstname.lastname@example.org
AIM: Currently, an increasing concern from governments and consumers about environmental sustainability of wine production provides new challenges for innovation in wine industry. Accordingly, the application of more-environmentally friendly vineyard treatments against fungal diseases (powdery and downy mildew) could have a cascading impact on yeast ecology of wine production.
METHODS: This study evaluated the effect of a wide range of environmentally friendly products applied in the vineyard on grape yeast ecology at harvest, as well as during spontaneous and inoculated fermentations in winery and laboratory scale conditions. Yeast ecology was investigated using culture-dependent (plate counts) and -independent (Next Generation Sequencing) methods. Main oenological parameters and volatile compounds were monitored during spontaneous and inoculated fermentations. Spearman’s correlation was used to assess associations between ASVs changes and chemical composition observed over fermentation.
RESULTS: No significant differences were observed among the alternative and conventional treatments, compared to the controls, in terms of yeast population and biodiversity. The only exception was the increased population levels of Auerobasidium pullulans as response to three alternative treatments. This increase can positively affect the quality and the safety of the grapes, since A. pullulans is considered a biocontrol agent of pathogens. Overall, wine composition was greatly influenced by the inoculation, rather than the type of treatment applied previously in the vineyard. Fermentation data suggested that complete alcoholic fermentation was positively correlated to the application of antifungal treatment in the vineyard and the inoculation protocol used. Spontaneous fermentations conducted in laboratory using grapes previously treated with laminarin showed a higher relative frequency of Saccharomyces cerevisiae than other treatments, and its corresponding fermentation led to compounds responsible for floral and fruity scents without increasing the levels of the acetic acid.
CONCLUSIONS: Yeast ecology in fermenting musts may be correlated to specific antifungal products and inoculation protocol employed, suggesting a link between principal active compounds, yeast biodiversity and wine chemical composition. These relationships could help to further control wine quality and improve consumer acceptance and economic value of wines.
Effect of plant fining agents in the must flotation process. Functional characterization
Bautista-Ortín, Ana Belén (Food Science Department, Faculty of Veterinary Sciences, University of Murcia)
Bermúdez-Galvez, Sonia (University of Murcia)
Gómez-Plaza, Encarna (University of Murcia)
Albendea-Roa, Mar (Agrovin S.A.)
Jurado, Ricardo (Agrovin, S.A.)
Email contact: anabel[@]um.es
Flotation is one of the most used processes for clarifying white grape must after the pressing process. To date, gelatine is the more used fining agent, its action being improved when combined with bentonite and silica sol. However, in recent years, there is a growing commercial interest in replacing this animal origin protein with plant proteins, due, on the one hand, to the problems associated with allergies and, on the other hand, also thinking in the vegan wine consumers. However the efficiency of plant proteins as floculating agents are lower than gelatine and varies among them, the reason behind the different behaviour being unknown (Marchal et al., 2003; Gambuti et al., 2016; Petinelli et al., 2020). The objective of this work was to compare the flocculating efficiency of a commercial gelatine, a pure pea protein and the same pea protein chemically modified and to relate this efficiency to their amino acid composition and protein functions.
The determination of the efficiency was carried out by measuring the percentage of clean must after 1 h from flotation beginning and the measuring of the absorbance at 440 nm to control the browning, while the content of amino acids and peptides was carried out by HPLC-MS. The UNIPROT database was used to obtain the protein functions associated with the peptides.
The results showed that the modified pea protein showed very similar effciency as flotation agent to that of the commercial gelatine and higher than the pure pea protein. The important structural modification made to the pea protein made it more reactive, probably due to a higher exposure of its structure and the apolar and positively charged amino acids, and to the appearance of peptides with protein functions of binding to carbohydrates and proteins, which are also present in animal protein.
With these results it can be concluded that pure vegetal proteins may not have sufficient functional properties to behave as good flocculating agents, although certain chemical modification in their structure may further simulate the behaviour shown by animal protein.
Gambuti, A.; Rinaldi, A.; Romano, R.; Manzo, N.; Moio, I. (2016). Performance of a protein extracted from potatoes for fining of white musts. Food Chem., 190, 237-243.
Marchal, R.; Lallement, A.; Jeandet, P.; Establet, G. (2003). Clarification of Muscat musts using wheat proteins and the flotation technique. J. Agric. Food Chem., 51, 2040-2048.
Pettinelli, S.; Pollon, M.; Costantini, L.; Bellincontro, A.; R Segade, S.; Rolle, L.; Mencarelli, F. (2020). Effect of flotation and vegetal fining agents on the aromatic characteristics of Malvasia del Lazio (Vitis vinifera L.) wine. J. Sci. Food Agric., 100, 5269-5275.
Application of UV-LED in wine as an alternative to sulphur dioxide
Fernando Salazar, Laboratorio de Fermentaciones Industriales, Escuela de Alimentos, Facultad de Ciencias Agronómica y de los Alimentos, Pontificia Universidad Católica de Valparaíso, Chile
Sebastián Pizarro, Laboratorio de Fermentaciones Industriales, Escuela de Alimentos, Facultad de Ciencias Agronómica y de los Alimentos, Pontificia Universidad Católica de Valparaíso, Chile
Mariela Labbé, Laboratorio de Fermentaciones Industriales, Escuela de Alimentos, Facultad de Ciencias Agronómica y de los Alimentos, Pontificia Universidad Católica de Valparaíso, Chile
Ismael Kasahara, Escuela de Alimentos, Facultad de Ciencias Agronómica y de los Alimentos, Pontificia Universidad Católica de Valparaíso, Chile
Felipe Aguilar, Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Chile
Pablo Ulloa, Instituto de Investigaciones Agropecuarias, INIA La Platina, Santiago, Chile
Liliana Godoy, Departamento de Fruticultura y Enología. Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Chile
Email contact: fernando.salazar[@]pucv.cl
Sulfites (SO2) are commonly used in the wine industry to preserve products during storage for antiseptic and antioxidant purposes (Oliveira et al., 2011). However, the presence of sulfites at varying concentrations has been linked to allergic reactions in some consumers, such as dermatitis, urticaria, abdominal pain, among others (Vally & Thompson, 2001). UV-LED irradiation has been is an attractive technology of non-thermal nature and is an alternative to partially or totally replace the addition of SO2 to wine, due to its antimicrobial effect (Conner et al., 1998; Falguera et al., 2013). In this study, the effect of the UV-LED irradiation on the activity of Acetobacter aceti ATCC 15973 of white wine (Sauvignon blanc) and red wine (Pinot noir) was evaluated. A laboratory scale static UV LED irradiation system was designed, composed of four diodes with wavelengths of 278 nm (8-12 mW), 275 nm (3-5 mW) and 265 nm (1-3 mW) and irradiation times of 10, 20 and 30 min. The results indicate that irradiation at a wavelength of 278 nm for 30 minutes completely eliminated the A. aceti concentration (CFU/ml) in white wine. Irradiation of white wine at wavelengths of 275 and 265 nm for 30 min resulted in a logarithmic reduction of approximately 2.4. UV-LED irradiation processing of red wine was not as efficacious in eliminating A. aceti (CFU/ml), however, a logarithmic reduction of 4 was evidenced over 30 min. Therefore, the results obtained from the static UV LED irradiation process for white wine (Sauvignon blanc) and red wine (Pinot noir) showed that with diodes at a wavelength of 278 nm and a time of 30 min, the concentration of A. aceti ATCC 15973 was significantly reduced, which is relevant to control to maintain the quality of the wines. Furthermore, this technology could be an advantageous alternative to avoid the excessive use of sulphites in wine products. The effect on the final quality aspects of wine needs to be further clarified.
Falguera, V., Pagán, J., Garza, S., Garvín, A., Ibarz, A. (2011). Ultraviolet processing of liquid food: A review: Part 2: Effects on microorganisms and on food components and properties, Food Research International. 44(6): 1580-1588.
Conner-Kerr TA, Sullivan PK, Gaillard J, Franklin ME, Jones RM (1998). The effects of ultraviolet radiation on antibiotic-resistant bacteria in vitro. Ostomy Wound Manage. 44(10):50–56.
Vally H, Thompson PJ (2001). Role of sulfite additives in wine induced asthma: single dose and cumulative dose studies. Thorax 56: 763-769.
Oliveira, C. M., Ferreira, A. C. S., De Freitas, V., Silva, A. M. S (2011). Oxidation mechanisms occurring in wines. Food Research International. 44: 1115–1126.