Macrowine 2021
IVES 9 IVES Conference Series 9 Preliminar study of adsorption of unstable white wine proteins using zirconium oxide supported on activated alumina by atomic layer deposition method

Preliminar study of adsorption of unstable white wine proteins using zirconium oxide supported on activated alumina by atomic layer deposition method

Abstract

A common problem in wineries is haze formation after bottling, mainly caused by unstable proteins present in white wine. The most used material to eliminate these proteins is bentonite. This material effectively removes proteins, but it is very harmful to white wine since it removes all kinds of proteins and other essential compounds from wine. Zirconium oxide (ZrO2) has been shown to remove the proteins responsible for haze selectively, but ZrO2 must be modified to increase the active surface area that adsorbs the proteins. This work aims to use zirconium oxide properties to produce a porous material coated on the surface by a new impregnation technology such as atomic layer deposition (ALD), which is highly active and allows the selective removal of haze-causing proteins from white wine. Zirconium oxide is deposited on 6 mm alumina spheres by the ALD method. As a result, two modified materials (MM) are obtained and are compared with pure zirconium (ZP) and the control wine. Batch and continuous experiments are carried out, subsequently analysed for total protein content by Bradford and polysaccharide and protein content by HPLC. Preliminary results indicate that the spheres remove 10-20% of total proteins from white wine, where the content of proteins <25 kDa decreases and proteins of higher molecular weight are not affected. Pure zirconium in 3 mm discs removes twice as much protein as MM. However, zirconium content in MM is in the order of ~1% and has a lower surface area than ZP is 100% zirconium, but it has a higher active surface area. The polysaccharide content is slightly reduced, but pure zirconium removes more than MM. Therefore, we can conclude that there is a selective reduction of proteins, but this is not enough; this may be due to two aspects: the surface area of pure zirconium is higher than the modified material, and the content is also lower. Therefore, to improve the protein removal with the modified materials, it is proposed to increase the active surface area reducing the spheres’ size from the original 6 mm to 2-4 mm.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Daniela Silva

Department of Chemical and Bioprocess Engineering, Pontificia Universidad Católica de Chile, Chile ,Fernando Salazar, Laboratorio de Fermentaciones Industriales, Escuela de Alimentos, Facultad de Ciencias Agronómica y de los Alimentos, Pontificia Universidad Católica de Valparaíso, Chile Francisco López, Departament d’Enginyeria Química, Facultat d’Enologia, Universitat Rovira i Virgili, España Néstor Escalona, Departamento de Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Chile José Pérez-Correa, Departamento de Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Chile

Contact the author

Keywords

haze, unstable proteins, protein stabilization, protein removal, zirconium oxide

Citation

Related articles…

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Phenological characterization of a wide range of Vitis Vinifera varieties

In order to study the impact of climate change on Bordeaux grape varieties and to assess the adaptation capacities of candidates to the grape varieties of this wine region to the new climatic conditions, an experimental block design composed of 52 grape varieties was set up in 2009 at the INRAE Bordeaux Aquitaine center. Among the many parameters studied, the three main phenological stages of the vine (budburst, flowering and veraison) have been closely monitored since 2012. Observations for each year, stage and variety were carried out on four independent replicates. Precocity indices have been calculated from the data obtained over the 2012-2021 period (Barbeau et al. 1998). This work allowed to group the phenological behaviour of the grapevine varieties, not only based on the timing of the subsequent developmental stages, but also on the overall precocity of the cycle and the total length of the cycle between budburst and veraison. Results regarding the variability observed among the different grape varieties for these phenological stages are presented as heat maps.

Climate modeling at local scale in the Waipara winegrowing region in the climate change context

In viticulture, a warming climate can have a very significant impact on grapevine development and therefore on the quality and characteristics of wines across different spatial scales, ranging from global to local. In order to adapt wine-growing to climate change, global climate models can be used to define future scenarios, but only at the scale of major wine regions. Despite the huge progress made over the last ten years in terms of the spatial resolution of climate models (now downscaled to a few square kilometres), they are not yet sufficiently precise to account for the local climate variability associated with such parameters as local topography, in spite of these parameters being decisive for vine and wine characteristics. This study describes a method to downscale future climate scenarios to vineyard scale. Networks of data loggers have been used to collect air temperature at canopy level in the Waipara winegrowing region (New Zealand) over five growing seasons. These measurements allow the creation of fine-scale geostatistical models and maps of temperature (at 100 m resolution) for the growing season. In order to model climate change at pilot site scale, these geostatistical models have been combined with regional climate change predictions for the periods 2031-2050 and 2081-2100 based on the RCP8.5 climate change scenario. The integration of local climate variability with regionalized climate change simulations allows assessment of the impacts of climate change at the vineyard scale. The improved knowledge gained using this methodology results from the increased horizontal resolution that better addresses the concerns of winegrowers. The results provide the local winegrowers with information necessary to understand current processes, as well as historical and future viticulture trends at the scale of their site, thereby facilitating decisions about future response strategies.

First step in the preparation of a soil map of the Protected Designation of Origin Valdepeñas (Central, Spain)

This work is a first step to make a map of vineyard soils. The characterization of the soils of the Protected Designation of Origin (D.P.O.) Valdepeñas will allow to group the studied profiles according to their physico-chemical characteristics and the concentrations of most relevant chemical elements. 90 soil profiles were analysed throughout the territory and the soils were sampled and described according to FAO (2006) and classified according to and Soil Taxonomy (2014). All samples were air dried, sieved and some physico-chemical parameters were determined following standard protocols. Also, major and trace elements were analysed by X-ray fluorescence. The statistically study was made using the SPSS program. Trend maps were made using the ArcGIS program. The studied soils have the following average properties: pH, 8.3; electrical conductivity, 0,20 dS/m (low); clay, 18.8% (medium) and CaCO3, 17.1% (high). In the study for the major elements. The major elements of these soils are Si, followed by Ca and Al, with an average content of 203.7 g/kg, 105.5 g/kg and 74.0 g/kg respectively. On the other hand, 27 trace elements have been studied. Of all of them, it can be highlighted the average values of Ba (361.8 mg/kg), Sr (129.3 mg/kg), Rb (83.4 mg/kg), V (74.2 mg/kg) and Ce (70.6 mg/kg). Ba, V and Ce values are higher and the values of Sr and Rb are lower to those found in the literature. The discriminant analysis shows a percentage of grouping of 91%. The content of chemical elements together with the physico-chemical characteristics allows grouping the soils in 4 group according to their order in the classification to Soil Taxonomy; due to the importance of the Calcisols in Castilla-La Mancha, it has been decided to establish them as their own group even if they do not appear in Soil Taxonomy classification.

Mechanisms involved in the heating of the environment by the aerodynamic action of a wind machine to protect a vineyard against spring frost

One of the main consequences of global warming is the rise of the mean temperature. Thus, the heat summation by the plants begins sooner in the early spring, and by cumulating growing degree-days, phenological development tends to happen earlier. However, spring frost is still a recurrent phenomenon causing serious damages to buds and therefore, threatening the harvests of the winegrowers. The wind machine is a solution to protect fruit crops against spring frost that is increasingly used. It is composed of a 10-m mast with a blowing fan at its peak. By tapping into the strength of the nocturnal thermal inversion, it sweeps the crop by propelling warm air above to the ground. Thus, stratification is momentarily suppressed. Furthermore, the continuous action of the machine, alone or in synergy, or the addition of a heater allow the bud to be bathed in a warmer environment. Also, the punctual action of the tower’s warm gust reaches the bud directly at each rotation period. All these actions allow the bud to continuously warm up, but with different intensities and over a different period. Although there is evidence of the effectiveness of the wind machines, the thermal transfers involved in those mechanisms raise questions about their true nature. Field measurements based on ultrasonic anemometers and fast responding thermocouples complemented by laboratory measurements on a reduced scale model allow to characterize both the airflow produced by the wind machine and the local temperature in its vicinity. Those experiments were realized in the vineyard of Quincy, in the framework of the SICTAG project. In the future paper, we will detail the aeraulic characterization of the wind machine and the thermal effects resulting from it and we will focus on how the wind machine warms up the local atmosphere and enables to reduce the freezing risk.