Macrowine 2021
IVES 9 IVES Conference Series 9 Some applications come from a method to concentrate proteins

Some applications come from a method to concentrate proteins

Abstract

All techniques usually used to assay proteins was not reliable in vegetable extract due to interferences with the components included in extracts like polyphenols, tanins, pectines, aromatics compounds. Absorbance at 280nm, Kjeldhal assay, Biuret and Lowry methods, Acid Bicinchonique technique and Bradford assay give the results depending on the composition of extract, on the presence or not of detergent and on the raw material (Marchal, 1995). Another difficulty in these extracts for the quantification of proteins comes from the large amount of water included in vegetable and the low concentration of proteins. Thus in red wines, proteins are usually not taken into account due to their low concentration (typically below 10 mgL-1) and to the presence of anthocyanis and polyphenols. Due to all these defects, alternative test should be developed. The perfect protein assay would exhibit the following characteristics: fast, easy to use, sensitive, accurate, precice and free from interferences. Futhermore this assay should be compatible with all substances commonly found in protein samples and at low concentration. Our purpose in this work is to combine the concentration of proteins by bentonite with separation electrophoretic 1D SDS Page and to examine some applications. First, wines were fined with 100g/hl of bentonite is largely sufficient to adsorbe all proteins (Paetzold and al.,1990). In these conditions, we observed at low concentrations of bentonite (under 20g/hl), the bentonite Electra® adsorbed only β glucanases and chitinases. Second after desorption by Laemmli buffer, proteins were separated by SDS-PAGE and quantified after coloration with Coomassie Blue R-250 by scanning coupled to the image analysis TotalLab software (Sauvage and al., 2010). The gels after destaining were scanned with a transmission scanner at 300 dpi to obtain a digitised image. The software compared the volume (area x intensity of each pixel) of each band to the volume of BSA band (included in standard file). Each band was characterized by the molecular weight and the quantity of proteins expressed in µg equivalent BSA. The sum of each band gave the total pool of proteins included in each sample. The standard deviation measured on 6 same sample on Chardonnay wine was 11%. The response was linear for each band up to 1µg/band. By this method we also got the relative composition of the majority of proteins. Last, but not least, proteins were desorbed from bentonite with buffer to denature proteins or only with a buffer to conserve the native form of proteins (like Tris buffer or NaCl solution). After this experimentation we checked if [1] Marchal R. Ph. Thesis, university of Reims, 1995.

[1] Paetzold M., Dulau L., Dubourdieu D. J.Inter.Sci.Vigne Vin, 1990, 24, 13-28. [2] Pocock K.F., Waters E.J. Aust.J.Grape Wine Res., 4, 136-139. [4] Sauvage F.X., Bach B., Moutounet M., Vernhet A. 2009, 118, 26-34.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Francois-Xavier Sauvage*, Patrick Chemardin

*INRA

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Influence of inactive dry yeast treatments during grape ripening on postharvest berry skin texture parameters and phenolic compounds extractability

Inactive dry yeast treatments in the vineyard are a tool used with the aim to improve the concentration and quality of secondary metabolites in grapes, leading to a better differentiation of the wines made from grapes differently treated. In this work, a foliar spraying treatment with yeast derivatives specifically designed to be used with the patent pending application technology of Lallemand Inc. Canada (LalVigne® Mature, Lallemand Inc., Montreal, Canada) was tested on Vitis vinifera L. cv. Barbera and Nebbiolo black winegrapes. The aim was to evaluate the effect of this treatment on the phenolic compounds accumulation, the skin physical-mechanical properties and the related phenolic extractability. Prior to analysis, the berries were sorted by flotation in order to evaluate their distribution by density class, and to determine the skin texture parameters of berries with different sugar contents, thus understanding also the ripening effect.

Innovations in the use of bentonite in enology: interactions with grape and wine proteins, colloids, polyphenols and aroma compounds.

The use of bentonite in oenology rounds around the limpidity and the stability that determine consumer acceptability. As a matter of fact, the haze formation in wine reduces its commercial value and makes it unacceptable for sale. Stabilization treatments are, therefore, essential to ensure a long-time limpidity and to forecast the formation of deposits in the bottle. Bentonite that is normally used in oenology for clarifying-fining purpose, shows a natural clay-based mineral structure allowing it to swell and to jelly in water and hence in must and wine.

Elicitors used as a tool to increase stilbenes in grapes and wines

The economic importance of grapevine as a crop plant makes Vitis vinífera a good model system to study the improvement of the nutraceutical properties of food products (Vezulli et al. 2007). Stilbenes in general, and trans-resveratrol in particular, have been reported to be responsible for various beneficial effects. Resveratrol´s biological properties include antibacteria and antifungal effects, as well as cardioprotective, neuroprotective and anticâncer actions (Guerrero et al. 2010 ). Stilbenes can be induced by biotic and abiotic elicitors since they are phytoalexins (Bavaresco et al. 2001).

Comparison of various storage conditions to preserve polyphenols in red-grape pomace

Red grape pomace, a waste from wine production, can be valorised by extracting polyphenols, high-added value compounds used in cosmetics or oenology. For use at an industrial level, using green extraction techniques, pomace need to be stored before being processed. The aim of this study is to test various storage conditions in order to maintain high level of polyphenols over 180 days, while keeping storage cost economically interesting. In a first step, different storage conditions (ambient temperature or cooled (4°C) temperature, anaerobic (saturation with N2) or aerobic conditions, and addition of sulphur dioxide (SO2)) were compared on small samples (1 kg) packed in plastic pockets. The quality of storage was assessed by following the optical density of the pomace extract at 280 nm (DO 280 expressed as mg/l eq gallic acid), which is an indication of the amount of remaining extractable polyphenols.

Characterization of free and glycosidically bound simple phenols in hybrid grape varieties using liquid chromatography coupled to high resolution mass (q-orbitrap)

Vitis vinifera is one of the most diffused grapevines over the word and it is the raw material for high quality wines production. The availability of more resistant interspecific hybrid vine varieties, developed from crosses between Vitis vinifera and other Vitis species, has generating much interest, also due to the low environmental effect of production. However, hybrid grape wine composition and varietal differences between interspecific hybrids are not well defined. Different studies revealed that wine consumption has health effects due to its high content of antioxidants, as phenolic compounds. In particular, simple phenols are appreciated not only for their physiological health benefits, including antioxidant, anti-inflammatory and cardioprotective effects, but also because they affect wines organoleptic profile and have a significant role in defining their nutritional characteristics.