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…

Pesticide removal in wine with a physical treatment by molecular sieving

All along the winemaking process, conditioning and aging, wine is susceptible to be contaminated by different molecules. Contaminations can have various origins, related to wine microorganisms or as a result of an exogenous contamination. The aforementioned contamination of the wine can be caused by the migration of molecules from the materials in contact with the wine or by a contamination from exogenous molecules present in the air. Regardless of the source of the contamination, mainly two types of consequences can be observed.

Comprehensive exploration of wine aroma-related compounds as promoted by alternative vinification procedures in case of Zelen (Vitis vinifera L.) grapes processing

Not only vintner’s decisions in the vineyard, but also winemaker’s choices of technology approaches in the cellar play a significant role in the final wine style and quality. Whereas traditional technologies within chosen terroir are quite well explored and thus somehow predictable, there is no proper knowledge available on possible outcomes in case of implementing novel, alternative winemaking strategies. To reveal their effects on wine aroma compounds and sensory characteristics, two alternative strategies
(cryoextraction or addition of whole grape berries during last stages of fermentation) were compared to classical Vipava valley winemaking approach as normally used for an autochthonous variety Zelen. After separate vinification and bottling, all the experimental wines were subjected to semiquantitative metabolic profiling of volatile compounds (VOCs) by means of GC/MS and were then also sensorialy evaluated by pre-trained panel.

Influence of wood chips addition during alcoholic fermentation on wine phenolic composition

This study investigates the effect of wood chips addition during the alcoholic fermentation on the phenolic
composition of the produced wines. A series of wood chips, originating from American, French, Slavonia
oak and Acacia were added at the beginning of wine alcoholic fermentation. Besides, a mixture consisting
of 50% French and 50% Americal oak chips were added during the experimentation. The wine samples
were analyzed one month after the end of malolactic fermentation, examining various chemical
parameters such as total anthocyanins, total phenolic content, tannins combined with protein (BSA) and
ellagitannin content.

Field-grown Sauvignon Blanc berries react to increased exposure by controlling antioxidant homeostasis and displaying UV acclimation responses that are influenced by the level of ambient light

Leaf removal in the bunch zone is a common viticultural practice with several objectives, yet it has been difficult to conclusively link the physiological mechanism(s) and metabolic berry impact to this widely practiced treatment. We used a field-omics approach1 in a Sauvignon blanc high altitude model vineyard, showing that the early leaf removal in the bunch zone caused quantifiable and stable responses (over years) in the microclimate where the main perturbation was increased exposure. We provide an explanation for how leaf removal leads to the shifts in grape metabolites typically linked to this treatment and confirm anecdotal evidence and previous reports that leaf removal treatment at an early stage of berry development affects “quality-associated” metabolites (monoterpenes and norisoprenoids).

A combination of biotechnology tools and coopers elements for an alternative the addition of SO2 at the end of the malolactic fermentation in red wines or at the “mutage” for the “liquoreux” wines

In red wines the post-MLF SO2 addition is an essential event. It is also the case for the “mutage” during the elaboration of the “liquoreux”. At these moments SO2 plays an antimicrobial action and an antioxidant effect. But at current pH of wines, ensuring a powerful molecular SO2 has become very difficult. Recent work on Brettanomyces strains have also shown that some strains are resistant up to 1.2 mg / L of molecular SO2. It’s also the case of the some Saccharomuces or Zygosaccharomyces strains suitable to re-ferment “liquoreux” wines after the “mutage”.