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…

Study of the content of amino acids and biogenic amines in sparkling red wines

The production of red sparkling wines is lower in Spain in comparison with the winemaking of white or rosé sparkling wines. In red sparkling wine processing it is essential to obtain suitable base wines that should have moderate alcohol content, high acidity, good color values, an adequate mouth-feel and a sweet tannin. Grapes for sparkling wine production have to be harvested at low maturity stages, with lower alcohol contents and higher acidities, which will that the phenolic maturity of the grapes is also low, showing green tannins. This paper analyses different treatments in order to minimize these inconveniences: cold maceration-prefermentation and delestage to elaborate the grapes with lower maturity, must nanofiltration, and the partial osmosis of the wines made from grapes with an adequate maturity degree.

Colour assessment of port wines using colorimetric and spectrophotometric methods

Colour is an important quality parameter in wines and is the result of a complex mixture of pigments
(including anthocyanins and their derivatives, quinones, xanthyllium compounds, etc.). Red wine colour changes over time as pigments react between themselves and with other wine macromolecules
(particularly polyphenols). During wine tasting, colour is normally assessed on the outer rim of the wine profile in a tilted glass, since most wines are too opaque to be analysed in the middle of the glass. Therefore, depending on the depth of observation considered, the perception of wine colour can be different.

Non-invasive headspace sorptive extraction for monitoring volatile compounds production by saccharomyces and non-saccharomyces strains throughout alcoholic fermentation

Wine is a solution containing abundant volatile compounds which contribute to their aroma. Many of them are produced by yeast as metabolism by-products. Different yeast strains produce different volatile profiles. The possibility of studying the evolution of volatile compounds during fermentation, using sampling methods that not alter the volume of fermentation media, is of great interest. In spite of this, non-invasive methods to monitoring the evolution of volatile profile during fermentation have been seldom used. The goals of this work were to use by first time the headspace sorptive extraction (HSSE) as non-invasive method to monitor the evolution of volatile profiles throughout alcoholic fermentation and to study the changes on volatile profiles produced by Saccharomyces cerevisiae and Lachancea thermotolerans during fermentation of a must with high sugar content.

Identification of green, aggressive and hard character of wines by a chemo-sensory directed methodology

With climate change, it is progressively more often to obtain grapes with an acceptable content in sugars or acids but with immature tannins described as green, aggressive or hard (noted as GAH onwards). During winemaking, the oenologist has to make decisions related to the elaboration of such grapes based mainly on empirical experience, given the lack of objective criteria to this concern. An increase in the chemical and sensory knowledge of immature tannins would allow managing this GAH character of grapes with the maximum possible efficiency during winemaking processes. The present work aims at isolating and identifying the group of compounds responsible for the GAH character present in wines.

Metabolomic profile of red non-V. vinifera genotypes

Vitis vinifera L. is the most widely cultivated Vitis species which includes numerous cultivars. Owing to their superior quality of grapes, these cultivars were long considered the only suitable for the production of fine wines. However, the lack of resistance genes in V. vinifera against major grapevine pathogens, requires for its cultivation frequent spraying with large amount of fungicides. Thus, the search for alternative and more sustainable methods to control the grapevine pathogens have brought the breeders to focus their attention on other Vitis species. In fact, wild Vitis genotypes present multiple resistance traits against pathogens, such as powdery mildew, downy mildew and phylloxera.