A Novel Method for the Quantification of White Wine Mannoproteins by a Competitive Indirect Enzyme-Linked Lectin Sorbent Assay (CI-ELLSA).

Matteo Marangon,Andrea Curioni,Mara Vegro,Alberto De Iseppi,Giovanna Lomolino,Simone Vincenzi

doi:10.3390/molecules23123070

Matteo Marangon, Andrea Curioni + Show 4 more

Open Access

https://doi.org/10.3390/molecules23123070

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Abstract

Mannoproteins (MPs) are cell wall proteoglycans released in wine by yeast during fermentation and ageing on lees, a procedure used for the production of several wines to enrich them in these components with consequences from both a technological and sensory point of view. Given the significance that wine MPs have for wine quality, winemakers would welcome a simple and accurate method for their quantification, as this would allow them to have a better control of this aspect at different winemaking stages. This study develops and validates a novel, simple and accurate method for MPs quantification in white wines based on a competitive indirect enzyme-linked lectin sorbent assay (CI-ELLSA), using the highly mannosylated yeast invertase as the standard. The method utilizes the lectin concanavalin A (ConA) as the immobilized ligand for MPs, and peroxidase, an enzyme rich in mannose, as the competitor for ConA. After addition of the peroxidase substrate, the intensity of the signal produced by the activity of this enzyme (absorbance at 450 nm) is inversely proportional to the amount of mannosylated proteins in the sample. Results have been validated on several wine styles including still, sparkling and sweet wines.

Highlights

Mannoproteins (MPs) are the second most abundant class of polysaccharides found in wine [1,2,3].They are located in the outermost layer of the yeast cell wall and can account for up to 50% of the cell wall dry mass of Saccharomyces cerevisiae [4]
The results of the CI-enzyme-linked lectin sorbent assay (ELLSA) method were intentionally not validated against previously published methods as none of them can be considered as the reference method for MPs quantification
Abs450 decreased at increasing concentration of yeast invertase, indicating that this mannose-rich glycoprotein was able to compete with peroxidase for binding to the concanavalin A (ConA) adsorbed on the plates

Summary

Introduction

Mannoproteins (MPs) are the second most abundant class of polysaccharides found in wine [1,2,3]. They are located in the outermost layer of the yeast cell wall and can account for up to 50% of the cell wall dry mass of Saccharomyces cerevisiae [4]. Wine MPs generally have protein contents ranging between 1% and 10% [1,5], and have been reported to have sizes that vary within the range 5–800 kDa [6], with typical range between 50 and 500 kDa [1]. MPs can: (i) act as protective colloids increasing the wine heat [13,14,15] and cold stabilities [16]; (ii) contribute to the growth of malolactic bacteria [17]; (iii) reinforce the aromatic components of a wine [18,19]; Molecules 2018, 23, 3070; doi:10.3390/molecules23123070 www.mdpi.com/journal/molecules (iv) contribute to the gustatory sensations of texture, roundness and mouthfeel [20,21,22]; (v) participate in the formation and stabilization of sparkling wine foams [7,12,23]

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