Technical Yearbook 2024

Clarifying efficacy Figure 3 shows that the molecular mass of plant-based proteins influences their clarifying ability. Controlled hydrolysis can increase the clarifying ability of these proteins. As a comparative example, gelatine with a low degree of hydrolysis (100 Bloom degrees) clarified Trebbiano wine to 5 NTU and Sagrantino wine to 2 NTU (data not shown).

10 15 20 25 30 35 40 45 50

TREBBIANO SAGRANTINO

NTU

0 5

CONTROL

PEA PROTEIN PEA PROTEIN MODERATE HYDROLYSIS

POTATO PROTEIN POTATO PROTEIN MODERATE HYDROLYSIS

FIGURE 3. The effect of hydrolysis on pea and potato proteins. Figure 4 shows the clarifying ability of potato proteins with different degrees of hydrolysis in two wines. The treated wine samples were purposely photographed in front of a background with horizontal black lines to make the difference in turbidity obtained more visible. FIGURE 3. The effect of hydrolysis on pea and potato proteins. Taking a long leap forward and arriving at the last decades of possible plant sources, given the potential allergenicity (Annex III European Directive 2007/68/EC)

Three-dimensionally, these molecules have a compact quaternary structure consisting of hexamers and tetramers with molecular masses varying between 380 KDa (hexamer ligumina) and 150 KDa (trimester vicillin). Potato proteins: chemical characteristics Potato ( Solanum tuberosum ) proteins are produced by two industrial potato processing processes: starch production and frying potato chip production. Chemically, the proteins in potato juice from chips represent the most homogeneous group. These compounds, belonging to the glycoprotein family, have a molecular mass of about 40KDa and an isoelectric point between 4.5 and 5.2. At neutral pH and room temperature, patatin is a dimer stabilised by hydrophobic forces. Changes in pH significantly affect its three-dimensional structure, and temperature above 60°C easily causes its denaturation. Solubility differences between plant-based proteins and animal proteins It is important to note that plant proteins are only partially soluble,

winemaking history, we can see that although the goal of improving the general characteristics of wine has not changed, the objectives are now more detailed (e.g., reduction of astringency, improvement of colour hue, increase in olfactory cleanliness, etc.). The compounds used have also been purified (e.g., from milk to potassium caseinate, eggs to albumin, etc.). The emergence of bovine spongiform encephalopathy (mad cow syndrome – UK 1986), the subsequent prohibition of blood albumin, and the rise in allergies and intolerances caused by milk and egg proteins created a pressing need for alternatives. In response to these health and safety concerns, the wine industry began to search for other options for animal-based clarifying proteins that could offer a better reputation and wholesomeness. Over the past two decades, many studies have been carried out on the oenological application of various categories of plant-derived proteins, such as proteins from legumes (soybean, pea and lupin), cereals (wheat, corn and rice), and tuberous plants such as potato. Among these

and the actual availability of products, only pea and potato proteins have an increasingly widespread and growing application today. The current OIV monograph on plant-based proteins (COEI-1-PROVEG 2016) considers wheat, pea and potato proteins usable. This monograph will be updated by excluding wheat (gluten) proteins from oenological use. This choice is because although the absence of post treatment gluten residues has been proven by ELISA tests, for reasons of potential allergenicity, no producer is interested in using them. In this article, we describe the oenological performance of pea and potato proteins. Pea proteins: chemical characteristics Pea proteins are extracted from the yellow pea ( Pisum sativum ). Many existing studies to chemically characterise pea proteins indicate that these proteins are represented by globulins and albumins with the function of storage proteins used as a nitrogen source during the seed germination stage. Globulins, present in greater quantities, are represented by legumin, vicillin and convicillin.

unlike animal proteins. Due to reactivity related to the surface

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TECHNICAL YEARBOOK 2024