###### Abstract
Therefore, the purpose of this article was to trace the results of research relating to the nutritional, functional, pro-health, antimicrobial and technological properties of potato proteins, as well as the directions of their use resulting from the structure, molecular weight and fractionality of proteins, the raw material used and the methods of isolation and modification. The processing of potatoes in the starch industry requires the management of large quantities of protein by-products. These include the potato juice separated from the potato pulp and the pulp left over after washing the starch from the potato cells. Annually, the European Union processes around 8 million tons of potatoes in this way, which generates around 6 million m\({}^{3}\) of potato fruit juice (PFJ) and potato pulp in large quantities [1,2]. Potato fruit juice as a by-product in the starch industry contains only around 1-2% of crude protein. Obtaining proteins from such large-volume by-products is a challenge for the industry but, at the same time, enables the production of protein with high nutritional value and significant added value due to the use of raw material with a potential threat to the human environment [3, 4, 5]. The management of waste by-products from the starch industry contributes also to the acquisition of relatively inexpensive and non-allergenic protein preparations [6] with favorable functional properties, allowing for the replacement of soy or milk proteins traditionally used in food production. Depending on the conditions of the isolation process of proteins from waste products in the starch industry, especially potato fruit juice, the obtained preparations have different properties and there are different potential directions for their use. Potato proteins, isolated under industrial conditions by acid-thermal coagulation, are primarily used as a valuable feed. In 2017, 63.900 tonnes of fodder potato protein were produced in Europe [7]. In the starch industry, traditionally obtained dried potato protein for fodder purposes has an important position in the market, being a relatively cheap source of protein for pigs and young calves [8]. Some studies in this area also show a positive effect of potato proteins on the health of farmed pigs [9]. The use of thermally coagulated potato proteins in food production is very limited due to the low solubility, often too-high content of glycoalkaloids and unfavorable organoleptic characteristics of these preparations [10,11]. Many years of research and laboratory-scale methods of obtaining native potato proteins with favorable functional and nutritional properties [12, 13, 14, 15] have not been implemented into the industry. This could be due to the high costs of isolation and purification of protein preparations, resulting from the complex chemical composition and high conductivity of potato fruit juice [14], the too-high content of glycoalkaloids and potassium, as well as partial denaturation of proteins and loss of functional properties. There are high hopes associated with the developed methods of separating the two main groups of potato proteins, i.e., patatin and inhibitory proteins, which can be applied on an industrial scale. As the research of many authors has shown [1,2,14,16, 17, 18, 19, 20], preparations of each of these fractions are characterized by different properties, more favorable compared to preparations containing all potato proteins. Intensive research in the field of isolation and modification of potato proteins, from both potato fruit juice (PFJ) and pulp, creates more and more opportunities for their use. They result both from the high nutritional value and valuable functional, antioxidant, antiradical and anti-obesity properties of potato protein preparations. The growing interest of both consumers and producers in enrichment with plant protein, including vegetable protein, of highly processed foods is also important [5,9,21].