## 1 Introduction  
The rapidly expanding world population has led to unprecedented pressure on bioreactor utilization, provoking largely uncontrolled overexploitation, ecosystem degradation, and severe environmental aggravation. An issue of utmost concern pertaining to crop cultivation and food production is the generation of outstanding amounts of waste. This residual biomass consists of biological tissues of high organic load, and their improper management and excessive dumping in landfills entails imminent risks of environmental pollution as well as risks to ecosystem conservation and public health [1, 2]. On the basis of the above considerations, there has been to-date a wide recognition that linear economy models are both inefficient and environment threatening, and thus circular economy aspects are gaining universal acceptance by adopting sustainable routes of agricultural production and food manufacturing. One of the major pillars associated with establishing circular economy strategies is the exploitation of food wastes in order to produce high value-added compounds, energy, and plant-form chemicals [3, 4]. Plant food wastes are particularly rich in bioactive phytochemicals, such as polyphenols, which are a prominent family of phytochemicals possessing a spectrum of bioactivities [5]. This has oriented the relevant research towards the development of eco-friendly technologies for their effective recovery and valorization [6, 7]. Aside from the utilization of non-toxic, benign solvents, the development of green extraction of polyphenols comprises implementing innovative techniques, such as microwave-assisted extraction, ultrasound-assisted extraction, etc., which in some instances have been proven far more efficient than conventional extraction techniques. Furthermore, recent reports have also introduced organosolv treatments, which have been shown to be extraction processes of high efficiency [8]. The organosolv processes, originally developed for the pretreatment of biomass to increase the recovery and fermentability of cellulose, aim at disintegrating the cell wall lignocellulosic matrix [9; 10]. At the same time, cell wall degradation enables intracellular metabolite (polyphenol) liberation and the entrainment of these compounds into the extraction solvent (liquid phase) [11]. This results in increased mass transfer, and, hence, improved extraction yield. Ethanol is commonly employed in organosolv processes, but other alcohols have also been used for this purpose, such as butanol, glycerol, and 2-propanol [12; 13]. Additionally, acid catalysis, usually by incorporating sulfuric acid into the solvent system, may significantly enhance treatment performance [14]. Potatoes are tubers from the plant _Solanum tuberosum_, and they are consumed by large populations around the world. After cereals, the potato is the most important food crop, and the global production was over 368 million tons in 2018. Apart from being one of the most commonly consumed plant tissues, potatoes are regularly processed to produce a number of commodities, such as puree, chips, French fries, hash browns, etc. The potato processing industry is one of the largest, and accounts for the generation of waste streams caused mainly by removal of peels, which account for 15% to 40% of the initial fresh weight [15]. This is translated into the production of about 70 and 140 thousand tons of potato peels (PP) worldwide on an annual basis. Thus, owing to their abundance and composition, PP have been the subject of extensive research regarding their exploitation through biorefinery processes but also the production of polyphenol-enriched extracts. The major polyphenol encountered in PP is chlorogenic acid, usually accompanied by other isomers (i.e., neochlorogenic acid), and simple hydroxycinnamates, such as ferulic acid and caffeic [16]. Polyphenols are considered the principal bioactives in PP, to which an array of properties have been attributed.