# Technological Aspects and Potential Cutaneous Application of Wine Industry By-Products
## 1 Introduction  
In 2022, wine production volume was estimated at between 257 and 262 million hectoliters (mhl), and the top four producer countries were Italy (50.3 mhl), France (44.2 mhl), Spain (33.0 mhl), and the United States (EUA) (23.1 mhl) [1]. According to [PERSON] et al. [2], each liter of wine produces around 166 g of grape pomace. Wine by-products contain a wide variety of compounds, such as nitrogen, salts, fats, and the main ingredients of economic interest, \"natural antioxidants\", notably phenolic compounds, representing up to 20% of all wine biomasses (seeds > skin > pulp) [3; 4; 5; 6; 7; 8; 9]. Winemaking is an important market in the food industry. About 30% of vinified grapes represent nearly 20 million tons of by-products [10], which can be reused for different purposes, such as in agriculture, livestock, distillery, biorefinery, and as a potential source of phytochemicals for health [10; 11]. However, when wine by-products are discarded without proper treatment, they can cause environmental concerns for the water system,animal and insect infestations, and soil acidification [5; 7; 8; 12]. Although the European Commission Decision 2000/532/EC includes waste from agriculture and horticulture, by-products from wine and beer production remained excluded, unlike spirit distillation residues [4; 13]. About 70% of grapes' phenolic content remains in the organic residue (Table 1) [6; 14]. The chemical composition and bioactivities of wine residues can be influenced by edaphoclimatic conditions and winemaking technology, including similar varieties grown at other sites [7; 11; 15]. Grapes are rich in health-promoting polyphenols [3; 5] and _Vitis vinifera_ L. is one of the most used polyphenol-rich grape species cultivated worldwide to produce wine, surpassing 70 million tons [5; 16; 17; 18]. The synergy of the circular economy involves reducing wine grape pomace and increasing the useful life of bioresources [7; 27] as functional food, nutraceutical, pharmaceutical, and cosmetic ingredients [5; 7; 28], which contributes positively to the environment, society, and the economy itself, as recommended by the United Nations Sustainable Development Goals [27]. Winery biowaste management strategies (first and second generation) are requirements for the development of a sustainable bioeconomy [16; 29]. First-generation biowaste is sent to facilities for composing, landfill, or biogas via anaerobic digestion; second-generation biowaste is directed to green technology, valuing products such as seed oil, fibers, tartaric acid, squalene, and ethanol, for example [2; 29]. It should also be taken into consideration that in many European and non-European countries, more than 5% of organic waste is prohibited in landfills. Winemaking residues with lower investment and transportation costs may be recycled if cooperatives in strategic locations assist the wineries. In Bulgaria, for example, waste-free technology was introduced to process winemaking by-products [8]. In this review, we aimed to present different extraction and encapsulation technologies of biologically active compounds from wine by-products (_Vitis vinifera_ L). We also focused on a particular application of such compounds towards the development of value-added skin protection products aligned with a sustainable circular economy. From our perspective, we believe this review could encourage the following: sustainable development of a circular economy based on wine agroindustry (zero waste and reduction in environmental damage and damage to living beings); the recovery of active compounds from winemaking residues to obtain products with high added value for health, especially for skin protection; increasing the visibility of functional polyphenols from _V. vinifera_