## 4 Potential of Bioactive Compounds Obtained from By-Products of the Wine Industry
### Feed and Food Industry  
The different compounds extracted from wine by-products and winery by-products can represent a significant value to the food and feed industry [166] (Table 3). These molecules or extracts can be used to produce enenological additives [167], obtain natural dyes [43], and obtain bioactive compounds [168]. In Europe, grape pomace is a highly valued by-product that is traditionally used for oil extraction, as well as a source of protein and tannins for animal feed [34]. The utilization of a winery by-products as a potential source of phenolic compounds has achieved great interest due to the multiple biological effects of these compounds as antioxidants and antimicrobials [6]. Extracts derived from grape by-products possess functional properties that make them useful in the development of a wide array of products. These applications range from food products to the inhibition of spoilage and pathogenic microorganisms, as well as the prevention of lipid oxidation [169]. The effects of natural antioxidants obtained from by-products produced from the wine industry have been studied in different raw materials for food industries, such as sunflower oil, fish oil, seaweed oil emulsion, beef, chicken, pork, and turkey meat, as well as in pre-prepared food, such as hamburgers, restructured meatballs, sausages, and marinated pates [170]. One of the main effects was related to their ability to delay lipid oxidation of these products during storage [171; 172]. Grape pomace ('Arinto' and 'Touriga', Monsaraz, Alentejo, Portugal) flour can be used in a natural, cost-effective, environmentally friendly, and socially beneficial way by employing it in the development of human food, such as crackers. In this way, traditional wheat flour was supplemented with grape pomace flour between 5% and 10% (\(w/w\)) to nutritionally enrich the product [166]. The findings indicate a preference for crackers with 10% pomace flour in both varieties regarding the parameters evaluated (color, taste, texture, purchase intention, and global appreciation) [166]. The crackers with the highest percentage of incorporated grape pomace flour were the most adopted and appreciated. Consequently, increasing the percentage of this ingredient in the future will promote improvement in the nutritional value of goods for human consumption [166]. [PERSON] et al. [173] tested the incorporation of 10 and 20% of grape pomace flour in the manufacture of muffins, and obtained a high level of acceptance for the 10% incorporation. The muffins produced had a lower protein content, were denser, and included more fiber and fat. Similarly, [PERSON] et al. [174] incorporated 6% of grape pomace flour in the manufacture of cookies, resulting in a better quality product with an improved flavor. Additionally, it was found that the phenol content and antioxidant potency of the cookie extract increased to 4.03 mg GAE.g\({}^{-1}\) of the cookie and IC50 0.72 mg. mL\({}^{-1}\) of the cookie extract, respectively, with increasing incorporation of pomace flour from 4 to 6%. Various studies have been conducted involving the incorporation of grape by-products in wheat bread [175; 176; 177]. [PERSON] et al. [177] incorporated different percentages (6, 10, and 15%) of grape pomace flour in wheat bread dough. It was found that the use of a mixture of wheat flour with grape pomace had a great impact on the rheological properties of the dough. The concentration of bagasse used was negatively correlated with the brightness and firmness of the bread, and also resulted in a reduction in water absorption. They also found that the cultivar from which the pomace is derived also has an impact on the properties of the bread produced, with the cultivar 'Zelen' leading to better results. Many nutraceutical compounds, particularly polyphenols, can be found in dried or lyophilized grape skins and seeds, as well as unfermented/semi-fermented and fermented varieties. These are commonly used to make infusions [178]. Grape by-product infusion is a method for valorizing grape by-products.