# Advance on the Capitalization of Grape Peels By-Product in Common Wheat Pasta
## 1 Introduction  
Food processing trends are heading more and more to waste reduction and sustainable approaches in order to diminish the impact of these activities on the environment. Large amounts of by-products resulted can be used as alternative ingredients to create value-added food or extract bioactive compounds. One of the industries that generate byproducts with high functional properties is winemaking. Grape vine (_Vitis vinifera_ L.) is cultivated all over the world, the total surface in 2020 summing up more than 7.3 million hectares, with a production of 230 mhL wine [1]. Grape pomac represents about 20-30% of the grape weight, with grape peel counting 63-75% of the total pomac [2]. Therefore, the disposal of such by-products greatly impacts the environment, the main uses being oriented towards animal feed or compost. Furthermore, some processors resort to the discarding of grape pomac on the soil without any pretreatment which will determine acidification due to the low pH of pomace and oxygen consumption in soil and ground waters caused by tannins and other compounds' presence [3, 4]. Common wheat flour is used for pasta production mainly in countries where durum wheat is less accessible and more expensive [5]. Refined wheat flour presents a low nutritional value due to its proximate composition, grain parts like bran and endospermare discarded during milling, depending on the extraction rate. Refined wheat flour has an extraction rate of 75% and thus presents low amounts of fiber, vitamins, minerals and bioactive compounds compared to whole wheat [6; 7]. The lack of fiber in the human diet could be related to negative effects on the digestive system. Thus, the supplementation of wheat flour with various fiber-rich ingredients drew increasingly attention from researchers and producers. Grape by-products give many health benefits due to the presence of bioactive compounds which are kept in grape pomace even after processing. Grape pomace has more than 60% dietary fiber [7; 8], the main fraction being insoluble dietary fiber represented by cellulose and hemicelluloses. Nevertheless, soluble dietary fiber is also found in grape by-products and exerts many health benefits given by water-soluble polysaccharides such as \(\upbeta\)-glucan, pectin and gum [9]. It was demonstrated that grape pomace could act as a prebiotic in the colon due to its ability to ferment, acting as a substrate for the colon microbiota [7; 10]. Grape by-products bioactive compounds include flavonoids such as anthocyanins, resveratrol, tannin and quercetin with antibacterial, anticancer, antioxidant and anti-inflammatory activities, hepatic and cardiovascular protection and chronic diseases prevention properties [11; 12; 13; 14; 15]. The proximate composition of grape pomace includes proteins, lipids and carbohydrates, the main micronutrients represented by vitamins and phenolic compounds that exert antioxidant activity against free-radicals [16; 17]. The chemical composition of grape by-products depends on various factors such as cultivar, climate, ripening stage and soil [18]. In food products supplementation for functional value increase, the use of valuable bioactive compounds is an essential goal to satisfy the diversified, escalating market demand. There are some studies revealing the possibility to use wine grape by-products such as pomace, peels and seeds in bakery and pasta products, as it was summarized in our previous work [19]. According to the results presented by [PERSON] et al. [20], grape marc incorporation in durum wheat pasta led to significant improvement of phenolics and anthocyanins contents and antioxidant activity compared to the control, higher bioaccessibility of polyphenols and lower glycemic index being obtained. Regarding cooked pasta texture, a decrease of firmness, adhesiveness and elasticity was reported, probably due to the gluten dilution effects [20]. [PERSON] et al.