## 1 Introduction  
In conventional wine processing, large amounts of grape pomace (GP) are produced annually, accounting for 25% of the original fruit mass [1]. Although GP represents an excellent source of dietary fibers and polyphenols, this renewable natural resource is still underutilized in nutraceutical products [2, 3]. However, deterioration of biologically active compounds caused by processing represents a major bottleneck for GP utilization in food production chains. Several studies have disclosed the possibility of creating value-added products by incorporating grape by-products in bakery products or pasta [4, 5, 6]. For example, the addition of GP to semolina has a positive impact on functional and physio-chemical properties of pasta such as adhesiveness, firmness and volatile profile. The inclusion of GP also leads to an increase in total polyphenol content and antioxidant activity and a decrease in the glycemic index as a result of an increase in resistant starch content [7]. As reported by [PERSON] and coworkers [8], grape peel powder also improves the technological properties of doughs used for the production of high quality gluten-free foods. The most economically viable approach of longterm storing GP is by reducing its highwater content (75-80%) by drying. That also leads to reduction in volume, thus lowering transportation costs. The drying method adopted is an important factor that affects both the content and activity of phenols, as well as functional properties of GP. In particular, high temperatures can compromise the bioactivity of thermally sensitive compounds. Thus, there is strong interest in the development of an economically and technically feasible technology for GP preservation at an industrial scale that results in a stable product with minimum presence of water and a high concentration of biomolecules. An optimal drying step could enhance the potential use of pomace as a powerful natural antioxidant ingredient in functional foods. To avoid the loss of bioactive compounds due to their thermal instability, freeze-drying is considered superior to oven drying [9]. However, this approach is time-consuming and too costly for industrial application [7]. However, as reported by [PERSON] et al. [10] freeze or oven dried (50 \({}^{\circ}\)C) GP skin showed no significant difference in total phenol content. Moreover, it has been shown that heat treatment over long periods can favorize the extraction of low molecular weight molecules, thus increasing their bioavailability [11]. Oven drying at 50\({}^{\circ}\) is preferred because it is faster, more reproducible and it allows for the storage of grape pomace [10]. GP stabilization and grape pomace flour (GPF) storage conditions play a significant role in their subsequent utilization as functional ingredients [12]. In fact, phenols (such as catechins, soluble acids, flavonoids, stilbenes and anthocyanins) and fatty acids present in GP exhibit antioxidative, cardioprotective, antidiabetic, gastroprotective and antilipemic effects [10]. The bioactive compounds that contribute to the positive health properties of grape-pomace-added foods are presumed to be poly and monounsaturated fats, fiber and antioxidants [13]. Moreover, previous studies [14; 15] have demonstrated potential applications of polyphenols in food preservation and product shelf life. In previous investigations, GP obtained from winemaking of white or red grape cultivars was studied for antimicrobial and antioxidant properties [14; 16]. The results suggested that the antioxidant and antimicrobial activities of different grape variety extracts were related to their phenolic profile. Given these results, flour pomace could be exploited for future applications in food, pharmaceutical and cosmetic industries. In this study, we prepared GPF as a functional food ingredient aimed at increasing the daily intake of dietary bioactive antioxidant compounds.