# Utilization of By-Products from the Fruit and Vegetable Processing Industry in Pasta Production
## 1 Introduction  
According to the Food and Agriculture Organization (FAO) [1], one-third of all food produced globally for human consumption is wasted. This waste leads to the squandering of land, water, energy, labor, and, in general, money. Moreover, it imposes an environmental cost as it contributes to greenhouse gas emissions [2]. Among all sectors of the food industry, the fruit and vegetable sector generates the highest percentage of by-products, up to 50%, in the form of peels, cores, pomace, immature and/or damaged fruits and vegetables [3]. Fruits and vegetables are also the most discarded products in distribution, partly due to their short shelf life. Traditionally, these residues have been used for animal feed, fertilizers, or anaerobic digestion. However, organizations such as the United Nations Environment Programme, the European Commission, FAO, the World Resources Institute, among others, assert that reintegrating these residues into the human food chain is preferable to other uses.  
The composition of these residues depends on the type of fruit or vegetable processed and the processing method (canning, jam, juice, etc.). In general, these by-products are characterized by a high fiber content [3], and in many cases, they are rich in bioactive components, such as phenolic compounds, which confer a high antioxidant capacity [4, 5]. These features make them nutritionally valuable ingredients, but in many cases, they have an unpleasant texture and taste, which limits their incorporation into food products to small amounts. In recent years, studies on the extraction of fibers and bioactive components from fruit and vegetable residues have increased. However, these applications do not fully consume theresidues, often leaving a significant amount of new waste. Therefore, the potential utilization of the entire residue is generally a better option from an environmental perspective.  
In most cases, these by-products have a high water content and a heavy organic load, which leads to rapid spoilage due to the action of various enzymes and microorganisms [6]. Therefore, it is usually necessary to dry and mill them to produce powders with a long shelf life and easy incorporation into various formulations. Beyond the origin and composition of the residues, the drying and subsequent milling processes also affect the characteristics of these ingredients.  
Studies on incorporating these by-products into bakery products have significantly increased and have been the subject of various scientific reviews [7; 8; 9; 10]. Research on the use of these ingredients in various types of pasta has also grown, and although there is a relatively recent review [11], the number of new studies is substantial, warranting an updated review of the literature. Figure 1 shows the number of articles on the incorporation of by-products in pasta published in SCI journals, demonstrating a clear increase in recent years.  
Several reviews have been published on the composition and characteristics of by-products derived from fruit and vegetable processing, focusing on their nutritional components [12; 13; 14; 15; 16]. There are also reviews focusing on by-products from specific fruits or vegetables, such as banana [17], apple [18; 19], grape [20; 21], mango [22; 23; 24], citrus [23; 25], berry [26], as well as those derived from processes like winemaking [27]. Brewer's spent grain and residues from other alcoholic beverages have also been addressed in various reviews and are among the most studied by-products of the plant-based industry [28; 29; 30]. For this reason, this review will not delve into these aspects but will focus on the applications of these by-products in pasta production. Neither legal issues nor consumer attitudes towards such products will be addressed here. These factors are evolving, driven by increased awareness among authorities and consumers, as well as more accessible information, but they must be considered when marketing these products.