# The Influence of Tomato and Pepper Processing Waste on Bread Quality
## 1 Introduction  
One of the major challenges facing the agri-food industry today is the elimination, reduction, or reuse of significant amounts of waste and by-products generated at various stages of the food production process [1]. These efforts align with the European Union's (EU) plan for a circular economy, which aims to reduce food waste, increase the value and longevity of products, and promote more efficient use of materials and resources in the economy [2]. According to data from the Food and Agriculture Organization (FAO), in the processing of oilseeds, approximately 20% of oilseeds are wasted, while for meat and dairy products, this figure is 20%; for grains, this figure is 30%; for fish, this figure is 35%, and for fruits and vegetables, it ranges from 40% to 50% [3]. Regarding total global food production, the amount of food wasted is estimated to be around 1.3 billion tons. Utilizing by-products from food processing that are rich in nutrients in new product development is a recommended approach for alleviating this [3; 4; 5; 6]. One potential source of by-products that can be used to modify food product recipes is vegetable processing waste, specifically tomato by-products (TP) and bell pepper by-products (PB). These by-products have been studied for their potential applications in various food products, contributing to reducing food waste and enhancing the nutritional value of food [7; 8; 9]. Previous research has shown that TP can be a good source of dietary fiber, with an approximate content of 61% on a dry basis, while PB has a dietary fiber content of approximately 33% on a dry matter basis [9]. Additionally, dried tomato waste, including seeds and skin, contains approximately 17-23% protein, and the placenta of bell peppers has a protein content of about 28% [8; 10]. Furthermore, both TP and PB are rich sources of lysine and sulfur amino acids such as methionine and cysteine, which can improve the overall protein quality of wheat-based food products [8; 9]. TP, which contain a large amount of seeds, are a rich source of bioactive compounds that have been shown to exhibit strong antioxidant, anticancer, and antimicrobial activity in numerous studies. Tomato seeds contain no antinutritive agents or toxic elements [11; 12]. The consumption of tomatoes is generally recognized as healthy, but as with all foods, there are limits and concerns to be mindful of. The vast consumption of tomato skin and seeds by humans may lead to irritable bowel syndrome, causing bloating and diarrhea [12]. Some research suggests that seed protein may be a relevant allergen, although whether it is predictive of systemic reactions remains to be determined [13]. Research also indicates that bell peppers are rich in phenolic compounds and flavonoids, which may offer benefits to human health. Diets rich in phytochemicals have been associated with a reduced risk of chronic non-communicable diseases, including diabetes, osteoporosis, and cancer. These beneficial effects are often attributed to the antioxidant capacity of polyphenols and flavonoids, which can help mitigate oxidative stress. The regular consumption of bell peppers can improve one's health and prevent degenerative diseases [14]. Bread is a widely consumed staple food globally, with an average per capita consumption of around 250 g per day [15]. It primarily provides carbohydrates (70-80% dry matter), proteins (10-14% dry matter), minerals (0.5-0.8% dry matter), and fats (0.7-1.35% dry matter). However, the dietary fiber content in bread is relatively low, typically around 2-3% [6; 16]. To enhance the nutritional value of bread, there is a growing trend of incorporating non-traditional raw materials, including high-protein waste products from the plant food industry [17; 18]. The introduction of additional ingredients, including by-products, into bread recipes not only affects the health-promoting properties of the resulting products but also the rheological characteristics of the dough. These changes can significantly impact the quality attributes of bread.