# Application of Natural Antioxidants from Fruits Waste for Improving Egg Quality Characteristics
## 1 Introduction  
The growing consumer preference for natural, high-quality food products has led to an increased use of natural additives in food processing industries including poultry-raising industries. This shift has occurred because eggs are a major source of nutrients, essential for daily human consumption on a regular basis. The main characteristics of an egg and how acceptable is to the consumers depend on its nutritional quality (proteins and lipids) and the shelf life during storage, among other individual preferences [1]. One of the biggest challenges in European egg production systems is the ability to keep the nutritional value and eggs' freshness intact for longer periods since eggs are subject to degradation through lipid oxidation, bacterial contaminations, and moisture loss [2]. Generally, antioxidants can be classified as synthetic or natural. They are chemical compounds that can delay the starting point or slow the rate of lipid oxidation reaction in different biological systems [3]. According to [PERSON] et al., these chemicals stop other molecules from oxidizing and damaging cells [4]. Free radicals (atoms, molecules, and other substances with one or more unpaired electrons) are known to be produced during oxidation reactions [5]. Free radicals that are significant to biological systems come fromnitrogen and oxygen, known as reactive nitrogen species (RNS) and reactive oxygen species (ROS) [6; 7], and their mechanism of action was recently reviewed by [PERSON] et al. [7]. Since 1954, synthetic antioxidants artificially produced or synthesized using various techniques that were used to counteract free radicals and stop chain reactions in compound feeds are butylated hydroxytoluene (BHT), beta-hydroxy acid (BHA), and _tert_-butylhydroquinone. Compared to other compounds, their consumption by humans is not allowed due to toxicity reasons; but their use in animal diets is a common practice due to their low cost and availability [8]. Based on the legislations of the Food Drug Administration (FDA), European Food Safety Agency (EFSA), and FAO/WHO Expert Committee on food additives, in terms of safety intake, BHT has a limit of 100 mg/kg, BHA has a limit of 200 mg/kg, and TBHQ has a limit of 120 mg/kg [9]. However, in the last two decades, growing consumer concern over their safety and potential health risks have been raised [10; 11]. This aspect correlated with consumers' requests for safe and healthier products of animal origin and pushed the food and feed industries to explore natural alternatives to antioxidants for food products over the synthetic ones. Natural antioxidants, derived from plant sources, have gained significant attention from the research industry for their potential to provide a safer and more sustainable solution to address the above-mentioned concerns. Among numerous studied plants in the scientific literature, fruit-derived waste, which includes by-products, peels, seeds, and pulp, presents a promising, underutilized resource, often discarded during food processing, leading to significant environmental waste [12; 13]. Although, these by-products are considered waste, they are rich in bioactive compounds with antioxidant potential, like polyphenols, flavonoids, and vitamins, with proven in vitro and in vivo antioxidant properties [5; 14]. The effectiveness of antioxidants is usually measured based on the extent to which their utilization promotes health and food safety and prevents or minimizes lipid peroxidation [15] which produces toxic compounds that deteriorate the nutritional values of food products. In this context, the poultry industry has intensively started to explore the potential of incorporating fruit waste into poultry diets as a natural way of improving overall egg quality and lipid oxidation while exploring ways to extend their shelf life.