# Physicochemical Properties and Sensory Attributes of Yanggaeng Treated with Citrus Peel Powder
## 1 Introduction  
In recent decades, global citrus fruit production and the fruit juice industry have experienced consistent growth. Citrus fruits serve a multitude of purposes, including consumption as fresh fruit, transformation into juice and concentrate, and utilization in byproducts such as essential oils [1, 2]. These versatile applications extend across various sectors, including the food and beverage, cosmetics, and fragrances industries [1, 2]. However, citrus fruit processing in these industries generates a significant amount of waste, primarily composed of citrus peels. The amount of citrus pome produced can vary based on the size and variety of citrus fruit being processed, as well as the processing methods employed. Collectively, citrus peels, seeds, and residual membranes represent a substantial portion of this waste. Typically, citrus peels, seeds, and leftover membranes account for50-60% of the overall weight of the fruit in the citrus processing industry [3]. According to a Food and Agriculture Organization (FAO) global report, 132 million tons of citrus were produced worldwide in 2020 [4]. Based on an estimate that approximately half to three-fifths of this weight constitutes citrus peel, the global production of citrus peel waste could be roughly estimated at 66-79 million metric tons. Citrus pomace stands as a significant waste byproduct in the citrus industry, and without proper management, it can lead to environmental contamination and various adverse consequences. The primary concern revolves around the release of methane gas during the decomposition of citrus peel in landfills [5; 6]. Methane is a powerful greenhouse gas that adds to the phenomenon of global climate change, and its emission escalates when substantial quantities of citrus peel are disposed of in landfills [5]. Additionally, the practice of open burning to dispose of citrus waste presents another challenge. The burning of pomace is prevalent in certain regions, particularly in developing nations, and results in the emission of carbon dioxide and other greenhouse gases into the atmosphere [6; 7; 8]. Furthermore, incinerating waste byproduct releases particulate matter and volatile organic compounds, pollutants that can have severe detrimental effects on both human health and the environment [6; 7; 8]. Given the harmful consequences of the considerable volume of citrus peel waste, it is imperative to explore strategies for converting this waste into valuable products that can yield economic benefits. Therefore, identifying sustainable and economically viable approaches to utilize citrus peel is essential to enhance the efficiency of the citrus processing industry. The most efficient approach to minimizing methane and carbon dioxide production stemming from citrus peels is to utilize them across various industrial sectors rather than merely disposing of them. Citrus peels are nutrient-dense resources, containing dietary fiber and an array of essential vitamins and minerals such as vitamin C, folate, potassium, and essential oils, which render them nutritionally valuable [2; 9; 10; 11; 12; 13]. Furthermore, citrus peels are rich in physiologically active functional polyphenols, including phenolic acids and flavonoids. The presence of these physiologically active compounds has prompted extensive research into possible applications of citrus peels within the food sector. Their ability to enhance nutritional composition, flavor, and aroma in various desserts has garnered significant attention, making them a focal point for research and product development across different dessert categories, including pan bread [14], yukgwa [15], rice cakes [16], sponge cakes [17], cookies [18], and madeleines [19]. Yanggaeng is a quintessential dessert snack that holds a special place in the hearts of Koreans, being one of their preferred nutrient-rich foods. At its core, Yanggaeng's primary ingredient is agar, mainly composed of dietary fiber.