## 1 Introduction  
With recent economic growth and increasing interest in health among consumers, the demand for health-oriented products containing functional ingredients rather than traditional materials has increased. Consequently, the food industry is experiencing a growing trend to emphasize both functionality and nutritional value, leading to active research on traditional food processing and the use of bioactive compounds [1]. Yanggaeng is a traditional Korean dessert made from agar and red beans. Modernization of traditional foods using naturally derived functional ingredients has been widely explored. For example, Yanggaeng products containing mugwort [2], black sesame [3], purple sweet potato [4], and ginger powder [5] have been developed [6]. Agar, a key ingredient of Yanggaeng, is a natural substance extracted from seaweed that promotes the growth of beneficial intestinal bacteria, improves bowel movement, inhibits cholesterol absorption, and regulates blood sugar levels, making it a valuable raw material for the development of health-oriented foods [7].  
Grape (_Vitis vinifera_), a deciduous climbing plant belonging to the Vitaceae family of the order Rhamales, is rich in organic acids such as tartaric, malic, and citric acids, as well as vitamins. A wide range of food development studies utilizing grapes has been conducted, including muffins containing grape powder [8], Yanggaeng with Juice grape juice [6], various grape-based products [9], baking using grape seeds [10], green grape konjac jelly [11], grape jelly [12], and grape vinegar [13; 14]. Grapes contain abundant antioxidants, such as polyphenols and anthocyanins, contributing to enhanced immunity, anti-aging effects, and cardiovascular health [6]. These functional compounds are primarily found in the grape skin and seeds [15].  
Flavonoids are key compounds that influence the color, taste, and health benefits of grapes and are mainly present in the skin and seeds. Flavonols protect grapes from ultraviolet radiation and contribute to the color stability of wine [16]. Flavonols are responsible for the bitterness and astringency of wine [17].  
Although the development of grape-based food products has been actively pursued [9; 11; 12], only a few studies have reported Yanggaeng made with Juice grape juice. However, research comparing Yanggaeng formulated with grape juice and grape powder remains limited. It is necessary to investigate the functional and physicochemical properties of Yanggaeng depending on the form of grape used. Grape powder, which contains concentrated solids and bioactive compounds, offers advantages in terms of functionality, whereas grape juice contributes more to the flavor and aroma [18]. These differences may affect the final product characteristics in distinct ways.  
Therefore, the aim of this study was to develop Yanggaeng using three commercially cultivated grape varieties in the Republic of Korea (Campbell Early, Kyoho, and Shine Muscat) [19] and to compare and evaluate the quality characteristics of products using grape juice (S) and freeze-dried grape powder (P). The grape varieties used in the present study exhibited distinct characteristics. Campbell Early is characterized by dark purple-black berries with a waxy bloom, thick but easily peelable skin, and abundant sweet juice. Kyoho features large, deep purple clusters with soft, sweet flesh that is rich in juice and nutrients. Shine Muscat has yellow-green seedless berries with a firm, crisp texture and a distinctive muscat aroma, making it suitable for transportation. This study aimed to promote awareness of Korean desserts and provide fundamental data for future product development.