## 1 Introduction  
Incorporation of various bioactive components into food systems towards enhancing the nutritional properties is an active research area within the functional food and nucleutracuticals industry. Directly incorporating these bioactive ingredients into food systems is most times restricted due to their instability under various food processing techniques, thus limiting their industrial applications [1]. In this context, encapsulation is an excellent technique involving integrating these bioactive food components into small capsules [2]. Thus, retaining the bioactive components within a protective wall tends to provide a barrier from extreme processing conditions (heat, moisture, chemical reaction), thereby increasing their stability [3]. The selection of wall material for encapsulation plays a vital role. Casein micelles are the cheapest and most familiar wall material, which possess various properties, such as surface activity, emulsifying, gelling and self-assembling [4]. Casein micelles exhibit flexible conformations that cause the prolongation of powders rehydration in aqueous solutions, with much slower premature release of encapsulated bioactives [5]. Casein micelles are also stable against various unit operations applied within food processing [6], such as heating, freezing and drying [7]. Most recently, casein micelles were used successfully to protect, \(\alpha\)-tocopherol [8], Benzydamine [9], jaboticaba extract [10], blueberry anthocyanin [11], curcumin [12], quercetin [13] and anthraquinones [14]. Several researchers have developed diverse encapsulation techniques to protect the bioactive components in casein micelles by preparing nanoemulsions that enhance bioavailability by increasing the surface area to volume ratio [15; 16; 17]. However, spray-drying is one of the most valuable and efficient single-step microencapsulation techniques because it can evaporate water rapidly and maintain a relatively low particle temperature [18]. Furthermore, spray-dried powders have excellent technical properties, such as excellent rehydration capacity, high fluidity, and long shelf life [19]. Spray drying is also beneficial for encapsulating various heat-sensitive food ingredients such as polyphenols, flavonoids, anthocyanins, prebiotics, phytosterols and polysaccharides because of limited temperature rises within the matrix during the drying process [20; 21]. The surface of the particles stays wet for most of the drying time, and the local ambient temperature does not exceed the wet-bulb temperature. Ultimately, the structural modification of temperature-sensitive compounds stays limited [22]. Our previous article used ultrasonication to encapsulate anthraquinones extracted from Aloe vera into casein micelles [14]. The study concluded that the incorporation of Anthraquinone powder resulted in the highest encapsulation efficiency and yield as opposed to in cooperation of spray-dried powder of aloe vera (SDP), freeze-dried powder of aloe vera (FDP) and whole leaf aloe vera gel (WLAG) based on the anthraquinones to casein micelles ratio, the structure of the anthraquinone, and pH of the solution. However, using these nanocapsules in liquid form while developing functional foods is sustainable due to their perishability and effect on the product's consistency and texture. Hence, all prepared nanocapsules have been spray dried and powders have been evaluated for possible undesirable changes to casein micelles' color and structure due to the Maillard reaction. The obtained powders must possess better applicability within the food industry due to logistical advantages such as less transport cost, easy handling, and more shelf life. According to that knowledge, this study aimed to dry the encapsulated nanoemulsions through spray-drying to understand the drying effect on the encapsulation efficiency and structure of casein micelles. Moreover, to date, no study has been conducted to determine the stability of these anthraquinone-encapsulated casein micelle solutions when subjected to spray-drying.