## 1 Introduction  
Prickly ash (_Zanthoxylum bungeanum_) is a deciduous shrub, or small tree, from the Rutaceae family and the _Zanthoxylum_ genus [1]. It is widespread in tropical and subtropical regions, including Asia, America, Africa, and Oceania [2]. Prickly ash is a popular spice that enriches the flavor and color of food and masks unpleasant odors. Prickly ash peel oleoresin (PPO) is the liquid concentrated essential oil extracted from prickly ash using organic, or super/subcritical solvents, which has a much stronger aroma and flavor than the original plant material, as well as medicinally useful biological activities [3, 4]. Studies suggest that flavors, such as linalool, D-limonene, \(\alpha\)-pinene, and \(\beta\)-myrcene, found in PPO not only significantly contribute to the presentation of woody, balsamic, and other flavors but also have biological activities, such as antioxidant and antibacterial [3, 5, 6, 7]. However, the quality, sensory attributes, and flavor compound composition of PPO degrade during transportation and storage. The flavor compound content of PPO decreased at temperatures above 70 \({}^{\circ}\)C [8] and some key flavors degraded, increasing the bitterness of PPO. The volatility and instability of these compounds restricts the potential applications of PPO. Microencapsulation is the conversion of essential oils into solid powders by embedding, which is a good potential approach for stabilizing and extending the shelf-life of oils and can reduce the formation of unpleasant flavors and odors, maintain biological activity, and expand the potential applications of PPO. Microencapsulation is a technique for packing a solid, liquid, or gaseous material into a sealed microcapsule and releasing its contents at a controlled rate under specific conditions [9]. Microencapsulation can effectively encapsulate flavor, stabilize the activity of sensitive compounds, such as vitamins and probiotics, against degradation, and maintain antioxidant capacity [10]. In recent years, microencapsulation of various plant-derived essential oils, such as lemon essential oil and sea buckthorn seed oil, has been used to stabilize their main components and extend their shelf-life [11; 12]. Various methods have been devised to prepare microcapsules, the most common of which are spray-drying and freeze-drying. Spray drying has a low cost for mass production and produces powders with excellent physicochemical properties, that are suitable for the rapid production of encapsulated flavor and essential oils [13; 14]. Freeze-drying needs much less water and is more suitable for microencapsulation of thermally unstable bioactive compounds [15], but is time-consuming and expensive, so it is not suitable for industrial production [16]. However, a systematic comparison between the two preparation methods has not been conducted for POM. The encapsulation efficiency (EE) achieved depends not only on the preparation method but also on the choice of encapsulating agent. Polysaccharides are the most widely used encapsulation materials for food use, of which maltodextrin (MD) has the advantages of high water solubility, neutral aroma and taste, low viscosity, and good oxidative stability in the presence of oxidizing encapsulated materials [10; 17]. However, MD sometimes has a suboptimal emulsification capacity and limited oil retention capacity, necessitating combination with other materials to enhance the EE [18]. Gum Arabic (GA) is a colorless plant polysaccharide exuded from acacia trees, which has good biocompatibility and biodegradability and is widely used in the food industry as an amphiphilic polysaccharide [19]. Soy protein isolate (SPI) is a major source of plant protein, because it has superior protein quality to those of other plant proteins, beneficial health effects, and can interact with small bioactive molecules through hydrophobic interactions, hydrogen bonds, and disulfide bonds [20].