## 1 Introduction  
Jujube (_Ziziphus jujuba_ Mill.) belongs to the _Rhamnaceae_ family and grows in subtropical areas [1]. China, Spain, and India are the main producers of jujube [2]. Approximately 700 cultivars of jujube are produced in China [3]. Jujube is a medium or large deciduous tree and its fruits are oval or round. Unripe jujube fruits are green, smooth, and taste like apples. When ripe, the fruits turn red, brown, or purplish-black [4]. Jujube bark is used as a remedy for flatulence, diarrhea, and vomiting. Jujube leaves are used for cold relief, decongestion, and mitigating diabetes symptoms and are consumed as a tea. Jujube flowers have high-quality nectar. Jujube fruits are used in traditional Chinese medicine because of their antiaging, immunomodulative, anticancer, sedative, hypnotic properties and other effects [5; 6; 7; 8; 9].  
Jujube fruit is rich in nutrients, including sugars, fatty acids, amino acids, polyphenols, flavonoids, fiber, and minerals such as calcium, magnesium, and iron [10; 11]. Jujube is a seasonal fruit and deteriorates rapidly after harvesting; therefore, it is typically dried for storage [12; 13]. It has been widely used as a food, a food additive, flavoring, and in processed forms such as jams, breads, cakes, and jelly [14; 15].  
There are different methods proposed to extract jujube fruit. [PERSON] et al. used ultrasound-assisted aqueous two-phase extraction by an ethanol/ammonium sulfate system as a multiphase solvent to extract polysaccharides from jujube fruit [16]. [PERSON] et al. applied subcritical water extraction at specific temperatures (ranging from 110 to 150 \({}^{\circ}\)C) and six atmospheric pressures to extract polysaccharides from jujube fruit powder [17]. [PERSON] et al. reported that ultrasonic extracts of pear-jujube fruit with methanol solution had a total phenolic content of 7.69 mg gallic acid equivalent (GAE) per gram fresh weight [18]. Furthermore, many solvent-based extraction methods were reported to extract jujube. For examples, [PERSON] et al. used 80% ethanol to extract jujube and found peel had a higher total phenolic content, 32.8 mg GAE per gram dry weight (DW), than pulp and seed [1]. [PERSON] et al. used 95% ethanol to extract seven cultivars of Chinese jujube and reported 4.54 to 12.99 mg GAE/g DW of extracts [19]. [PERSON] et al. used 80% methanol solution to extract jujube fruit and found 11 to 24 mg GAE/g DW of pulp extracts [20]. Solvent-based extraction is the most widely used method for extraction of natural products. It offers an easy and convenient way for extraction and does not destroy compounds.  
Gong-Guan, Maioli, is the main area of jujube cultivation in Taiwan [21]. In this study, jujube fruit from Miaoli was used as the object of antioxidant research. Many papers have revealed that jujube fruits from Spain [22], China [19], India [23], and Taiwan [24] have considerable antioxidant capacities. Studies on the antioxidant capacities of jujube fruit have focused on extraction using different solutions or on comparison of the antioxidant capacities of different cultivars [10; 13; 19; 25]. Limited information is available on the antioxidant capacities of different parts of jujube fruit. Therefore, this study investigated differences in antioxidant capacities between the seeds and peel pulp of Miaoli jujube fruit extracted using deionized (DI) water and 50% ethanol under different temperatures.