The Grade of Dried Jujube (Ziziphus jujuba Mill. cv. Junzao) Affects Its Quality Attributes, Antioxidant Activity, and Volatile Aroma Components

Jujube (Ziziphus jujuba Mill. cv. Junzao) has attracted a large number of consumers because it is rich in nutrients, such as carbohydrates, organic acids, and amino acids. Dried jujube is more conducive to storage and transportation, and has a more intense flavor. Consumers are affected by subjective factors, and the most important factor is the appearance of the fruit, including size and color. In this study, fully matured jujubes were dried and divided into five grades according to their transverse diameter and jujube number per kilogram. In addition, the quality attributes, antioxidant activities, mineral elements, and volatile aroma components of dried jujube were further analyzed. As the dried jujube grade increased, the total flavonoid content increased, which was positively correlated with the antioxidant activity. The results showed that small dried jujube had a higher total acidity and lower sugar–acid ratio than large and medium dried jujube, thus, large and medium dried jujube had a better flavor than small dried jujube. However, the antioxidant activity and mineral elements of medium and small dried jujube were superior to large dried jujube. From the edible value analysis of dried jujube, medium and small dried jujube were better than large dried jujube. Potassium is the highest among the measured mineral elements, with contents ranging from 10,223.80 mg/kg to 16,620.82 mg/kg, followed by Ca and Mg. Twenty-nine volatile aroma components of dried jujube were identified by GC–MS analysis. The main volatile aroma components were acids including n-decanoic acid, benzoic acid, and dodecanoic acid. The fruit size affected the quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. This study provided a piece of reference information for further high-quality production of dried jujube fruit.


Introduction
Jujube (Ziziphus jujuba Mill.) is a plant of the genus Ziziphus in the family Rhamnaceae. It has been cultivated for a long time and has many varieties in China [1][2][3][4]. Jujube contains numerous essential nutrients, vitamins, and minerals, and also has high medicinal value, with anti-obesity [5], antioxidative [6], antibacterial, and anti-hepatoma activities [7]. Jujube fruit can be eaten not only fresh, but also dried. In addition, jujube is one of the highest yield dried fruits in China [7]. Junzao, as a kind of dried jujube, has been high-profiled due to its high yield, outstanding tolerance, and excellent taste. In 2018, China produced 8.5 million tons of jujube and nearly 5.47 million tons of dried jujube. Among them, Junzao accounted for about 37% of the total dried jujube production [7,8].

Materials and Treatments
Jujube fruits (Ziziphus jujuba Mill. cv. Junzao) were hand-harvested at the commercial maturity stage at a local farm (Xinjiang, China) and dried in a ventilated oven (GZX-9240MBE, Boxun Co., Shanghai, China) at 45 • C for 72 h. According to the transverse diameter and the number of jujube fruits per kilogram, we divided the dried jujube without diseases and pests into five grades (G1, G2, G3, G4, and G5, respectively), as shown in Table 1, and then 500 g of jujube was randomly selected from each group for further experiments. Three biological replications were carried out.  TSS and TA content determine the taste and flavor of dried jujube. In Figure 1 TSS content of dried jujube ranged from 81.8% to 72.2%, and the smallest jujube (G the lowest TSS content. However, The TA content of dried jujube increased from 4. to 6.45 g/kg with the increase of grade from G1 to G5 ( Figure 1D). The sugar-acid the of five grades if dried jujube were 169.4%, 178.4%, 165.6%, 118.6%, and 111.9%, tively. These indicated that dried jujube of G2 have a sweeter texture and a more flavor.
Li et al. [29] studied the five cultivars of Chinese jujube and pointed out that th content and composition of jujube with different varieties and growing enviro vary widely. Chen et al. [22] also proposed that the TSS of fresh Junzao fruit fro different cultivation districts varied from 27.2% to 30.6%. However, the TSS of dried was even higher. The trend of moisture content in dried jujube was similar to tha TSS content, which indicates that moisture content in dried jujube may be related content. When the content of TSS is low, and the water in the fruit is easy to spread drying, and the drying efficiency is high, the moisture content is low. In addition, the G1 group, the change trend of moisture content in the other four groups was th as that of fruit shape index, which indicated that the drying effect was related shape, and the grade of dried jujube affected the moisture content. Khalid et al. [30 that mandarin fruit size is inversely proportional to TA content, which is similar conclusion. Similarly, they pointed out that a lower sugar-acid ratio is recorded i sized fruit in contrast to medium and large sized fruit [30]. The dried jujubes were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

TP and TF of Dried Jujube
Phenolics are the most common secondary metabolites in fruit, and they influence the quality, color, and flavor of fruit [31]. The composition and content of phenolics in fruit varies with the variety, texture, and processing of fruit. In Figure 2A, the TP content of dried jujube in different grades was similar, ranging from 8.54 g/kg to 9.14 g/kg. Wojdyło et al. [32] found 25 phenolic compounds in Spanish jujube, and total phenolic compounds (especially polymer proanthocyanin and quercetin derivatives) and ascorbic acid contributed significantly to the antioxidant capacity of jujube. The growth and development of jujube affected the TP content [20,33]. The maturity of different graded jujube was the same, which may be the reason for the little difference in the TP content. Barbagallo et al. [34] analyzed the TP content of grapes with different fruit size and found that the TP content decreased with grape weight and was affected by environment, region, climate, and other factors, thus, the phenomenon of TP content variation in this experiment could be explained.
Flavonoids are phenolic compounds that are widely found in fruits and are particularly important for human health [10,35]. Jujube is rich in flavonol glycosides composition, and the difference in variety and maturity can lead to differences in the flavonoid content in jujube [20,[36][37][38]. In Figure 2B, the TF content of dried jujube increased from 2.95 g/kg to 6.14 g/kg with the increase in grade of G1 to G5. These results indicated that fruit enlargement accelerated the consumption and decreased the accumulation of flavonoids. Barbagallo et al. [34] pointed out that the TF amount increased with grape size, which was similar to our results. TP and TF contents of fruit in different parts was also differ-Foods 2023, 12, 989 6 of 12 ent. Zhang et al. [10] found that the peel of all jujube species had the highest antioxidant capacity, reflecting the highest levels of total phenols, flavonoids, and anthocyanins in peel.
Foods 2023, 12, x FOR PEER REVIEW 6 of 13 development of jujube affected the TP content [20,33]. The maturity of different graded jujube was the same, which may be the reason for the little difference in the TP content. Barbagallo et al. [34] analyzed the TP content of grapes with different fruit size and found that the TP content decreased with grape weight and was affected by environment, region, climate, and other factors, thus, the phenomenon of TP content variation in this experiment could be explained.
Flavonoids are phenolic compounds that are widely found in fruits and are particularly important for human health [10,35]. Jujube is rich in flavonol glycosides composition, and the difference in variety and maturity can lead to differences in the flavonoid content in jujube [20,[36][37][38]. In Figure 2B, the TF content of dried jujube increased from 2.95 g/kg to 6.14 g/kg with the increase in grade of G1 to G5. These results indicated that fruit enlargement accelerated the consumption and decreased the accumulation of flavonoids. Barbagallo et al. [34] pointed out that the TF amount increased with grape size, which was similar to our results. TP and TF contents of fruit in different parts was also different. Zhang et al. [10] found that the peel of all jujube species had the highest antioxidant capacity, reflecting the highest levels of total phenols, flavonoids, and anthocyanins in peel. The contents of (A) total phenolics (TP), (B) total flavonoids (TF), (C) ascorbic acid (AsA), (D) cyclic adenosine monophosphate (cAMP), (E) 2,2-diphenyl picrylhydrazyl (DPPH) radical scavenging activity, and (F) ferric reducing antioxidant power (FRAP) of dried jujube. The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

AsA and cAMP of Dried Jujube
AsA has the effect of antioxidation and scavenging of free radicals, which widely exists in fruit and vegetables, and has a high content in jujube [24]. In Figure 2C, the AsA content of dried jujube increased gradually from G1 to G3, and then decreased. AsA content ranged from 51.71 mg/kg to 90.80 mg/kg, which was higher than that of pear-jujube at different ripening stages, as previously reported. The AsA content of G3 was the highest, being 1.76 times that of G1. This conclusion was partly similar to the findings of Wu et al. [39], who found that the AsA content decreased during pear-jujube ripening. In addition, the results of AsA and moisture were similar, which may be related to the fact that AsA is a water-soluble and heat-sensitive compound [40].
cAMP is a physiologically active substance involved in the regulation of material metabolism and biological functions in cells, and plays an important role in the regulation of sugar, fat metabolism, nucleic acids, and protein synthesis. In Figure 2D, the cAMP content of dried jujube increased gradually from G1 to G4, but the cAMP content of G5 decreased. The cAMP content in different grades of dried jujube reached the peak at G4 (363.55 mg/kg), and the cAMP content of G1 of dried jujube was the lowest (210.26 mg/kg). The cAMP content of dried jujube was similar to that of moisture content and AsA content, except at the highest point. The cAMP content of jujube fruit was higher than that of most fruits [24]. There were significant differences in the cAMP content of different cultivars and cultivation areas in jujube fruit. Zhang et al. [6] pointed out that many factors, such as sample collection period and extraction method, would affect the content of cAMP, which might lead to the results of our experiment. Chen et al. [22] found that the cAMP content of fresh Junzao jujube in the Kashi district was the lowest (50.31 mg/kg), while that in the Aksu district was 87.90 mg/kg. Different processing methods can also affect the cAMP content of jujube. Previous studies have shown that the cAMP content of dried jujube increases while that of steamed jujube decreases [41].

The Antioxidant Activity of Dried Jujube
Free radicals induce the oxidation of lipids, proteins, and DNA, which can lead to adverse events, thus, free radical scavenging is one of the important functions of antioxidants [24]. We quantified the antioxidant activity of five grades of dried jujube by DPPH and FRAP methods. In Figure 2E, the DPPH radical scavenging activity of dried jujube increased with grades, and the difference between groups G3 and G4 was more pronounced, with a 7.84% increase in DPPH radical scavenging activity in G4. The DPPH radical scavenging activities of G4 and G5 were higher than those of the other three groups. In Figure 2F, the FRAP of dried jujube also increased with grades, and the FRAP of G1 was the lowest in the five grades at 0.43 g TE/kg. These results indicated that the small dried jujube had a higher antioxidant activity measured from the DPPH method, and medium and small dried jujube had higher antioxidant activity measured from the FRAP method. The change trend was similar to the TF content, and the accumulation of flavonoids increased the antioxidant activity of dried jujube. This conclusion was similar to Li et al. [26], who point out that DPPH radical scavenging activity and FRAP were positively correlated with rutin and other flavonoid metabolites through correlation analysis.

The Mineral Elements of Dried Jujube
The results of the analysis of the mineral contents of dried jujube were summarized in Table 2. Potassium regulates intracellular osmotic pressure and the acid-base balance of body fluids, and is also involved in the metabolism of intracellular sugars and proteins. In addition, potassium was the predominant mineral in the five grades of dried jujube. The K contents ranged from 10,223.80 mg/kg to 16,620.82 mg/kg, and the richest source of K in this study was G5. Calcium helps to lower blood pressure, regulate the nervous system, and participate in muscle contraction. From the statistical analysis, the Ca content of the five grades of dried jujube were significantly different (p < 0.05), and the richest source of Ca in this study also was G5. Magnesium is an activator of enzymes, which participates in the normal life activities and metabolic processes of organisms. The Mg contents ranged from 206.35 mg/kg to 253.37 mg/kg, and the richest source of Mg in this study was G4. The five grades of dried jujube contained relatively low amounts of Zn and Cu, which are important because Zn is nutritionally essential for all organisms and Cu participates in numerous enzyme-catalyzed oxidation-reduction reactions and processes [29]. Regarding Zn content, the highest value was found in G3 (4.10 mg/kg), followed by G5 (3.75 mg/kg), and G4 (3.63 mg/kg). There were also significant differences in the Cu content of the five grades of dried jujube, in which the highest Cu content was found in G5 (3.06 mg/kg) and the lowest Cu content was found in G3 (1.70 mg/kg).
The content of mineral elements is influenced by many factors, such as jujube cultivar, development stage, soil, and climate in the cultivation area. Li et al. [29] measured the mineral content of five cultivars of jujube in their experiment, and found that the Ca content of Junzao jujube (1179.88 mg/kg) was higher than that of the other four cultivars of jujube (Jinsixiaozao, Yazao, Jianzao and Sanbianhong), but Mg content was the lowest (246.12 mg/kg). The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

The Volatile Aroma Components of Dried Jujube
The main volatile aroma components of dried jujube are shown in Table 4; among these, the highest volatile aroma components of dried jujube were acids (n-decanoic acid, benzoic acid, and dodecanoic acid). In Table 4, the relative content of benzoic acid, ndecanoic acid, dodecanoic acid, benzoic acid, and octanoic acid were the highest among the five grades of dried jujube (up to 17.19%, 16.37%, 18.85%, 22.63%, and 17.94%, respectively). The relative content of 2-octenoic acid, methyl (Z)-9-hexadecenoic acid, methyl dodecanoic acid, and methyl myristoleate of the G2 dried jujube reached the maximum in the five grades. Among the five grades of dried jujube, the relative contents of five volatile aroma components (1-octadecene, dibutyl phthalate, dodecanoic acid, hydrocinnamic acid, octadecane) reached a peak in the G3 dried jujube, and the relative contents of the other five volatile aroma components (acetic acid, benzaldehyde, heptanoic acid, nonanoic acid, and octanoic acid) were the highest in the G5 dried jujube. In addition, the relative contents of 6,10,14-trimethyl-2-pentadecanone and benzoic acid of the G4 dried jujube were the highest in the five grades. This was similar to the previous conclusion [42,43]. However, Wang et al. [44] identified 31, 31, 32, and 32 volatile aroma components from Tangzao, Muzao, Lizao, and Qingrunhongzao, respectively, and pointed out that aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. aldehydes were the main volatile aroma components in jujube. Bi et al. [21] found that after drying, the relative content of aldehydes in jujube decreased, but the content of alkanes and ketones increased. The volatile aroma components of dried jujube are very complex. Spadafora et al. [45] pointed out that many factors, such as fruit maturity, storage temperature, and processing process, can affect the volatile aroma components. These may account for the results. The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis Heptadecane 0.57 ± 0.17 a 0 ± 0c 0.70 ± 0.13 a 0.51 ± 0.12 ab 0.31 ± 0.04 b 2-Undecanone, 6,10-dimethyl-0.85 ± 0.19 b 1.16 ± 0.08 a 0.37 ± 0.13 c 0.91 ± 0.13 ab 0.99 ± 0.17 ab 9-Hexadecenoic acid, methyl ester, (Z)-0.40 ± 0.05 c 1.30 ± 0.13 a 0.76 ± 0.08 b 0.19 ± 0.04 d 0.20 ± 0.08 d The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis The dried jujube were arranged in the order from large to small, which were G1, G2, G3, G4, and G5 groups, respectively. Data are expressed as means ± standard deviation (SD) from three replications. Means with different letters are significantly different (p < 0.05).

Conclusions
Consumers are influenced by subjective factors when buying dried jujube, and the most important factor is the fruit appearance. This study found that fruit size had effects on quality attributes, antioxidant activity, mineral elements, and volatile aroma components of dried jujube. From the flavor analysis of dried jujube, the flavor of large and medium dried jujube was better than that of small dried jujube. The correlation analysis showed that the TF content of dried jujube was positively correlated with antioxidant activity, and AsA content was positively correlated with cAMP content. However, from the analysis of edible value, medium and small dried jujube had a higher antioxidant capacity. Potassium, as an essential element in organisms, was the highest of the measured mineral elements of dried jujube. The volatile aroma components of dried jujube were complex, among which the relative content of acid was the highest. This study provided a reference for the evaluation of dried jujube fruit quality and the improvement of grading standards, which aimed to improve the commercial value and market competitiveness of dried jujube.