Physicochemical properties and antioxidant activity of Yulingdang jujube (Ziziphus jujuba Mill.) fruit at different stages of maturity

Figures & data

Figure 1. The appearance of YLD at different maturity stages.

Figure 2. Changes of moisture content in YLD at different stages of maturity. Different lowercase letters between the columns are significantly different at p < .05. Error bars represent the standard deviation.

Figure 3. Changes of ascorbic acid content (a) and soluble protein content (b) in YLD at different stages of maturity. Different lowercase and uppercase letters between the columns are significantly different at p < .05. Error bars represent the standard deviation.

Table 1. Changes of total sugar content, total acid content, and sugar-acid ratio in YLD at different stages of maturity.

Maturity stages	TSC (%)	TAC (%)	Sugar-Acid Ratio
S1	15.92 ± 0.04^g	3.86 ± 0.05^g	4.13 ± 0.01^a
S2	17.30 ± 0.04^f	5.15 ± 0.09^f	3.36 ± 0.01^c
S3	22.26 ± 0.07^e	6.43 ± 0.09^e	3.46 ± 0.01^b
S4	32.87 ± 0.16^d	12.01 ± 0.08^d	2.74 ± 0.13^e
S5	37.93 ± 0.24^c	13.29 ± 0.12^c	2.85 ± 0.11^d
S6	41.81 ± 0.15^b	15.87 ± 0.11^b	2.64 ± 0.09^e
S7	61.41 ± 0.55^a	24.87 ± 0.13^a	2.47 ± 0.04^f

The values are the means ± SD. (n = 3). Different lowercase letters within the same column are significantly different at p < .05. TSC: Total sugar content, TAC: Total acid content.

Figure 4. Changes of total phenolics content (a) and total flavonoids content (b) in YLD jujube at different stages of maturity. Different lowercase and uppercase letters between the folded lines are significantly different at p < .05. Error bars represent the standard deviation.

Figure 5. Changes of DPPH radical scavenging rate (a), reducing power (b), and antioxidant activity coefficient (c) in YLD at different stages of maturity. Different lowercase letters, uppercase letters, and Greek letters between the columns are significantly different at p < .05. Error bars represent the standard deviation.

Table 2. Correlation of antioxidant activity and components of YLD at different stages of maturity.

	Total sugar	Ascorbic acid	Total phenolic	Total flavonoid	DPPH	Antioxidant activity coefficient	Reducing power
Total sugar	1
Ascorbic acid	−0.279	1
Total phenolic	−0.840**	−0.179	1
Total flavonoid	−0.669**	−0.395	0.949**	1
DPPH	−0.932**	0.115	0.944**	0.815**	1
Antioxidant activity coefficient	−0.934**	0.039	0.906**	0.757**	0.962**	1
Reducing power	−0.910**	−0.035	0.954**	0.833**	0.973**	0.988**	1

Highly significant correlation **p < .01.