Comparative Analysis of Pigments, Phenolics, and Antioxidant Activity of Chinese Jujube (Ziziphus jujuba Mill.) during Fruit Development

Abstract

Chinese jujube (Ziziphus jujuba Mill.) fruit are much admired for their unique flavor and high nutritional value. This study tracks changes in skin color and antioxidant activity over six stages (S1 … S6) of fruit development in two cultivars of jujube, ‘Junzao’ and the color mutant ‘Tailihong’. The study records the changing levels of chlorophylls, carotenoids, anthocyanins, and phenolic compounds during fruit development. Contents of chlorophylls, β-carotenes and anthocyanins decreased throughout the developmental stages in two jujube cultivars, while lutein contents decreased at first and then increased to a maximum at S6. The levels of total phenolics, total flavonoids, total flavanols, total anthocyanins, procyanidin B1, procyanidin B2, procyanidin B3, (+)-catechin, quercetin, and ferulic acid are significantly higher in ‘Tailihong’ than in ‘Junzao’ before the onset ripening (before S3). However, after S3 the level differences of these components in the two cultivars are not significant. In both cultivars, antioxidant activity reduces gradually throughout fruit development. Our findings indicate how the skin color of jujube fruit during maturation is due to changes in the levels of flavonoids, carotenoids, and anthocyanins. The color changes are also associated with changes in antioxidant activity.

Elevated temperature and drought stress significantly affect fruit quality and activity of anthocyanin-related enzymes in jujube (Ziziphus jujuba Mill. cv. ‘Lingwuchangzao’)

“…Fresh dates are usually harvested before they are fully ripe, in order to have the best quality, flavor and a good balance of sugar and acid content. Jujube fruit undergo significant texture and color changes during fruit development and postharvest ripening [16] The flavor and external attractiveness (color) are the most important quality attributes that determine consumer recognition and commercial value [13,17]. High-quality fruit typically have a deep red color, high sugar content and a balanced sugar-to-acid ratio [18,19].…”

“…The type and content of pigment determine the color of jujube fruit. The green and yellow colors of the fruit (epidermis) are derived from chlorophyll and carotenoids, while the red and reddish-purple mainly determined by the content and proportion of phenolic acid, flavonoids, flavanols and anthocyanins, which are associated with antioxidant activity and the medicinal properties of jujube fruit [ 16 , 21 – 23 ].…”

Chinese jujube (Ziziphus jujuba Mill.) – a promising fruit from Traditional Chinese Medicine

“…Cosmulescu et al (2017) mentioned that jujube fruits are rich in bioactive compounds ( avonoids, carotenoids and anthocyanin) and can complement a healthy human diet. Shi et al (2018) concluded that changes in jujube fruit colour are associated with changes in antioxidant activity. Flavonoids and polysaccharides could contribute to the antioxidative e ect of jujube (Choi et al, 2011).…”

Anthocyanin Synthesis and the Expression Patterns of bHLH Transcription Factor Family during Development of the Chinese Jujube Fruit (Ziziphus jujuba Mill.)

“…Samples (about 0.5 g) of jujube fruit skin were extracted with 5 mL of 0.1% HCl in methanol for 24 h, at 4 • C in the dark. After centrifuging at 12,000 rpm for 15 min, three replicates were used for each sample [29]. The total anthocyanin content (TAC) was measured by the pH differential method.…”

“…In the color mutant jujube cultivar 'Tailihong' (TLH), the red color is due to anthocyanins [29]. Many studies have shown that bHLH transcription factors are involved in numerous physiological and biochemical processes in other plants.…”