Bioscience Evidence 2026, Vol.16, No.4, 291-303 http://bioscipublisher.com/index.php/be 292 2021; Yang et al., 2023). Under commercial production conditions, cultivar characteristics, light availability, temperature, water supply, soil acidity, fertilization practices, canopy structure, and harvest maturity can all affect the expression of this genetic potential. This review summarizes the major bioactive compounds involved in blueberry fruit quality formation and analyzes their changes among different ripening stages and cultivars. Based on production practices in major blueberry-growing regions of China, this study further summarizes management strategies for improving bioactive compound accumulation under different ecological conditions and provides scientific references for quality improvement in commercial orchards. Sustainable production of high-quality blueberries requires appropriate matching between cultivars and environmental conditions, coordination between canopy structure and light distribution, adaptation of cultivation substrates to blueberry root physiological requirements, and proper decisions regarding harvest timing and target markets. Only through integrated management can growers consistently produce blueberries with high bioactive compound contents and stable fruit quality. 2 Major Bioactive Compounds Determining Blueberry Fruit Quality 2.1 Anthocyanins and fruit coloration Anthocyanins are the major pigments responsible for the transition of blueberry fruit from green or reddish immature berries to fully ripened blue-purple fruit. They are also important bioactive compounds determining fruit appearance quality. The distribution of anthocyanins is not uniform among different fruit tissues. The peel is the main accumulation site, which explains why blueberry fruit may show complete external coloration while pigment accumulation inside the fruit is still continuing. Sun et al. (2018) investigated changes in bioactive compounds during different developmental stages of southern highbush blueberry (Vaccinium corymbosum L.). As fruit developed from the green stage to the fully ripe blue stage, total anthocyanin content increased rapidly from 3.43 mg/g FW to 153.39 mg/g FW, representing more than a 40-fold increase. At the same time, anthocyanin levels in the peel of mature fruit were much higher than those in the pulp, indicating that the peel is the main storage tissue for anthocyanins and an important contributor to the strong antioxidant capacity of blueberries. In addition to changes in total content, anthocyanin composition also changed during ripening. The number of detected anthocyanin compounds increased as fruit matured, and malvidin gradually became one of the dominant anthocyanins in ripe blueberry fruit. 2.2 Polyphenols and antioxidant capacity Polyphenols in blueberry fruit mainly include anthocyanins, flavonols, flavanols, proanthocyanidins, and phenolic acids. Common non-anthocyanin phenolic compounds include chlorogenic acid, quercetin derivatives, myricetin derivatives, catechin, and epicatechin. During fruit development, different polyphenolic compounds do not accumulate at the same rate. Green immature fruit generally contains higher total phenolic content and stronger in vitro antioxidant activity, while total phenolics gradually decrease during fruit enlargement and coloration, accompanied by rapid anthocyanin accumulation at the blue stage. Vasquez-Rojas et al. (2025) compared blueberry fruit from two production seasons and found that total phenolic content, DPPH radical scavenging activity, and FRAP values generally declined as fruit developed from the green and pink stages to the blue stage, whereas anthocyanin content increased markedly in fully ripe fruit. These results indicate that ripening is not simply a process of increasing all antioxidant compounds, but rather involves metabolic rearrangement, with immature fruit dominated by defensive phenolics such as chlorogenic acid and flavanols, while mature fruit shifts toward anthocyanin accumulation associated with coloration and improved eating quality. The contribution of different phenolic compounds to antioxidant capacity varies according to their chemical structures, hydroxyl groups, and relative abundance. Therefore, blueberry samples with similar total phenolic contents may still show different antioxidant capacities due to differences in anthocyanin, flavonol, and phenolic acid composition. Zheng et al. (2024) reported that preharvest application of 0.5 mmol/L melatonin significantly increased total phenolic and total flavonoid contents in blueberry fruit. Meanwhile, total anthocyanin content increased by 50.38%, and ABTS radical scavenging activity and FRAP values increased by 116.49% and 94.28%, respectively. Metabolomic analysis identified 459 flavonoid-related metabolites, suggesting that improved
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