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The main phenolic derivatives and antioxidant capacity of ninety-three yellow maize varieties were investigated, together with their color parameters. Sixteen phenolics were identified in the free extract by UPLC-ESI-MS/MS, N′, N ″-diferuloyl putrescine and N ′ , N ″-dicoumaryl spermidine were the major phenolic derivatives. Fourteen phenolic compounds were found in the bound extract, with trans - p -coumaric acid, trans- and cis- ferulic acid being the predominant phenolic acids. The orange-yellow maize varieties presented the highest total phenolic content (TPC) and total flavonoid content (TFC), along with significantly higher antioxidant potential. Correlation analysis showed that b* value (corresponding to yellow degree) was positively correlated with the total carotenoid content (TCC), phenolic content, and antioxidant capacity (p < 0.05). Through Hierarchical Clustering Analysis (HCA), the 93 maize varieties could be divided into three categories according to b* value and antioxidant activity. The heatmap visualization further underscored the component differences across various varieties, unveiling the intricate phytochemical profiles of these maize varieties. [Display omitted] • Totally 30 phytochemicals were identified in 93 yellow maize varieties. • Trans - p -coumaric acid, Trans- and cis- ferulic acid were major antioxidant components. • Multivariate and metabolomics were combined to analyze 93 maize varieties. • b* value was positively correlated with TCC and antioxidant capacity of yellow maize. [ABSTRACT FROM AUTHOR]

• NaCl induced a higher carotenoid content and improved the antioxidant capacity in yellow maize sprouts. • Upregulation of carotenoid biosynthesis genes promoted carotenoid accumulation. • Supplemental CaCl 2 treatment plays a positive role in protecting maize sprout growth. • CaCl 2 treatment further enhanced the carotenoid content and antioxidant capacity in maize sprouts. Germinated edible seeds and sprouts are becoming increasingly common in the human diet because they are rich in bioactive compounds and antioxidants and are highly nutritious. In this study, the effects of NaCl stress and supplemental CaCl 2 on carotenoid accumulation, antioxidant capacity and expression of key enzymes in yellow maize kernels were investigated. The results showed that the lutein and zeaxanthin contents increased with NaCl treatment, and further increased with supplemental CaCl 2. Additionally, germinated yellow maize kernels showed increased antioxidant capacity in response to NaCl and CaCl 2. The transcript levels of carotenogenic genes ZmPSY and ZmCYP97C were upregulated and the expression levels of ZmLCYB and ZmBCH1 were downregulated under NaCl stress. The expression of all key carotenogenic genes was upregulated by CaCl 2 supplementation. These results suggested that NaCl and CaCl 2 contribute to carotenoid accumulation via increased expression of related carotenogenic genes and increased antioxidant capacity in germinated yellow maize kernels. [ABSTRACT FROM AUTHOR]