Integrated metabolite analysis and health-relevant in vitro functionality of white, red, and orange maize (Zea mays L.) from the Peruvian Andean race Cabanita at different maturity stages

**Background:** Maize (Zea mays L.) is a staple food in Latin America, and Peru harbors exceptional maize diversity with 52 recognized races. The Andean race Cabanita, cultivated since the Pre-Inca period in southern Peru at ~3,000 m altitude, exhibits variable kernel pigmentation (white, red, orange). Despite its cultural and dietary importance, limited data exist on its bioactive composition and health-relevant properties across maturity stages. This study aimed to comprehensively characterize primary and secondary metabolites and in vitro functionality of three Cabanita types at different kernel developmental stages.

**Methods:** White, red, and orange Cabanita maize were cultivated in pots under open air in Arequipa, Peru (2,240 m altitude) from November 2020 to June 2021. Ears were harvested at three maturity stages: milk (S1; 28–33 DAP, 74–79% moisture), dough (S2; 36–43 DAP, 64–68% moisture), and mature (S3; 75–77 DAP, 45–46% moisture). Free and bound phenolic fractions were extracted and analyzed by UHPLC-DAD. Carotenoids were analyzed by UHPLC after saponification. Fatty acid profiles were determined by GC-FID. Polar primary metabolites were analyzed by untargeted GC–MS. In vitro antioxidant capacity was measured by DPPH and ABTS assays on hydrophilic and lipophilic fractions. α-Amylase and α-glucosidase inhibitory activities were assessed at multiple sample doses. Statistical analyses included two-way ANOVA, Pearson correlations, PCA, and hierarchical clustering.

**Key Results:** All maize types contained hydroxybenzoic (HBA) and hydroxycinnamic acids (HCA) in free phenolic fractions. Luteolin derivatives were specific to orange maize (22.7 mg/100 g DW at S1, decreasing to 5.1 at S3); anthocyanins were exclusive to red maize (0.6 mg/100 g DW at S1, increasing to 14.5 at S3). Major bound phenolics were ferulic acid, ferulic acid derivatives, and p-coumaric acid. Total UHPLC phenolic contents (free+bound) ranged from 162.2–225.0 mg/100 g DW (white), 193.4–229.8 (red), and 223.9–274.4 (orange). Total HBA decreased ~80–90% from S1 to S3. Orange maize had the highest total carotenoids (3.19–5.87 μg/g DW), dominated by all-trans-lutein and all-trans-zeaxanthin; white and red maize had much lower levels (0.56–0.84 μg/g DW). Carotenoids in orange maize declined ~50% from S2 to S3. Fatty acid profiles were similar across types: linoleic acid > oleic acid > palmitic acid > α-linolenic acid > stearic acid. Total fatty acids increased with maturity (e.g., white: 28.0 mg/g DW at S1 to 39.8 at S3). The ω-6:ω-3 ratio was lower at S1 (9.2–10.4:1) than S3 (15–16:1). DPPH hydrophilic antioxidant capacity decreased 37–49% from S1 to S3 across types; ABTS hydrophilic capacity decreased 36–51%. α-Glucosidase inhibition (10 mg HF) decreased 63% (white), 37% (red), and 45% (orange) from S1 to S3. α-Amylase inhibition (125 mg HF) decreased ~85% (white), ~54% (red), and ~58% (orange). Both enzyme inhibitory activities correlated strongly with free phenolic content (r = 0.8064–0.8545 for α-glucosidase; r = 0.6358–0.6574 for α-amylase). PCA explained 58.1% of total variability; PC1 (45.2%) separated S3 samples from earlier stages, while PC2 (12.9%) separated orange from white/red types.

**Clinical Implications:** The findings suggest that Cabanita maize, particularly at earlier maturity stages, contains bioactive phenolic and carotenoid compounds with in vitro antioxidant and carbohydrate-hydrolyzing enzyme inhibitory activities relevant for hyperglycemia management. Orange and white Cabanita maize at S1 and S2 stages offer higher phenolic and carotenoid contents, better ω-6:ω-3 fatty acid ratios, and greater in vitro functional potential, while red maize at S3 provides higher anthocyanin levels. These results support diversifying consumption of this Andean landrace beyond the traditional mature form, potentially enhancing its nutraceutical value within indigenous food systems. Further studies on processing characteristics and transcriptomic mechanisms are warranted.