Decoding citrus diversity: Insights from multivariate data analysis of nutritional and antioxidant profiles in diverse species and hybrids

• Biochemical diversity of 19 Citrus species and six hybrids collected across various regions in India. • Total Soluble Solids (TSS) and Ascorbic acid (vitamin C) are positively correlated indicating sweet fruits are also rich in vitamin C. • Vitamin C and Ferric Reducing Antioxidant Potential (FRAP) showed a very high positive correlation, but not with Total Titrable Acidity (TTA) indicating Vitamin C contributes majorly to antioxidant activity. • The essential oil yield ranged from 0.1 % to 3.5 % (v/w). • The ratio of TSS to TTA ranged from 0.99 to 48.8. The genus Citrus L., a crucial member of the orange sub-family Aurantioideae within the Rutaceae family, is renowned for its nutritional, medicinal, and cosmetic properties. This study investigates the biochemical diversity of 19 Citrus species and five hybrids across various regions in India, focusing on ascorbic acid content, total titratable acidity (TTA), total soluble solids (TSS), TSS/TTA ratio, ferric reducing antioxidant power (FRAP), and essential oil yields. Ascorbic acid content ranged from 19.6 to 232 µg/ml, with Khasi papeda ( Citrus latipes Hook.f. & Thomson) exhibiting the highest concentration. Antioxidant activity (FRAP) varied, with a mean of 117 ± 47.4 µg GAE/ml, reaching a maximum of 221 µg GAE/ml in the Carrizo citrange hybrid. TSS values ranged from 4.80 to 12.75°Brix, with Khasi papeda and Cleopatra mandarin ( Citrus × reshni (Engl.) Yu.Tanaka) being the sweetest. TTA values spanned from 0.25 % to 8.39 %, with Melanesian papeda ( Citrus macroptera Montrouz.) having the highest acidity. The TSS/TTA ratio ranged from 0.99 to 48.8, and essential oil yields varied from 0.1 % to 3.5 %. Multivariate data analysis (MVDA), including Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), revealed complex relationships among these parameters. PCA identified two principal components accounting for 66.9 % of the total variance, associated with antioxidant activity, vitamin C content, and the sweetness-acidity balance. HCA grouped accessions into distinct clusters, providing insights for breeding programs. Significant correlations were found between ascorbic acid and FRAP ( r = 0.703, p < 0.001) and between TSS and FRAP ( r = 0.565, p < 0.001). The inverse relationship between TTA and the TSS/TTA ratio ( r = -0.599, p < 0.001) underscores the role of acidity in fruit taste. This study highlights the nutritional and commercial potential of underutilized Citrus germplasm. Leveraging this biochemical diversity can enhance disease resistance, nutritional content, and consumer appeal in citrus breeding programs, leading to superior cultivars with enhanced health benefits and sensory attributes.