Nutritional Quality, Bioactive Compounds, and Functional Characteristics of Guar (Cyamopsis tetragonoloba L.)...

Guar (Cyamopsis tetragonoloba L.) is a valuable and multifunctional summer legume crop that is widely exploited for seed gum extraction due to the presence of galactomannan in the seed endosperm, as well as for its protein-rich by-products (germ and hull), which are extensively used in various industries. The objective of this study was to conduct a comprehensive evaluation of the nutritional value, bioactive compounds, and functional characteristics of seeds from fifteen guar genotypes in order to identify superior genotypes for breeding programs and industrial applications. In this study, a wide range of key traits was assessed, including seed gum percentage (SG), gum viscosity, dry matter digestibility (DMD), protein, fiber, total oil, ash, tannin, total phenolic content (TPC), flavonoids, total antioxidant capacity (TAC), and carotenoids. Seed gum content varied from 25.7% in the Pishen genotype to 32.8% in the RGC-986 genotype. Similarly, gum viscosity ranged from 2353.67 to 3466.67 cP, with the highest value observed in RGC-986. Dry matter digestibility differed markedly among genotypes, ranging from 43.37% in Pishen to 51.97% in RGC-986, reflecting genotypic variation in seed nutritional quality. Fiber and protein contents also showed considerable variability, with ranges of 10.57%-12.95% and 25.33%-33.33%, respectively, and RGC-986 exhibited the highest values for both traits. Antioxidant-related attributes, including TAC and carotenoids, varied significantly among genotypes; to enable simultaneous selection of superior genotypes based on multiple nutritional and functional traits, the multi-trait genotype-ideotype distance index (MGIDI) was applied. According to this index, genotype BR-99, with the lowest MGIDI value (2.04), was identified as the most desirable genotype, followed by RGC-986 with a value of 2.45. Overall, the findings of this study highlight the considerable genetic variability among guar genotypes in terms of nutritional, biochemical, and functional traits, and demonstrate the potential of exploiting this diversity in breeding programs aimed at developing guar cultivars with enhanced nutritional value and improved industrial performance.