Comparative Analysis of Amino Acid Composition and Nutritional Quality Evaluation between Pseudobulbs and Flowers of Edible Dendrobium Species

To clarify the nutritional differences between different organs of edible Dendrobium and screen high-quality germplasm resources, this study analyzed the amino acid composition in pseudobulbs and flowers of 30 common edible Dendrobium species. The contents of 17 amino acids were determined using acid hydrolysis combined with an automatic amino acid analyzer. Total amino acids (TAA), essential amino acids (EAA), their ratio (EAA/TAA), and cluster analysis were used for comprehensive nutritional evaluation. Results showed that all materials contained 17 amino acids, but exhibited significant interspecific variation and organ-specific accumulation patterns. The TAA content in flowers ranged from 35.66 to 75.10 mg/g, compared to 18.99–79.09 mg/g in pseudobulbs, with an average 23.6% higher TAA in flowers than in pseudobulbs. The EAA/TAA ratios ranged from 48.45% to 69.92%, with most species exceeding the FAO/WHO recommended pattern. Methionine and isoleucine contents were generally high, overcoming common nutritional bottlenecks in plant proteins. Seven Dendrobium species—D. primulinum, D. officinale, D. chrysanthum, D. aphyllum, D. thyrsiflorum, D. findlayanum, and D. exile—exhibited high TAA and EAA contents, small differences between flower and pseudobulb, and good nutritional stability. Cluster analysis classified the 30 Dendrobium species into three groups: high, medium, and low amino acid accumulators. The study indicates that the nutritional value of edible Dendrobium flowers is generally superior to that of pseudobulbs. It is recommended to emphasize flower utilization in resource development and prioritize the breeding of nutritionally stable, high-quality germplasms.