Comparative Analysis of Differences in Leaf Phenotype, Physiological Parameters, and Elemental Composition between Two Fruit-Color Types of Rubus hirsutus

Rubus hirsutus Thunb., a wild raspberry species typically bearing red fruits, was recently discovered to include a yellow-fruited type. This study compared the nutrient composition, mineral elements, amino acids, and antioxidant properties of leaves from red-fruited (R) and yellow-fruited (Y) R. hirsutus. Significant differences were observed in sugar and antioxidant profiles. While glucose levels were similar between R and Y, fructose and sucrose contents were significantly higher in R (e.g., sucrose: 45.39 vs. 33.04 mg/g). Total phenolic content in R leaves exceeded Y by 2.18 mg/g, whereas Y exhibited 1.9-fold higher peroxidase (POD) activity. Mineral analysis revealed potassium (K) as the predominant macronutrient and iron (Fe) as the most abundant micronutrient, with R leaves generally containing higher mineral levels. Essential amino acids constituted 45.83% of total amino acids in R and 46.77% in Y, both exceeding the FAO/WHO ideal protein standard. These findings highlight the nutritional and medicinal potential of both germplasms, particularly the yellow-fruited type, and provide critical data for biodiversity conservation and resource utilization.