Chemical Composition and Mineral Content of Common Vetch Seeds during Maturation

Common vetch (Vicia sativa L.) is an important legume cultivated for feed grain and forage in the Mediterranean and Central Asia regions. Little information is available about the changes in seed mass, chemical composition, and mineral concentration in the developing seeds of common vetch. Therefore, the objective of this experiment was to study the changes in seed mass, moisture content, fat, fiber, proteins, carbohydrates, reducing sugars, and macro- and microelements in common vetch seeds sampled at four pod developmental stages described based on pod color. Common vetch pods were harvested at four pod developmental stages: 1) full-size seed (FS), 2) greenish-yellow pods (GY), 3) yellow pods (Y), and 4) brown pods (B). Common vetch seeds attained maximum mass accumulation when pod color turned to yellow (the Y stage), which was a good indication of seed physiological maturity in common vetch. Results showed that ash, fat, fiber, protein, and carbohydrate content increased between the FS and GY stage. There was no significant change in the accumulation of these components at the Y stage as compared with the GY stage. During the desiccation phase (the Y to B stage), there was an increase in carbohydrate and reducing sugars and a decrease in proteins. Seed content (μg seed-1) of macro- and microelements levels increased as the seed matured, reaching the maximum level by the GY stage [for phosphorus (P), sodium (Na), zinc (Zn), and manganese (Mn)], the Y stage [for copper (Cu)], and the B stage [for potassium (K) and iron (Fe)]. These results suggest that the majority of seed chemical composition was accumulated by the GY stage where farmers can harvest common vetch seed without reducing seed mass and nutrient loss. These data serve as a useful characterization of changes in chemical composition based on pod developmental stages for further studies.