Nutritional Quality of the Walnut Male Inflorescences at Four Flowering Stages

Nutrients, bioactive compounds and antioxidant activities of walnut male inflorescences at four flowering stages were analyzed in this study. The results showed that the male inflorescences were rich in carbohydrate, protein and mineral contents, and had antioxidant activities due to high contents of phenolic and flavonoid compounds. The nutritional compositions were varied at four stages. In the first half stage, including early flowering stage (EFS) and flowering stage (FS), the contents of protein, total amino acids, carbohydrates, antioxidants (phenolic, flavonoid and ascorbic acid) and some minerals (phosphorus, zinc and copper) were higher than that of the second half stage, including pollen-scattering stage (PSS) and later pollen-scattering stage (LPSS). Due to high contents of phenolic and flavonoid at EFS, the highest antioxidant activity was also observed at this stage. However, the higher amounts of crude fat, crude fiber and some mineral elements (potassium, iron, manganese, calcium and magnesium) were found in the second half stage. These results could contribute to using walnut male inflorescences as food, as well as developing new food products, and obtaining the bioactive substances from walnut male flowers.