Analysis and comparison of seed protein, oil, and sugars in edamame dried using two oven‐drying methods and mature soybeans

BACKGROUND Edamame, a vegetable soybean (Glycine max) grown mainly in Asia, has high nutritional and market value and is a relatively new crop to North America. By 2 years of field trials, we evaluated the seed composition traits in 54 genotypes to analyze the differences and relationship between edamame seeds dried by two oven‐drying methods and mature soybeans. RESULTS The genotypic differences were significant for all the traits investigated. Significant differences also existed between the two sets of dried edamame and mature seeds. Protein content in mature soybean averaged 426.8 g kg−1, and 432.8 g kg−1 and 405.6 g kg−1 for shelled‐dried and unshelled‐dried edamame respectively. Oil content in shelled‐dried and unshelled‐dried edamame averaged 206.3 g kg−1 and 212.6 g kg−1 respectively, and 195.8 g kg−1 for mature soybean. Sucrose content in mature soybean (60.2 g kg−1) was approximately 1.5 and 3 times that of unshelled‐dried and shelled‐dried edamame respectively. Mature soybean also exhibited the highest concentrations of stachyose and total sugars, followed by unshelled‐dried and shelled‐dried edamame. The broad‐sense heritability estimates of traits in mature soybean (49.41–89.16%) were higher than those of edamame (10.26–78.96%). Higher broad‐sense heritability was uncovered for protein and oil, but lower estimates for sugars, fiber, and ash. Positive correlations were detected between the two sets of edamame seeds and mature soybean for protein and oil (r = 0.63–0.88). CONCLUSION The results suggest that indirect selection through mature seeds is helpful for the improvement of protein and oil in edamame, whereas the improvement of seed sugars in edamame is more challenging. © 2020 Society of Chemical Industry