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

Abstract

BACKGROUNDEdamame, 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.RESULTSThe 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).CONCLUSIONThe 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

Comparison of seed fatty and amino acids in edamame dried using two oven‐drying methods and mature soybeans

“…In addition, the two‐year averages of oleic and linoleic acid contents in the unshelled–dried edamame were slightly larger than those in the shelled–dried edamame. The changes of oleic and linoleic acid contents were consistent with those of seed oil content 22 . This is reasonable as of the five major components of oil in soybean, oleic and linoleic acids contribute the most proportion of the total oil, approximately 20–30% and 50–60% in commercial soybean, respectively 1,35–37 …”

“…The result indicated that the concentrations of seed fatty acids in the edamame were more influenced by the external factors than those in mature soybean. In other words, selection for seed fatty acids in mature soybean would be more effective than in edamame, a finding consistent with the seed oil content 22 . Higher estimates of broad‐sense heritability in the range 0.69–0.97 for fatty acids were reported in commercial mature soybeans 37,47,48 .…”

“…Relatively, linoleic acid content exhibited a higher correlation coefficient between the seed sets/types than others (Table 3), which was consistent with the estimates of broad‐sense heritability (Table 2). The correlation coefficients between seed sets/types for linoleic acid content were similar to those for seed oil content, 22 while for all the other fatty acids the correlation coefficients were smaller than those for oil content.…”

“…The materials and experimental design were the same as described in a previous article 22 . Briefly, 54 soybean genotypes, including 6 locally released or introduced cultivars and 48 breeding lines of maturity group (MG) V and VI, were evaluated in the crop seasons of 2015 and 2016.…”

“…A diallel analysis of sugar composition was also performed using ten vegetable soybean genotypes 20 . More recently, the breeding lines have been tested for agronomic/yield traits of fresh edamame and seed protein, oil and sugars 10,21,22 …”