Determination of total protein and lipid contents in some soybean varieties

Soybean seeds consist of a lot of necessary nutrients for health, they are considered a complete source of protein andvegetable lipids for the human body. In this study, six soybean varieties (DT22, Coc Chum B, black soybean, Kwangan, Cuc Ha Bac and DT84) were evaluated for total protein, lipids contents and acid and iodine indexes. Total protein content was determined by the Kjeldahl method. Oil was extracted from mature seeds using the Soxhlet system with diethyl ether solvent. The results showed that levels of total protein and lipids are relatively high in tested soybean varieties. The total protein content ranged from 29.36 to 37.32%, and lipids ranged from 19.8 to 21.2%. The free acid index was from 0.12 to 1.69 mg KOH/g, the iodine value was about 52.43 to 68.64 g I2/100 g. Varieties with high protein content were black soybean and Cuc Ha Bac. Nutritionally, these varieties are all sources of high nutritional value in providing protein and essential fatty acids for humans.