Variation in composition of storage proteins, minor proteins and amino acids across faba bean cultivars

This study aimed to investigate variations in protein profiles and amino acid (AA) compositions in faba bean seeds among 10 different cultivars. The compositions of salt-soluble proteins and AA were identified and quantified by label-free nano LC-MS/MS and LC-MS/MS (Triple Quadrupole), respectively. The protein contents (dry basis) in faba bean seeds were measured using the DUMAS method, ranging from 21.6 % to 26.8 %. By nano LC-MS/MS, 103 unique proteins were identified under point mutation monitoring analysis and of these, 61 proteins were quantified by label-free quantification. In all cultivars, vicilin and legumin were the most abundant proteins, respectively, varying from 16 to 39 % and 12 to 34 % of total protein content (w/w). The relative abundance of minor proteins like Bowman-Birk proteinase inhibitors was quantified to constitute around 1 % of the total protein content (w/w). There were 400 mg essential amino acids (EAAs) detected per gram protein, where histidine showed the highest concentration (64–82 mg/g protein) in all faba beans.