A comparison of chemical, structural and functional properties of fenugreek (Trigonella foenum graecum) protein isolates produced using different defatting solvents

•Effect of different defatting solvents on protein characterizations of fenugreek protein isolate was investigated.•Hexane and diethyl ether resulted in comparable amino acid content, surface and functional properties, and thermal stabilityin fenugreek protein isolate.•Ethanol promoted foaming properties in fenugreek protein isolate by lowering surface tension.•Acetone created better protein solubility, foaming capacity, also the most thermal stability in fenugreek protein isolate. This study showed defatting solvents including hexane, diethyl ether, chloroform, ethanol and acetone, due to their influence on protein denaturation and structure, have considerable effect on the amino acid composition, thermal characterizations, surface and functional properties of fenugreek protein isolate. FTIR analysis while confirmed the presence of secondary structures in all fenugreek protein isolates, showed differences in these structures. Hexane and diethyl ether resulted in comparable coagulated protein percentage, interfacial tension, emulsifying properties, surface hydrophobicity, Td and SDS-PAGE profile in fenugreek protein isolates. The lowest surface tension in fenugreek protein isolate produced from ethanol defatted flour was in accordance with its considerable foaming properties. Maximum Td and ΔH were observed in fenugreek protein isolate obtained from acetone defatted fenugreek flour. The highest amounts of hydrophobic and charged hydrophilic amino acids in fenugreek protein isolate produced from hexane and acetone defatted fenugreek flours respectively, were in accordance with the polarity of the applied defatting solvents. Thermograph and coagulated protein percentage confirmed that chloroform caused the lowest thermal stability in fenugreek protein isolate.