KARAKTERISASI SIFAT FISIKO-KIMIA DAN FUNGSIONAL ISOLAT PROTEIN BIJI KECIPIR (Psophocarpus tetragonolobus L.) [Characterization of Physicochemical and Functional Properties of Winged-Bean (Psophocarpus tetragonolobus L.) Protein Isolate]

Slamet Budijanto (Departemen Ilmu dan Teknologi Pangan, Fakultas Teknologi Pertanian, Institut Pertanian Bogor)
Azis Boing Sitanggang (Departemen Ilmu dan Teknologi Pangan, Fakultas Teknologi Pertanian, Institut Pertanian Bogor)
Wita Murdiati (Departemen Teknologi Industri Pertanian, Fakultas Teknologi Pertanian, Institut Pertanian Bogor)

Jurnal Teknologi Dan Industri Pangan
Vol. 22 No. 2 (2011): Jurnal Teknologi dan Industri Pangan

Winged-bean (Psophocarpus tetragonolobus L.) has similar protein concentration to soybean. Higher productivity of winged-bean as compared to soybean and ground nut makes it feasible to develop this legume as a natural source of vegetable protein. Protein isolate was made by isolating protein from defatted winged-bean flour employing its isoelectric point, and several stages of centrifugation. The protein content of winged-bean protein isolate was 83.87% (db). Analysis of physicochemical properties of winged-bean protein isolate, suggested that the bulk density was 0.60 g/ml with water and oil absorption capacity of 2.61 g H2O/g solid; 1.60 ml oil/g solid, respectively. Moreover, this protein isolate had emulsion capacity of 70.5%; foam capacity of 89.5% and formed gel at concentration of 15%. Data on amino acids composition indicated that glutamic acid was the highest concentration (6.37%), whereas tryptophan was the lowest one (0.37%). Several essential amino acids, such as leucine dan lysine, were found in winged-bean protein isolate at a  concentration of 3.2% and 2.8%, respectively, calculated from the total amino acid.