[Globulin fraction and functional characteristics of protein isolates from ten Indonesian soybean varieties]

English. The aim of this study was to evaluate composition of major protein and functional properties of soy protein isolated from ten Indonesian soybean varieties. Fractionation of soybean protein were readily based on differential isoelectric point of the protein fractions. The functional properties analyzed were water and oil absorptions, viscocity, emulsion capacity, foam stability, and nitrogen solubility index. Globulin 7S content of the ten soybean varieties ranged from 8.6 to 17.5 percent (dry basis) and globulin 11S content ranged from 12.0 to 28.2 percent (dry basis). Ratio of globulin 11S and globulin 7S ranged from 0.77 to 3.28. Result showed that functional properties of ten soybean varieties were water absorption (128.4-216.9 percent), oil absorption (115-236 percent), viscocity (1.02-1.66 cps), emulsion capacity (22.50-54.00 percent), foam stability (63-90 percent), and nitrogen solubility index (31-86 percent). On the 10 percent protein concentration, the average gel formation seem very weak, while on the 12.5 and 15 percent of protein concentration resulted in very strong gel

Indonesian. Penelitian ini bertujuan untuk mengetahui komposisi protein utama dan sifat-sifat fungsional isolat protein kedelai dari sepuluh varietas kedelai Indonesia. Fraksinasi protein kedelai dilakukan berdasarkan perbedaan titik isoelektrik fraksi-fraksi protein. Analisis sifat fungsional yang dilakukan adalah daya serap air, daya serap minyak, viskositas, dan kapasitas emulsi. Kadar globulin 7S sepuluh varietas kedelai berkisar antara 8,6 sampai 17,5 persen bobot kering (bk), sedangkan kadar globulin 11S berkisar antara 12,0 sampai 28,2 persen bk. Perbandingan globulin 11S dan globulin 7S antara 0,77 sampai 3,28. Sifat fungsional protein dari sepuluh varietas kedelai yang dianalisis adalah penyerapan air (128,4-216,9 persen), penyerapan minyak (115-236 persen), viskositas (1,21-1,66 cps), kapasitas emulsi (22,50-54,00 persen), stabilitas buih (63-90 persen), dan kelarutan nitrogen (31-86 persen). Pada konsentrasi protein 10 persen gel yang terbentuk rata-rata sangat lemah, sedangkan pada konsentrasi 12,5 dan 15 persen gel yang terbentuk sangat kuat