The improvement of soybean seed quality using globulin manipulation

• Main Author: Adie, M.M. (Pemuliaan Kedelai Balitkabi, Malang (Indonesia))
• Format: Conference Proceeding
• Language: English
• Published: Bandung (Indonesia) PERIPI 1997
• Subjects: BIOCHEMICAL ENGINEERING; CONTENIDO PROTEICO; GENIE BIOCHIMIQUE; GLOBULINAS; GLOBULINE; GLOBULINS; INGENIERIA BIOQUIMICA; PROTEIN CONTENT; SEED; SEMENCE; SEMILLAS; SOJA; SOYBEANS; TENEUR EN PROTEINES

The major protein components of soybean seed protein are betha-conglycinin (7S) and glycinin (11S) globulin which account for about 70 percent of the total seed proteins. Both globulin show a very strong negative correlation between their content. The manipulation of these globulin is effective and useful for developing commercial varieties with the improved composition of seed proteins and food processing characteristics. Soybean has the highest protein content among seed crops, the protein quality is poor due to the low content of the sulfur, containing amino acids, namely cystein and methionine. Glycinin contains three to four times more cystein and methionine than betha-conglycinin globulin. It is anticipated that the increase of the glycinin and the decrease of the content of betha-conglycinin globulin may result in enhanced protein quality in soybean seed. The globulin of Betha-conglycinin is characterized by greater in emulsifying capacity and emulsion stability than glycinin globulin. Soybean varieties with high 7S/11S ratio could be effectively used by soy food and soft-tofu industry. Furthermore, glycinin globulin is closely related to the gelatine rate and gel properties, the high ratio of 11S/7S, it is important for hard-tofu industry. The soybean variety of Rinjani were identify higher in 11S/7S ratio and is possible to use as a gene donor for the improvement of the quality of soybean seed. The soybean globulin content is controlled by a single heritable resessive allele, therefore manipulation of globulin composition in soybean seed for seed quality protein through breeding is extremely feasible Pada biji kedelai, globulin berperanan penting karena merupakan penyusun utama protein kedelai. Hampir 70 persen globulin tersebut terdiri dari beta-conglycinin (7S) dan glycinin (11S), keduanya memiliki hubungan yang negatif. Manipulasi kedua globulin di atas dapat ditujukan untuk peningkatan kualitas protein dan kualitas olahan kedelai. Kualitas protein pada biji kedelai dinilai rendah karena rendahnya kandungan sistein dan methionin. Glycinin memiliki kandungan sistein, dan methionin 3-4 kali lebih tinggi dibanding beta-conglycinin. Dengan demikian mengurangi atau meniadakan globulin beta-conglycinin secara nyata akan meningkatkan kandungan sistein dan methionin pada biji kedelai. Globulin beta-conglycinin memiliki kapasitas dan stabilitas emulsi lebih baik dibanding glycinin, sehingga diperolehnya nisbah 7S/11S yang tinggi, penting untuk industri pengolahan pangan asal kedelai dan untuk industri tahu bertekstur tidak keras. Sebaliknya glycinin memiliki tekstur dan pengerasan gel yang baik sehingga nisbah 11S/7S cukup tinggi berpotensi digunakan pada industri tahu dengan tekstur keras. Disinyalir bahwa varietas Rinjani memiliki nisbah 115/7C cukup tinggi sehingga berpeluang untuk digunakan sebagai donor gen perbaikan kualitas kedelai. Globulin beta-conglycinin dan glycinin dikendalikan secara genetik dan bersifat temurun, sehingga manipulasi globulin memiliki harapan besar untuk perbaikan kualitas biji kedelai