The soy sauce industry uses black soybeans as the main ingredient for making soy sauce. According to Muchlish Adie and Ayda Krisnawati, researchers from the Research Institute for Legumes and Tuber Crops (Balitkabi), 73 soybean varieties were released during the period of 1918-2012, and 7 of them were black soybeans.
The black soybean varieties that are rich in anthocyanin pigments, include cikuray, detam 1 and detam 2, merapi, and mallika varieties. All of these varieties have a medium lifespan and can be harvested within 80-90 days after transplanting.
Mallika, a black soybean variety that was released as a superior soybean in 2007, has been planted in Yogyakarta, Central Java, West Java, and East Java. Dr Ir Setyastuti Purwanti MS conducted the assembly of mallika varieties at the Seed Technology Laboratory, Faculty of Agriculture UGM. The name mallika is derived from the Sanskrit word for Kingdom. This variety is renowned for its high protein content, longer shelf life, and stable and uniform plant growth, with a productivity rate of 1.6-2.9 tons/hectare.
In 2014, two new black soybean varieties were released: mutiara 2 and mutiara 3. The name mutiara indicates that they are superior mutants resulting from isotope and radiation technology. Both varieties have inherited the genetic traits of the black soybean variety cikuray, which was released in 1992 and is known for its tolerance to leaf rust disease. However, its productivity has not been maximized, averaging only 1.6-1.7 tons/hectare.
The cikuray variety has the advantage of high protein content, reaching 35%, and low fat content, at 17%. Researchers at the National Nuclear Energy Agency (Batan) utilized these features when developing the mutiara 2 and mutiara 3 varieties. To achieve this, they irradiated the cell nucleus of the cikuray variety with gamma rays at a dose of 200 grays. Multi-location trials showed that the productivity of the varieties reached 2 tons/hectare.
