Characteristics of Korean Soybean Paste (Doenjang) Prepared by the Fermentation of Black Soybeans

Abstract

The changes in components and biological activities of doenjang samples prepared with black soybeans and fermented with Bacillus subtilis SCB were investigated. The amino nitrogen (A-N) contents of samples increased with increasing black soybean content. A doenjang product made using a 1:1 ratio of soybeans-black soybeans showed a maximum level of genistein and daidzein isoflavones (1111.6 μg/g) at 110 days of fermentation, along with decreasing contents of genistin and daidzin due to the conversion to aglycones. The black soybean-only doenjang sample showed higher protease activity, including caseinolytic and fibrinolytic enzyme activities, than the other samples, and had relatively higher polyphenol content and DPPH radical scavenging activity. Therefore, doenjang made with additions of black soybeans and fermented by B. subtilis SCB may have improved physiological properties, suggesting this to be a valuable method of preparation.

Antioxidant and antihypertensive properties of liquid and solid state fermented lentils

“…Niki and Noguchi (2000) postulated that the interaction among antioxidants can affect total antioxidant capacity, producing synergistic or antagonistic effects. Results obtained from lentil flour (Dueñas et al, 2005) and black soybeans (Kim, Son, & Oh, 2009) fermentations support this statement. …”

Biological activities of fermented soybean paste (Doenjang) prepared using germinated soybeans and germinated black soybeans during fermentation

“…In addition, a study (20) in which the antioxidant activity was measured in doenjang produced by mixing of black soybeans and regular soybeans with a specific ratio, showed high DPPH radical scavenging activity levels, compared with other doenjang types that were produced using only black soybeans. It was estimated that the high electron donating ability levels in doenjang using black soybeans was due to the color causing ingredients of the black soybeans, which were used as raw materials.…”

Antioxidant Activity and Health Benefits of Anthocyanin of Black Soybeans

“…During fermentation, the isoflavone aglycone and malonylglycoside were increased, which is believed to contribute to the higher antioxidant activity of cheonggukjang. Meanwhile, a published study of doenjang was done by Kim et al (2009). Doenjang was made from black soybean fermented using Bacillus subtilis.…”