Relationship between the color of soybean past and antioxidative activity

Abstract

  Antioxdative activity of brown pigment melanoidin, which is responsible for the color of soybean paste, was examined by measuring of chromaticity with a color-difference meter and DPPH radical scavenging activity with a spectrophotometer.
  There are a variety of soybean paste colors, such as dark brownish red, brownish red and pale yellow. Results indicated that the darkest colored soybean paste, which had the highest melanoidin content, showed the highest DPPH radical scavenging activity. Soybean has a high antioxidant content, and soybean paste made from soybean only had higher DPPH radical scavenging activity than any other soybean pastes.
  There were a negative correlation (r=-0.755 ; α‹0.05) between value of soybean paste and DPPH radical scavenging activity, and a strong positive correlation, (r=0.961 ; α‹0.01) between the quantities of melanoidins, which are created by amino-carbonyl reaction of L-lysine and D-glucose, and DPPH radical scavenging avility.
  We examined soybean paste, a Japanese traditional food, and found that people who eat soybean paste every day have a constant antioxidative composition.