Quality characteristics of Korean traditional Kanjang containing Astragalus memvranaceus

Abstract

This study investigated the physiochemical properties of Kanjang (soy sauce) contaning Astragalus memyranaceus to improve the acceptability and functionalities of Kanjang during its six-month ripening period. Kanjang was fermented in the traditional manner, and then 5 and 10% Astragalus memyranaceus (AM) were added to two samples of it, respectively. The pH, salinity, sugar content, crude protein, amino nitrogen, optical density, total polyphenol content, total flavonoid content, and sensory test results of Kanjang contaning Astragalus memyranaceus (AK) were then investigated. The pH remained the same in the two samples. The salinity was slowly increased, and the sugar content (°Brix) was highest after 3 months. The crude protein and amino nitrogen contents increased with time. The optical density showed significant differences according to the rate of addition of AM. The total polyphenol contents were highest in the AK 5% sample aged for six months (up to 25.01 mg/mL). The flavonoid contents of the AK 5% sample was higher at five months (up to 200.15 mg/mL). Finally, the sensory test results of the AK 5% sample was higher than that of the other sample. These results suggest that Kanjang containing 5% Astragalus memyranaceus can be used as a functional Kanjang.