Quality characteristics and antioxidant activities of Sulgidduk (rice cake) added with chia (Salvia hispanica L.) seed powder

Chia seed (Salvia hispanica L.) originated from Central America is a highly nutritious food containing large amounts of linolenic acid, dietary fiber, and protein. This study investigated the quality properties and antioxidant activities of Sulgidduk prepared with chia seed powder as a functional material. Freeze-dried chia seed powder was replaced with 0, 1, 3, 5, and 7% of rice flour. The addition of chia seed powder did not affect water content, whereas the pH value of the chia seed group decreased as compared to the control. For color measurements, a and b values increased as the amount of chia seed powder increased, whereas L value decreased. Hardness and chewiness of Sulgidduk with chia seed powder were lower than those of the control, whereas springiness of the chia seed group was higher than that of the control. Cohesiveness was not significantly different in all samples. According to retrogradation analysis based on changes in hardness during storage, it was confirmed that addition of chia seed powder inhibited aging of Sulgidduk. Retrogradation of CSP5 was the slowest. Consumer acceptability analysis did not show significant differences in all samples. Total polyphenol and flavonoid contents tended to significantly increase as chia seed content increased. DPPH and ABTS radical scavenging activities of Sulgidduk were also elevated due to addition of chia seeds. From the results, addition of chia seed softened texture, inhibited aging, and enhanced antioxidant activities of Sulgidduk. It is concluded that addition of 5% chia seed powder, which showed high effectiveness for aging, is the most suitable for commercialization.