We investigated the quality characteristics of cookies prepared following the addition of various concentrations of used Hongkuk powder (0%, 1%, 3%, 5%, all w/w) as a substitute for flour. In this study, the moisture content of dough decreased and pH increased by adding Hongkuk powder. The L and b value were decreased significantly, but the a value of cookies increased by addition of Hongkuk powder. The spread factor of cookies was slightly decreased by the addition of Hongkuk powder. The hardness of the control group was higher than that of the cookies prepared with different levels of Hongkuk powder. The result of the sensory score showed that cookies added with 1% Hongkuk powder had higher taste, flavor, and overall acceptability scores than other samples. As a result of this study, the quality of cookies with the addition of 1% Hongkuk powder were the most suitable in terms of its taste, flavor, texture, and sensory properties.

To reproduce the brewing process of Hongkuk-ju and to identify the functional properties of it, Hongkuk-ju was brewed using different additions of Hongkuk (100%, 90%, 70%, 50%) and Nuruk (0%, 10%, 30%, 50%). The quality elements, including pH, total acidity, reducing sugar content, alcohol content and pigments (yellow, red, monacolin K and citrinin), were measured. The pH values of Hongkuk-ju showed a slight difference (pH 4.08～4.58) right after the 1st stage mash; further, the pH on all groups (H1, H2, H3 and H4) in the terminal of the 2nd stage mash (9 days in fermentation) were similar, ranging approximately at pH 3.70. The total acidity change did not show a difference directly the 1st stage mash (nearby 0.2 %); however, it began to show a slight difference at the terminal of the 2nd stage mash between the range of 0.69～0.76%. The residual reducing sugar of the content was decreased with the increased Nuruk content. The alcohol concentrations of the treatment brew with Nuruk ranging from 12.3% to 13.7% were higher than Hongkuk on its own. The yellow and red pigment contents of Hongkuk-ju ranged from 7.2～8.8 O.D. units (yellow pigment) and from 4.4～5.1 O.D. units (red pigment). The production of monacolin K and citrinin was the highest (9.48 ㎎/㎏ and 10.14 ㎎/㎏) when the treatment solely brewed Hongkuk. The concentration of Nuruk and the preparation of the seed mash from it were critical factors compared to the treatment of rice in brewing Hongkuk-ju

In order to produce Hongkuk-ju, the production and characterization of Hongkuk (Monascus red koji) by Monascus anka KCTC 6121 were investigated. The optimum cultural conditions for the production of enzyme (α-amylase and glucoamylase) and pigment (yellow and red) from this strain on solid culture (steamed rice) were examined. The results showed that the production of α-amylase and glucoamylase reached the highest for 9 days and 8 days, respectively. Since then, the productions decreased slightly. The production of yellow and red pigments reached the highest for 8 days, decreasing slightly soon after. The optimal content of the initial moisture equally presented 30% in the enzyme and pigment production. After that, the enzyme production decreased slowly, whereas pigment production decreased sharply. The optimal temperature of the culture also showed 30℃ in the production of enzyme and pigment. It was found that the initial inoculum size in enzyme and pigment production was 10% and 20%, respectively. Under these optimal conditions, the production of monacolin K and citrinin was 74.35 ㎎/㎏ and 5 ㎎/㎏ for 12 days, respectively.