Korean rice cake Jeung-pyeon as a sustainable upcycling strategy for Korean brewers’ spent grain byproduct Makgeolli Lees

The necessity of upcycling for sustainable dietary cultures is being increasingly recognized. Makgeolli Lees, the organic waste generated during brewing, is a valuable byproduct with high potential for reuse. Therefore, exploring effective upcycling strategies for food byproducts such as Makgeolli Lees is essential. In this study, we investigated steamed Jeung-pyeon, a rice cake fermented using Makgeolli. Based on previous research, we compared a control Jeung-pyeon formulation with samples incorporating Makgeolli Lees as a substitute for Makgeolli. Quality characteristics, including internal microstructure (using scanning electron microscopy [SEM]) and texture, were analyzed. All samples showed similar expansion in height and appearance during fermentation. Texture and SEM analyses indicated that substituting 10% of Makgeolli with Makgeolli Lees yielded a quality similar to that of the control, exhibiting a uniform network structure. The results showed that height (22.81–24.10 mm) and moisture content (45.38–47.91%) across all experimental groups were comparable to the control. Specifically, the L10 sample exhibited a hardness of 4.67 N, thereby showing no significant difference compared to the control (4.54 N). These findings suggest that substituting 10% of Jeung-pyeon ingredients with Makgeolli Lees effectively enhances sustainable upcycling.