The effect of turmeric powder (Curcuma xanthorrhiza Roxb.) addition and steaming time on the physicochemical properties and sensory acceptability of sponge cake
Javanese turmeric (Curcuma xanthorrhiza Roxb.) is a rhizome that grows abundantly in Indonesia. It contains antioxidants that are beneficial to the human body and has potential as a functional food ingredient, such as in cakes. Sponge cakes containing antioxidant activity from the addition of the rhizome have not been widely published. In this work, the physical, chemical, and organoleptic effects of adding Javanese turmeric powder and varying the steaming time on wheat-sago steamed cakes were characterized. The research variables were designed using a completely randomized design (CRD) with two factors: the addition of Javanese turmeric powder (1.5, 3, and 4.5 g) and steaming duration (25, 30, and 35 minutes). The wheat-sago cakes were analyzed for physicochemical properties and preference levels. Data were analyzed statistically using ANOVA at the 95% confidence level, followed by Duncan’s multiple range test (DMRT) if significant differences were detected. The selected product and the control were chemically analyzed for moisture content, protein content, antioxidant activity, total phenols, and flavonoids. The results obtained showed that the addition of Javanese turmeric powder and variations in steaming duration significantly affected the physicochemical properties and sensory preference levels of the wheat-sago steamed sponge cake. Interestingly, wheat-sago sponge cake preferred by the panelists was the formulation containing 1.5 g of Javanese turmeric powder and a steaming time of 25 minutes, which contained 13.52% protein, 9.5% RSA antioxidant activity. Overall, the results of this study showed that the addition of Javanese turmeric powder can enhance the functional value of steamed sponge cake as an antioxidant-rich food while remaining organoleptically acceptable to consumers.