Abstract
Steamed sponge cake (bolu kukus) is a widely consumed traditional snack in Indonesia; however, its reliance on refined wheat flour limits its micronutrient and dietary fiber density. Incorporating composite flours from indigenous crops, such as tropical pumpkin (Cucurbita moschata) and green pea (Vigna radiata L.), offers a promising strategy for nutritional fortification and dietary diversification. This study aimed to evaluate the proximate composition, sensory acceptability, statistical differences, and production cost feasibility of steamed sponge cakes formulated with varying proportions of pumpkin and green pea flours as partial replacements for refined wheat flour. An experimental design was applied using three formulations: AF09 (Control: 100% wheat flour), BW91 (10% pumpkin flour, 20% green pea flour), and CB88 (15% pumpkin flour, 15% green pea flour). Proximate testing measured moisture, ash, protein, fat, crude fiber, and total carbohydrates (by difference). Sensory acceptance (color, aroma, taste, and texture) was evaluated by 50 semi-trained panelists using a hedonic scale. Data were analyzed non-parametrically using Kolmogorov-Smirnov, Kruskal-Wallis, and post-hoc Mann-Whitney tests. All formulations complied with the Indonesian National Standard (SNI 01-3840-1995) for moisture (31.69%–33.74%), total ash (0.66%–1.05%), crude protein (5.80%–6.65%), and crude fat (1.64%–2.82%). Formula CB88 achieved the highest crude fiber content (0.69%) and lower total energy density (269.88 kcal/100 g). Kruskal-Wallis testing indicated statistically significant differences (p<0.05) among formulations for color, taste, and texture, while aroma exhibited no significant variation (p=0.672). Formula CB88 emerged as the optimal treatment, receiving superior sensory acceptance ratings for color (90% liked) and crumb softness (88% liked) driven by natural β-carotene and pectin-moisture gelation. Production cost analysis demonstrated high economic feasibility for CB88 at IDR 3,374 per 55 g serving. Partial substitution with 15% pumpkin flour and 15% green pea flour (Formula CB88) yields a nutrient-dense, fiber-enriched, and cost-effective functional snack suitable for targeted school nutrition and dietary diversification programs.
