Nutritional, Physicochemical and Sensory Evaluation of Geblek, a Traditional Food from Kulon Progo Regency Enriched with Ulva sp. from Gunungkidul Coast

Abstract

Geblek is a traditional cassava-based snack from Kulon Progo, Yogyakarta, that generally has limited nutritional value because of its relatively simple ingredient composition. Ulva sp., a green seaweed, contains macro- and micronutrients, antioxidants, and other bioactive compounds, making it a potential functional food ingredient. This study aimed to evaluate the effects of Ulva sp. supplementation on the nutritional composition, physicochemical properties, and sensory characteristics of geblek. Ulva sp. was obtained from seaweed farmers in Gunungkidul, dried, processed into powder, and incorporated into geblek at concentrations of 0% (STD), 2% (GU2), 4% (GU4), and 6% (GU6). Proximate composition, antioxidant activity (IC??), crude fiber content, color parameters (L*, a*, and b*), texture, and sensory characteristics were evaluated. The results showed that Ulva sp. supplementation increased fat and ash contents, reduced moisture content, and did not significantly affect carbohydrate or protein contents. Antioxidant activity improved significantly (p < 0.05), whereas crude fiber content remained unchanged. Texture measurements were significantly higher in geblek supplemented with 4% Ulva sp. (13.63 ± 1.85 N) than in the control (9.17 ± 1.07 N). The color values of the supplemented samples decreased because of the green pigmentation of Ulva sp. powder. Sensory evaluation indicated that the appearance, taste, and overall acceptability of geblek supplemented with 4% Ulva sp. were comparable to those of the control, whereas supplementation at 6% reduced sensory preference. No significant differences in aroma or texture attributes were observed among the treatments. In conclusion, supplementation with Ulva sp. improved selected nutritional and physicochemical characteristics of geblek while maintaining sensory acceptability at moderate supplementation levels.