Physicochemical properties and sensory evaluation of Lizardfish (<i>Saurida tumbil</i>) nuggets with purple sweet potato flour substitution

This study investigated the impact of purple sweet potato Ipomoea batatas var. purpurea flour substitution on gluten reduction and physicochemical properties of lizardfish ( Saurida tumbil ) nuggets. The research employed a completely randomized design (CRD) with seven treatment levels representing different ratios of I. batatas var. purpurea flour to wheat flour (w/w): 0:100 (P1), 10:90 (P2), 20:80 (P3), 30:70 (P4), 40:60 (P5), 50:50 (P6), and 60:40 (P7), with three replications per treatment. Sensory evaluation (n=30) and physicochemical analyses were conducted to assess product quality. The physicochemical parameters included proximate composition (moisture, ash, protein, fat, and carbohydrate content), gluten content, textural properties, and colorimetric measurements. Data were subjected to analysis of variance (ANOVA) followed by Tukey's post-hoc test (p &lt; 0.05). The de Garmo optimization method was utilized to determine the optimal formulation. The results demonstrated that I. batatas var. purpurea flour substitution significantly influenced all evaluated parameters. While the control treatment (P1) exhibited optimal characteristics, formulations with 30% (P4) and 60% (P7) substitution levels also met the Indonesian National Standard (SNI) requirements, suggesting potential commercial viability.