Effects of starch type and concentration on the physicochemical, antioxidant, textural, and sensory properties of tomato juice-incorporated Gwapyeon

Gwapyeon is a molded Korean starch confection traditionally prepared by heating a fruit-derived liquid with starch and cooling the paste to form a cuttable gel. The present study examined whether a contemporary tomato-juice formulation could retain the inherited processing identity of Gwapyeon while accommodating formulation-dependent differences in product quality. Commercial 100% tomato juice was diluted 1:1 with distilled water and formulated with corn or potato starch at 9–11% (w/v) or mung bean starch at 7–9% (w/v). Physicochemical characteristics, color, refrigerated-storage syneresis, total phenolic and flavonoid contents, ABTS radical-scavenging capacity, texture profile, and consumer liking among 37 untrained participants were evaluated. Sample pH ranged from 4.46 to 4.62, whereas soluble-solids values did not differ among formulations. Potato-starch gels were darker, and corn-starch gels showed the lowest syneresis over 5 days. Total phenolic content and ABTS capacity differed among formulations, but total flavonoid content did not. Mung bean starch produced the greatest hardness, gumminess, and chewiness, particularly at 9%, while corn and potato starches generally formed softer gels. Only liking of chewiness differed significantly in the consumer test; TM9 received the highest score, but overall acceptance and purchase intention remained statistically similar and low across formulations. These findings indicate that tomato juice–incorporated Gwapyeon represents a contemporary application of a Korean ethnic-food processing framework, but requires formulation-specific optimization of flavor, texture, and refrigerated stability.