Effects of Gelatin Concentration on the Physicochemical Properties, Texture, and Microstructure of Asteraceae Namul Gels

Asteraceae vegetables are widely consumed in Korea as “namul” and are rich sources of bioactive compounds, yet their fibrous textures may pose challenges for mastication and swallowing in older adults. We evaluated the phytochemical contents and antioxidant properties of 70% ethanolic extracts of four source Asteraceae vegetables ( Ligularia fischeri , Aster scaber , Lactuca indica , and Glebionis coronaria ) and investigated the effects of gelatin concentration on the texture characteristics of gelatin‐based Asteraceae vegetable gels. Total phenolic and flavonoid contents and antioxidant activities were determined from the source vegetable extracts using the ABTS radical scavenging and ferric reducing antioxidant power (FRAP) assays. Texture was modulated by varying the gelatin content (2, 4, or 6 g) and was evaluated using IDDSI‐based texture assessments, instrumental hardness measurements, and the Korean Industrial Standards (KS) texture criteria. Total phenolic contents ranged from 21.616 to 22.969 mg GAE/g, total flavonoid contents from 0.241 to 0.595 mg QE/g, ABTS radical scavenging activities from 4.763 to 4.873 mg TE/g, and FRAP values from 3.067 to 3.685 mg AAE/g, with significant species‐dependent differences ( p < 0.001). IDDSI‐based texture assessment classified the 2 and 4 g formulations as Level 6 (Soft & Bite‐Sized) and the 6 g formulations as Level 7 (Easy to Chew). Instrumental hardness increased from 16,858–21,951 N/m ² in the 2 g formulations to 83,575–102,929 N/m ² in the 6 g formulations; the 2 g samples corresponded to KS Levels 2 or 3 depending on vegetable type, the 4 g samples to KS Level 2, and the 6 g samples to KS Level 1. SEM observations showed that increasing gelatin content promoted the formation of a more continuous and compact gel network. Overall, gelatin concentration effectively modulated the physicochemical, textural, and microstructural characteristics of the gels. The antioxidant measurements represent the source vegetable extracts rather than the final processed gel products, and further studies are required to evaluate antioxidant retention after processing as well as sensory acceptability and swallowing safety in target populations.