Development and Characterization of a Resveratrol-Loaded Agar-Based Functional Jelly: Preliminary Pilot Study on Cognitive Outcomes in Healthy Adults

Functional jellies represent attractive matrices for delivering bioactive compounds. This preliminary pilot study aimed to develop and characterize an agar-based jelly formulated with trans-resveratrol (RSV) and explore cognitive outcomes following its consumption in healthy adults. An agar-based jelly was formulated with a nominal amount of 200 mg of trans-resveratrol incorporated per approximately 5 g serving. RSV-containing and placebo formulations were evaluated for color, water activity, textural and viscoelastic properties, and sensory acceptance. Compared with the milk powder-containing placebo formulation, the RSV-containing jelly exhibited significantly lower firmness, hardness, springiness, gumminess, and chewiness than the placebo (p < 0.05), while adhesiveness, cohesiveness, and resilience did not differ significantly. Stress relaxation analysis revealed viscoelastic behavior in both formulations, with significantly higher equilibrium stress, relaxation time, equilibrium modulus, and viscosity in the placebo formulation (p < 0.05). In a randomized, placebo-controlled, single-blind pilot study, 20 healthy adults consumed one jelly daily for 21 days. There were no significant differences in working-memory performance over the intervention period and shorter TMT completion time in the RSV group at day 21 compared with placebo. No between-group differences were observed in Stroop interference. Given the study limitations including small sample size, potential practice effects, single-blind design, and compositional differences between formulations, the cognitive findings should be regarded as preliminary and hypothesis-generating.