Effects of Konjac Glucomannan-Based Double Emulsions as Palm Oil Substitutes on the Stability, Texture, and Quality of Functional Ice Cream

To develop palm oil-reduced functional ice cream, this study investigated the effects of replacing palm oil with konjac glucomannan (KGM)-based double emulsions (PDEs) at varying substitution rates (0–100%) on the physicochemical properties, structural performance, and sensory quality of ice cream. A conventional full-fat formulation containing the original palm oil level was used as the control. The results showed that, compared with the full-fat control, increasing the palm oil replacement ratio increased the viscosity and shear-thinning behavior of the aged ice cream mix. Microstructural analysis revealed reduced fat globule size and an altered bubble structure. Overrun and gas-hold-up decreased, whereas melt resistance and hardness increased. The apparent DPPH radical scavenging activity increased with the replacement ratio and reached 94.16% at a 100% replacement ratio, which was mainly attributed to the encapsulated epigallocatechin gallate (EGCG) and β-carotene. Sensory evaluation indicated that 50% replacement formulation had the closest overall acceptability to the full-fat control, whereas higher replacement ratios reduced acceptability, likely because of the bitter taste of EGCG. Correlation analysis confirmed significant relationships between overrun and melting rate and between hardness and sensory acceptability. In summary, KGM-based PDEs can be used to replace palm oil in functional ice cream, and a 50%replacement ratio maintained sensory acceptability while enhancing antioxidant activity.