Influence of Agar and Konjac on the Quality and Stability of Coffea liberica–Infused Marshmallows

Abstract

This study investigated the physicochemical effects of incorporating agar and konjac powders into Coffea liberica–infused marshmallows as alternatives to gelatin, addressing dietary preferences such as halal and vegan requirements. Various analyses, including total phenolic content (TPC), texture profile, color, moisture content, water activity, and scanning electron microscopy (SEM), were conducted during storage. Results showed that marshmallows containing Coffea liberica had higher TPC, with MKAC exhibiting the highest value (0.8740 mg GAE/g) compared to the gelatin control (0.2294 mg GAE/g). Texture profile parameters, including hardness, gumminess, chewiness, and resilience, increased consistently across all formulations during six days of storage. Color analysis revealed a strong positive correlation (r = 0.977) between hydrocolloid b* values and marshmallow lightness (L*). Significant differences (p < 0.05) were observed in moisture content, whereas water activity showed no significant variation (p > 0.05) throughout storage. SEM analysis distinguished hydrocolloid-based samples by differences in surface roughness, smoothness, and pore distribution. Overall, agar and konjac powders, together with Coffea liberica, significantly influenced the physicochemical properties of marshmallows, offering potential as plant-based alternatives for the confectionery industry.