Preservative Properties of Ginger (Zingiber officinale) and Alligator Pepper (Aframomum danielli) on Fried Soybean Cake (Tofu/Wara): Antioxidant, Microbial, and Sensory Evaluation

Spices have long been valued as flavor enhancers, coloring agents, and medicinal substances. This study investigated the preservative properties of ginger (Zingiber officinale), alligator pepper (Aframomum danielli), and their mixture on fried soybean cake (Tofu/wara). Three concentrations (0.25 g, 0.5 g, and 0.75 g) were tested, alongside untreated and chemically treated controls. Antioxidant and anti-inflammatory activities were evaluated using DPPH radical scavenging, reducing power, and membrane stabilization assays. Proximate composition, including moisture, ash, protein, lipid, fiber, and carbohydrate content, was assessed, along with microbiological quality using aerobic plate, coliform, and fungal counts. Storage stability tests and sensory evaluations were also conducted. Results demonstrated that the spices exhibited strong antioxidant and anti-inflammatory properties, which increased with concentration. Food samples treated with spices showed enhanced protein and fiber content, reduced moisture levels, and a significant decrease in bacterial and mold counts compared to untreated samples. Coliform levels were within acceptable limits, with no fecal coliform detected. Storage stability tests revealed reduced spoilage rates, with alligator pepper showing the greatest inhibitory effect, followed by ginger. However, the combination of the spices was less effective than individual applications. Sensory evaluation indicated high acceptance of treated samples in terms of appearance, taste, texture, and flavor. This study highlights the potential of ginger and alligator pepper as natural preservatives, providing a basis for their application in food processing and industrial uses. Further research should explore additional spices and combinations to enhance preservative efficacy and synergistic effects.