INCREASING THE DURABILITY AND FUNCTIONALITY OF NATURALLY COLORED Se'I TUNA RAISE BY ADJUSTING THE pH, ADDING POTASSIUM NITRATE, AND CALCIUM PROPIONATE

The performance of tuna se’i can be enhanced by adding natural red yeast rice dye (angkak); however, its short shelf life of only 3 days limits its distribution. Spoilage primarily results from bacterial and mold growth. This study aimed to extend the shelf life of tuna se’i using antimicrobial agents—potassium nitrate and calcium propionate—within permitted BPOM-2019 limits (2 g/kg and 50 mg/kg, respectively). A factorial experiment was conducted by applying these preservatives in curing solutions at pH levels of 4, 5, and 6, with storage at room temperature for 0, 4, 8, 12, and 16 days. Parameters evaluated included hedonic sensory attributes, Total Plate Count (TPC), yeast and mold counts, water content, peroxide value, thiobarbituric acid (TBA), color, and texture. Results showed that microbial growth remained within safe limits until day 12, while physicochemical indicators—water content, peroxide value, and TBA—remained below the SNI thresholds even at day 16. The untreated control was safe for consumption up to day 8. Declines in red color intensity, texture, and sensory acceptance were observed during storage. The best formulation was cured at pH 4, extending shelf life to 15 days with a TPC of 5.4×10⁴ cfu/g, acceptable sensory ratings (mean score of 5 out of 7), and compliance with quality standards. Angkak also contributed nutraceutical compounds with antioxidant, antimicrobial, anti-inflammatory, and anti-gout potential, highlighting its dual functionality as a colorant and preservative.