Hydrothermal process optimization, product characterization and storage stability evaluation of red bao rice instant porridge mix

Dry instant porridge mix was developed by optimizing hydrothermal processing using Response Surface Methodology for three red pigmented bao rice namely Kenkowa, Amona and Badal. The optimized rice concentration and cooking time were 18.68 g, 10 min for Kenkowa and 22.5 g, 12.5 min for Amona and Badal, resulting in high WAI and SP and low WSI and ⍴_b. Post optimization, the technofunctional properties improved enabling instant properties. X-Ray diffractometry revealed loss of crystallinity, Differential scanning calorimetry showed reduced enthalpy, Fourier transform infrared spectroscopy confirmed molecular modifications and Scanning electron microscopy indicated granule deformation all owing to gelatinization. Resistant starch content increased by ~ 35% across varieties. Consistency improved by ~ 30% and cohesiveness by ~ 75%. L* decreased while a* values increased (p ≤ 0.05). Bioactive compounds decreased (p ≤ 0.05), with total phenolic content reducing by ~ 65–75%, total flavonoid content by ~ 40–65%, DPPH radical scavenging activity by ~ 40–45% and ferric reducing antioxidant potential by ~ 55%. Principal component analysis (96.55%) depicted highest overall acceptability (OAA) in the optimized Kenkowa mix (8.10), followed by Badal (8.05) and Amona (7.95) Storage elevated free fatty acid, peroxide value and thiobarbaturic acid reactive substances, while reducing consistency, taste and OAA. Kenkowa and Badal varieties were found to be more promising for instant food applications.