RETORT-PROCESSED SEERAGA SAMBA RICE BIRYANI AMBIENT STORAGE QUALITY

Abstract

Seeraga Samba (Oryza sativa var. indica), a premium aromatic short-grain rice cultivar from Tamil Nadu, India, has not previously been investigated for its suitability in retort-processed ready-to-eat (RTE) foods. This study aimed to optimize the retort processing conditions for Seeraga Samba vegetable biryani and evaluate its physicochemical, microbiological, and sensory stability during ambient storage. Response Surface Methodology (RSM) using a Central Composite Design (CCD) was employed to optimize processing temperature (110–121.1°C) and holding time (5–15 min), with colour (Lovibond L*), moisture content, pH, and microbial count as response variables. The optimized process conditions of 121.1°C for 10 min achieved a composite desirability of 0.900 and a thermal lethality (F₀) value of 10.3 ± 0.4 min, ensuring commercial sterility. The optimized product was packaged in multilayer retort pouches (PET/Al/PA/CPP) and stored at ambient temperature (28 ± 2°C) for 90 days. During storage, carbohydrate, protein, fat, moisture, ash, and crude fibre contents ranged from 24.14–25.47%, 2.48–2.80%, 1.62–2.37%, 68.56–70.76%, 0.94–1.05%, and 0.53–0.86%, respectively. The pH decreased from 6.3 to 5.9, while the Lovibond L* value declined from 52.1 ± 0.8 to 50.1 ± 0.6, indicating only slight physicochemical changes during storage. No microbial growth was detected throughout the storage period, confirming the commercial sterility of the product. Sensory evaluation showed that the overall acceptability remained above the acceptable limit, with a score of 6.7 ± 0.3 on a 9-point hedonic scale after 90 days. The findings demonstrate that retort processing is an effective preservation technique for producing a safe, shelf-stable, and acceptable Seeraga Samba vegetable biryani with a minimum ambient shelf life of 90 days, thereby providing a scientific basis for the commercial utilization and value addition of this traditional rice cultivar in the growing RTE food sector.