Impact of Hydrothermal Treatment on the Bioactive Compounds of Different Brown Rice Varieties in India

Hydrothermal processing is known to influence the nutritional and functional properties of cereals; however, its effects on the bioactive metabolite composition of traditional Indian brown rice varieties remain underexplored. In this study, we investigated the impact of hydrothermal treatment on four indigenous rice varieties, Seeraga samba, Kattu ponni, Kuzhiyadichaan, and Poongar, focusing on the compositional changes in lipophilic bioactive compounds. Using GC-MS/MS analysis, we quantified the alterations in fatty acids, phytosterols, triterpenes, and tocopherols before and after processing. Significant varietal responses were also observed. Seeraga samba exhibited a 20.38% increase in total fatty acid post-treatment, whereas Kuzhiyadichaan showed a 13.72% increase in β-sitosterol (p < 0.01). Poongar displayed an 18.92% increase in polyunsaturated fatty acids, whereas Kattu ponni showed a 2.13% increase in squalene content. Notably, vitamin E and γ-tocopherol were detected exclusively in hydrothermally processed Kuzhiyadichaan and Poongar, indicating enhanced micronutrient release. Statistical analysis revealed significant compositional differences (p < 0.05) between the raw and processed samples with distinct clustering patterns. These findings suggest that hydrothermal processing can be strategically optimized to enhance the nutraceutical value of traditional brown rice, thereby offering a promising approach for dietary biofortification and functional food development.