Volatile Compound Profiling and Quality Assessment of Sweet Fermented High-Amylose Rice: A Comparative GC-MS Analysis with Traditional Glutinous Rice Fermentation

High-amylose Lueang Patew Chumphon (LPC) rice, a geographical indication variety from Thailand, represents an underutilized resource for functional food development. This study comprehensively investigated sweet fermented LPC rice (SFLPC) in comparison to conventional sweet fermented glutinous rice (SFGR) through microbial characterization, volatile compound profiling, and nutritional analysis. Microbial communities were identified using ITS/16S rRNA sequencing and MALDI Biotyper, while volatile compounds were analyzed by HS-SPME-GC-MS. Starter cakes contained Aspergillus sp., Rhizopus stolonifer, and Pediococcus pentosaceus (>99% simi-larity). Both varieties showed similar fermentation patterns (pH ~3.5, lactic acid ~6,000 mg/L). GC-MS analysis revealed distinct volatile profiles: SFLPC contained higher isoamyl alcohol (30.45% vs. 22.85%) and unique unsaturated fatty acid esters (9-octadecenoic acid methyl ester, ethyl oleate), while SFGR exclusively produced medium-chain fatty acid ethyl esters and 2,4-di-tert-butylphenol. SFLPC demonstrated mineral retention (phosphorus: 1444.52 vs. 686.66 mg/kg; potassium: 1137.69 vs. 611.63 mg/kg) and exceptional antioxidant activity (IC₅₀: 0.0033 mg/mL) compared to SFGR (IC₅₀: 0.0052 mg/mL) and BHT standard (IC₅₀: 0.0041 mg/mL). These findings demonstrate SFLPC's potential as an alternative fermented food to traditional glutinous rice products, offering enhanced nutritional properties and unique aroma characteristics through traditional fermentation processes.