Comparative study on starch and protein secondary structures in brown, red, and black rice influenced by microwave treatment

Le résumé fourni par la source

This study compares the effects of microwave treatment (up to 220 s) on the starch and protein structures in brown, red, and black rice flours with 12 % initial moisture, representing typical low-moisture conditions. FTIR and XRD analyses revealed increased starch crystallinity, with brown rice showing the highest increase (9.71 %), followed by red (9.15 %) and black rice (4.40 %). A-type crystallinity rose in all rice types, while V-type decreased, suggesting disruption of amylose-lipid complexes. AFM and SEM confirmed partial starch granule disruption and reorganization into more compact structures. Protein analysis showed decreased β-sheet content, increased α-helix and β-turn structures, reduced hydrophobicity (by 10.06 %–51.65 %), and increased disulfide bonds, particularly in black rice (82.96 %), indicating enhanced molecular stability. These changes suggest potential improvements in texture, thermal stability, and possibly a reduced glycemic response, warranting further investigation of functional and digestibility properties. • Microwave treatment of pigmented rice with low moisture rises starch crystallinity. • Microwave treatment increases the A-type starch crystallinity in pigmented rice. • Polyphenols in pigmented rice promote A-type and reduce V-type crystallinity. • Microwave treatment enhances the ordered protein structure in rice flours. • Brown rice is the most sensitive to microwave while black rice is the most stable.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.