Precursors of 2-Acetyl-1-pyrroline, a Potent Flavor Compound of an Aromatic Rice Variety

Abstract

The biological formation of a potent flavor compound, 2-acetyl-1-pyrroline, in the aromatic rice variety (Khao Dawk Mali 105) was studied in seedlings and callus of the rice. Concentrations of 2-acetyl-1-pyrroline were determined by GC-MS-SIM using an isotope dilution method. Increases in concentration occurred when proline, ornithine, and glutamate were present in solution, with proline increasing the concentration by more than 3-fold compared to that of the control. Results of tracer experiments using (15)N-proline, (15)N-glycine, and proline-1-(13)C indicated that the nitrogen source of 2-acetyl-1-pyrroline was proline, whereas the carbon source of the acetyl group was not the carboxyl group of proline. 2-acetyl-1-pyrroline was formed in the aromatic rice at temperatures below that of thermal generation in bread baking, and formed in the aerial part of aromatic rice from proline as the nitrogen precursor.

Badh2, Encoding Betaine Aldehyde Dehydrogenase, Inhibits the Biosynthesis of 2-Acetyl-1-Pyrroline, a Major Component in Rice Fragrance

“…In fragrant rice, L-Pro is a precursor to 2AP, providing the nitrogen of the pyrroline ring but not the carbon of the acetyl group (Yoshihashi et al, 2002). 2AP formation positively correlates with an accumulation of Pro, resulting in the strong aroma of the Thailand fragrant rice variety Khao Dawk Mali 105, which is grown in the drought region Tung Kula Rong Hai (Yoshihashi et al, 1999).…”

Efecto De Las Condiciones De Muestreo Sobre Los Compuestos Olor-Activos Del Jamón Ibérico Effect of Sampling Conditions on the Odour-Active Compounds of Iberian Ham

“…Su estabilidad térmica y la presencia de precursores (ej. prolina, Yoshihashi et al, 2002) son responsables de su incremento al utilizar las condiciones de extracción drásticas. La coelución de la 2-propionil-1-pirrolina y el octanal se detectó de forma similar ante las dos condiciones de extracción.…”

Karakteristik Flavor Beras Varietas Padi Aromatik dari Ketinggian Lokasi yang Berbeda

“…Aroma khas ini disebabkan oleh senyawa volatil 2 acetyl-1-pyrroline (2AP), yang juga ditemukan pada bagian kalus dan organ vegetatif tanaman padi (Yoshihashi et al 2002).…”

“…Banyak penelitian yang menunjukkan bahwa aroma pandan beras aromatik dipengaruhi oleh gen pada kromosom 8, seperti varietas Surjarmkhi (Bangladesh), Della (Amerika), dan Azucena (Filipina). Penelitian biosintesis 2AP masih sedikit dilakukan, tapi perkiraan prekursor dari 2AP sudah diketahui, yaitu asam amino yang mengandung prolin, asam glutamate, dan ornitin (Yoshihashi et al 2002). Biosintesis senyawasenyawa volatil seperti 2AP masih menjadi pertanyaan (Dudareva et al 2006).…”