2-Acetyl-1-Pyrroline Levels in Fragrant Rice as Affected by Storage Condition and Packaging

The study investigated the aroma compound 2-acetyl-1-pyrroline (2AP) in fragrant rice as affected by storage condition and packaging of fragrant rice. 2AP levels (expressed as ratio of peak area of 2AP to peak area of internal standard 2,4,6-trimethylpyridine, or TMP, determined through gas chromatography flame ionization detector, GC-FID) in milled and brown rice of fragrant rice were significantly affected by storage condition or form of rice and storage time, and packaging type. There were significant interaction effects of packaging material and storage time on 2AP levels in milled rice stored as milled or rough rice. The highest 2AP levels were obtained when rice was vacuum packed after 10 wk of storage at ambient. For the 2AP levels in milled rice stored as brown rice, and the 2AP levels in brown rice stored as brown or rough rice, only the main effects were significant. The highest 2AP levels were observed in samples kept in sacks and stored as rough rice. Diffusion or loss of 2AP in brown rice was faster than in milled and rough rice forms. Moreover, 2AP levels of fragrant rice were significantly affected by storage time. Thus, vacuum packaging can be used to store milled and rough rice of fragrant rice for maximum 2AP level in milled rice and to prevent weevil infestation. Storage of fragrant rice in rough rice form could help in attaining maximum 2AP levels in rice.