Evaluation of Aromatic Compound : 2-Acetyl-1-Pyrroline(2AP) in Khao Dawk Mali 105 Brown Rice by NIR Spectroscopy

Abstract

Khao Dawk  Mali 105  is  an  aromatic  rice  with  variable Prices  due  to  the  smell  from   volatile   gas  called 2-Acetyl - 1-pyrroline (2AP). The  smell  was  rapidly  gone  after 6 months of storage  or  at  high temperature  condition. lmprovement  of  aromatic  rice  variety  is rather  difficult  to detect  in  the  smell  of 2AP practically  amount   amount   of screem. The conventional  method  of  determination is  time consuming,  sample  destroyed, high  experience  needed  and costly. Hence,  NIR  spectroscopy  is  new  idealtechnigue  for 2AP determination  because  of  saving  time,  free  chemicals, and  nondestructive  sample. Then introduction of determination the amount of aromatic compound : 2AP was made. One  hundred  and  five test  samples  of  brown  rice namely KDML105 were  prepared  by oven  at  50C. In order to  get  various  amount  of 2AP, the samples  were  divided into 2 sets, one  was  scanned   by  NIR  spectroscopy  with  800-2500 nm  in  mode  of  reflection  and  another was  analyzed  the  amount  2AP  by GC-headspace. The correlation Between 2AP peak by GC instead of the amount of 2AP and pretreated   spectra with second derivative was  analyzed. The model  was  accepted  with  high  R: 0.89 and  low  SEP: 0.96 pA*s. Regression  coefficient  contained  the  wavelengths involved   with  aroma, starch  and  cellulose  were 1143, 1410, 1540, 1705 and. 1920 mm, respectively.