ARS | Publication request: Aroma compounds in fresh cut pomegranate arils.

Submitted to: United Fresh Produce Association
Publication Type: Abstract Only
Publication Acceptance Date: February 22, 2010
Publication Date: April 21, 2010
Citation: Beaulieu, J.C., Grimm, C.C., Lloyd, S.W., Stein, R.E. 2010. Aroma compounds in fresh cut pomegranate arils. United Fresh Produce Association.

Technical Abstract: Little published information exists regarding flavor and aroma compounds in pomegranate (Punica granatum). Although arils have fruity and sweet characteristics, we found no publications describing actual compounds responsible for their typical flavor. Since most commercial usage of pomegranates involve juices, we investigated the oxidative changes in volatiles with an inhibitor. Our goal is to determine compounds in "Wonderful", fresh cut arils and juices that have “flavor” importance. Hand-pressed (Miracloth) aril juice was analyzed, and compared with blended arils and arils blended with a lipoxygenase inhibitor, n-propyl gallate (n-PG) under low oxygen, which restricts secondary volatile generation arising from oxidation. A divinylbenzene carboxen polydimethylsiloxane solid phase microextraction (SPME) was performed with 10-ml juice in the headspace of 20-ml vials for 12.5 minute exposure at 40°C, prior to injection into a HP6890/5973 GC-MS with a DB-5 column. Compounds were identified in triplicate runs with our in-house index, and/or HP ChemStation software searched against the NIST and Wiley libraries. Miracloth expressed arils contained several low molecular weight esters, alcohols, aldehydes, and terpenoids. The predominant compounds were ethanol, hexanal, hexanol, a-pinene, b-pinene, limonene, 4-terpineol, and bergamotene. Also recovered, were ethyl 2-methylbutanoate, (E)-2-hexenal, 2-methylbutyl acetate, ethyl hexanoate, and eucalyptol. Several of these compounds are known to be flavor/aroma-important in fruits. The predominant compounds in arils blended in the presence of n-PG in low O2 were ethanol, ethyl acetate, a-pinene, b-pinene, limonene, and bergamotene. Tentatively, we believe that 3-methylbutanal, hexanal, (Z) 3-hexanol, hexanol, (E,E) 2,4 hexadienal, 4-terpineol, a-terpineol, and p-cymene were generated oxidatively, and their flavor contribution during mastication and juicing operations remains to be evaluated.