title: Changes of headspace volatile constituents of palm olein and selected oils after frying French fries.
abstract: Changes of aroma constituents of palm olein and selected oils after frying French fries have been studied. The aroma constituents of used oils were collected using a solid-phase microextraction (SPME) headspace technique with an absorbent of a divinylbenzene/carboxen (DVB/CAR) (50/30 microm) on polydimethylsiloxane (PDMS) fibre. The extracted volatiles were desorbed from the fibre in the injection port of the gas chromatograph at 250 degrees C and the aroma constituents were identified by GC-MS. Analytical data showed that volatile constituents of palm olein, soybean oil, corn oil and sunflower oil changed while frying continued from 2 to 40 h, respectively. In palm olein, the 2t,4t-decadienal content decreased from 14.7 to 5.5 microg g(-1) (40 h) whilst hexanal increased from 7.9 microg g(-1) (2 h) to 29.2 microg g(-1) (40 h), respectively. Similar result was also obtained from soybean oil after frying French fries. The 2t,4t-decadienal content decreased from 15.9 microg g(-1) (2 h) to 3.2 microg g(-1) after 40 h frying whilst hexanal increased from 10.2 microg g(-1) (2 h) to 34.2 microg g(-1) (40 h). Meanwhile, in corn oil, it was found that 2t,4t-decadienal decreased from 15.6 microg g(-1) (2 h) to 3.2 microg g(-1) (40 h) whilst hexanal increased from 11.3 microg g(-1) (2 h) to 33.8 microg g(-1) when frying time reached 40 h. In sunflower oil, it was found that 2t,4t-decadienal, decreased from 16.8 microg g(-1) (2 h) to 1.2 microg g(-1) (40 h) while hexanal increased from 9.5 microg g(-1) (2 h) to 32.4 microg g(-1) when frying time reached 40 h. It also showed that used oils exhibited off-odour characteristics due to the increasing amount ofhexanal while their freshness characteristics diminished due to the decreasing amount of 2t, 4t-decadienal.
authors.affiliation: Malaysian Palm Oil Board, No. 6 Persiaran Institusi Bandar Baru Bangi, 43000 Kajang Selangor, Malaysia.
authors.forename: Muhammad Nor Bin
authors.initials: MN
authors.lastname: Omar
authors.forename: Nor Nazuha M
authors.initials: NN
authors.lastname: Nor
authors.forename: Nor Aini
authors.initials: NA
authors.lastname: Idris
mesh_terms: D003296:Cooking; D004042:Dietary Fats, Unsaturated; D009812:Odorants / Q000032:analysis; D009822:Oils, Volatile / Q000737:chemistry*; D000073878:Palm Oil; D010938:Plant Oils / Q000737:chemistry*; D011198:Solanum tuberosum / Q000737:chemistry*
chemical_list: D004042:Dietary Fats, Unsaturated; D009822:Oils, Volatile; D010938:Plant Oils; D000073878:Palm Oil