Changes in the volatile profile of oats induced by processing.
Samples of an Australian oat cultivar, Echidna, were pilot-scale processed. At each stage of the processing (raw oats, groats, kiln dried dehulled oats (KDHO), and rolled (flaked)) samples were removed for later sensory and GC-MS analysis of the flavor components. Mean taste panel scores from a trained taste panel were calculated according to attributes (cereal, burnt, toasted, floury, and yeasty). Attributes were generally similar for both KDHO and flaked oats except in the yeasty attributes. Panelists were able to differentiate between groats, KDHO, and flaked oats (raw oats were not included). The largest effects of heat processing were found for the attributes toasted and yeasty aroma; toasted, cereal, and yeasty flavor; and toasted and yeasty aftertaste. A multi-organoleptic sensor analyzer was able to differentiate all samples when the output was subjected to discriminant function analysis. A reintroduced sample was recognized with a confidence level better than 96%. Solid-phase microextraction (SPME) of headspace followed by GC--MS was used to identify volatiles after either dry or slurry heating. Several SPME fiber types were evaluated as to their ability to sorb oat volatiles. A 100-microm poly(dimethylsiloxane) SPME fiber was found to provide the best adsorption profile as measured by number of compounds sorbed and peak area response. A range of alcohols, aldehydes, alkyl benzenes, dienes, and ketones was identified in the processed samples.
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School of Science and Technology, Charles Sturt University, Private Bag 588, Wagga Wagga 2678, Australia.
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Helliwell
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D018554:Avena / Q000737:chemistry*; D004043:Dietary Fiber / Q000032:analysis; D005511:Food Handling / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D012680:Sensitivity and Specificity; D012903:Smell; D013649:Taste; D014835:Volatilization