DEVELOPMENT OF VOCABULARY AND REFERENCES FOR DESCRIBING OFF-ODORS IN RAW GRAINS

An objective, consistent method for grading grain based on odor parame ters is needed by inspectors. Grains with off-odors receive a lower gr ade and a lower price because these off-odors can appear in products m ade from the grain. Initially, professional sensory panelists examined 122 samples of grain with off-odors. They used all the words they cou ld (81 descriptors) to describe the samples. By eliminating redundanci es, terms that poorly described the aroma, and most multidimensional t erms (those words that incorporated several concepts), 29 odor propert ies that completely described the off-odors in the grains examined wer e generated. Descriptive definitions and chemical references were dete rmined for most terms. More than 85 chemicals were examined and descri bed in the search for suitable references. Using 400 grain samples, mo st with off-odors, the terms and references were checked to document t heir relevancy and to determine if additional descriptors needed to be added; two were added. The 31 attributes describe in specific terms t he majority of off-odors found in unprocessed grain. Some off-odors th at are rare are covered by general descriptors such as ''chemical.'' T he vocabulary developed increases current knowledge about grain odors and will facilitate improved sensory and instrumental grading methods for grains.