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Title:The characterization of rum as an odor object
Author(s):Beckett, Courtney
Advisor(s):Cadwallader, Keith R.
Contributor(s):Engeseth, Nicki; Pepino, Yanina
Department / Program:Food Science & Human Nutrition
Discipline:Food Science
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Odor Object
Partial Napping
Abstract:Humans have a difficult time distinguishing individual odorants when presented in mixtures, especially when the number of odorants exceeds six. Due to this limitation, researchers have evaluated the mode in which brains process complex odorant mixtures, elemental or configural perceptions, in which mixtures maintain the odor quality of the parts or the sum of the parts create a new odor. Odor images are created by the brain as means to process configural mixtures. Rum is a distilled spirit that possesses an aroma distinction that is easily distinguished from other distilled spirits, thus creating the rummy odor object. In an attempt to explore if people can distinguish rum from other spirits based on the basis of aroma, a preliminary sensory evaluation study was conducted using a new variation of the Napping technique, called Partial Napping, in which panelists evaluate the perceived similarity of a set of samples limited to a specific sensory modality, i.e. aroma. In one session, 17 untrained panelists completed the Partial Napping of 22 alcoholic spirits belonging to 5 different spirit categories. This was paired with the Ultra-Flash Profiling technique for the development of aroma descriptive terms to assist in the understanding of what perceived aroma characteristics differentiate the various spirit types. The X and Y coordinates and descriptive terms of the samples were collected and analyzed using Multiple Factor Analysis, producing factor maps and hierarchical clusters to visualize the degree of similarity of each of the samples. Rum and brown whiskey aromas were regarded as most similar among all panelists, thus forming one cluster. The vodkas formed another cluster and were considered most different from the other spirit types. Meanwhile, tequilas, cachaças, and a white whiskey existed in a separate cluster. The supplementary descriptive terms collected from Ultra-Flash Profiling provided some insight into the perceived aroma similarities of the samples within each cluster and spirit type. With the data from PN and the further rum sample evaluation by a trained focus group, three rums were selected as the rummiest rums and thus used for further instrumental evaluation: Appleton Estate White, Appleton Estate 12 Year, and Diplomatico Reserva Blanco. Through decreasing headspace gas chromatography, seven impact compounds were identified, with five of them being detected in all three rum samples. Next, headspace solid phase microextraction was utilized as a more sensitive verification step, identifying fourteen key odorants in the headspace fraction, with twelve of them being detected across the three rums. Stable isotope dilution analysis paired with gas chromatography mass spectrometry was used for identification confirmation and quantitation of the compounds. Odor activity values (OAVs) were calculated for all of the quantitated compounds, leading to the identification of nine key odorants for the rummy odor object: 2-methylbutanal, 3-methylbutanal, acetal, acetaldehyde, ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, ethyl 3-methylbutanoate, ethyl butanoate, and ethyl hexanoate. This study is the first to utilize Partial Napping for various alcoholic beverage types, as well as the first to identify rum aroma as an odor object.
Issue Date:2018-12-04
Rights Information:Copyright 2018 Courtney Beckett
Date Available in IDEALS:2019-02-08
Date Deposited:2018-12

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