title: Investigating Mixture Interactions of Astringent Stimuli Using the Isobole Approach.
abstract: Astringents (alum, malic acid, tannic acid) representing 3 broad classes (multivalent salts, organic acids, and polyphenols) were characterized alone, and as 2- and 3-component mixtures using isoboles. In experiment 1, participants rated 7 attributes ("astringency," the sub-qualities "drying," "roughing," and "puckering," and the side tastes "bitterness," "sourness," and "sweetness") using direct scaling. Quality specific power functions were calculated for each stimulus. In experiment 2, the same participants characterized 2- and 3-component mixtures. Multiple factor analysis (MFA) and hierarchical clustering on attribute ratings across stimuli indicate "astringency" is highly related to "bitterness" as well as "puckering," and the subqualities "drying" and "roughing" are somewhat redundant. Moreover, power functions were used to calculate indices of interaction (I) for each attribute/mixture combination. For "astringency," there was evidence of antagonism, regardless of the type of mixture. Conversely, for subqualities, the pattern of interaction depended on the mixture type. Alum/tannic acid and tannic acid/malic acid mixtures showed evidence of synergy for "drying" and "roughing"; alum/malic acid mixtures showed evidence of antagonism for "drying," "roughing," and "puckering." Collectively, these data clarify some semantic ambiguity regarding astringency and its subqualities, as well as the nature of interactions of among different types of astringents. Present data are not inconsistent with the idea that astringency arises from multiple mechanisms, although it remains to be determined whether the synergy observed here might reflect simultaneous activation of these multiple mechanisms.
authors.affiliation: Sensory Evaluation Center, The Pennsylvania State University, University Park, PA 16802, USA and Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, Rodney A. Erickson Food Science Building, University Park, PA 16802, USA Present address: Mars Chocolate North America, Hackettstown, NJ 07840, USA.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Fleming
authors.affiliation: Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, Rodney A. Erickson Food Science Building, University Park, PA 16802, USA.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Ziegler
authors.affiliation: Sensory Evaluation Center, The Pennsylvania State University, University Park, PA 16802, USA and Department of Food Science, College of Agricultural Sciences, The Pennsylvania State University, Rodney A. Erickson Food Science Building, University Park, PA 16802, USA jeh40@psu.edu.
authors.forename: John E
authors.initials: JE
authors.lastname: Hayes
mesh_terms: D000293:Adolescent; D000328:Adult; D000534:Alum Compounds / Q000494:pharmacology; D001252:Astringents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008293:Malates / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D013634:Tannins / Q000494:pharmacology; D013649:Taste; D055697:Taste Perception / Q000187:drug effects*; D014987:Xerostomia
chemical_list: D000534:Alum Compounds; D001252:Astringents; D008293:Malates; D013634:Tannins; C041524:aluminum sulfate; C030298:malic acid
keywords: antagonism; isobole method; organic acids; polyphenols; salts; synergy