Trained judges rated intensities of astringency and bitterness of four phenolic substances in white wine by scalar and time—intensity methods. According to scalar rating, astringency and bitterness increased as a linear function of concentration for catechin, gallic acid, grape seed tannin and tannic acid. The polymeric tannic acid and grape seed tannin were rated more astringent than bitter; the reverse was found for their respective monomers, gallic acid and catechin. Similar results were obtained for maximum intensity ratings by time—intensity methods. As maximum intensity of astringency or bitterness increased directly with concentration, the total duration of aftertaste increased; however, little or no changes in time to maximum were observed. A slightly longer time to maximum perception for bitterness was observed than for astringency.

Astringency and bitterness of selected phenolics in wine

Potato chips, popcorn, puffed corn curls, and saltines were equilibrated to various water activities (aw) over saturated salt solutions. Sensory panels determined the crispness and textural hedonic quality of the humidified products by the magnitude estimation technique coupled to a verbal concept scale. Critical water activities (ac), where the products became organoleptically unacceptable, generally fell in the 0.35–0.50 aw range. Instron analyses showed that the force-deformation curve changed distinctly near the ac for saltines and puffed corn curls, while the curve changed more gradually with increasing aw for popcorn. Potato chips did not produce a consistently shaped force-deformation curve. The cohesiveness value of popcorn was found to be a good indicator of its sensory crispness.

Effect of Water Activity on the Sensory Crispness and Mechanical Deformation of Snack Food Products

http://theses.univ-lyon2.fr/documents/lyon2/2005/plailly_j/pdfAmont/plailly_j_annexe2.pdf

fMRI of emotional responses to odors: influence of hedonic valence and judgment, handedness, and gender.

The study of the human response to food is a complex and rapidly evolving field. It encompasses a wide range of scientific disciplines, ranging from food science and technology to nutrition, biochemistry, physiology, psychology, marketing and catering. As may be expected in such an interdisciplinary area, numerous scientific concepts have evolved to describe various aspects of the phenomenon under investigation. However, the terminology used to describe these concepts, as well as the methods for measuring them, differ from one discipline to another. Food ‘acceptance’ is one such concept. Since the focus of this chapter concerns factors that influence food acceptance, I would first like to describe and define food acceptance and then to detail the operational approach that we have used to measure it in the laboratory.

Consumer expectations and their role in food acceptance

The flavor perception we derive from eating a food product is determined by the nature and quantity of the flavor components, the availability of these components to the sensory system as a function of time, and the mechanisms and strategies of perception and scaling which determine the flavor quality and intensity over time as recorded by a panelist. An overview is given of the current state of knowledge in these fields as relevant to the understanding of flavor release. Special attention is given to the breakdown of the food matrix through mastication and the convective transport of the released volatiles through the upper airways to the olfactory epithelium. The effects of ingredients and the influence of the structure of food on the flavor release are also discussed. The overview is based on literature data and on results of work carried out at Unilever Research Laboratorium Vlaardingen which have not been published previously.

Flavor release in the mouth

By paired comparison methods, concentrations of 0.75% and 0.86% calcium cyclamate and of 0.17% and 0.19% aspartame were equivalent in sweetness to 10% sucrose in distilled water at 3° and 22°C, respectively. Inherent bitterness of the compounds prevented precise assessment of relative sweetness for sodium saccharin in distilled water, and for the saccharin and cyclamate in flavored drinks. By application of linear regression to the paired comparison data, 0.07% aspartame was calculated as equal in sweetness to 10% sucrose in lemon, strawberry and orange drinks. Because the underlying bitterness of saccharin interfered with assessment of its sweetness, a time-intensity technique was applied. Using a chart recorder to monitor time, time-intensity (T-I) measurements were made of the intensity and the duration of sweetness, bitterness, sourness and flavor in distilled water, and the same characteristics, plus flavor in three flavored drinks, and two flavored gelatins, sweetened with sucrose, cyclamate, or saccharin. T-I curves for the sensory properties of aspartame closely resembled those for sucrose in all media. Cyclamate and saccharin imparted a marked, persistent bitterness to all carriers. In gelatin, samples containing 18% sucrose were firmer initially and took longer to manipulate to a liquid in the mouth than did gelatins containing 0.105% aspartame, 0.55% cyclamate, or 0.05% saccharin.

Paired comparison and time-intensity measurements of the sensory properties of beverages and gelatins containing sucrose or synthetic sweeteners

Two descriptive sensory methods, anchored (deviation from a sucrose reference) and unanchored, were used to quantify differences in aroma, flavor and aftertaste in five media – strawberry, lemon and orange drinks, and strawberry and orange gelatins – varying in type of sweetener. With both methods, samples sweetened with sodium saccharin deviated the most from the sucrose standard, those sweetened with aspartame the least, and calcium cyclamate was intermediate. In general, drinks sweetened with sucrose or with aspartame could be characterized as “sweet-clean”, and those sweetened with cyclamate or with saccharin as “sweet-chemical” and “bitter”. Gelatins containing synthetic sweeteners generally were more astringent, bitter and sour, with less strawberry flavor, and were significantly less hard, springy and viscous than those sweetened with sucrose. In all media, more significant differences were observed among the sweeteners with the anchored method than with the unanchored procedure. Advantages and limitations of these two quantitative descriptive procedures are discussed.

Nancy Larson-Powers

Papers

Paired comparison and time-intensity measurements of the sensory properties of beverages and gelatins containing sucrose or synthetic sweeteners

Descriptive analysis of the sensory properties of beverages and gelatins containing sucrose or synthetic sweeteners1