Lisa M. Duizer

A review of acoustic research for studying the sensory perception of crisp, crunchy and crackly textures

Abstract The relationship that acoustic sensations have with the perception of texture has been studied for crisp, crunchy and crackly products. This has involved evaluating the contribution of chewing sounds to the perception of these textures or recording noises produced during mastication and evaluating various acoustic parameters from the resulting amplitude–time curves. Combining the analysis of acoustic recordings with mechanical testing results has been successful for predicting crispness and crunchiness of snack foods. The next stage for acoustic research should be to relate the structure of the products to the sounds produced during mechanical breakdown of the products in order to fully understand the textural properties of the food.

Dual-attribute time-intensity sensory evaluation: A new method for temporal measurement of sensory perceptions

Dual-attribute time-intensity was evaluated as a method for the collection of the perception of two attributes simultaneously. Perceptions of sweetness and peppermint flavour within chewing gum were measured by 10 trained time-intensity panelists using both single-attribute and dual-attribute time-intensity sensory evaluation. Four chewing gum samples, varying in rate of release of sweetness and peppermint flavour were presented for evaluation. In general, dual-attribute time-intensity was as sensitive as single-attribute testing in distinguishing between the sweetness and peppermint perceptions of chewing gum. In comparison to the single-attribute test, the dual-attribute test required half the time to complete and provided a means of assessing complex taste interaction during mastication. The dual-attribute test can be used to study relationships between two attributes within food products which possess a large degree of sample variability, such as the tenderness and juiciness of meat.

Genetic Variation in Putative Salt Taste Receptors and Salt Taste Perception in Humans

The objective of this study was to determine whether single nucleotide polymorphisms (SNPs) in the SCNN1A (3), SCNN1B (12), SCNN1G (6), and TRPV1 (10) genes affect salt taste perception. Participants were men (n = 28) and women (n = 67) from the Toronto Nutrigenomics and Health study aged 21-31 years. Taste thresholds were determined using a 3-alternative forced-choice staircase model with solutions ranging from 9×10(-6) to 0.5 mol/L. Suprathreshold taste sensitivity to 0.01-1.0 mol/L salt solutions was assessed using general labeled magnitude scales. None of the SNPs in the SCNN1A and SCNN1G genes were significantly associated with either outcome. In the SCNN1B gene, 2 SNPs in intronic regions of the gene modified suprathreshold taste sensitivity (mean iAUC ± SE). Those homozygous for the A allele of the rs239345 (A>T) polymorphism and the T allele of the rs3785368 (C>T) polymorphism perceived salt solutions less intensely than carriers of the T or C alleles, respectively (rs239345: 70.82±12.16 vs. 96.95±3.75, P = 0.02; rs3785368: 57.43±19.85 vs. 95.57±3.66, P = 0.03) In the TRPV1 gene, the rs8065080 (C>T, Val585Ile) polymorphism modified suprathreshold taste sensitivity where carriers of the T allele were significantly more sensitive to salt solutions than the CC genotype (98.3±3.8 vs. 74.1±8.3, P = 0.008). Our findings show that variation in the TRPV1 and the SCNN1B genes may modify salt taste perception in humans.

Making the most of mealtimes (M3): grounding mealtime interventions with a conceptual model.

In this issue of the journal, Whear and colleagues1 present the results of a systematic review focused on mealtime interventions in long term care (LTC) and their effect on behavioral and psychological symptoms of dementia (BPSD) (e.g., fear, agitation). In a companion article2 these authors focus on nutritional outcomes of mealtime interventions. Key findings from both of these systematic reviews are that: 1) there is the potential to positively influence nutrition parameters and BPSD by changing the mealtime environment, 2) quality of these studies is generally poor due to small sample sizes, lack of randomization, and inadequate control for confounding factors within resident, staff and organizational levels, and 3) interventions are only briefly articulated, limiting understanding of how they work and how they can be replicated in typical LTC homes. The authors recommend that high quality studies be conducted to demonstrate the value of these interventions for improving nutritional health and quality of life of residents.1,2 We would add to this recommendation that intervention research needs to be based on a conceptual framework grounded in current evidence that demonstrates that there are several influences on the varied activities (e.g., arriving, eating, waiting socializing) that occur during a mealtime3 and that there are several intermediate (e.g. BPSD, food intake, strength) and ultimate outcomes (e.g., nutritional status, comorbidity, quality of life, functional ability, mortality) to consider. Mealtime is a complex process with multiple levels of influence including residents, staff, home and government.3 For example, organizational practices around when the dining room is open for meals can result in rushed mealtimes and if staffing is short or staff are drawn away from assisting others to encourage an agitated resident to remain at the table, all meal participants, including staff, are affected. Fully understanding the problem and its determinants is needed to design interventions that have the greatest impact.4

The relationship between sensory time-intensity, physiological electromyography and instrumental texture profile analysis measurements of beef tenderness

The relationship between the perception of tenderness, chewing activity and instrumental compression was explored by time-intensity, electromyography and instrumental texture profile analysis (ITPA). Bovine m. longissimus dorsi from five treatments were evaluated by seven individuals. Time-intensity results showed that the Decrease Area and Area Under the Curve provided the most information regarding sample differences, with the former providing the best sample discrimination. Electromyographic results of mastication rate demonstrated the number of chews required to reach maximum force to chew. The results suggest a need to re-examine the effects of early mastication vs the late mastication effects for the measurement of meat tenderness.

Sensory characteristics and consumer acceptance of bread and cracker products made from red or white wheat.

Whole grain consumption is being promoted due to a number of associated health benefits. However, whole grain consumption is below recommendations possibly due to the presence of characteristic flavors that consumers find unacceptable. The objective of this study was to investigate the sensory characteristics and consumer acceptance of products made from commercial whole grain flours produced from red or white wheats, and with fine or coarse bran particle sizes. Descriptive analysis and consumer acceptance panels were used to characterize both low (cracker) and intermediate (bread) moisture products made with the flours. Partial least squares (PLS) regression was used to correlate the descriptive and consumer data. Sensory differences in whole grain products made from red or white wheat with small or large bran particles sizes and product moisture contents were observed. Bran particle size had a greater effect on the sensory properties of the whole grain products, particularly within the cracker; conversely bran particle size had little influence on consumer acceptance. Red wheat products were found to be more acceptable than the white wheat products. However, a number of color × bran particle interactions were observed in both the descriptive and consumer data. PLS regression demonstrated that consumers could be divided into groupings based upon certain attributes and characteristics.

The effect of line orientation on the recording of time-intensity perception of sweetener solutions

Abstract A trained time-intensity panel was used to evaluate the effect of scale orientation on time-intensity responses. Equisweet samples of aspartame, acesulfame k, sucralose and 9% sucrose were presented to 10 panelists for evaluation on both horizontal and vertical scales. For the most part, horizontal and vertical scales yielded similar results. However, Maximum Intensity responses on the vertical scale were approximately 13% greater than Maximum Intensity responses on the horizontal scale. The parameters of Decrease Angle, Decrease Area and Area Under the Curve were also significantly larger when vertical scales were used than when horizontal scales were used. We suggest that differences can be minimized by anchoring reference samples to the scales and by counterbalancing the presentation of the scales within and amongst panelists. These results demonstrate the use of time-intensity scales on two dimensions and suggest the possibility of multi-attribute evaluations of taste.

Addition of Soluble Soybean Polysaccharides to Dairy Products as a Source of Dietary Fiber

Increasing consumption of dietary fiber in food leads to many important health benefits: for example, reduction in blood cholesterol, reduced risk of diabetes, and improved laxation. Water soluble soybean polysaccharide (SSPS) is a dietary fiber extracted and refined from okara, a byproduct of soy manufacturing. It was incorporated into 3 categories of dairy-based products, thickened milkshake-style beverages, puddings, and low-fat ice cream, to the maximum amount without over-texturing the food. Rheological measurements and sensory tests were used to develop desirable SSPS-fortified products. From the rheological data, 4% SSPS-fortified dairy beverages and 4% SSPS -fortified puddings were in the range of commercial products. From sensory analyses, 4% SSPS-fortified dairy beverage with 0.015%kappa-carrageenan, 4% SSPS-fortified pudding with 0.1%kappa-carrageenan, and 2% SSPS-fortified low-fat ice cream gained the highest scores in consumer hedonic rating. Panelists also indicated their willingness to consume those products if they were available commercially. Practical Application: Since the dietary fiber intake of many people is below their suggested adequate intake values, strategies to successfully fortify foods with fiber may help alleviate this gap. We have developed 3 dairy products, a beverage, a pudding, and a low-fat ice cream, that have been fortified with soluble soybean polysaccharide at levels of 4%, 4%, and 2%, respectively. These products were within acceptable ranges of rheological parameters and other physical stability measurements and were judged to be acceptable by sensory analyses.

Development of soy-based bread with acceptable sensory properties.

UNLABELLED Consumption of soy protein has been associated with benefits related to numerous areas of health. Due to the widespread consumption of bread, one means of contributing to the health of individuals is through the incorporation of soy protein into bread. To this end, soy flour (SF) or soy protein isolates (SPIs) in 20% and 12% substitution levels, respectively, were added to flour during bread manufacture. The developed breads were tested using a consumer panel for acceptability, using a refined white bread as a control. These data were compared to attribute intensity data collected by the trained panel to identify specific flavor and texture characteristics affecting liking. The sensory profile of the 20% SF bread was acceptable and comparable to the control bread, despite a significantly stronger beany flavor. No significant differences in sensory properties of the SF and control breads were detected by the trained panel for many sensory attributes. The SPI bread, however, had a sensory profile that was significantly more firm, dense, sour, beany, bitter, and astringent with a strong aftertaste in comparison to the wheat control bread. Consumer liking scores for the SPI bread was significantly lower than the liking of the control and the SF added bread. PRACTICAL APPLICATION Many soy-enriched foods, while contributing positively to health, are considered unacceptable by consumers. This is due to negative sensory properties, such as beany, painty, and astringent notes, often perceived by consumers. This study provides information on the level of SF that can be included in bread in an amount that does not detract from consumer acceptability. This level also allows for a Food and Drug Administration (FDA) health claim to be made.

Variation in the TAS1R2 Gene, Sweet Taste Perception and Intake of Sugars

Background/Aims: To determine whether variation in the TAS1R2 gene affects sucrose taste perception and sugar intake. Methods: Participants were men (n = 238) and women (n = 458) aged 20-29 years. A subset (n = 95) with body mass index (BMI) data available completed a sensory analysis study. A food frequency questionnaire assessed dietary intake, and eight polymorphisms were genotyped (rs12033832, rs12137730, rs35874116, rs3935570, rs4920564, rs4920566, rs7513755 and rs9701796). Sucrose taste thresholds were determined by staircase procedure (solutions: 9 × 10-6 to 0.5 mol/l). Suprathreshold sensitivity to 0.01-1.0 mol/l sucrose solutions was assessed using general Labeled Magnitude Scales. Results: A significant genotype-BMI interaction was observed for rs12033832 (G>A) for suprathreshold sensitivity (p = 0.01) and sugar intake (p = 0.003). Among participants with a BMI ≥25, G allele carriers had lower sensitivity ratings (mean incremental area under the taste sensitivity curve ± SE; GG/GA 54.4 ± 4.1 vs. AA 178.5 ± 66.6; p = 0.006), higher thresholds (GG/GA 9.3 ± 1.1 vs. AA 4.4 ± 4.3 mmol/l; p = 0.004) and consumed more sugars (GG/GA 130 ± 4 vs. AA 94 ± 13 g/day; p = 0.009). G allele carriers with a BMI <25 had lower thresholds (GG/GA 8.6 ± 0.5 vs. AA 16.7 ± 5.7 mmol/l; p = 0.02) and consumed less sugars (GG/GA 122 ± 2 vs. AA 145 ± 8 g/day; p = 0.004). Conclusion: The rs12033832 single nucleotide polymorphism in TAS1R2 is associated with sucrose taste and sugar intake, but the effect differs depending on BMI.