Sensitivity Comparison of Sequential Monadic and Side-by-Side Presentation Protocols in Affective Consumer Testing

ABSTRACT:  The relative sensitivity of side-by-side and sequential monadic consumer liking protocols was compared. In the side-by-side evaluation, all samples were presented at once and evaluated together 1 characteristic at a time. In the sequential monadic evaluation, 1 sample was presented and evaluated on all characteristics, then returned before panelists received and evaluated another sample. Evaluations were conducted on orange juice, frankfurters, canned chili, potato chips, and applesauce. Five commercial brands, having a broad quality range, were selected as samples for each product category to assure a wide array of consumer liking scores. Without their knowledge, panelists rated the same 5 retail brands by 1 protocol and then 3 wk later by the other protocol. For 3 of the products, both protocols yielded the same order of overall liking. Slight differences in order of overall liking for the other 2 products were not significant. Of the 50 pairwise overall liking comparisons, 44 were in agreement. The different results obtained by the 2 protocols in order of liking and significance of paired comparisons were due to the experimental variation and differences in sensitivity. Hedonic liking scores were subjected to statistical power analyses and used to calculate minimum number of panelists required to achieve varying degrees of sensitivity when using side-by-side and sequential monadic protocols. In most cases, the side-by-side protocol was more sensitive, thus providing the same information with fewer panelists. Side-by-side protocol was less sensitive in cases where sensory fatigue was a factor.     

ALKALI-NEUTRALIZATION PROCESS MAINTAINS THE FIRMNESS AND SENSORY QUALITY OF CANNED SWEETPOTATO PIECES1

Jewel cultivar SP stored 1, 5, and 10 months after harvest were peeled, cut into pieces, treated, and canned in 15 and 30 deg Brix syrups. Samples were evaluated for degree of disintegration (wholeness), firmness (shear force), chemical composition, and sensory acceptance. Untreated samples (controls) disintegrated as storage time prior to processing increased, while treated samples remained intact; firmness and sensory texture scores declined with increasing storage time. Treated samples were significantly firmer than controls throughout the study, and, although shear force declined over time, sensory panelists did not detect any texture change. Overall sensory acceptance at 10 months was greatest for phosphate-treated samples in 30 deg Brix syrup. Thus, the alkali-neutralization process retains firmness, wholeness, and sensory quality of SP canned after long-term storage. This process will permit commercial processing of SP roots stored for up to 10 months.     

Consumer acceptance of dairy products with a saturated fatty acid–reduced,monounsaturated fatty acid–enriched content

Agriculture-based reformulation initiatives, including oleic acid–rich lipid supplementation of the dairy cow diet, provide a novel means for reducing intake of saturated fatty acids (SFA) at a population level. In a blinded manner, this study evaluated the consumer acceptance of SFA-reduced, monounsaturated fatty acid–enriched (modified) milk, Cheddar cheese, and butter when compared with control and commercially available comparative samples. The effect of providing nutritional information about the modified cheese was also evaluated. Consumers (n = 115) rated samples for overall liking (appearance, flavor, and texture) using 9-point hedonic scales. Although no significant differences were found between the milk samples, the modified cheese was liked significantly less than a regular-fat commercial alternative for overall liking and liking of specific modalities and had a lower liking of texture score compared with the control cheese. The provision of health information significantly increased the overall liking of the modified cheese compared with tasting the same sample in a blinded manner. Significant differences were evident between the butter samples for overall liking and modalities of liking; all of the samples were significantly more liked than the commercial butter and sunflower oil spread. In conclusion, this study illustrated that consumer acceptance of SFA-reduced, monounsaturated fatty acid–enriched dairy products was dependent on product type. Future research should consider how optimization of the textural properties of fatty acid–modified (and fat-reduced) cheese might enhance consumer acceptance of this product.     

Prediction of consumer liking from trained sensory panel information: Evaluation of neural networks

This study was set out to establish artificial neural networks (ANN) as an alternative to regression methods (multiple linear, principal component and partial least squares regression) to predict consumer liking from trained sensory panel data. The sensory profile and acceptability of 10 market samples of beef bouillon products were measured. The products were distinct as evaluated by the trained sensory panel. A total of 100 regular beef bouillon product users from Manila measured overall liking, flavour, aftertaste and mouthfeel of the products. Curve fitting method was applied to identify sensory drivers of consumer liking. The sensory drivers of consumer liking were used as explanatory variables in artificial neural networks and regression methods. To overcome the limitations of regression methods we have used artificial neural network techniques to model consumer liking score as a function of trained sensory panel scores and achieved quite encouraging results. Our simulation experiments show that though the regression methods such as multiple linear regression (MLR), principal component regression (PCR) and partial least square (PLS) give an accurate prediction of consumer liking scores, this approach is not robust enough to handle the variations normally encountered in trained sensory panel data. ANNs were trained using the sensory panel raw data and transformed data. The networks trained with sensory panel raw data achieved 98% correct learning, the testing was in a range of 28–35%. Suitable transformation method was applied to reduce the variations in trained sensory panel raw data. The networks trained with transformed sensory panel data achieved about 80–90% correct learning and 80–95% correct testing. It is shown that due to its excellent noise tolerance property and ability to predict more than one type of consumer liking using a single model, the ANN approach promises to be an effective modelling tool.     

Influence of Acidification on Texture of Canned Carrots

Texture of acidified canned carrots was evaluated using a shear compression procedure. Carrots canned with as little as 0.77% gluconic acid in the brine retained firmer texture than those packed without acid. Softening phenomena of acidified carrots do not appear to be consistent with a two substrate first order rate expression model.     

Effect of pig sex on consumer ratings for pork chops and bacon

The study was conducted to determine whether consumer acceptability of fresh and cured pork differed among gilt, intersex, cryptorchid, and intact male market pigs. Samples of chops and bacon from 12 animals of each sex were tested using 9-point hedonic scales for sensory characteristics. Androst-16-ene steroid levels, blood levels of testosterone and estrogen were determined, as was ‘taint’ by a fry test of fat. A significant sex effect for tenderness (P < 0·0092) and juiciness (P < 0·0095) resulted from chops of intact males being liked least. Low consumer ratings were usually texture related. Cryptorchid pigs varied most in eating characteristics being the only sex to exhibit significant differences for liking of aroma and flavour of chops. The few significant differences obtained for bacon were not related to those obtained for chops. Fry test and steroid levels were not related to liking with the exception of testosterone which reduced mean liking.     

UHT纯牛奶消费喜好和关键感官特性的关联分析

以14种市场上不同类型超高温（Ultra-high temperature,UHT）纯牛奶为研究对象,采用9点喜好标度、适合项勾选法（Check-All-That-Apply,CATA）和恰好标度,同时结合偏最小二乘回归分析（PLS）分析不同类型UHT奶消费喜好和关键感官特性接受性差异。研究表明：不同类型UHT奶的整体喜好值范围为4.07~6.25,脱脂奶和部分全脂奶的喜好值最低（<5）,全脂和低脂奶的整体喜好差异不显著（p>0.05）。不同类型UHT奶的乳香、甜味、余味、浓稠和爽滑5个关键感官特性接受性上存在显著差异（p<0.05）,通过PLS回归模型筛选出导致消费喜好差异的7个关键感官特性接受性指标,分别为余味、乳香、甜味、浓稠、爽滑（-）、甜味（-）和乳香（-）。甜味和乳香偏弱以及爽滑度不够是分别导致低脂奶和部分全脂奶样品整体喜好偏低的关键感官特性。相关研究旨在为后期UHT纯牛奶消费喜好和产品感官品质研究提供基础理论和数据参考。     

The role of product familiarity and consumer involvement on liking and perceptions of fresh meat

The objective of this work was to compare consumer’s liking and perception of meat quality attributes as a function of their familiarity and involvement with fresh meat.Ninety-three meat consumers were classified on the basis of their familiarity with fresh meats. Socio-demographic differences between the clusters were found to relate to gender and age, and high familiarity (HF) consumers showed higher involvement with meat. HF consumers enjoyed consuming meat, and they associated a symbolic value to it. In addition, their liking ratings were higher than those of low familiarity (LF) consumers for both appearance and taste of three specific types of fresh meat over the course of product shelf-life. The perceived risks associated with meat consumption and product choice were similar between groups. Both consumer segments reported that the most important driver of fresh meat purchase is its appearance, while the role of extrinsic cues differed among the groups. The HF group needed more information when choosing meat. Regardless of familiarity level, liking was consistent with beef appearance as affected by storage, but the prediction of experienced sensory quality lacked consistency when the perceived intrinsic cue variation was not associated with meat freshness.     

Quality Comparison of Thermoprocessed Fishery Products in Cans and Retortable Pouches

The physical, chemical and sensory properties of rainbow trout, pollock and shrimp processed at equal lethalities in cans and retortable pouches were compared at certain storage periods. Pouched rainbow trout, pollock and shrimp required respectively 34%, 32% and 37% less thermal processing time than the canned product. The pouched products had lower amounts of ammonia, trimethylamine and total carbonyl compounds than the canned products. The pouched products retained 17%, 9% and 15% more Vitamin B₁ than the canned products for rainbow trout, pollock and shrimp, respectively. Pouched products had a firmer texture and lighter color than the canned products. In sensory evaluations, the pouched products were scored higher, in most cases, for color, flavor and overall acceptability.     

PARAFAC: Adjustment for modeling consumer study covering probiotic and conventional yogurt

The feasibility of the parallel factors model (PARAFAC) as a modeling tool for consumer sensory acceptance data of complex food matrices was investigated. The attributes of aroma, flavor, taste, texture, and overall liking of probiotic and conventional yogurts were evaluated by 120 consumers using a 9-point hedonic hybrid scale. Six yogurt samples were used: three were prototypes supplemented with a glucose oxidase/glucose system, which is a potential oxygen scavenging system, and the other three were commercial yogurts. The yogurts supplemented with the glucose oxidase/glucose system presented similar sensory acceptance towards commercial probiotic and conventional yogurts (p > 0.05), besides having garnered lower mean scores for the sensory attributes. Appearance and overall liking were the most significant attributes for the first two components of the PARAFAC model. Finally, the advantage of using this method to explore the intrinsic nature of consumer sensory data is discussed and compared to principal component analysis (PCA).     

Quality Enhancement of Sexually Mature Chum Salmon Oncorhynchus keta in Retort Pouches

Sexually mature or late-run chum salmon muscle was packaged in thin-profile retort pouches and in conventional 307 × 200 metal cans. After retort processing to equivalent lethality, samples were evaluated by sensory and instrumental methods. The pouch product was firmer, more fibrous, drier and chewier than the canned. Less late-run flavor and greater overall acceptability were reported for pouch-processed samples. More free liquid was found in pouches than in cans. Histological examination revealed a more compact structure in chum muscle processed in retort pouches, possibly due to air over-pressure applied to flexible pouches during processing.     

Identifying ideal products using three different consumer profiling methodologies. Comparison with external preference mapping

The aim of the present work was to identify consumers’ ideal product by three consumer profiling techniques and to compare the agreement among the three techniques. Two studies were carried out in which consumers evaluated seven samples of orange-flavoured powdered drinks. In the first study 108 consumers scored their overall liking, whereas in the second one three groups of 50 consumers evaluated the sensory characteristics of the samples using projective mapping, a check-all-that-apply question or intensity scales. After completing the task consumers were asked to identify their ideal product.The different approaches yielded similar information regarding the sensory characteristics of the products and consumers’ ideal product, providing similar recommendations for product improvement. However, they differed in the position of consumers’ optimum product within the sensory space defined by the sensory characteristics of the evaluated samples. Projective mapping identified the consensus position of the ideal product within the range of sensory characteristics of the evaluated samples, providing similar results than external preference mapping. Differences and similarities between the methodologies are discussed, as well as potential applications.