Comparison of a central location test versus a home usage test for consumer perception of ready-to-mix protein beverages

Online consumer testing beyond central location tests: A case study for brewed coffee

Due to the constraints of the COVID-19 pandemic, conducting sensory evaluations requiring direct interactions became challenging. In response, researchers have been motivated to devise non-face-to-face testing methods as alternatives. This study aimed to compare two non-face-to-face home-use tests (HUT) with the traditional face-to-face central location test (CLT). Both HUTs involved online recruitment and sample delivery to participants' homes. One HUT provided a written protocol with no direct interaction (contactless HUT; C-HUT), whereas the other included an online meeting with a researcher for live guidance (online HUT; O-HUT). Four coffee samples were evaluated on the basis of liking and sensory and emotional attributes. The comparison between CLT and O-HUT showed RV coefficients of 0.92, 0.93, and 0.98 (P < 0.05) for liking and sensory and emotional attributes, respectively. In addition, based on the RV coefficient, the CLT results showed a significantly greater similarity to those of O-HUT compared to those of C-HUT. The O-HUT also outperformed the C-HUT in its ability to significantly discriminate between samples. Hence, real-time interactions between researchers and participants, as facilitated by O-HUT, may be more suitable in certain scenarios compared to C-HUT, which relies solely on a written protocol. Overall, these findings suggest that C-HUT and O-HUT are suitable methods for collecting sensory data and overcoming geographic and face-to-face contact limitations, providing greater flexibility, and reducing the time and cost associated with traditional sensory evaluations.

Sensory Perception and Food-Evoked Emotions of Older Adults Assessing Microwave-Processed Meals with Different Salt Concentrations

This study employed a home-use test to explore the sensory perception and evoked emotions of older adults in the assessment of chicken pasta meals with different salt concentrations. Ready-to-eat (RTE) meals with three salt levels (100%, 75%, and 50%) and two treatments-with and without added herbs-were tested. Multiple sensory attributes and overall meal liking were evaluated by participants (n = 54; 60-86 years of age) with hedonic and just-about-right scores. Twenty-five food-evoked emotions were also tested. Sensory results suggested a 50% salt reduction is possible with minimal impact on the overall liking, while a 25% salt reduction did not affect the saltiness and flavor liking of the meals. Herb addition positively impacted the aroma, flavor, and spiciness liking of the meals. The emotions that differed (p < 0.05) among meals were active, aggressive, bored, calm, happy, and wild, with the meals with herbs added eliciting more positive emotions. A questionnaire elicited information about participants' interest in healthy eating, food technology neophobia, and picky behaviors to determine the influence of these factors on participants' salt consumption habits. Sensory acceptance data combined with questionnaires explored what influenced this group of older adults in their acceptance of and interest in RTE meals.

Sensory Analysis and Consumer Preference: Best Practices

Sensory science is a multidisciplinary field that encompasses a wide variety of established and newly developed tests to document human responses to stimuli. Sensory tests are not limited to the area of food science but they find wide application within the diverse areas of the food science arena. Sensory tests can be divided into two basic groups: analytical tests and affective tests. Analytical tests are generally product-focused, and affective tests are generally consumer-focused. Selection of the appropriate test is critical for actionable results. This review addresses an overview of sensory tests and best practices.

Effects of Test Location and Sample Number on the Liking Ratings of Almond Beverage and Vegan Ramen Products

The present study investigated the effects of the evaluation environment and sample number on liking ratings within the same testing session. It comprised two experiments that determined consumer taste ratings of the following food products: (1) almond beverage and (2) vegan ramen, as rated by 322 and 287 Korean consumers, respectively. Consumers tasted each food product under either laboratory or home-used test conditions. Additionally, three levels of sample numbers were established for evaluation (almond beverage test: 1, 2, and 4; vegan ramen test: 1, 3, and 5) in each test condition. A target sample was selected for each of the two food products to directly ascertain the effects of the evaluation environment and sample number on the liking ratings. The results revealed that during the same evaluation session, the sample number affected the liking ratings of the target sample more than the testing location. Moreover, the sample number effect was product item dependent, that is, no significant change was noted in the liking ratings of the target almond beverage sample according to sample number, whereas significant differences were observed in the liking ratings of the target vegan ramen sample. Furthermore, the sample number effect was more prominent under laboratory test conditions than under home-used test conditions probably due to the serving order effect driven by hedonic contrast, carry over effect, and sensory specific satiety. The findings demonstrate that home-used tests should be recommended over laboratory tests when measuring the liking of a small number of multiple sample food items with high flavor complexity.

Variations in consumer acceptance, sensory engagement and method practicality across three remote consumer-testing modalities

In the context of the COVID-19 pandemic, it has become challenging for sensory scientists to conduct in-person sensory tests, particularly large central location tests. Sensory literature comparing central location and home use tests shows no clear consensus about how each methodology affects sample ratings and panelist engagement. Research on instructional delivery suggests that the most effective method of increasing engagement involves interactive video conferencing. The objective of this study was to compare three methods of remote consumer testing regarding sample acceptance, sensory engagement, and method practicality. Eighty-four participants rated five chocolate-chip cookie products on a 9-pt hedonic scale in each of three methods: 1) a live (synchronous) Zoom session, 2) an asynchronous video-guided session, and 3) a fully written protocol session. Results showed no significant differences in sample liking pattern across the methods used. Engagement scores approached the limit of significance for the Active Involvement dimension, indicating panelists were least likely to feel distracted, zoned out or lose interest in the written protocol method. There were no significant differences in the time spent on the test by the panelists across the three methods. Asynchronous methods showed to be most suitable in terms of the convenience of the time of day at which the tests were completed, but showed no significant differences in other aspects of method practicality. Overall, a written protocol method of remote consumer testing is recommended, as it is less time-consuming for researchers while providing similar acceptance and engagement as other methods.

Physical and sensory properties of lemon-flavored acidic beverages formulated with nonfat dry milk during storage

Sensory and physical properties of 2 lemon-flavored beverages with 5% and 7.5% wt/wt nonfat dry milk (NFDM) at pH 2.5 were studied during storage. The 2 beverages had similar volatile compounds, but the 5% NFDM had higher aroma and lemon flavor, with a preferred appearance by consumers due to the lower turbidity and viscosity. After 28 d of storage at 4°C, lemon flavor decreased in the 5% NFDM beverage but was still more intense than the 7.5% one. During 70 d of storage, no microorganisms were detected, and the beverages were more stable when stored at 4°C than at room temperature according to changes of physical properties measured for appearance, turbidity, color, particle size, zeta potential, rheological properties, and transmission electron microscopy morphology. Findings of the present study suggest that NFDM may be used at 5% wt/wt to produce stable acidic dairy beverages with low turbidity when stored at 4°C.

Characterizing Individual Differences in Sweet Taste Hedonics: Test Methods, Locations, and Stimuli

Sweetness drives the consumption of added sugars, so understanding how to best measure sweet hedonics is important for developing strategies to lower sugar intake. However, methods to assess hedonic response to sweetness vary, making results across studies difficult to integrate. We compared methods to measure optimal sucrose concentration in 21 healthy adults (1) using paired-comparison preference tracking vs. ratings of liking, (2) with participants in the laboratory vs. at home, and (3) using aqueous solutions vs. vanilla milk. Tests were replicated on separate days to assess test-retest reliability. Test-retest reliability was similar between laboratory and home testing, but tended to be better for vanilla milk and preference tracking. Optimal sucrose concentration was virtually identical between laboratory and home, slightly lower when estimated via preference tracking, and about 50% lower in vanilla milk. However, optimal sucrose concentration correlated strongly between methods, locations, and stimuli. More than 50% of the variability in optimal sucrose concentration could be attributed to consistent differences among individuals, while much less variability was attributable to differences between methods. These results demonstrate convergent validity between methods, support testing at home, and suggest that aqueous solutions can be useful proxies for some commonly consumed beverages for measuring individual differences.

On the validity of longitudinal comparisons of central location consumer testing results prior to COVID-19 versus home use testing data during the pandemic

Consumer testing assays a panel's liking of a food or other sensory stimulus. However, liking can be influenced by mood, with people feeling more uncomfortable, or more unhappy reporting lower liking ratings than those in a higher affect. Though consumer testing typically takes place as a central location test (CLT, usually in a set of standardized sensory booths), the COVID-19 pandemic has resulted in a global pivot to home use tests (HUTs), where panelists can taste and smell samples unmasked more safely while in their own homes. Unfortunately, as this situation differs in many ways to a central location test, this puts the validity of longitudinal comparisons of liking scores under question. Further, as people across the globe report feelings of worry, unease, and stress during the pandemic, this may present a second source of variation in affect with previous years. We tested a set of snack bar samples both at home and in a central location, in repeated measures with the same panel, to test the validity of comparisons across locations. We further compared CLT results to those when testing the same samples in a previous year. Finally, we performed a meta-analysis of existing data on this subject. While liking behavior in CLTs did not differ between years, panelists rated some samples higher when in their own homes, in line with results from the meta-analysis of previous reports. Interestingly, panelists in the study also assigned fewer penalties in the HUT, implying a less analytical mindset when in the home. Results suggest that care should be taken when comparing results taken at home during the COVID-19 pandemic to those taken previously in a central location. PRACTICAL APPLICATION: Consumer testing is applied in the food industry to evaluate a panelist's liking for a food product or stimulus. However, liking is also dependent on factors extrinsic to the samples tested. Thus, with the switch to in-home testing due to COVID-19, we compared liking scores from in-home and central locations testing, with higher scores common in HUTs.

Consumer Acceptance of a Ready-to-Eat Meal during Storage as Evaluated with a Home-Use Test

A home-use test (HUT) is one method that provides a measure of ecological validity as the product is consumed in home under common daily use circumstances. One product that benefits from being evaluated in-home are ready-to-eat (RTE) meals. This study determined consumer acceptance of microwave-thermally-pasteurized jambalaya, a multi-meat and vegetable dish from American Cajun cuisine, and a control (cooked frozen jambalaya) through an on-line home-use test (HUT) over a 12-week storage period. Paralleling the HUT, an online auction determined consumers’ willingness to pay. The study also explored how the social environment may impact the liking of the meals when a partner of the participants joined the sensory evaluation of the meals. Consumers (n = 50) evaluated microwave-processed jambalaya stored at 2 °C and a control (cooked frozen jambalaya stored at −31 °C) after 2, 8 and 12 weeks of storage. Consumer liking of different sensory attributes was measured. Participants could choose to share the meals with a partner as a way to enhance ecological validity. The responses from 21 partners to the sensory-related questions were collected. After the sensory evaluation, the participants bid on the meal they had just sampled. Results showed that processing method (microwave vs. control) did not significantly influence the measured sensory attributes. Only flavor liking decreased over storage time (p < 0.05). The inclusion of partners significantly increased (p = 0.04) the liking of the appearance of the meals. The mean values of the bids for the meals ranged from $3.33–3.74, matching prices of commercially available jambalaya meals. This study found suggests that the shelf- life of microwave-processed meals could be extended up to 12 weeks without changing its overall liking. The study also shows the importance of exploring HUT methodology for the evaluation of consumers’ acceptance of microwave-processed jambalaya and how including a partner could contribute to enhance ecological validity.

Comparison of Home Use Tests with Differing Time and Order Controls

Consumer tests are classified in terms of the location of testing as laboratory tests or central location tests (CLTs) and home use tests (HUTs). CLT is generally used in sensory tests due to the ease of test control, whereas HUT has higher validity because of real consumption. However, the lack of test control in HUT is a major issue. In order to investigate the error occurrence and efforts required to minimize errors, three groups of tests were designed differing time and order control and evaluation was conducted using six snacks with texture differences. Errors related to time, order, and consumer or sample number were higher for more controlled conditions, however, most errors were recoverable using identification information except for cases of no response. Additionally, consumers preferred to consume all snacks in the evening at home, which differed from the typical 9 a.m. to 6 p.m. evaluation time in CLT. However, the timing differed for consumers with self-reported snacking time. The research title that included the term 'home' might have influenced the participants' choice of location for evaluation. Overall, there was no significant difference between the results of groups despite different time and order controls, which could increase the applicability of HUT.

Influence of Age and Individual Differences on Mouthfeel Perception of Whey Protein-Fortified Products: A Review

Protein needs are considered to increase with age, with protein consumption being associated with many positive outcomes. Protein-fortified products are often used to improve nutritional status and prevent age-related muscle mass loss in older adults. Accordingly, older adults are commonly provided with products fortified with whey protein; however, such products can cause mouthdrying, limiting consumption and product enjoyment. Currently, the extent to which age and individual differences (e.g., saliva, oral health, food oral processing) influence the perception of whey protein-derived mouthdrying is relatively unclear. Previous research in this area has mainly focused on investigating mouthdrying, without taking into account individual differences that could influence this perception within the target population. Therefore, the main focus of this review is to provide an overview of the relevant individual differences likely to influence mouthfeel perception (specifically mouthdrying) from whey protein-fortified products, thereby enabling the future design of such products to incorporate better the needs of older adults and improve their nutritional status. This review concludes that age and individual differences are likely to influence mouthdrying sensations from whey protein-fortified products. Future research should focus more on the target population and individual differences to maximise the benefits from whey protein fortification.

Consumer perceptions of anticake agents on shredded Cheddar cheese

Prepackaged natural cheese shreds are a growing consumer category. Anticake agents are applied to commercial cheese shreds to assist with shelf life and ease of use. The objective of this study was to investigate consumer perception of 3 anticake agents applied at various levels to Cheddar cheese shreds. Three common anticake agents (80% potato starch/20% cellulose blend, 100% potato starch, or potato starch/corn starch/calcium sulfate blend) were applied to duplicate lots of Cheddar cheese shreds at 1, 2, 3, 4, and 5% (wt/wt). Control Cheddar cheese shreds with no anticake were also included. Sensory properties (appearance, flavor, texture, and hot texture) were documented using a trained sensory panel (n = 8), and 3 consumer acceptance tests were also conducted. In test 1, consumers (n = 110) visually evaluated liking of cold shred appearance. In test 2, consumers (n = 100) evaluated melted shreds on a flour tortilla for overall liking and appearance, flavor, and texture liking. In test 3, consumers (n = 49) participated in a home usage test. Two-way ANOVA (anticake × anticake application rate) was used to interpret the collected data from each test. Visual appearance of shreds was the primary attribute influenced by anticake application and anticake agent. Trained panel evaluation demonstrated that the 100% potato starch anticake had minimal effects on visual appearance. The other 2 agents (80% potato starch/20% cellulose blend and potato starch/corn starch/calcium sulfate blend) showed increases in visible powder at >3% (wt/wt). Consistent with results from trained panelists, higher application rates decreased consumer appearance and color liking for Cheddar shreds with 80% potato starch/20% cellulose and potato starch/corn starch/calcium sulfate blends at >2 or 3% (wt/wt), respectively. Appearance liking of melted shreds decreased with increased anticake application percent but decreased the most for 100% potato starch anticake at greater than 1% (wt/wt) application. Overall liking, flavor liking, and texture liking attributes for melted shreds were negatively affected at >3% (wt/wt) application regardless of anticake agent used. In general, anticake agents can be applied to Cheddar cheese shreds at up to 3% (wt/wt) with minimal effect on consumer perception.

Invited review: Astringency in whey protein beverages

Astringency is the sensation of mouth drying and puckering, and it has also been described as a loss of lubrication in the mouth. Astringency is perceived as an increase in oral friction or roughness. Astringency caused by tannins and other polyphenols has been well documented and studied. Whey proteins are popular for their functional and nutritional quality, but they exhibit astringency, particularly under acidic conditions popular in high acid (pH 3.4) whey protein beverages. Acids cause astringency, but acidic protein beverages have higher astringency than acid alone. Whey proteins are able to interact with salivary proteins, which removes the lubricating saliva layer of the mouth. Whey proteins can also interact directly with epithelial tissue. These various mechanisms of astringency limit whey protein ingredient applications because astringency is undesirable to consumers. A better understanding of the causes of whey protein astringency will improve our ability to produce products that have high consumer liking and deliver excellent nutrition.