Sensory and consumer science methods used with older adults: A review of current methods and recommendations for the future

Clean-label products: Factors affecting liking and acceptability by Portuguese older adults

Consumers are preferring more "natural" foods, made of "healthier" and "familiar" components - the "clean-label" trend. As the population ages, understanding the older adult consumer segment becomes increasingly important. This study aims to identify the factors influencing the acceptability and liking of clean-label products in older adults living in the community. A convenience sample of 100 older adults was used for this cross-sectional study. Socio-demographic data, health status, independence level, lifestyle characteristics, nutritional status, and food and nutrient intake data were collected. The acceptability and liking for clean-label products comprised two parts: Sensory analysis with overall liking evaluation of three pairs of products, using a 9-point hedonic scale and free comments; Willingness to eat and preference assessment of nine pairs of products using the Food Action scale and a simple preference test. The participants were 80% female with a mean age of 75 years old. The overall liking for clean-label versions of cookies and mayonnaise was lower than for traditional versions. However, participants were more willing to eat the clean-label versions of products, particularly ham and yogurt. Most of the participants would prefer buying the clean-label version of all nine pairs of products, especially for ham, loaf bread, sausages, and yogurt. In sum, older adults living in the community exhibit a lower liking but, a greater willingness to eat and a higher preference for buying clean-label products. Older adults who favor clean-label products have higher levels of education and are reported to have a more adequate diet.

The effect of high-polyphenol sumac (Rhus coriaria) on food intake using sensory and appetite analysis in younger and older adults: A randomized controlled trial

Aging is accompanied by a decline in appetite and food intake with associated deficiencies in both macronutrients and micronutrients. The aim of this study was to investigate the impact of adding Iranian brown sumac (Rhus coriaria) (CIBS) into butternut squash soup on sensory evaluation and food intake among older adults (n = 20; >65 years old) and younger adults (n = 20; 18-35 years old). To evaluate the polyphenol content and antioxidant activity of the sumac samples, a Folin-Ciocalteu assay (FCR) and ferric ion reducing antioxidant power (FRAP) assay were used, respectively. L-glutamic acid was assessed using a Megazyme L-glutamic acid assay. Compusense software was used to assess the sensory evaluation attributes of free-living older adults and younger adults receiving different doses of sumac in butternut squash soup. Nutritics software was used to assess food intake following the addition of 0.37 g of sumac to soup. CIBS was selected based on a preliminary assessment in vitro for L-glutamic acid, antioxidant, and polyphenol content of six varieties of sumac. Sensory evaluation results revealed that the difference in perceived intensity of brown color between the soup samples with different doses of CIBS was greater in the younger adults' group (p = .001) than in older adults (p = .037). In addition, the food intake study found that during the ad libitum lunch, older adults consumed more energy (kcal; p = .014), protein (g; p = .025), carbohydrate (g; p = .013), and fat (g; p = .002) after soup with sumac compared to control soup. The overall findings of this study suggest that the addition of sumac to food may have a potential benefit in enhancing ad libitum lunch intake in older adults leading to effective management of malnutrition. This may promote healthy aging and minimize the burden and the consequences of anorexia of aging as main public health concerns.

A Timely Application-Temporal methods, past, present, and future

Eating is a dynamic experience, and temporal sensory methods have been proposed to document how products change over the course of consumption or use (nonfood). A search of online databases yielded approximately 170 sources related to temporal evaluation of food products that were compiled and reviewed. This review summarizes the evolution of temporal methodologies (past), offers guidance in selecting appropriate methods (present), and provides insights into the future of temporal methodologies in the sensory space. Temporal methods have evolved to document a variety of characteristics in food products including how the intensity of a specific attribute changes over time (Time-Intensity), which specific attribute is dominant at each time during evaluation (Temporal Dominance of Sensations), which attributes are present at each time point during evaluation (Temporal Check-All-That-Apply), and many others (Temporal Order of Sensations, Attack-Evolution-Finish, and Temporal Ranking). In addition to documenting the evolution of temporal methods, this review considers the selection of an appropriate temporal method based on the objective and scope of research. When choosing a temporal method, researchers should also consider the selection of panelists to perform the temporal evaluation. Future temporal research should focus on validation of new temporal methods and explore how methods can be implemented and improved to add to the usefulness of temporal techniques for researchers.

Guiding the formulation of soft cereal foods for the elderly population through food oral processing: Challenges and opportunities

As the elderly population is growing steadily, more age-friendly food products that allow them to cover their nutritional needs and are enjoyable need to be designed. Since their oral physiology is considerably altered, the study of Food Oral Processing has become an essential discipline in food development, as it takes into consideration the complex interactions between food structure, oral processing, physiology and perception. Cereals are staple foods in many countries, and their consumption as bakery products is popular among the elderly population. In addition, when fortified with pulse proteins, they can help meet the protein needs of seniors and help fight against sarcopenia. For these reasons, this chapter presents an overview of the various aspects involved in the oral processing and formulation of soft cereal foods, translating them into challenges and opportunities that are of relevance to the design of realistic soft cereal foods targeted for the elderly that are nutritious and sensory appealing. This review focuses on the healthy elderly population and does not intend to cover the needs of the dependent elderly suffering from chronical diseases.

Identification of aroma compounds in a commonly prescribed oral nutritional supplement and associated changes in olfactory abilities with human ageing

Undernutrition is prevalent in the older adult population. Oral nutritional supplements (ONS) are a clinically effective nutritional intervention, however, patient acceptance of ONS can be limited by their palatability. While sensory attributes such as sweetness and mouthfeel have been investigated, the contribution made by aroma to the perceived flavour of ONS has not been studied. Firstly, this research aimed to identify the aroma active compounds within a commonly prescribed ONS using estimated odour activity values (OAV) and gas chromatography olfactometry mass spectrometry (GC-O-MS). Secondly, age related differences in olfactory detection were explored. Eight aroma active compounds were identified within the ONS, including diacetyl (sweet), isoamyl acetate (banana), dimethyl trisulfide (sulfur) and methanethiol (sulfur). When compared with younger adults (n = 24, 18–44 years), older adults (n = 24, 62–80 years) had higher detection thresholds for all aroma compounds and this was significant for isoamyl acetate (sweet, fruity) and methanethiol (sulfur) (p = 0.01 and p = 0.03, respectively). Thus, a decline in olfactory sensitivity was present in the older subjects included in the study, and this reduced detection sensitivity was aroma specific. Thus, older adults’ flavour perception of ONS likely depends on the combined effect of product factors (the aroma profile) along with age related consumer factors (the degree of impairment in perception). This is a fundamental study which will aid future research into how the aroma profile, and associated age related impairments in perception, shape the global perception of ONS for nutritionally at risk older individuals.

Age group determines the acceptability of protein derived off-flavour

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Heat-treatment of protein ingredients can impart sulfurous flavours into beverages.

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Sulfurous flavours negatively impacted consumer acceptance of a dairy beverage.

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Older adults had greater acceptance of sulfurous flavours compared to younger adults.

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Diacetyl reduced the negative impact of these compounds for both age groups.

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Best estimate thresholds give a conservative estimate of off-flavour acceptability.

Many older adults fail to meet their daily protein requirements, potentially due to social, physical and medical factors, including sensory and appetite changes. Additionally, our previous research has identified potential sulfurous off-flavours, originating from heat-treatment of protein ingredients, which could play a role in consumer acceptance. This study aims to determine the hedonic impact of these potential off-flavours when added to a dairy beverage, identify the specific off-flavour concentrations which cause rejection by consumers, and lastly investigate difference in acceptance between older and younger consumers. A rejection threshold (RjT) protocol was used, in combination with Best Estimate Thresholds (BET), whereby sulfurous flavours (dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide), and diacetyl were added to create a range of concentrations. 95 participants (younger n = 49, 18–38 years; older n = 46, 60–79 years) tasted 7 pairs of samples (one blank and one with ascending off-flavour concentration) and selected their preferred samples. Sulfurous flavours negatively impacted consumer acceptance, however, the extent to which they impart a negative effect differs between age groups. Younger adults rejected samples containing low concentrations of sulfurous off-flavours (1.55 ppb), however, older adults rejected samples with concentrations over 3 times higher (5.08 ppb). When combined with sulfurous flavours, diacetyl increased the rejection threshold for both groups. In conclusion, these observations imply that a greater quantity of off-flavour may be present before acceptance is reduced in the older consumer group. Moreover, diacetyl demonstrates partial masking abilities of sulfurous off-flavours, and BET gave a more conservative estimate of acceptability. This knowledge will help guide sensory innovation of high-protein beverages for older consumers to support product acceptance and optimal intake.

Acceptance of oat-based beverages tailored for patients with cancer

Oat-based beverages are a nutritious product with the potential to support increased nutrient intake of patients with cancer. The aim of this research was to evaluate the sensory acceptance of oat-based beverages and perceptions of oats among patients with cancer as future vehicles for nutrient delivery. In study 1, three flavors of oat-beverages were well accepted without significant difference in liking among flavors or serving temperature, or between patients with cancer and healthy participants. Patients with cancer more frequently rated the beverages as too sweet compared to healthy participants; flavor intensity was just about right for all participants. In the second study, one of two formulations fortified with protein and fish oil was not different in liking compared to the unfortified chocolate product. Patients associated oat food products with specific oat-based food products and oat health benefits in a free-word association task in the third study. Together, sensory acceptance and the perceived health benefits of oats indicate the potential for oats to be incorporated in fortified and unfortified products tailored for patients with cancer. PRACTICAL APPLICATION: The three studies presented here to assess the sensory acceptance of oat-based beverages and perceptions of oats among patients with cancer demonstrate that oats can be incorporated in fortified and unfortified products tailored for patients with cancer. Inadequate nutrition is highly prevalent among oncology patients and there is a lack of available products targeted to improve their nutritional intake. These findings can support product developers and sensory scientists in the development and evaluation of food products acceptable to this population.

Dysphagia-Related Health Information Improved Consumer Acceptability of Thickened Beverages

Most people tend to think that healthy foods do not taste good. This view could have a negative impact on the taste of the food that people eat for health. However, if health-related information is provided to avoid negative aspects, acceptability may improve. Thus, this study investigated changes in consumers’ sensory perception of thickened beverages before and after the provision of dysphagia-related health information. Sixty young (19–39 years old) and middle-aged (40–64 years old) consumers participated in two experiment sessions conducted one week apart. The first session proceeded without any information and the second provided information about dysphagia and the need for dietary modification before evaluation. Three beverages (orange juice, red bean water, and sports drink) were used in nectar-like (51–350 cP) and honey-like (351–1750 cP) forms; original beverage samples (0%) were used as the control. Consumers were asked about acceptability, liking the flavor, intensity, and general health interest (GHI). An analysis of variance was performed to show the change in flavor rating and acceptability between the two sessions. Although there were age-related differences in response to the samples, thickened beverages were rated as more acceptable, in terms of their characteristics (swallowing, viscosity, and mouthfeel) after the information was provided. There were no significant differences for the 0% samples. The mean GHI values were 3.97 ± 0.85 and 4.81 ± 0.68 for the young and middle-aged groups, respectively. High and low GHI groups were analyzed. The high GHI group showed significant differences in acceptability in the informed evaluation, whereas the low GHI group was not influenced by the information.

Critical review of sensory texture descriptors: From pureed to transitional foods for dysphagia patients

Dysphagic people need to change their diet to avoid pain or risk of choking. For example, they can eat texture modified foods (including pureed and transitional foods, that is, food that start with one texture and change into another because of moisture or heating). Simple testing methods proposed by the IDDSI initiative can be performed to characterize texture modified food but these methods are not always relevant for understanding oral texture and mouthfeel properties. Sensory characterization is essential to develop or optimize a food product and to meet consumer's expectations and needs especially for dysphagic persons. However, sensory methods and texture descriptors are complex to target and evaluate for different severity of dysphagia. Sensory texture descriptors can be determined by different methods and assessed in different ways. This review is useful for listing the sensory methods used to generate sensory descriptors to characterize the oral texture of cereal and pureed foods. We found that 55% of the reviewed publications used specific oral texture descriptors and that 17 descriptors could be identified as the most used and relevant for all the products studied (sticky), for pureed (e.g., cohesiveness, floury, and soft) and for cereal-based foods (e.g., hard, fatty, and crispy). These results should be considered to facilitate the choice of sensory texture descriptors in future studies on pureed and transitional foods such as cereal-based foods according to the IDDSI level. This review also demonstrates that it is difficult to find a consensus between studies using different evaluation methods for the same descriptor.

A culinary twist of a two-course meals-on-wheels menu in a cluster-randomized controlled trial influencing health-related quality of life in nursing home residents

BACKGROUND AND AIMS

Meals-on-wheels in nursing homes are sensory diminished because of the packaging and reheating of the food, which creates less appetite stimulation and an impaired meal experience for nursing home residents. This background is crucial since nursing home residents are a frail and often malnourished group that is physiologically affected by sensory, physical and mental alterations. The study aimed to increase health-related quality of life in nursing home residents receiving meals-on-wheels using an intervention menu with favourite meals that added a culinary twist and were sensory improved by chefs.

METHODS

A double-blinded cluster-randomized controlled trial with two arms, one group receives an intervention menu, and the other group receives a non-optimized menu. The intervention menu included popular meals-on-wheels (a main meal for dinner and a starter/dessert before or after dinner with culinary improvements). The participants received the same meals without culinary improvements in the control group. Health-related quality of life (EQ5D3L) was the primary outcome of the study. Secondary outcomes were mental and nutritional status and muscle strength. The measurements were assessed at a baseline and end visit (12 weeks after baseline visit).

RESULTS

Fifty-two nursing home residents were included in the study (There are 20 in the intervention group and 32 in the control group). Following the principle of intention-to-treat, a significant decreasing effect (p-value 0.026) was found between the groups on health-related quality of life. The treated group experienced the largest decrease from the baseline to the end visit. The intervention group had a significant decrease in the second item on Satisfaction With Food-related Life (SWFL2) (I am very pleased with my food). No changes were found either within or between the groups, on the rest of the measured parameters.

CONCLUSIONS

Nursing home residents are a target group experiencing natural aggravation, why the health-related quality of life might be difficult to improve using a culinary meal intervention. The decreasing effect of Satisfaction With Food-related Life found in the intervention group could be related to these older adults being too unfamiliar with the culinary twist added to the intervention menu. The study was registered on ClinTrials.gov (Identifier NCT03133364).

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.

Consistent Effects of Whey Protein Fortification on Consumer Perception and Liking of Solid Food Matrices (Cakes and Biscuits) Regardless of Age and Saliva Flow

Although there are numerous high protein products on the market, they are typically not designed with, or for, older consumers. This is surprising considering that dietary guidelines recognise the need for higher protein intake in later life. Protein fortified products are, however, associated with negative sensory attributes and poor consumer acceptance. This paper investigates the extent of mouthdrying sensations within a high protein solid food matrix, along with the effect of age and saliva flow. Solid models using cakes and biscuits, with or without protein fortification, were investigated. The sensory profile and physical properties were analysed and two volunteer studies (n = 84; n = 70) were carried out using two age groups (18–30; 65+). Volunteers rated individual perception and liking of products, and salivary flow rates (mL/min) were measured. Unstimulated salivary flow rates were significantly lower (p < 0.05) in older adults, although this was not found to influence product perception. Protein fortification of cakes and biscuits significantly increased (p < 0.05) perceived mouthdrying, hardness and “off” flavours, and significantly reduced (p < 0.05) melting rate, moistness and liking compared with the control versions. There is a clear need to address negative sensory attributes associated with protein fortification of cakes and biscuits to ensure product suitability for older adults.

Sensory Acceptability of Dual-Fortified Milled Red and Yellow Lentil (Lens culinaris Medik.) Dal in Bangladesh

This study evaluated the sensory properties of uncooked and cooked milled lentils that were fortified with varying concentrations of Fe and Zn in the form of NaFeEDTA and ZnSO4.H2O, respectively. Our study was carried out among 196 lentil consumers residing in rural Bangladesh who experience with growing, processing, and marketing lentils. A nine-point hedonic scale was used to rate the appearance, odor, taste, texture and overall acceptability of three uncooked and two cooked lentil (dal) samples made from each of the three milled lentil product types (LPTs), red football, red split and yellow split. Preferences for sensory properties were found to be significantly different among all uncooked lentil samples, but not significantly different for cooked samples, with a few exceptions. This means that the fortification process minimally affects dual-fortified lentil sample (fortified with 16 mg of Fe and 8 mg of Zn per 100 g of lentil), which was compared to another cooked sample (unfortified control), in terms of consumers liking for all four attributes (appearance, odor, taste, and texture).

Acceptability of tropical fruit pulps enriched with vegetal/microbial protein sources: viscosity, importance of nutritional information and changes on sensory analysis for different age groups

The combination of products traditionally consumed with other components with the alleged classification of functional food has become a continuous reality, if not a necessity. This article investigated the supplementation of tropical fruit pulps (acerola-Malpighia emarginata, guava-Psidium guajava, passion fruit-Passiflora edulis and mandarin-Citrus reticulata), with 5-10% (m/V) on vegetal/microbial protein sources (soy protein, beer yeast and bee pollen). Viscosity and colour analysis were carried out and differences between fruit pulp with no addition and those supplemented were verified, with a specific importance to soy protein, which increased 5-10 times pulps viscosity, while the remaining supplemented formulations, 1.5-3 times. Between the sensory factors (colour, flavour, aroma and appearance), flavour significantly influenced the acceptance of the product (p < 0.05). The nutritional information provided to tasters, as well as to specific age groups (children, elderly and youngsters/adults), significantly increased the product's acceptance; with values ranging between 70 and 80% in some cases, demonstrating the importance of cognitive response on those factors.

Altered Salivary Flow, Protein Composition, and Rheology Following Taste and TRP Stimulation in Older Adults

Taste and smell perceptions diminish in older age, impacting upon quality of life and nutrition, yet the causes of taste loss are largely unknown. Transient receptor potential channels (TRP) found on the oral mucosa are also involved in oral sensations including cooling and burning and may contribute to the eating experience of older people. Older adults often have reduced salivary flow and the physical properties of saliva may change, but the role of saliva in oral sensations of older adults is yet to be elucidated. Here, the effect of older age on subjective (perception) and objective (stimulated salivary response) measures of TRP stimulants, odors, and basic tastants was investigated. Whole mouth saliva was collected from younger (mean age 24 years) and older adults (mean age 72 years) following stimulation of taste [mono sodium glutamate (MSG) and caffeine], olfaction (menthol), and TRP receptors (capsaicin). Participants rated perceived intensity of each stimulus, and salivary properties were assessed. Older age was associated with 15% lower umami taste and 26% lower menthol odor perception, coupled with 17% lower salivary response to MSG. Interestingly, there were no differences for perception of TRP stimulants, so chemo-sensation was not affected by age. Younger adults had four times greater elasticity (Spinnbarkeit) with MUC7 levels almost double and 66% greater resting salivary flow rate. Stimulated salivary responses in the younger group were also higher compared to the older group, with changes in protein and viscoelasticity in response to taste and TRP stimulation. These results show the impact of older age upon taste and smell sensation which may lead to changes in the physical and compositional properties of saliva in response to taste/odor stimulation. Measurement of stimulated salivary flow and rheology provides an objective measure of taste in addition to subjective perceptions which can be influenced by participant bias. Chemo-sensation may be retained with age and trigeminal stimuli such as chili could be employed in future studies to enhance meals for an age group at risk of malnutrition. Alteration in salivary properties due to advanced age could impact on ability to taste due to poor diffusion of tastants and reduced oral surface protection.

Acceptance of texture-modified in-between-meals among old adults with dysphagia

BACKGROUND AND AIMS

Old adults suffering from dysphagia have difficulties swallowing, chewing and/or eating, and are therefore at high risk of undernutrition. In-between-meals that are texture modified are of particular importance for people suffering from dysphagia. To meet their adequate daily amount of food intake they are recommended to eat 3-5 in-between-meals daily. The aim of the current pilot study was to identify the most liked in-between-meals for old adults based on flavour and describe the basic sensory properties of these in-between-meals. Following, the equality between flavour and appearance-based preferences was investigated.

METHODS

From three nursing homes 30 old adults aged 70 years or older suffering from dysphagia were recruited. They were assessing 20 texture modified in-between-meals based on their flavour and appearance on a 3 point hedonic scale.

RESULTS

When participants were asked to assign liking based on flavour, the most liked in-between-meals were frozen, cold and sweet (vanilla ice cream, strawberry parfait and panna cotta). These meals were among the in-between-meals richest in fat and energy. Liking based on flavour and appearance was equal in 18 out of 20 samples. Furthermore, nutritional and sensory characteristics of the preferred meals were described.

CONCLUSION

Flavour and sensory-based ranking of in-between-meals opens the possibility to design new in-between-meals to old adults with dysphagia, by choosing the most liked in-between-meals to offer the target group.

Mitigating Nutrition and Health Deficiencies in Older Adults: A Role for Food Innovation?

The aim of this review is to describe the factors contributing to diminished food intake, resulting in nutritional deficiencies and associated health conditions in older adults and proposes food innovation strategies to mitigate these. Research has provided convincing evidence of a link between healthy eating patterns and healthy aging. There is a need to target new food product development (NPD) with functional health benefits specifically designed to address the particular food-related needs of older consumers. When developing foods for older adults, consideration should be given to the increased requirements for specific macro- and micronutrients, especially protein, calcium, vitamin D, and vitamin B. Changes in chemosensory acuity, chewing difficulties, and reduced or poor swallowing ability should also be considered. To compensate for the diminished appetite and reduced intake, foods should be energy dense, nutritionally adequate, and, most importantly, palatable, when targeting this cohort. This paper describes the potential of new food product development to facilitate dietary modification and address health deficiencies in older adults.

Changes of Olfactory Performance during the Process of Aging - Psychophysical Testing and Its Relevance in the Fight against Malnutrition

OBJECTIVES

Olfactory performance plays a vital role in several aspects of everyday life. A decrease in olfactory function leading to reduced appetite and inadequate food intake could contribute to higher risk of malnutrition and has a significant impact on quality of life. Early detection of olfactory impairment may help to maintain normal, or - through early training - to improve olfactory function and could thus contribute to the prevention of malnutrition. This review summarizes recent findings on the association between decreased olfactory performance in older adults, its implication for overall health and discusses issues regarding the assessment of olfactory performance in older people.

METHODS

A non-systematic literature search using databases (PubMed, ScienceDirect, Google Scholar) was conducted up to March 2016 to review recent findings on the topics of olfactory impairment, age, malnutrition and issues in psychophysical testing.

RESULTS

Although the association of olfactory impairment and malnutrition is widely accepted strong evidence is scarce. This could be because existing psychophysiological olfactory performance tests are not suitable and inefficient for older adults or people with cognitive impairment due to their required time and concentration. Since prevalence of olfactory impairment remains poorly documented in European regions and varies from 13.9% to >60% depending on age and due to considerable methodological diversity in studies there is need to develop rapid and efficient screening tools which are suitable for this target group.

CONCLUSION

Due to numerous causes and health consequences of olfactory impairment in older people, early detection of olfactory malfunction by rapid, inexpensive but valid tests, which could be used by geriatricians and other healthcare professionals, might be useful in patient counselling by identifying individuals at nutritional risk.