Gastrophysics: Nudging consumers toward eating more leafy (salad) greens

An Appraisal of Nonmicrobial Biostimulants' Impact on the Productivity and Mineral Content of Wild Rocket (Diplotaxis tenuifolia (L.) DC.) Cultivated under Organic Conditions

Modern agriculture urgently requires viable alternatives to synthetic chemical substances, such as pesticides and fertilizers, to comply with new and stringent international regulations and meet the growing demands of consumers who prefer chemical-free food. Consequently, organic agriculture has garnered increasing interest over time. To compensate for yield reduction resulting from opting out of the use mineral fertilizers, research has focused on the use of biostimulants to sustain the productivity of horticultural crops. To this end, a greenhouse experiment was conducted to assess the effects of three nonmicrobial biostimulants (a plant extract, vegetable protein hydrolysate, and a seaweed extract) and an untreated control on the production and mineral content of wild rocket (Diplotaxis tenuifolia (L.) DC.) cultivated under organic conditions and harvested three times during the growth cycle. In general, the nitrate content, which defines the commercial quality of wild rocket, was not influenced by the application of biostimulants. At each harvest, the application of biostimulants resulted in improved production performance, although this was not always accompanied by an increase in mineral content. Specifically, the best results were obtained with the use of plant-derived protein hydrolysate and plant extract, which led to an improvement in total yield of 32.1% and 27.2%, respectively compared to that of control plants. These results reconfirm that biostimulants represent a valid and indispensable tool for organic growers.

On the manipulation, and meaning(s), of color in food: A historical perspective

While there has long been public concern over the use of artificial/synthetic food colors, it should be remembered that food and drink products (e.g., red wine) have been purposefully colored for millennia. This narrative historical review highlights a number of reasons that food and drink have been colored, including to capture the shopper's visual attention through to signaling the likely taste/flavor. Over the course of the last century, there has, on occasion, also been interest in the playful, or sometimes even deliberately discombobulating, use of food coloring by modernist chefs and others. The coloring (or absence of color) of food and drink can, though, sometimes also take on more of a symbolic meaning, and, in a few cases, specific food colors may acquire a signature, or branded (i.e., semantic) association. That said, with food color being associated with so many different potential "meanings," it is an open question as to which meaning the consumer will associate with any given instance of color in food, and what role context may play in their decision. Laboratory-based sensory science research may not necessarily successfully capture the full range of meanings that may be associated with food color in the mind of the consumer. Nevertheless, it seems likely that food color will continue to play an important role in dictating consumer behavior in the years to come, even though the visual appearance of food is increasingly being mediated via technological means, including virtual and augmented reality.

A preliminary study on the impact of contextual information regarding the origin of food on consumers’ judgments and skin conductance responses

Explicit and implicit responses to food and beverage are known to be modulated by expectations generated by contextual factors. Among these, labelling regarding the country of origin has been systematically shown to impact on consumers' evaluations of products. However, it is not clear yet whether the presence of food origin biases also affects humans’ physiological (i.e., implicit) responses, as well as whether different conditions of sensory appreciation of products are equally influenced. The present preliminary study investigated the psychophysiological responses to food samples paired to labels of declared (i.e., Italy, Spain/Germany, EU) or undeclared origins. Food items (i.e., olives and cracker) were presented in visual or taste conditions to thirty Italian participants, whose behavioral (i.e., liking, willingness to buy, and estimated cost) and physiological (i.e., skin conductance responses) responses were collected. The results indicated that the food samples elicited stronger liking and willingness to buy responses by participants and were estimated as more expensive, when being firstly experienced through vision than taste. No differences in the physiological arousal state were found as a function of food origin or sensory condition of presentation.

•

Explicit choices related to food are modulated by expectation generated by contextual factors.

•

Labelling regarding the country-of-origin impacts the consumer evaluations of products.

•

The study investigated the behavioral and psychophysiological responses to food products comparing different labelling.

•

Food items were presented in visual or taste conditions.

•

The sensory modalities and the labeling information affect the behavioral choice (but not the physiological response).

How do trained panelists characterize baby leafy greens? A comparison of descriptive analysis and Napping

Baby leafy greens are one of the fastest growing segments of the salad green market. Baby leafy greens are generally more mild tasting than their fully-mature counterparts. Nevertheless, a diversity of plant species can be grown as baby greens, which exhibit a wide range of sensory attributes. Sensory profiles of baby leaf varieties have not been well described in the literature. This study aimed to describe the differences between several baby leafy green varieties from the plant family Brassicaceae and those which were non-Brassicaceae, and to compare two descriptive methods, traditional descriptive analysis (DA) and Napping, a rapid profiling technique. Both methods used the same trained panelists. In the first study, the panel (n = 11) developed a lexicon for and evaluated four samples grown in a controlled aeroponic environment. In the second study, 12 commercially available samples were evaluated with DA (n = 8) and Napping (n = 11). Panelists identified differences in the pungency, bitterness, and ''green'' attributes across all samples. Principal component analysis (PCA) was used to model associations between the samples and the sensory attributes. The PCA extracted three factors. PC1 ranged from pungent qualities to sweet/grassy, PC2 included green color, and PC3 included saltiness and sourness. The Napping showed similar sample separation (RV = 0.67), but included relevant textural terms (''chewy''; ''rubbery'') not used in the DA. The current lexicon can be applied to a large range of baby leafy greens. Napping showed good correspondence with DA and can be deployed with agricultural products where time and other resources may be limited. PRACTICAL APPLICATION: Sensory evaluation methods have traditionally been applied in the food industry with processed products.While traditional methods such as descriptive analysis have been used to profile products, rapid and inexpensive profiling methods should be screened for their value in describing agricultural products. The results of this study can be applied to breeding and grow-out programs to aid in optimization of the processing,storage, and quality control for the rapidly expanding baby leafy green market.

A virtual reality-based study of color contrast to encourage more sustainable food choices

In order to identify effective strategies to increase more environmentally friendly food choices, we conducted an experimental study to examine how the color contrast between the food and the background might influence people's choices between meat and vegetable dishes. Participants were instructed to choose three desirable dishes out of a choice set presented on a red- or green-colored table in a simulated restaurant environment. Each choice set consisted of two meat and two vegetable dishes, so the participants had to choose between the meat-heavy and vegetable-forward meals. The participants chose the meat-heavy meals more often than the chance level. However, the results revealed that using a red table to present the choice set could shift them toward choosing fewer meat-heavy meals and thus more vegetable-forward meals, and the visual attractiveness of the meat dishes was decreased when presented on the red tables. These findings provide empirical evidence regarding how the contrast between the color of food and the background color of the dining table can be used to modulate the sensory appeal of foods in order to promote sustainable food choices.

VeggieSense: A non-taste multisensory exposure technique for increasing vegetable acceptance in young children

Vegetable consumption falls well below recommended levels for children in the UK. Previous research has found that repeated non-taste sensory exposure over the course of several days increases young children's willingness to touch and taste vegetables. The current study examined the impact of a one-off multisensory non-taste exposure intervention that took place on a single day on children's willingness to taste and intake of the exposed vegetables. Children (N = 110) aged 3- to 4-years-old were assigned to one of three intervention groups or to a control group. Children in all groups participated individually in a single activity session delivered in their nursery. Children in the intervention conditions took part in fun activities that provided either (a) visual exposure, (b) smell and visual exposure, or (c) smell, touch and visual exposure to six raw and prepared vegetables. Children in the control group engaged in a visual exposure activity with non-food items. After the exposure activities, all children were offered the prepared vegetables to eat; their willingness to taste and intake of the vegetables were measured. Results confirmed previous findings of sensory exposure activities increasing children's willingness to taste and intake of vegetables and revealed linear trends in both measures of acceptance with the number of senses engaged; children who took part in smell, touch and visual activities showed the highest level of acceptance. Findings suggest that multisensory exposures are effective in increasing consumption of vegetables in young children and that the effect of sensory exposure to healthy foods may be cumulative, with the more senses engaged prior to offering a food, the better.

A nudge in the right direction: the role of food choice architecture in changing populations' diets

Populations' diets typically fall short of recommendations. The implication of this on ill health and quality of life is well established, as are the subsequent health care costs. An area of growing interest within public health nutrition is food choice architecture; how a food choice is framed and its influence on subsequent food selection. In particular, there is an appeal to manipulating the choice architecture in order to nudge individuals' food choice. This review outlines the current understanding of food choice architecture, theoretical background to nudging and the evidence on the effectiveness of nudge strategies, as well as their design and implementation. Interventions emphasising the role of nudge strategies have investigated changes to the accessibility, availability and presentation of food and the use of prompts. Empirical studies have been conducted in laboratories, online and in real-world food settings, and with different populations. Evidence on the effectiveness of nudge strategies in shifting food choice is encouraging. Underpinning mechanisms, not yet fully explicated, are proposed to relate to salience, social norms and the principle of least effort. Emerging evidence points to areas for development including the effectiveness of choice architecture interventions with different and diverse populations, and the combined effect of multiple nudges. This, alongside further examination of theoretical mechanisms and guidance to engage and inspire across the breadth of food provision, is critical. In this way, the potential of choice architecture to effect meaningful change in populations' diets will be realised.

High Glucosinolate Content in Rocket Leaves (Diplotaxis tenuifolia and Eruca sativa) after Multiple Harvests Is Associated with Increased Bitterness, Pungency, and Reduced Consumer Liking

Rocket (Diplotaxis tenuifolia and Eruca sativa) leaves delivered to the UK market are variable in appearance, taste, and flavour over the growing season. This study presents sensory and consumer analyses of rocket produce delivered to the UK over the course of one year, and evaluated the contribution of environmental and cultivation factors upon quality traits and phytochemicals called glucosinolates (GSLs). GSL abundance was positively correlated with higher average growth temperatures during the crop cycle, and perceptions of pepperiness, bitterness, and hotness. This in turn was associated with reduced liking, and corresponded to low consumer acceptance. Conversely, leaves with greater sugar content were perceived as more sweet, and had a higher correlation with consumer acceptance of the test panel. First cut leaves of rocket were favoured more by consumers, with multiple leaf cuts associated with low acceptance and higher glucosinolate concentrations. Our data suggest that the practice of harvesting rocket crops multiple times reduces consumer acceptability due to increases in GSLs, and the associated bitter, hot, and peppery perceptions some of their hydrolysis products produce. This may have significant implications for cultivation practices during seasonal transitions, where leaves typically receive multiple harvests and longer growth cycles.

Factors related to sensory properties and consumer acceptance of vegetables

Many consumers perceive the bitter taste or other sensory characteristic of vegetables as unpleasant, posing a challenge to dietary recommendations aiming to increase vegetable consumption. Food experience is multisensory, with complex interactions between the senses and individual differences in sensory perception. This review focuses on the factors affecting sensory properties of vegetables and sensory perception of vegetables among adults. Topical examples of sensory quality and evaluation of vegetable samples are presented. Cultivar and growing conditions are related to the internal sensory quality of vegetables. The effects of different processing methods, such as freezing and cooking, on the sensory properties of vegetables are also reviewed. Flavor modification of vegetables with seasonings may be used to improve palatability and incorporating vegetables to meals may increase the intake of vegetables. Recently, external factors (e.g. visual and odor stimuli) have been tested in multisensory research in the context of vegetable perception and choice. These options to achieve better sensory quality, more palatable meals and pleasant eating context may be used to promote vegetable intake among adults.

Food and beverage flavour pairing: A critical review of the literature

The recent explosion of interest in the topic of flavour pairing has been driven, at least in part, by the now-discredited food-pairing hypothesis, along with the emergence of the new field of computational gastronomy. Many chefs, sommeliers, mixologists, and drinks brands, not to mention a few food brands, have become increasingly interested in moving the discussions that they have with their consumers beyond the traditional focus solely on food and wine pairings. Here, two key approaches to pairing that might help to explain/justify those food and beverage combinations that the consumer is likely to appreciate are outlined. Historically-speaking, many conventional pairings emerged naturally from cultural/geographical matches, presumably internalized as semantic knowledge amongst consumers. In this review, such conventional pairings are framed as but one example of a cognitive/intellectual food-beverage strategy. The alternative approach to pairing that has become increasingly popular in recent years involves experts/commentators making recommendations based on the perceptual relationship, or interaction, between the component stimuli, be it one of perceived similarity, contrast, harmony, emergence, or modulation (either suppression or enhancement). Physicochemical accounts of pairing, based on the presence of shared flavour molecules (e.g., aromatic volatiles) in the to-be-combined flavours or ingredients, have also gained in popularity. Here, though, the latter approach is framed as an ultimately unsuccessful attempt to predict matches based on perceived similarity. This review summarizes the available evidence concerning food-beverage pairing and proposes a new dichotomy between intellectual/cognitive and perceptual pairing principles in the case of food-beverage matching.