A traditional literature search method was used initially to provide the scope of this review. The initial findings were strengthened with a comprehensive search for relevant literature conducted across Google Scholar, Scopus, and PubMed. Search terms were constructed using Boolean operators to capture key terms based on the initial scope narrowing down to find literature at the intersections between sensory science, consumer behaviour, and indigenous fruits and vegetables. Keywords included combinations such as: “indigenous fruits and vegetables” OR “neglected and underutilized fruits and vegetables” AND “sensory evaluation” OR “consumer testing” AND “product development” OR “food innovation,” as well as phrases like “indigenous fruits and vegetables,” “indigenous fruits and vegetables sensory evaluation,” “indigenous fruits and vegetables product development.” This search was done between November 6th and 11th 2025. The papers were selected based on the following criteria, the study focused on product development using indigenous fruits and vegetables and sensory evaluation was used in the product development. All selected studies comprised research papers written in English and did not include any textbooks or papers written in different languages.

Relevant information was extracted from the selected papers using a data charting sheet. Empirical case studies from the Sensory Laboratory at the University of Ghana were integrated to illustrate applied methods including consumer surveys (n = 203), sensory lexicon development using a trained sensory descriptive panel (56 descriptors for Chrysophyllim albidum (Alasa fruit)), descriptive profiling with and without focus group discussion (Xanthosoma sagittifolium (Kontomire) leaves) and conjoint analysis (Azadirachta indica (Neem) beverage). Each method was employed to gather both consumer perceptions and technical sensory data, integrated with cross-disciplinary insights from nutrition, marketing, and product development fields.

The success of any new food product hinges not only on its nutritional value or functional ingredients but also, critically, on how the consumer perceives it. Sensory and consumer science provides a systematic approach to understanding how people experience food through their senses and how these experiences drive consumption, preferences, choices, and ultimately, market acceptance (Lawless and Heymann, 2010). In the context of food innovation, particularly with underutilized ingredients such as Indigenous Fruits and Vegetables, sensory evaluation serves as both a creative and strategic tool for guiding product development (Jaeger and MacFie, 2010). Some commonly used sensory methods are briefly described below.

Although not limited to the field of sensory science, consumer surveys are a default sensory tool for understanding consumers in the development process. When used in sensory and consumer research, consumer surveys quantitatively assess awareness, consumption patterns, and preferences. In product development, consumer surveys help developers identify which IFVs are culturally embedded and favoured, as well as those that require repositioning and education for broader adoption (Horvat et al., 2019). For example, a Ghanaian survey showed high recognition for Chrysophyllum albidum (Alasa or African star apple), Annona muricata (Soursop) and Dialium guineense (Velvet tamarind), guiding their prioritization in product development (Addo-Preko et al., 2025). This example is expanded on as a case study further in the review.

Focus group discussions fall under qualitative consumer tests that provide rich consumer insights for the sensory scientist. A focus group discussion is a semi structured discussion with a small group of target users, guided by a moderator who keeps the conversation moving without steering it. The aim is to uncover attitudes, motivations, and insights that do not appear in surveys or other quantitative methods. Because the data are qualitative, the focus is on beliefs, personal experiences, and the meaning people attach to products. Participant interaction often surfaces subtle issues such as emotional ties, lifestyle influences, and quiet expectations that shape strong product ideas. Focus group discussion support early new product development by revealing unmet needs before concept generation, providing reactions to early designs, and offering feedback on refined concepts. They fit well within iterative design because hearing users think aloud builds empathy and sharpens decisions. In food product development, early sessions uncover sensory expectations and cooking habits, while later sessions test packaging or presentation, helping designers avoid mistakes and shape a clear product identity (McDonagh-Philp and Bruseberg, 2000). In the IFV realm, focus group discussions have been used to understand consumers beliefs about mushrooms when this was selected as an ingredient to develop baby food. The discussion revealed cultural elements that guided developers on how to integrate the ingredient into the target group (Hagan et al., 2018).

Aside the consumer centric methods described above, analytical sensory methods are also important in the product development process. Within this group of tests, lexicons form the foundation for quantitatively analysing sensory properties of products. A lexicon is a standardized list of sensory terminology generated by trained assessors. When used on its own, this list enables development teams to communicate clear and objective sensory attributes across the formulation and marketing pipeline (Suwonsichon, 2019). It is especially valuable for IFVs given their novel, diverse and complex sensory profiles, which are not well known to the general consumer. In a case study example provided further in this review a comprehensive lexicon of 56 descriptors was created and used for reproducible sensory evaluation and product differentiation for Chrysophyllum albidum (Alasa) (Tagoe et al., 2025). Lexicons can further be used to quantitatively characterize products when scored in descriptive profiling of products.

A commonly used descriptive profile method is the Quantitative Descriptive Analysis (QDA) technique (Lawless and Heymann, 2010). Generally descriptive profiling methods use trained panels to conduct detailed characterization and scoring of product attributes, from, appearance, aroma and flavour to aftertaste. Descriptive profiles allow for the mapping of sensory drivers of liking when linked with consumer preferences (de Souza et al., 2024). On their own, descriptive profiles provide in depth elucidation of the sensory properties of IFVs and can be used to track sensory changes of these IFVs as they are processed. A case study with on leafy greens highlights the value of descriptive profile for tracking the changes in sensory properties as they are processed using different processes (Aboagye et al., 2025b).

Conjoint analysis (Green et al., 2001), borrowed from marketing, has gained favour in the sensory scientists toolbox as it provides a meaningful way to identify relevant sensory and consumer attributes that are favoured in a product by consumers. It is a statistical technique that uncovers how consumers make trade-offs among multiple product features, revealing which combinations drive preference and purchase intent (Hoppert et al., 2012; Green et al., 2001). The method was used to determine optimal levels of key sensory attributes; bitterness, aftertaste, and ingredient profiles in a neem beverage case study (Aboagye et al., 2025a).

These methods are not the only tools available to the sensory scientist that wishes to incorporate sensory insights into the CLPD approach. They however provide meaningful illustrations on using sensory and consumer science insights in the product development process.

A consumer-led product development approach places consumer needs and preferences at the centre of the product development process (Costa and Jongen, 2006). Rather than assuming what the market wants, this method emphasizes active engagement with target consumers at various stages of development from idea generation to prototype testing. Unlike traditional product development that may rely solely on expert input or technical feasibility, CLPD ensures that innovations are rooted in consumer realities and desires. This is particularly relevant when working with IFVs, where consumer knowledge, familiarity, and cultural relevance are pivotal to acceptance (Kehinde et al., 2023). By involving consumers early, food developers can (1) Align product concepts with market demands, (2) Enhance satisfaction by producing tailored offerings, (3) Reduce the risk of product failure, and (4) Drive innovation by identifying unmet needs (Guiné et al., 2020; Linnemann et al., 2006).

These researchers assert that consumer participatory approach not only increase the likelihood of market success but also ensures more efficient resource allocation by minimizing investment in concepts that do not resonate with end users (Falahat et al., 2024). CLPD can enhance market readiness, cultural resonance, and consumer acceptance. It however, requires dedicated resources, ethical engagement, and ongoing iterative refinement. As consumer preferences can shift; integration with regulatory and nutritional frameworks remains crucial while using CLPD.

A variety of sensory and consumer research tools (surveys, focus groups and interviews, lexicon development and descriptive profiling, conjoint analysis and acceptance tests) are available to capture insights that can inform IFV product development.

Consumer acceptance testing sits at the heart of consumer-led product development (CLPD), particularly when the goal is to transform indigenous fruits and vegetables (IFVs) into appealing, culturally grounded, and commercially viable foods. Unlike descriptive sensory analysis, where trained panels generate objective profiles of appearance, aroma, taste, and texture, consumer testing requires large numbers of naïve consumers who represent the actual target market. In sensory science, a minimum of 112consumers is considered essential for reliable, generalizable results (Hough et al., 2006), and trained or semi-trained panels are never an appropriate substitute for consumer acceptance testing. Across the IFV literature, however, practices vary widely. While some studies follow established standards, others rely on small, semi-trained groups whose assessments cannot reliably predict real-world liking. This review synthesizes the evidence from numerous IFV studies, evaluating both their sensory findings and the methodological rigour behind them, to illustrate how consumer insight, when gathered correctly, can drive innovation, reformulation, and the broader revitalization of indigenous crops.

The strongest examples of consumer-appropriate methodology come from studies that employ large samples of naïve participants. Mbhatsani et al. (2023) provides a model aligned with CLPD by evaluating school-meal dishes incorporating Amaranthus, cowpea leaves, and Bidens pilosa using 152 primary-school children. This sample size enhances statistical confidence, and the use of the target consumers, children, ensures the validity of the findings. The study not only identified the most acceptable dish (Amaranthus-enriched cabbage) but also linked hedonic ratings with actual consumption. This integration of sensory testing with behavioural outcomes exemplifies how consumer data can guide product optimization, menu planning, and intervention design.

Likewise, Schiassi et al. (2018) evaluated pulps from four Cerrado fruits with 100 adult consumers and identified key sensory drivers for their use in functional beverages. Here too, the choice of appropriate panellists and sample size strengthens the study’s conclusions.

and demonstrates how IFVs can successfully compete in commercial beverage categories. But many IFV studies use designs that diverge from best practice. Several rely on trained or semi-trained individuals, a practice that introduces conceptual and statistical limitations. Trained assessors are experts in detecting subtle differences; they do not represent ordinary consumers and therefore cannot provide meaningful measures of liking or purchase intent. Semi-trained individuals, often laboratory staff or students familiar with sensory evaluation, occupy an ambiguous middle zone that still fails to reflect consumer preferences. Studies with small samples, 15, 10, even nine panellists, further limit generalizability. As a result, many reported findings must be interpreted as preliminary rather than indicative of market potential. Adedokun et al. (2022), for example, evaluated juice blends of baobab, black plum, and pineapple using only 15 semi-trained laboratory staff. While the study provides insight into attribute differences such as mouthfeel and flavour intensity, these judgments cannot be extrapolated to consumer liking. Similarly, wine formulations from Balanites aegyptiaca (Bayoï and Etoa, 2024) were assessed by just 10 wine consumers. Although these individuals may have some product familiarity, the small sample size still prevents any meaningful inference about broader market appeal. The trend continues in Qureshi et al. (2024), where paneer enriched with date paste was evaluated by 10 semi-trained panelists; in Meti (2018), where Basella alba products were scored by nine assessors; in Pradhan et al. (2020), where ash-gourd products were evaluated by 10 trained panelists; and in Suliman et al. (2012), where just 15 panelists assessed jakjak juice. These studies contribute valuable prototype-level insights, but they cannot answer the fundamental consumer-led question: Will people like it? Other studies fall closer to acceptable standards yet still contain methodological pitfalls. Goyary et al. (2022) used 50 panelists, an appropriate number, but mixed trained and untrained individuals, which introduces bias because trained assessors evaluate differently from naïve consumers. Kumari et al. (2022) do not report sample size at all, a critical omission that undermines confidence in their findings. On the other hand, several studies provide robust examples of consumer-aligned testing that advance CLPD for IFVs. Tagubase et al. (2018) used 50 consumers to assess durian cultivars, employing both preference ranking and intensity perception. Samuel et al. (2020) evaluated a fruit-based soup from Corchorus olitorius with 30 consumers, slightly under ideal sample size, but still using the correct type of panel. Van der Hoeven et al. (2013) used 98 children to evaluate African leafy vegetable dishes, aligning both sample size and participant identity with the intended beneficiaries of school-feeding interventions. A large portion of IFV sensory literature combines consumer tests with descriptive analysis. This combined approach can reveal drivers of liking, bitterness, colour, texture, sweetness, and guide targeted formulation. For instance, Onyeoziri et al. (2018) integrated descriptive profiling with consumer testing of canned African leafy vegetables, identifying specific sensory attributes that limited acceptance. Such studies exemplify how lexicon-driven sensory insights complement CLPD by pinpointing attributes requiring modification. Multiple researchers have shown how indigenous fruits can be reformulated, blended, or processed to enhance acceptability. Jam development appears frequently across IFV studies and is a particularly illustrative example of how consumer feedback shapes product trajectories. Rafique et al. (2023) used a 9-point hedonic test to determine optimal karonda–apple jam ratios, while de Jager et al. (2025) used a two-step consumer protocol—first visual testing with nearly 100 consumers, then hedonic evaluation with 47—to identify preferred jam types.

These studies, though variable in sample size, underline how appearance and flavour jointly determine product acceptance. Functional or fortified products enriched with probiotics, antioxidants, or nutrient-dense IFV powders also demonstrate the balancing act between health benefit and palatability. Harriden et al. (2025) used sensory evaluation to determine the optimal inclusion level of Davidson plum in sorbet, finding that functional enhancement quickly becomes a sensory liability at high concentrations. Similarly, Micheni et al. (2024) showed that horned-melon supplementation in fermented milk decreased liking at high levels, particularly around colour and taste. Such formulations demonstrate how CLPD can reconcile nutritional goals with sensory feasibility.

Several studies focus on leafy vegetables, where bitterness, fibrousness, and colour changes often challenge consumer acceptance. Matenge et al. (2012) found that tomato-based cowpea leaf stew was more acceptable than other preparations, underscoring the importance of culinary context. Muniu (2020) demonstrated that solar drying reduces liking for some species but enhances it for others, showing how preservation interacts with sensory traits. Across beverages, jams, confectioneries, soups, porridges, pickles, and even chocolates fortified with IFV powders, sensory evaluation appears repeatedly as the guiding mechanism for product refinement. Some studies, such as those by Tepe (2022), go further by integrating consumer liking with economic models such as willingness-to-pay, demonstrating how sensory appeal directly predicts market behaviour. Yet the methodological weaknesses across much of the literature highlight the urgent need for improved standards. Studies using small, trained panels generate data that are more relevant for descriptive analysis than consumer acceptance. Mixing trained and untrained panellists produces inconsistent results. Failure to report sample sizes reduces replicability and credibility. In some cases, the absence of clear target consumer groups (e.g., children, adolescents, adults, specific cultural communities) further limits applicability.

For CLPD to meaningfully support the revitalization and commercialization of IFVs, sensory consumer studies must adhere to established principles: naïve consumers, adequate sample sizes, context-specific recruitment, and clear reporting. The studies reviewed demonstrate that when these standards are met, sensory consumer evaluation becomes a powerful engine for innovation. It identifies feasible formulations, clarifies optimal preparation methods, determines acceptability thresholds, and guides product-type selection. It also provides insights into storage stability, ingredient interactions, and the trade-offs between nutritional enhancement and palatability. Together, these studies show that consumer testing, when methodologically sound, anchors CLPD by positioning consumer perception at the centre of product development. IFVs often carry exceptional nutritional value but limited market penetration due to sensory unfamiliarity or stigma. Sensory evaluation provides the mechanism for transforming these culturally significant crops into appealing foods suited for modern markets, thereby linking biodiversity, nutrition, and consumer behaviour in a single integrative framework.

Focus groups are a central qualitative tool in consumer-led product development (CLPD) because they generate rich, contextual insights into how people think, feel, and talk about foods. Unlike structured surveys, which capture breadth, focus groups capture depth, revealing cultural meanings, sensory expectations, preparation habits, and the social narratives that shape acceptance. They allow researchers to probe why certain attributes matter, how consumers interpret quality, and what barriers or motivations influence adoption. This qualitative foundation often guides early formulation choices and helps frame subsequent sensory or consumer testing within the lived realities of target populations.

Matenge et al. (2012) illustrate this approach through their work with Traditional Leafy Vegetables (TLVs), focusing on cowpea leaves (Vigna unguiculata L.). The authors developed three recipe variations that reflect common preparation styles: cowpea leaves cooked with salt and vegetable oil (Sample A); a tomato-based stew with potatoes, onions, salt, and oil (Sample B); and a preparation incorporating groundnut powder (Sample C).

To understand consumer beliefs and contextual factors shaping acceptance, four focus group discussions were held across rural and urban communities. Thematic content analysis revealed perceptions related to taste expectations, cultural familiarity, preparation convenience, and the symbolic value of cowpea leaves in traditional diets. These insights helped clarify not only what people preferred but why those preferences existed.

Sensory evaluation was then used to complement the qualitative data by providing empirical, quantitative evidence of product acceptance. It revealed clear differences in preference patterns across age groups and communities and identified Sample B as the most promising formulation. The sensory findings also highlighted the pivotal role of taste and texture in shaping consumption intent.

By combining focus group insights with consumer acceptance testing, the study demonstrated how qualitative understanding, and quantitative testing can work together to guide CLPD. This integrated approach helps ensure that product concepts for Indigenous and Forgotten Vegetables (IFVs) are grounded in cultural relevance while meeting sensory expectations that drive actual consumer uptake.

While descriptive profiling offers a structured understanding of a product’s sensory characteristics, conjoint analysis complements this by revealing the relative importance of those characteristics alongside other product attributes in shaping consumer choice. As a statistical technique rooted in behavioural science and marketing research, conjoint analysis is particularly valuable in CLPD. It allows researchers and product developers to understand how consumers make decisions when faced with products that differ across multiple features such as flavour, texture, packaging, ingredient sources, and health claims (Hoppert et al., 2012; Green et al., 2001).

Unlike methods that test one feature at a time, conjoint analysis mimics real-life decision-making, where consumers evaluate multiple product attributes simultaneously. In a typical study, participants are presented with a set of product profiles that vary systematically in their attribute combinations. These profiles can be introduced in various formats depending on the nature of the product and the development phase. For instance, actual product samples may be used when evaluating features like taste or texture (De Pelsmaeker et al., 2013). In other cases, especially during early development stages or when product prototypes are unavailable visual presentations such as packaging mock-ups or verbal descriptions of the attributes are used to convey the product concept. Consumers then rank, rate, or choose between the options, enabling researchers to model preference behaviour (Ares et al., 2016).

Through this process, conjoint analysis provides three major insights: the relative importance of each attribute in influencing consumer choice, the preferred levels within each attribute, and the optimal combination of features that define the most appealing product. These outcomes help product developers prioritize formulation efforts, target consumer segments more precisely, and refine marketing strategies based on what truly matters to their audience (Moskowitz et al., 2012). Moreover, because conjoint analysis allows developers to simulate consumer preferences before investing in full-scale production, it offers a highly cost-effective tool for reducing risk during product innovation.

A relevant example comes from a study conducted at UGSENLAB, where conjoint analysis was applied in the development of a ready-to-drink neem beverage (Aboagye et al., 2025a). Neem, known for its strong medicinal properties and characteristically bitter flavour, presents formulation challenges when developing a beverage intended for broad consumer appeal. In this study, physical samples were not created. Instead, pictorial representations of the product, along with detailed verbal descriptions of the attributes, were shown to participants. The product concepts varied across key features such as bitterness intensity, aftertaste quality, authenticity, form of product, and the inclusion of added natural ingredients.

Participants were asked to rank the combinations from most liked to least liked, simulating a realistic decision-making scenario. The analysis revealed that bitterness, aftertaste, and ingredient addition were the most influential attributes in determining consumer preferences. The preferred product profile was clearly defined using this approach giving the developers the needed directions on which attributes were most important and relevant to maintain. The insights provided information on the form, the added ingredient and the sensory experience that was most important to the consumers given that these were the key factors that were important to the consumer. This insight not only clarified the sensory expectations surrounding neem but also offered guidance for developing a prototype that would likely perform well in consumer acceptance testing.

This case illustrates the strategic advantage of conjoint analysis in early-stage product development particularly for IFV-based products, which may be unfamiliar or underutilized. By identifying which attribute combinations resonate most with consumers, developers can focus resources on formulations that balance sensory appeal with health, cultural relevance, and practicality. Additionally, conjoint analysis complements other sensory tools such as descriptive profiling and acceptance testing, making it a crucial component in a comprehensive, consumer-driven product development framework.

Conjoint analysis equips developers with evidence-based insights into consumer priorities and decision-making. When applied thoughtfully alongside other sensory science methods, it ensures that IFV-based innovations are not only nutritionally sound and culturally meaningful but also market-ready and aligned with consumer expectations.

While CLPD provides significant benefits, it also comes with practical challenges. Engaging consumers meaningfully throughout the development process requires careful planning, ethical considerations (particularly when working with vulnerable groups like children), and access to diverse populations. The process can be resource-intensive, requiring time, trained personnel, and coordination between sensory scientists, marketing teams, and product developers (Guiné et al., 2020). Another challenge lies in managing expectations—both from consumers, who may anticipate immediate product availability, and from development teams, who may underestimate the time required to integrate iterative feedback effectively. In contexts involving IFVs, developers may also contend with negative perceptions or limited familiarity, which can affect how consumers engage with and evaluate prototypes.

Despite these challenges, the advantages of CLPD are substantial. It increases the likelihood that products will succeed in the marketplace by grounding development in real needs, preferences, and sensory expectations. It also enhances consumer satisfaction and trust by offering products that feel personally relevant and culturally appropriate. In the context of IFVs, CLPD can play a transformative role in repositioning traditional ingredients within modern diets, thereby supporting biodiversity, local economies, and public health (Van Trijp and Steenkamp, 2005).

CLPD also promotes cross-functional collaboration, encouraging scientists, marketers, and product developers to work together from the start. This leads to more cohesive and targeted product strategies and better alignment between product features and consumer value.

In contrast to its advantages despite its participatory nature, consumer preferences are not always static or rational. They can be shaped by marketing, trends, or situational factors that may not be stable over time. Therefore, the insights gained from one round of testing may have a limited shelf life or relevance in other markets or cultural contexts (Guiné et al., 2020). Moreover, consumer-led approaches do not always guarantee success if used in isolation. They must be integrated with technical, regulatory, and nutritional considerations, especially when developing products for specific dietary needs or health goals. Relying solely on consumer preferences may also undervalue emerging innovations that consumers are not yet familiar with but could accept once properly introduced (Van Trijp and Steenkamp, 2005). To mitigate some of these challenges, certain attitudes and steps must be adopted when using the CLPD approach.

First, management buy-in and institutional support is crucial to reduce the limitations of the CLPD approach and enhance the chances of success. CLPD requires an investment of time and resources, and without leadership commitment, it is difficult to sustain the process (Jaeger and MacFie, 2010; Falahat et al., 2024). Secondly, developers must use the right tools and methodologies from properly designed surveys and descriptive profiling protocols to validated conjoint analysis platforms. A most abused tool, the consumer acceptance test must be used appropriately considering the target consumer, the context of the test and the scale type used. The use of robust tools ensures that consumer data is reliable and actionable. Time is also an essential factor. CLPD is not a one-off activity but a process that unfolds over stages from initial exploration and concept testing to prototype evaluation and reformulation (Hagan et al., 2018). Teams must be willing to iterate, revisit assumptions, and allow insights to emerge organically rather than forcing outcomes too quickly (Fuller, 2004). Finally, the process must be guided by a clear and actionable objective. Understanding the development context whether nutritional, cultural, or market-driven is vital for interpreting consumer data accurately and making informed development decisions (Fuller, 2004; Falahat et al., 2024).

Consumer-led product development offers a practical, inclusive, and evidence-based approach to food innovation, particularly for underutilized products like Indigenous Fruits and Vegetables. By combining rigorous sensory science with deep consumer engagement, it is possible to develop food products that are not only nutritious and culturally resonant but also desirable, competitive, and impactful. As food systems evolve to meet the health, environmental, and cultural challenges of our time, placing the consumer at the heart of product innovation is not just a strategy, it is a necessity.