Functional Goat Milk Yogurt Dessert Enriched with Antioxidant Extract from Spent Coffee Grounds: Sensory and Consumer Insights

Abstract

The growing demand for health-promoting and eco-friendly foods has driven interest in biofunctional dairy products. Goat milk yogurt, though nutritionally beneficial, faces sensory challenges, while antioxidant-rich spent coffee grounds (SCGs), a coffee by-product, offer sustainable enhancement potential. This study assessed the consumer acceptance of goat milk yogurt enriched with 2% and 3% SCG extract. A total of 137 untrained consumers evaluated six sensory attributes—appearance, aroma, taste, texture, coffee–yogurt balance, and aftertaste—on a five-point hedonic scale. Due to non-normal data, Wilcoxon rank-sum tests and Spearman correlations were applied. No significant differences emerged between formulations (p > 0.05). Taste, aftertaste, and aroma were strongly correlated (r > 0.65). All attributes significantly predicted purchase intent (p < 0.01), with taste as the strongest driver (OR = 2.24). Consumers aged 26–35, usually presenting health or environmental concerns, showed greater acceptance. The addition of SCG extract did not compromise sensory quality, supporting its viability as a sustainable functional ingredient. These findings present high acceptance of a newly developed eco-friendly and nutritionally beneficial product, responding to consumers’ current qualitative demands related to the food they consume.

1. Introduction

In recent years, the growing demand for healthier food options has driven both researchers and the food industry to focus on the development of novel foods that may offer added health benefits beyond basic nutrition [1]. In parallel, the consumer demand for environmentally sustainable choices has increased, while the environmental impact of production remains on the public agenda [2]. This trend in consumer preferences has led to an increased interest in the development of biofunctional foods, designed not only for their nutritional value but also to support human health and prevent diseases, as well as protecting the environment [2,3]. Dairy industries are actively innovative towards the creation of biofunctional dairy products that align with these health-conscious consumer trends while ensuring the products’ acceptance [3].

As consumer awareness of health and wellness continues to rise, people increasingly seek food contributing to disease prevention and overall well-being [4]. Moreover, nowadays consumers are willing to purchase food products that are in line with the principles of environmental sustainability and circular economy [5]. However, the success of these innovative products ultimately depends on their acceptance by consumers, which is heavily influenced by their sensory characteristics. Attributes such as taste, texture, smell, and appearance play a critical role in shaping consumer perceptions and preferences [4]. Sensory evaluation, a scientific method used to assess these responses, involves systematically measuring how individuals perceive food through their senses. It serves as a vital tool in product development and quality control, ensuring that functional dairy products both meet health expectations and provide sensory satisfaction for consumers [6]. As a result, consumer demand, sensory appeal, and acceptance are key drivers in the successful introduction of biofunctional dairy products to the market.

A substantial share of the dairy product sector comprises yogurt, which is produced through milk fermentation [7]. Protein, fat, and essential minerals are all present in yogurt, which has been proven to have an elevated nutritional value [8]. Yogurt’s superior digestion properties make it a very popular dairy product [9], appropriate in some cases as a dietary supplement for those who are lactose intolerant [10].

Even though cow’s milk is commonly consumed and used in the production of dairy products like yoghurt, issues related to gastrointestinal intolerance, alongside consumer demand for innovative dairy products, are fuelling the increasing need for cow’s milk counterparts [7,11]. On these grounds, goat’s milk represents a valuable alternative to cow’s milk, differing in its nutrient composition by containing higher levels of total solids, casein, total protein, fat, and certain mineral compounds [12,13]. These characteristics may offer nutritional advantages depending on individual dietary needs and tolerances. Additionally, goat’s milk has a distinctive fatty acid profile, with a higher concentration of volatile fatty acids (capric, caprylic, and caproic) providing the produced dairy products their distinctive flavour and aroma [14]. Furthermore, goat milk has a higher concentration of medium-chain fatty acids, which also explains why its bacteriostatic effect extends further [11]. Medium-chain fatty acids can inhibit bacterial growth (“bacteriostatic”) or induce bacterial cell lysis and cell killing (“bactericidal”) [15].

Just like yoghurt, which is one of the most consumed dairy products, coffee is one of the most consumed beverages globally. Its typical flavour, aroma, colour, and beneficial health effects render coffee one of the most traded commodities [16]. According to the International Coffee Organization (2024) [17], the total global coffee consumption was estimated at 73.0 million bags during the year 2022/2023, with Europe leading at a percentage of 31.1% of the world’s coffee consumption, followed by Asia and Oceania (25.8%) and North America (16.9%). Coffea arabica L. (arabica) and Coffea canephora Pierre (robusta) species prevail across the entire coffee trade [18]. Coffee has proven to be a significant source of phenolic substances in the daily human diet [19]. Coffee contains around 2000 different chemical components, including trigonelline, chlorogenic acids, vitamin B-3, and volatile chemicals, alongside the well-known caffeine [20]. Numerous bioactive substances found in coffee beans can interact intricately with the human organism to produce a variety of positive effects, including enhanced scavenging and antioxidant activities [21]. The primary phenolic components of coffee are chlorogenic acids (CGAs), which include caffeoylquinic acids (CQAs), feruloylquinic acids (FQAs), p-coumaroylquinic acids (pCo-QAs), and dicaffeoylquinic acids (diCQAs). Additionally, throughout roasting, caffeoylquinic acid lactones (CQLs) and feruloylquinic acid lactones (FQLs) are formed [19,22]. Moreover, coffee extracts contain melanoidins, compounds that, according to Andriot et al., can present strong hydrophobic interactions with volatile compounds, providing a plausible mechanism by which SCG extract could modulate or mask the characteristic odour of goat yogurt [23].

Considering the quantity of coffee produced, there are also numerous by-products being discarded that may negatively impact the environment, like pulp, husk, and silverskin, in addition to spent coffee grounds [16]. The valorisation of coffee by-products is of major importance, not only coming in line with circular economy values but also contributing to the development of high-added-value products and promoting sustainability. Along with the industrial manufacturing of soluble coffee, customers also produce spent coffee in homes, coffee shops, and retail establishments [24]. Given their antimicrobial and antioxidant properties, spent coffee extracts may be added to food matrices to boost their value while upscaling by-products, introducing novel and environmentally friendly components to industries, and promoting sustainable growth by utilizing alternative sources to produce bioactive compounds with potential food industry market significance [25]. The spent coffee grounds’ composition varies among the different types of coffee beans, their roasting process, and the extraction methodology followed [26,27].

Typically, food additives are added to food for technological purposes such as preservation or sensory properties. Sometimes though, besides basic nutrition, the additives could potentially have an advantageous impact on well-being, leading to functional food products [28]. The process of incorporation of the additives or their form affects the composition and the physicochemical and sensory properties of the original food. In the literature, lately, there have been efforts to enhance yogurt with different kinds of additives in order to intensify its nutritional value or sensory characteristics [3,29,30,31].

The aim of this study was to assess the sensory profile and consumer acceptance of a newly developed product created by using goat milk and an extract of spent coffee grounds to produce a yogurt dessert. In parallel, this study aimed to identify whether the enhanced properties of the novel goat yogurt fortified with SCG extract eliminated the characteristic odour of goat yogurt, which is sometimes unpleasant to consumers.

2. Materials and Methods

2.1. Spent Coffee Extraction

The spent coffee grounds were obtained from a local coffee shop one day after brewing, which was conducted at 95 °C and 20 bar pressure. The coffee variety was 100% arabica and ground at 7 on a scale from 1 to 14. Spent coffee extract was extracted by solid/liquid extraction with water as the solvent and was freeze-dried. The choice of the method used was based on food safety regulations as water is a safe food-grade solvent and is also an environmentally sustainable alternate to other solvents. The ratio of coffee to water was 1:4, and the water temperature was 98 °C. After the completion of the method, the extracts were centrifuged, and the supernatant was freeze-dried (Table Top Freeze Dryer BK-FD10P–Biobase Biodusty (Shandong) Co., Ltd, Jinan, Shandong, China). The freeze-dried extract was stored at −18 °C for 2 weeks until the yogurt dessert production. To ensure hygienic collection, staff at the coffee shop were provided with single-use, food-grade sterile containers and received both verbal and written instructions regarding immediate transfer of the SCGs post-brewing. The containers were sealed, labelled with the collection date, and stored at 4 °C until processing within 24 h.

2.2. Yoghurt Dessert Production

Two batches of yoghurt dessert were prepared with minor alterations in the recipe. The selected concentrations of 2% and 3% SCG extract were determined through preliminary formulation trials, which showed that higher levels negatively affected flavour and appearance. These concentrations also ensured adequate dispersion, textural stability, and fermentation compatibility. The goats’ milk used in the yogurt was obtained from the agricultural cooperative MENIKIO of Drama (Prosotsani, Greece). The milk was pasteurized at 85 °C and left to cool until it reached 42 °C. The recipe was 92% milk, 5% fructose (standardized commercial product, obtained from a local retailer in Larissa, Greece), 2% (1st batch) or 3% (2nd batch) SCG extract, and yoghurt starter culture YF-L903 (Chr. Hansen, Hoersholm, Denmark) 0,05% (supplied by the ELTON Group of Companies, Sindos, Thessaloniki, Greece; kept frozen at −18 °C until use). Fructose was chosen for the recipe instead of other sweeteners because of its low glycaemic index and taste profile. The mixtures were incubated at 42 °C for 5 h and then stored in a refrigerator at 4 °C until the tasting and the sensory evaluation.

2.3. Sensory Evaluation

Yogurt samples were transported after two days to a secondary location, where the sensory evaluation took place during the Zootechnia 2025 Agricultural Exhibition (Thessaloniki, Greece). Sensory data were collected from 137 adult untrained panellists of both genders who voluntarily participated in this study. The evaluation protocol was approved by the Experimental Protocols Evaluation Committee of the Department of Animal Science, University of Thessaly (Greece) (12579/25).

Prior to the evaluation, the participants received hygiene and food safety information (such as that regarding potential allergies or milk intolerances), as well as oral instructions regarding the procedure. Each participant completed a standardized questionnaire designed according to the Likert methodology, using

• A 5-point hedonic scale (1 = “Dislike extremely” to 5 = “Like extremely”) for sensory attributes;
• A 5-point Likert scale for overall satisfaction (1 = “Dissatisfied” to 5 = “Very satisfied”);
• A 5-point Likert scale for purchase intention (1 = “Would never buy” to 5 = “Would definitely buy”).

All yogurt samples were produced in accordance with Good Manufacturing Practices (GMPs) in a certified food-safe laboratory. Microbiological safety was assessed prior to the sensory evaluation through tests for the Total Plate Count, yeasts, and moulds. Only samples meeting safety standards were used for the consumer study.

2.4. Statistical Analysis

All statistical analyses were performed using the R programming language (R-Studio environment). The results are presented as the mean ± standard deviation. To assess whether the sensory attribute scores followed a normal distribution, Shapiro–Wilk tests were applied separately for each variable (appearance, aroma, taste, texture, coffee–yogurt balance, aftertaste) and for each yogurt series (Yogurt A and Yogurt B). A significance threshold of p < 0.05 was used to indicate deviation from normality. Given the non-normal distribution of the sensory data, Wilcoxon rank-sum tests (Mann–Whitney U) were used to compare the attribute scores between the two yogurt sample groups. Wilcoxon rank-sum tests were performed on the six sensory attributes, and the resulting p-values were adjusted using the Bonferroni correction (α = 0.05/6 ≈ 0.0083). A p-value of <0.05 was considered statistically significant. These tests enabled the detection of sensory differences between the samples without assuming normality. To provide a visual summary of the sensory performance of each yogurt series, mean scores for all attributes were plotted in a radar chart. This method facilitated direct comparison across multiple sensory dimensions in a single graphic representation. To explore associations among the sensory attributes, Spearman rank correlation coefficients were computed for all variable pairs. This non-parametric method was appropriate given the ordinal nature of the data and the lack of normality. Correlation matrices were used to display the strength and direction of the relationships among attributes. To assess how individual sensory attributes influence purchase intent, univariate proportional-odds ordinal logistic regression models were fitted. Each model examined the association between a single sensory attribute (appearance, aroma, taste, coffee–yogurt balance, aftertaste) and the ordered purchase intent categories (“Definitely No” to “Yes Definitely”). The results were interpreted as odds ratios, indicating an increased likelihood of higher purchase intent with each one-point increase in the sensory attribute score. For each univariate ordinal logistic regression, we evaluated the proportional-odds assumption using the Brant test. All models showed non-significant results (p > 0.05), supporting the parallel-lines assumption.

3. Results and Discussion

The incorporation of plant-derived extracts into dairy products represents a growing strategy for enhancing both the functionality and sustainability of food systems [28]. In particular, the use of by-products such as spent coffee grounds (SCGs) offers dual added value: the potential to increase the nutritional and antioxidant content and reduce agro-industrial waste. This study investigated—for the first time, to the best of our knowledge—the integration of an arabica SCG extract into goat milk yogurt.

3.1. Demographics

A total of 137 individuals participated in the sensory evaluation study. The gender distribution was skewed towards males, who comprised 61.3% of the sample (n = 84), compared to 38.7% females (n = 53). The age of the participants ranged across diverse groups, with the majority belonging in the category “Over 50” (30.7%), followed by the 36–50 age group (23.4%) and the 18–25 age group (21.2%) categories. Participants aged 26–35 represented 16.1% of the sample, while participants under 18 accounted for 8.8%. Regarding yogurt consumption habits, most participants reported consuming yogurt 2–3 times per week (43.1%) or daily (22.6%), indicating a high level of familiarity with the product category. A smaller proportion consumed yogurt once per week (19.0%) or rarely (14.6%), and only one individual (0.7%) among the participants reported never consuming yogurt. Coffee consumption was notably high as well among the respondents, with 67.9% indicating daily consumption of coffee and an additional 8.0% consuming coffee 2–3 times per week. In contrast, 13.9% reported never drinking coffee, while smaller proportions reported occasional (7.3%) or once-weekly (2.9%) consumption. These consumption patterns highlight a consumer pool frequently exposed to and familiar with yogurt and coffee products, an important factor likely influencing their receptiveness to a yogurt dessert fortified with SCG extract (

Table 1. Demographics and consumption summary.

Variable	Category	Count	Percentage
Gender	Female	53	38.7%
	Male	84	61.3%
Age Group	<18	12	8.8%
	18–25	29	21.2%
	26–35	22	16.1%
	36–50	32	23.4%
	Over 50	42	30.7%
Yogurt Consumption	Never	1	0.7%
	Rarely	20	14.6%
	Once per week	26	19.0%
	2–3 times per week	59	43.1%
	Daily	31	22.6%
Coffee Consumption	Never	19	13.9%
	Rarely	10	7.3%
	Once per week	4	2.9%
	2–3 times per week	11	8.0%
	Daily	93	67.9%
	Total respondents	137	100%

). Cultural and emotional links make familiar products more likely to be accepted, but too much familiarity may occasionally stimulate consumers’ curiosity, particularly among those who are eager to try new things [32]. The product was evaluated sensorially by 137 consumers, a sample notably larger than those used in many similar previous studies, e.g., n < 50 [33,34,35], thereby providing a high level of statistical robustness to the findings.

3.2. Sensory Analysis

The results demonstrated that the inclusion of SCG extract at 2% and 3% concentrations did not negatively affect the organoleptic properties of the yogurt. On the contrary, its taste and texture were positively received by certain consumer segments. This aligns with previous findings by Bertolino et al. [30], who added coffee silverskin to yogurt, increasing its dietary fibre and phenolic content, and Osorio-Arias et al. [31], who fortified Greek-style yogurt with cheese whey–SCG powder without impairing its texture. More specifically, Shapiro–Wilk tests were applied in order to assess normality for each sensory attribute within Yogurt A and Yogurt B. Because the distributions deviated from normality, Wilcoxon rank-sum tests were used to compare ratings (appearance, aroma, taste, texture, coffee–yogurt balance, aftertaste) between the two series. After the Bonferroni adjustment, no attribute even approached significance (all adjusted p ≥ 0.37), confirming no meaningful differences between Series A and Series B (

Table 2. Mean ± SD of sensory attributes (Yogurt A—2% SCG vs. Yogurt B—3% SCG).

Attribute	Series A	Series B	p-Value	p-Value (Adjusted) *
Aftertaste	3.81 ± 1.20	3.99 ± 1.24	0.283	1.000
Appearance	3.97 ± 1.10	3.93 ± 1.12	0.848	1.000
Aroma	3.80 ± 1.05	3.97 ± 1.08	0.253	1.000
Coffee–Yogurt Balance	3.52 ± 1.08	3.66 ± 1.23	0.271	1.000
Taste	3.84 ± 1.04	3.99 ± 1.11	0.282	1.000
Texture	3.81 ± 1.30	4.19 ± 1.18	0.062	0.372

* p-values were adjusted by Bonferroni correction (α = 0.05/6 ≈ 0.0083).

).

The results revealed that no significant differences were observed across any of the evaluated attributes at the conventional 0.05 level. Specifically, the raw p-values for aftertaste (p = 0.283), appearance (p = 0.848), aroma (p = 0.253), coffee–yogurt balance (p = 0.271), and taste (p = 0.282) indicated no statistically significant differences between the two series. Texture showed the lowest p-value (p = 0.062), suggesting a trend toward significance and indicating that further investigation may be warranted, as Series B tended to be rated slightly higher in this attribute (4.19 ± 1.18 vs. 3.81 ± 1.30). However, after Bonferroni correction, none of the attributes came close to the adjusted significance threshold, confirming there were no meaningful sensory differences between Series A and Series B. Overall, the sensory perception of the two formulations appeared to be broadly similar, implying that the modifications applied in Series B did not result in substantial changes to the consumer-perceived sensory quality. According to the results, consumers ranked the yogurt attributes in a similar way, picturing high acceptance. These findings come in line with those of other studies assessing the sensory properties of dairy products fortified with plant-origin extracts [3,36], especially coffee and coffee by-product extracts [30,33,34], indicating the potential usage of novel ingredients for the development of innovative yogurts. These findings also support the viability of diversifying dairy products with organic components, in line with customer preferences for healthier options [33].

To illustrate the comparative sensory characteristics of the two yogurt series (Yogurt A and Yogurt B), the mean scores of the six evaluated attributes—appearance, aroma, taste, texture, coffee–yogurt balance, and aftertaste—were plotted in a radar chart (Figure 1). This visual representation enables rapid and intuitive assessment of the overall sensory profile, offering a multidimensional view of performance across key descriptors [37]. From Figure 1, it is observed that both yogurt types exhibit closely aligned profiles, indicating generally similar sensory perceptions across the attributes. However, Yogurt B consistently scores marginally higher than Yogurt A in all attributes, particularly in texture and coffee–yogurt balance, where the divergence is visually more pronounced. These small but consistent differences may reflect subtle formulation variations or ingredient interactions, possibly linked to the concentration or dispersion of coffee elements. The slightly enhanced performance of Yogurt B in terms of texture could suggest an improved mouthfeel or creaminess, factors known to significantly influence consumer preference and product acceptability in dairy systems [38]. Additionally, a better coffee–yogurt balance may denote a more harmonious integration of the coffee flavour into the dairy matrix, enhancing overall product coherence—an aspect that is particularly important in hybrid or flavoured yogurts [39]. Despite the visual differences, the overlap of polygonal areas between the two samples remains high, implying that the sensory differences, while present, may not be large enough to drive dramatic consumer segmentation based solely on these dimensions. This observation aligns with the earlier statistical findings obtained using the Wilcoxon rank-sum test, where although some attribute scores differed significantly, the magnitude of the difference was moderate. Radar charts like this are widely used in sensory science due to their effectiveness in comparing multivariate sensory data at a glance [40]. Nevertheless, they are best interpreted in combination with quantitative statistical methods, as visual proximity does not necessarily indicate statistical equivalence.

The Spearman rank correlation analysis revealed significant positive relationships among the sensory attributes evaluated in the two yogurt dessert variations. Specifically, appearance showed moderate positive correlations with other attributes, particularly with aftertaste (r = 0.61), coffee–yogurt balance (r = 0.60), and aroma (r = 0.59). Texture was also positively correlated with appearance (r = 0.59) and taste (r = 0.57), indicating the perceived linkage between mouthfeel and the overall sensory impression. Taste exhibited stronger correlations with aroma (r = 0.65) and aftertaste (r = 0.66), reflecting their joint contribution to flavour perception. Furthermore, the coffee–yogurt balance attribute demonstrated high correlations with aroma (r = 0.67), aftertaste (r = 0.68), and taste (r = 0.58), suggesting its pivotal role in shaping the product’s overall sensory quality (Figure 2). Aftertaste emerged as the most interrelated characteristic, showing strong positive correlations with nearly all other attributes, especially coffee–yogurt balance, aroma, and taste. These findings underscore the interconnected nature of sensory perception and highlight aftertaste, aroma, and balance as critical drivers of consumer acceptance. Understanding such correlations can inform product optimization strategies aimed at enhancing sensory appeal. A correlation of roughly 0.70 implies a significant association, according to Bourne [41]. An increase in one parameter raises the other when there is a positive connection; the opposite applies for a negative correlation [42].

Compared to other yogurt enhancements, such as the addition of pomegranate or basil extracts [8], pectin from wine pomace [36], or hydroponic ginseng root extract [3], the use of SCGs stands out for its environmental and economic advantages, while also meeting or exceeding expectations in sensory acceptance.

3.3. Consumer Acceptance

The predictive role of individual sensory attributes in shaping consumers’ purchase intent for coffee-flavoured yogurt desserts was assessed using univariate ordinal logistic regression models. Brant tests for all five univariate models were non-significant (p > 0.05), confirming that the proportional-odds assumption holds across all sensory predictors. Each attribute—namely appearance, aroma, taste, coffee–yogurt balance, and aftertaste—was found to exert a statistically significant effect on purchase intention (p < 0.05), indicating that even small differences in the sensory evaluation meaningfully influenced consumer decision-making (

Table 3. Univariate ordinal logistic regression: odds ratios (95% CI) for sensory attributes predicting purchase intent.

Predictors	Odds Ratios	CI	p-Value
Appearance	1.76	1.19–2.62	0.005
Aroma	1.73	1.19–2.51	0.005
Taste	2.24	1.41–3.57	0.001
Coffee–Yogurt Balance	1.63	1.14–2.34	0.008
Aftertaste	1.79	1.27–2.53	0.001

). Among all the predictors, taste emerged as the strongest determinant (OR = 2.24; 95% CI: 1.41–3.57; p = 0.001), suggesting that a one-point improvement in the taste rating more than doubled the likelihood of consumers expressing a higher purchase intent. This is consistent with the existing literature, which highlights that taste is the primary driver of yogurt acceptability, particularly in formulations containing added flavourings or functional compounds [34,43]. The incorporation of coffee, which may introduce bitterness, acidity, or roasted notes, likely makes taste especially salient for overall acceptability. Similarly, aftertaste (OR = 1.79; CI: 1.27–2.53; p = 0.001) and aroma (OR = 1.73; CI: 1.19–2.51; p = 0.005) demonstrated strong associations with increased purchase intention. These findings reinforce the importance of both immediate olfactory perception and residual sensory impressions in determining consumer responses to dairy products with complex flavour profiles, such as those combining coffee and yogurt. In line with observations in prior studies, products enhanced with coffee extracts not only develop a distinctive aroma but also benefit from an increased antioxidant content, which may contribute to a more rounded and pleasant aftertaste [34]. Appearance (OR = 1.76; CI: 1.19–2.62; p = 0.005) and coffee–yogurt balance (OR = 1.63; CI: 1.14–2.34; p = 0.008) also significantly predicted purchase intent, albeit with relatively smaller effect sizes. The participants’ purchase intent increased with their yogurt consumption frequency. The single “Never” consumer reported “No” purchase intent. Rare consumers (n = 20) split into 10.0% “No,” 35.0% “Maybe,” and 55.0% “Yes.” Once-per-week consumers (n = 26) reported 7.7% “No,” 15.4% “Maybe,” and 76.9% “Yes.” Those consuming yogurt 2–3 times weekly (n = 59) had 3.4% “No,” 27.1% “Maybe,” and 69.5% “Yes,” while daily consumers (n = 31) showed 6.5% “No,” 6.5% “Maybe,” and 87.1% “Yes.” Overall (n = 137), 6.6% expressed “No,” 21.2% “Maybe,” and 72.3% “Yes,” indicating a clear positive trend between consumption frequency and purchase intent. While appearance has less of an influence compared to the flavour-related dimensions, it remains an important visual cue, especially at the point of initial product evaluation. This aligns with findings suggesting that texture and colour, often altered by functional or natural additives, can influence consumer perceptions of quality and freshness [43]. Regarding coffee–yogurt balance, the results suggest that successful sensory integration—not just the intensity of added flavour—is key to product acceptance. This echoes the conclusions made by Elera et al. [33], who emphasized the importance of harmonizing novel ingredients with the base dairy matrix to optimize consumer appeal. The use of the proportional-odds model in this analysis allowed for a nuanced interpretation of how incremental changes in sensory scores relate to shifts in purchase likelihood. This is particularly relevant in consumer research, where intention often exists along a gradient rather than on a binary scale.

The analysis of purchase intent revealed meaningful patterns across both gender and age groups. As shown in Figure 3, the distribution of purchase intent between male and female respondents was relatively similar. A substantial proportion of both genders expressed a high likelihood of purchasing the yogurt dessert, with approximately equal percentages selecting “Yes, Definitely” and “Yes, Probably.” A smaller portion of respondents from each gender indicated hesitation (“Maybe”) or a negative purchase intent (“Probably No” or “Definitely No”), suggesting that gender did not exert a pronounced influence on overall purchase behaviour in this sample. This observation aligns with previous findings indicating that sensory preferences and health perceptions are more influential than gender identity in shaping functional food acceptance [44]. In contrast, age emerged as a more decisive factor (Figure 4). Consumers aged 26–35 demonstrated the highest purchase intent, followed closely by the 36–50 and over-50 age groups. These findings resonate with prior research showing that young and middle-aged adults tend to be more receptive to functional food innovations, largely due to their heightened health awareness and alignment with sustainable consumption practices [45]. In contrast, younger participants (<18 and 18–25) displayed more neutral or uncertain responses, likely reflecting less familiarity with functional dairy products or a preference for more traditional taste profiles. According to Bogue et al. [46] and Hayat et al. [47], women tend to be more favourable towards food with enhanced nutritional benefits than men. However, the results of the present study imply that gender may not significantly influence purchase decisions for this product. On the other hand, age plays a more critical role, with middle-aged adults showing the greatest propensity to purchase. Understanding these demographic trends is essential for effective market segmentation and targeted product positioning.

The demographic analysis indicated that age played a more critical role than gender in purchase intent. Participants aged 26–35 exhibited the highest positive purchase intent, suggesting that adults of this age are more receptive to innovative functional foods. This trend is consistent with studies highlighting that younger adults are more open to high-technology food processing and novel food products [48]. In addition to demographic variables, it is plausible that psychographic factors could influence how consumers perceive functional food innovations. Although not assessed here, such influences may partially explain the variability in acceptance and should be explored in future studies. Although environmental consciousness was not directly assessed in this study, it is plausible that individuals who are more attuned to sustainability issues could perceive added value in products utilizing upcycled ingredients such as spent coffee grounds. This interpretation aligns with prior research suggesting that environmentally conscious consumers tend to exhibit stronger purchase intentions toward eco-friendly food products [49]. Likewise, previous studies indicate that health-oriented consumers—particularly women—are generally more receptive to foods with added nutritional benefits [46]; however, we observed no significant gender differences. This divergence could reflect sample-specific factors, the cultural context, or the particular attributes of the product tested. These insights highlight the potential of psychographic segmentation as a useful approach in the strategic development and positioning of functional dairy products, especially those aligned with emerging sustainability and health trends.

This focus on consumer acceptance and segmentation provides valuable data for the strategic formulation and potential commercialization of the product. The absence of adverse sensory impacts further strengthens the case for advancing this product within the framework of functional food innovation. Future research should aim to explore the stability of phenolic compounds, along with their bioaccessibility, impact on probiotic viability, and interaction with pH, as suggested in studies such as those by Lee et al. [3] and Aguiar et al. [28].

4. Conclusions

This study demonstrated the feasibility of incorporating antioxidant extracts from spent coffee grounds (SCGs) into goat milk yogurt without compromising its sensory quality. Taste, aftertaste, and aroma emerged as the most influential attributes in shaping consumer perception and purchase intent, underlining their central role in the sensory optimization of functional dairy products. Nonetheless, attributes such as texture, visual appeal, and coffee–yogurt flavour balance should not be overlooked, particularly when developing novel indulgent formulations that aim for broader market acceptance. The use of SCGs—a rich source of bioactive phenolic compounds—as a functional additive not only addresses consumer demand for health-promoting foods but also aligns with circular economy principles. The valorisation of this coffee industry by-product adds environmental value by reducing agro-industrial waste and transforming it into a high-value food ingredient. Consumer segments, particularly younger adults aged 26–35, along with environmentally conscious and health-oriented individuals, showed higher acceptance of the product, providing valuable insights for targeted marketing strategies. Importantly, the SCG-fortified yogurt was well received even by untrained consumers, indicating that upcycled plant-based additives can be successfully introduced into traditional animal-based food matrices. In conclusion, SCG extracts offer a sustainable, health-promoting option for enriching goat milk yogurt, contributing to both product innovation and environmental stewardship.