The incorporation of plant-based protein ingredients into processed meat products represents a promising strategy for reformulating meat products while addressing sustainability and resource efficiency concerns within the food industry. This study investigated the effect of sweet lupin flour incorporated at 2%, 4%, and 6% substitution levels on the quality characteristics of chicken meat sausages. Four batches were produced: a control (CB0%) and three lupin-enriched formulations (CLS2%, CLS4%, CLS6%), and evaluated for proximate composition, pH, water activity, colorimetric parameters, Warner–Bratzler shear force, and sensory acceptability. Lupin flour incorporation significantly modified all parameters, increasing ash, fat, carbohydrate, and energy content while moderately reducing moisture and protein. A progressive decrease in pH and water activity was observed alongside a colorimetric shift toward higher lightness and yellowness, with total color differences exceeding the visual perceptibility threshold of 5 at CLS4% and CLS6%. Shear force and work of cutting increased proportionally with substitution level, reflecting structural reinforcement of the protein matrix. Sensory evaluation confirmed that 2% substitution maintained overall acceptability within the positive range of the hedonic scale, while 4% remained acceptable but with some sensory decline, and the 6% received scores below the scale midpoint. These results suggest that lupin flour can be incorporated at up to 4%, while maintaining overall sensory scores within the positive range of the hedonic scale, supporting its potential as a plant-derived ingredient in the reformulation of poultry-based processed meat products. Currently, according to World Demographics, of the total global population of 8.2 billion people, 58.5% live in urban areas, compared to 46% in the year 2000 [ 1], and by 2050, two thirds of global population growth will take place in cities. Moreover, the World Urbanization Prospects 2025 report notes that approximately 60% of the land converted to urban use since 1970 was previously productive agricultural land [ 2]. In this context, population growth, accelerating urbanization, and increasing pressure on global food systems have intensified the need for solutions to maintain and improve human health by ensuring adequate access to healthy and affordable food, both in developed and developing countries [ 3], as the global food crisis represents a challenge from both the demand and supply side [ 4]. At the same time, urban populations are largely food purchasers and depend almost exclusively on markets for their food supply, making them vulnerable to economic fluctuations that affect food prices, and also making dietary quality increasingly dependent on the composition and nutritional value of processed food products [ 5, 6 Furthermore, the shift in dietary behavior has also contributed to a nutritional transition toward increased consumption of processed foods, particularly from animal protein sources, fats, and refined sugars, which carry long-term health consequences [ 7]. Complementary strategies are therefore needed, oriented toward the reformulation of processed food products with sustainable and accessible plant-based protein sources. In Romania, poultry meat occupies a central place in meat consumption, compared to beef, pork, sheep and goat meat, and represents an important segment of the meat industry due to its affordability and high consumer acceptance, making it a suitable matrix for reformulation with plant-derived ingredients [ 15, 16 According to FAOSTAT data, poultry meat production in Romania exceeded 500 thousand tonnes in 2023, while poultry consumption reached 25.38 kg per capita, reflecting the importance of this product within the national food sector [ 17 At the same time, increasing interest is being directed toward healthier and more sustainable food formulations incorporating plant-based ingredients, stimulating research focused on improving the nutritional profile and functional value of processed meat products. This trend is consistent with recent consumer behavior of reducing meat consumption and greater openness toward plant-based foods, particularly for health-related reasons [ 18 Recent studies conducted on chicken meat products have confirmed that partial substitution of animal protein with plant-based ingredients can be achieved without major compromise of physicochemical quality and consumer acceptability, supporting the broader applicability of this reformulation strategy across different legume sources and product types [ 19 Lupin belongs to this category, a leguminous plant of the genus Lupinus, with over 400 varieties, of which only four are cultivated for human or animal consumption: white lupin ( Lupinus albus L.), narrow-leaved or blue lupin ( Lupinus angustifolius L.), yellow lupin ( Lupinus luteus L.), and Andean lupin ( Lupinus mutabilis L.) [ 20, 21]. Out of all varieties, the most important edible species is L. angustifolius [ 22, 23 Although lupin naturally contains antinutritional components such as tannins, flavonoids, and alkaloids in variable concentrations, as well as naturally occurring bitter compounds (mainly quinolizidine alkaloids) [ 20, 23], sweet lupin varieties have been developed that are suitable for animal and human consumption, with nutritional advantages related to a reduced content of antinutritional factors such as lectins, trypsin inhibitors, and saponins [ 14, 24, 29]. Additionally, procedures have been developed to remove the bitter taste from lupin seeds by eliminating alkaloids from whole seeds through washing using water as a solvent [ 20, 30], through alkaline treatments [ 31], probiotic fermentation (yeast) [ 30], or microwave and infrared treatments [ 32 The use of lupin as a food ingredient can be highly diverse, ranging from consumption as a snack or in salads, through the production of tofu [ 33], chips [ 34], or plant-based milk from lupin seeds [ 35], to the incorporation of lupin flour into a wide range of food products such as cheese and meat substitutes, fermented products, mayonnaise, noodles, pasta, and baked goods [ 14, 22, 24, 36], or even the extraction of oil from the seeds (rich in monounsaturated and polyunsaturated fatty acids) [ 37]. One advantage of lupin flour is that it contains no gluten-forming proteins, making it suitable for gluten-free foods intended for people with celiac disease [ 20]; however, an important note is that lupin is classified as a major allergen under European legislation, in accordance with EU Regulation 1169/2011 [ 38], which requires mandatory labelling of these ingredients. Although it falls within the category of non-animal ingredients, alongside dietary fibers, which can be used in meat products for their potential to improve nutritional quality and nutraceutical properties, lupin flour may impart a bitter, rancid-like off-flavor to products [ 14, 22, 29, 39 The nutritional potential of lupin flour has thus been documented across various food matrices; however, limited data are available regarding the incorporation of lupin flour into cooked chicken sausages, particularly at relatively low substitution levels. Previous studies on sausage-type products have primarily focused on beef sausages [ 22] and fermented pork sausages [ 40 In this context, the present study aimed to evaluate the effect of lupin flour addition at substitution levels of 2%, 4%, and 6% on the overall quality of chicken meat sausages, compared to a control batch without lupin addition (0%). These levels were selected to investigate the feasibility of low incorporation rates, in order to evaluate the effects of progressively increasing lupin flour incorporation on product quality. The main physicochemical parameters, instrumental texture properties, and sensory quality of the products were evaluated, with the aim of identifying the optimal substitution level that ensures a sustainably reformulated product with an acceptable balance between product composition, technological performance, and sensory quality. 2. Materials and Methods 2.1. Raw Materials and Experimental Design For this research, four batches of chicken sausages were prepared: a control batch without lupin flour (CB0%) and three experimental batches in which sweet lupin flour replaced 2%, 4%, and 6% of the chicken meat fraction. The lupin flour used in this study was a commercial organic product (Rapunzel Naturkost GmbH, Legau, Germany) purchased from a local retailer, with the following approximate composition according to the manufacturer’s declaration: 14 g fat, 13 g carbohydrates, 23 g dietary fibre and 40 g protein per 100 g. The flour was incorporated as a partial replacement of the chicken meat fraction. The substitution levels corresponded to 1.93%, 3.86%, and 5.80% of the total formulation, as shown in Table 1. All raw materials were sourced from local suppliers and stored under refrigeration at 2–4 °C prior to processing. 2.2. Manufacturing Process The manufacturing process was conducted in the Meat Processing Workshop of the “Ion Ionescu de la Brad” Iasi University of Life Sciences, following standard procedures described in previous studies [ 41, 42], with specific adaptations for chicken meat sausage formulation. Boneless chicken thigh meat was ground using a WP-105 meat grinder (Revic Sp. z o.o., Sosnowiec, Poland) equipped with a 6 mm diameter sieve. Each formulation was produced as an independent batch of approximately 5 kg. The ground meat was transferred to a Titane 45V cutter (DADAUX SAS, Bersaillin, France), where salt and the pre-weighed spice mix were first incorporated. Subsequently, lupin flour was added according to the formulation. The batter was mixed for approximately 10 min, while monitoring batter consistency to obtain a homogeneous and cohesive meat matrix, while maintaining the temperature below 10–12 °C throughout the process. The resulting mixture was then stuffed into natural sheep casings (with a diameter of 18–20 mm), using a vacuum filler RVF 327 (REX-Technologie GmbH & Co. KG, Thalgau, Austria) and twisted into individual sausage units. The thermal treatment was carried out in an industrial smokehouse equipped with an integrated core-temperature probe (INDU iMAX500, STAWIANY, Pszczółki, Poland) using natural beech wood smoke. The process consisted of a four-stage cycle (as shown in Table 2): drying, hot smoking, steam cooking until a core temperature of 72 °C was reached, followed by a cooling period to an internal temperature below 20 °C. Relative humidity was maintained at approximately 10% during the drying and smoking stages and at 99% during steam cooking. Core temperature was monitored using the calibrated probe thermometer inserted into the geometric center of the product. After processing, the sausages were cooled and stored under refrigerated conditions (4 ± 1 °C) until physicochemical, textural, and sensory analyses were performed. 2.3. Physicochemical Analyses The pH values of the chicken sausage samples were determined using a digital pH meter HI98163 (Hanna Instruments, Cluj-Napoca, Romania), specifically designed for meat products. Prior to measurements, the instrument was calibrated using two buffer solutions with known pH values (pH 4.01 and pH 7.01). The electrode was inserted directly into the sample after calibration, and the pH value was recorded once the device stabilized. The electrode was cleaned with distilled water between measurements to prevent cross-contamination [ 39 Water activity (a w) of the chicken sausages was determined using a humimeter RH2 portable water activity meter (Schaller Messtechnik, St. Ruprecht an der Raab, Austria), by placing the ground samples into the measuring chamber and sealing it. Readings were recorded after reaching moisture equilibrium, indicated by a stable display value with variations below 0.002 a w over a period of 5 to 8 min. The proximate composition of the chicken sausages was determined using standard analytical methods of the Association of Official Analytical Chemists (AOAC). Moisture content was assessed gravimetrically using the oven-drying method (AOAC 950.46) at 105 °C until constant weight. Crude lipid content was determined using the Soxhlet extraction method (AOAC 960.39), while crude protein content was measured using the Kjeldahl method (AOAC 981.10, N × 6.25), and ash content was determined via dry-ashing in a muffle furnace at 550 °C (AOAC 923.03) until constant weight [ 39, 43]. All determinations were performed in triplicate. The total carbohydrate content of the sausage samples was calculated by difference [ 22], using Equation (1); the resulting value represents total carbohydrates by difference and includes dietary fibre originating from lupin flour. The energy value was calculated according to Equation (2) [ 44Carbohydrate content % = 100 − % moisture + % fat + % ash + % protein (1) Energy kcal / 100 g = Protein ୍ଠ 4 + Fat ୍ଠ 9 + Carbohydrates ୍ଠ 4 (2) 2.4. Instrumental Analyses The instrumental color parameters of the sausage samples were determined using the Chroma Meter CR-410 colorimeter (Konica Minolta Inc., Tokyo, Japan) in the CIELAB color space, following the method described in previous studies [ 45, 46]. Color measurements were performed on three independent sample replicates from each batch, at locations equally distributed over the sample surface and cross-section; the reported results are expressed as mean values. The light source used was D65 with a 2° observation angle and a measuring aperture of 8 mm illuminating a 50 mm diameter surface area. Color parameters were expressed by the instrument as L* (lightness: black-white), a* (green-red), and b* (blue-yellow). Additionally, chroma (C*), hue angle (h°) and color difference (ΔE) were calculated according to Equations (3)–(5) [ 39, 45, 47]: h ° = arctan b ∗ / a ∗ (3) C* = √(a* 2 + b* 2) (4) ∆ E = ( L 0 − L 1 ) 2 + ( a 0 ∗ − a 1 ∗ ) 2 + ( b 0 ∗ − b 1 ∗ ) 2 (5) Instrumental texture for the chicken sausages was evaluated using the Warner–Bratzler shear test, with a Texture Analyzer (TAPlus, Lloyd Instruments, Ametek Inc., Bognor Regis, UK), following the procedure applied in previous studies on reformulated meat products, with minor adaptations for the specific product type analyzed [ 39]. Three independent sausages from each treatment were analyzed. Prior to testing, all samples were conditioned at room temperature (20 ± 1 °C) for approximately 30 min to minimize temperature-related variability and were prepared into uniform cylinders of 5 cm length and 1.5 cm diameter. A V-shaped Warner–Bratzler blade attached to a 500 N load cell was used for all measurements. One section from each sausage was positioned horizontally on the test platform, with its longitudinal axis perpendicular to the direction of blade movement, and cut at a crosshead speed of 100 mm/min. The results were recorded as shear force (N) and work of cutting (mJ). 2.5. Sensory Evaluation The sensory evaluation of sausage samples was conducted in February 2026 in the Sensory Analysis Laboratory of the “Ion Ionescu de la Brad” Iasi University of Life Sciences, Romania. A panel of 20 semi-trained evaluators, aged between 25 and 42 years, consisting of faculty members and graduate students from the Food Engineering majors at the University of Life Sciences with previous experience in the sensory analysis of various meat products, evaluated the products with regard to sensory parameters of appearance, aroma, taste, texture, and overall acceptability. Prior to testing, all panelists received a briefing session to familiarize them with the evaluation procedure, attribute definitions, and scoring scale. Room-temperature water was provided to the panelists for palate cleansing between sample evaluations. The sensory assessment was conducted using a hedonic acceptance test, whereby participants evaluated the four formulations of chicken meat sausages through the following sensory attributes: appearance, aroma, taste, texture, and overall acceptability. A 9-point hedonic scale was used for scoring (1 = extremely unpleasant; 5 = neither pleasant nor unpleasant; 9 = extremely pleasant). Each sample was evaluated once by each panelist in individual sensory booths designed to minimize external distractions and interactions among evaluators. Samples were presented in pieces of approximately 2–3 cm, coded with three-digit random codes, and served at room temperature (20 ± 1 °C) in a randomized order under standardized laboratory conditions [ 42, 48 2.6. Statistical Analysis The determinations were performed in triplicate, and the results were presented as mean value ± standard deviation (SD). Statistical analysis was performed using SPSS software (IBM SPSS Statistics version 21.0); one-way analysis of variance (ANOVA) and Tukey’s test were utilized to determine significant differences between the variables, with a significance level of p 3 [ 58] indicating a perceptible color difference and ΔE > 5 [ 59] indicating a more evident visual difference, the observed values were interpreted in relation to both criteria. Using the higher threshold reported in the literature (ΔE > 5) [ 59], clearly visible differences were observed starting from the CLS4% level, both at the surface (5.64 ± 0.85) and cross-section (5.80 ± 0.39). In contrast, the ΔE value recorded for CLS2% in cross-section (2.52 ± 0.34) remained below the lower threshold, indicating only a limited color difference compared to the control. At the cross-sectional color level, L* did not differ significantly between batches ( p = 0.173), whereas all other parameters (a*, b*, C*, h°, ΔE) showed significant differences ( p < 0.05). Colorimetric parameter analysis reveals a synergistic effect of lupin flour addition on the optical properties of the products, manifested by an increase in L* and b* values, alongside moderate variations in the a* component. This trend is observed at both the surface and cross-sectional levels, indicating a systemic influence of the plant-based ingredient on the product matrix. Similar results were reported by Papavergou et al. [ 40] in fermented pork sausages and by Alrahaife & Abu-Alruz [ 14] in beef burgers with lupin flour, where the substitution of animal protein with plant-based ingredients led to increased lightness and yellow color intensity of the products, alongside a reduction in redness. In contrast, Leonard et al. [ 22], for beef sausages with lupin, reported an increase in lightness for raw samples and an opposite effect—a decrease in lightness (L*) and an increase in red and yellow color—for thermally treated sausages. The authors explain these differences through the higher percentage of lupin flour added (reaching up to 36%), as well as the conditioning of lupin flour and spices through roasting, which promotes the development of the Maillard browning reaction, resulting in reduced lightness and a more intense red color in cooked samples. For a more complete characterization of the color changes induced by lupin flour addition, the derived parameters chroma (C*) and hue angle (h°) were also analyzed, providing additional information about the saturation and dominant hue of the color. Chroma expresses the intensity or vividness of the color, with higher values indicating a more saturated, visually intense color. In contrast, hue angle describes the dominant color hue and is expressed in degrees; conventionally, 0° corresponds to red, 90° to yellow, 180° to green, and 270° to blue [ 59 The increase in C* values observed in the lupin-enriched batches indicates an intensification of chromatic saturation, suggesting that the product acquires a more vivid visual appearance. In parallel, the increase in h° values highlights the color dilution effect [ 64] through a shift of the dominant color toward the yellow zone of the colorimetric space, which is consistent with the increase in b* values and with the intrinsic cream-yellow color of lupin flour. Thus, the addition of the plant-based ingredient not only influences the lightness of the product but also modifies its overall chromatic profile, shifting it toward more yellow and more saturated tones. 3.3. Sensorial Analysis of Supplemented Chicken Sausages The sensory properties of chicken sausages with different levels of lupin flour substitution are presented in Table 6 and illustrated in . Sensory evaluation was performed using a 9-point hedonic scale (1 = extremely unpleasant; 9 = extremely pleasant) by a panel of evaluators, and significant differences between batches were determined using the Tukey HSD test ( p < 0.05). The sensory parameters evaluated showed a decreasing trend with increasing lupin flour substitution level, with significant differences between batches ( p < 0.05) for most attributes, particularly for the CLS6% batch, which obtained the lowest acceptability scores. Scores for general external appearance and cross-sectional appearance decreased non-significantly from 7.40 ± 0.60 and 6.90 ± 1.65 (CB0%), respectively, up to the 4% lupin flour addition level (CLS4%), before decreasing significantly to 7.05 ± 1.47 (CLS4%) and 5.00 ± 1.38 (CLS6%), respectively. The color changes induced by lupin flour, through increased lightness and a shift in hue toward yellow, as shown by instrumental analysis in the previous section, may explain the less favorable visual perception of the batches with higher substitution levels. Furthermore, the perception of appearance is also correlated with the colorimetric changes of the product, both at the surface and in cross-section, where ΔE values exceeded the threshold of visual perception, recording values of 5.91 and 6.73, respectively, and the yellow component b* increased significantly with substitution level. The texture attribute showed a decreasing trend, from 6.85 ± 1.35 (CB0%) to 5.75 ± 1.12 (CLS6%), with statistically significant differences observed at the highest substitution level ( p < 0.05). This trend is consistent with the increase in shear force measured instrumentally, suggesting the formation of a denser matrix and a firmer texture in samples with higher lupin flour content. A similar negative sensory perception of texture was also reported by Leonard et al. [ 22] for beef sausages, who observed a decline in texture acceptability with increasing levels of lupin flour substitution, reaching a score of 3.25 at the maximum inclusion level of 36%. The lower texture scores may be attributed to a grainy or dry mouthfeel during mastication, likely caused by the high content of insoluble dietary fiber in lupin flour. Similar results regarding the sensory modification of perceived texture as a function of lupin substitution level were reported by Hall & Johnson [ 67], who conducted sensory evaluation of several products containing lupin flour ( Lupinus angustifolius) and observed that overall acceptability decreased compared to the control for muffins and bread, while cookies and breakfast bars maintained scores similar to the control, suggesting that the effect of lupin on perceived texture is strongly dependent on the food matrix and the substitution level used. Additionally, Holkovičová et al. [ 68] associated the addition of lupin flour to baked goods with product densification and reduced elasticity, effects attributed to the high fiber content that disrupts the protein network and modifies the rheological properties of the matrix. Abreu et al. [ 29] support these observations in a systematic review of consumer perception and acceptability of lupin-derived products, stating that, while the addition of lupin to food products may represent an acceptable approach for improving nutritional value, the exploitation of its potential as an ingredient is limited by sensory aspects, particularly the intrinsic aroma, taste, and olfactory sensations, which are frequently perceived negatively by consumers. Overall acceptability decreased significantly from 7.20 ± 0.77 (CB0%) to 4.55 ± 1.28 (CLS6%), with statistically significant differences starting from the 4% addition level ( p < 0.05). The CB0% and CLS2% batches obtained overall acceptability scores of 7.20 and 6.95, respectively, both situated in the “pleasant” zone of the scale, while CLS4% (6.00) remained at the lower limit of positive acceptability, and CLS6% (4.55) fell below the neutral threshold of the hedonic scale (5 = neither pleasant nor unpleasant), suggesting that this substitution level significantly compromises the overall acceptability of the product from the consumer’s perspective. In their study, Leonard et al. [ 22] indicated that lupin flour can be incorporated into beef sausage manufacturing at up to 12% of the total composition without significantly affecting consumer acceptability, while another study reported high overall acceptability for a 20% lupin powder addition in chicken burgers, compared to substitution levels of 10% and 35% [ 70 In addition to the ANOVA/Tukey comparison presented in Table 6, the sensory data were additionally analyzed using the Friedman test to account for the repeated-measures nature of the sensory evaluation. The Friedman test revealed significant differences among formulations for section appearance (χ 2 = 15.617, p = 0.001), taste (χ 2 = 20.911, p < 0.001), and overall acceptability (χ 2 = 31.850, p < 0.001), whereas no significant differences were observed for appearance ( p = 0.138), texture ( p = 0.055), and flavor ( p = 0.369). The relationships among the physicochemical parameters of chicken meat sausage samples enriched with lupin flour were investigated using Principal Component Analysis (PCA), as illustrated in . The PCA biplot explained 99.19% of the total variance, with the first principal component (PC1) accounting for 92.35% and the second principal component (PC2) for 6.84%, providing an excellent two-dimensional representation of the dataset. These results support the reliability of the visual interpretation of the relationships among variables and sample distribution. Along the F1 axis, the main discriminant component, the control batch (CB0%) is clearly positioned in the left quadrant, showing positive correlations with protein, moisture, aw, pH, and red color (a*), which reflect the typical profile of chicken meat sausages without substitution—namely, higher protein and moisture content, increased water activity, higher pH, and characteristic surface redness. This distinct separation from the other batches confirms that the incorporation of lupin flour induces significant and systematic modifications in the physicochemical profile of the final product. The CLS4% and CLS6% batches are grouped in the right quadrant of the biplot, exhibiting positive correlations with work of cutting, shear force (N), lightness (L*), hue angle (h), chroma (C*), yellow color (b*), ash, fat, dry matter and carbohydrates content, and also energetic value, parameters that increase progressively with the level of substitution, in agreement with the trends observed in the instrumental analyses. The close proximity of these two batches on the biplot suggests that, in terms of the overall physicochemical profile, CLS4% and CLS6% are more similar to each other than to the control or CLS2%, which is consistent with the absence of statistically significant differences between them for certain individual parameters. 4. Conclusions The study demonstrated the feasibility of using lupin flour as a plant ingredient for the partial substitution of chicken meat in sausage formulations. The partial substitution of chicken meat with lupin flour at 2%, 4%, and 6% produced dose-dependent changes across all quality parameters evaluated. In terms of proximate composition, lupin flour increased ash, fat, carbohydrate, and energy content while moderately reducing moisture and protein (only by 0.8 percentage points at the highest level of substitution). In the context of increasing interest in sustainable food systems and reformulated meat products, these results indicate that low levels of lupin flour can be incorporated while maintaining the overall quality of the final product. Between the formulations, the 2% level of substitution offers the most favorable balance between quality and sensory acceptance, while 4% remains a technically feasible alternative with minor sensory compromise, and higher incorporation levels registered a gradual reduction in consumer acceptability. 4.1. Practical Implications for Consumers The partial replacement of chicken meat with lupin flour in poultry-based meat sausages may contribute to the diversification of dietary protein sources and support the development of products containing both animal- and plant-derived ingredients, without major changes in dietary habits. Such reformulated products can represent a strategy for consumers seeking to reduce their reliance on exclusively meat-based foods due to health, nutritional, or environmental concerns, while maintaining the sensory characteristics and familiarity associated with traditional meat products. 4.2. Implications for the Food Industry The present findings can provide information for the development of reformulated poultry meat products incorporating plant-based ingredients. The results indicate that the successful incorporation of lupin flour into chicken sausage formulations is highly dependent on the level of substitution. Therefore, the study highlights the importance of formulation optimization and the identification of substitution levels that balance nutritional characteristics, technological performance, and sensory acceptability. These findings may support food manufacturers in diversifying meat product portfolios and developing hybrid meat products, while contributing to ongoing efforts toward more sustainable product reformulation strategies. 4.3. Study Limitations and Future Research Directions The research study was limited to the evaluation of physicochemical characteristics, colorimetric attributes, Warner–Bratzler shear test parameters, and sensory quality of freshly produced sausages. Storage stability, oxidative changes, microbiological quality, or consumer acceptance under market conditions were not investigated. Future research should therefore focus on the shelf-life evaluation of lupin-enriched sausages, the assessment of oxidative and microbiological stability under refrigerated storage, and evaluate the potential to extend consumer-acceptable substitution thresholds without compromising sensory quality. Author Contributions Conceptualization, M.-M.C. and D.-R.M.; methodology, D.-R.M.; software, M.C.C.; validation, M.-M.C., D.-R.M. and M.C.C.; formal analysis, D.-R.M.; investigation, D.-R.M.; resources, M.-M.C.; data curation, D.-R.M. and M.C.C.; writing—original draft preparation, D.-R.M. and M.C.C.; writing—review and editing, D.-R.M.; visualization, M.C.C.; supervision, M.-M.C.; project administration, M.-M.C.; funding acquisition, M.-M.C. All authors have read and agreed to the published version of the manuscript. Funding This research received no external funding. Institutional Review Board Statement The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Faculty of Agriculture, University of Life Sciences in Iasi, Romania (4428/21 January 2026). Informed Consent Statement Informed consent was obtained from all subjects involved in the study. Data Availability Statement The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author. Acknowledgments During the preparation of this manuscript, the authors used AI tools (GPT version 5.5) for the purpose of improving language clarity, readability, and overall editorial quality. The authors carefully reviewed, revised, and edited the output and take full responsibility for the final content of this publication. Conflicts of Interest The authors declare no conflicts of interest. References pH and water activity (a w) of chicken sausages with different levels of lupin flour substitution. Different lowercase letters above the bars indicate significant differences between samples according to Tukey’s HSD test ( p < 0.05). CB0%—control sample (0% lupin flour); CLS2%—2% lupin flour substitution; CLS4%—4% lupin flour substitution; CLS6%—6% lupin flour substitution. pH and water activity (a w) of chicken sausages with different levels of lupin flour substitution. Different lowercase letters above the bars indicate significant differences between samples according to Tukey’s HSD test ( p < 0.05). CB0%—control sample (0% lupin flour); CLS2%—2% lupin flour substitution; CLS4%—4% lupin flour substitution; CLS6%—6% lupin flour substitution. Radar plot of hedonic mean scores for appearance, flavor, taste, texture, and overall acceptability of the control sample and lupin flour-added samples. CB0%—control sample; CLS2%, CLS4%, CLS6%—2%, 4%, and 6% lupin flour substitution. Radar plot of hedonic mean scores for appearance, flavor, taste, texture, and overall acceptability of the control sample and lupin flour-added samples. CB0%—control sample; CLS2%, CLS4%, CLS6%—2%, 4%, and 6% lupin flour substitution. Principal Component Analysis (PCA) biplot illustrating the relationships between physicochemical parameters and chicken sausage formulations with different levels of lupin flour substitution. CB0%—control sample; CLS2%, CLS4%, CLS6%—2%, 4%, and 6% lupin flour substitution. Principal Component Analysis (PCA) biplot illustrating the relationships between physicochemical parameters and chicken sausage formulations with different levels of lupin flour substitution. CB0%—control sample; CLS2%, CLS4%, CLS6%—2%, 4%, and 6% lupin flour substitution. Recipe for chicken sausages with lupin flour. Recipe for chicken sausages with lupin flour. Batches CB0% CLS2% CLS4% CLS6% Ingredients Amount (%) Chicken thigh 96.62 94.69 92.75 90.82 Lupin flour 0 1.93% 3.86% 5.80% Salt 1.93 1.93 1.93 1.93 Spice mix 1.45 1.45 1.45 1.45 Total 100% 100% 100% 100% CLS2%, CLS4%, and CLS6% indicate formulations in which lupin flour replaced 2%, 4%, and 6% of the chicken meat fraction. Thermal treatment schedule applied in the industrial smokehouse for chicken sausages. Thermal treatment schedule applied in the industrial smokehouse for chicken sausages. Stage Chamber Temperature (°C) Duration (min) Drying 55 20 Smoking 68 40 Boiling/Steam cooking 78 - Hot air drying 80 5 Proximate composition of control and supplemented chicken sausages. Data are expressed as mean ± standard deviation. Proximate composition of control and supplemented chicken sausages. Data are expressed as mean ± standard deviation. Chemical Characteristics CB0% CLS2% CLS4% CLS6% p-Value Dry matter (%) ୩୪.୨୬ ବ୍ଦ ୦.୦୬ a୩୫.୩୨ ବ୍ଦ ୦.୦୮ b୩୬.୦୬ ବ୍ଦ ୦.୧୦ c୩୬.୯୮ ବ୍ଦ ୦.୦୩ d<0.001 Moisture (%) ୬୫.୭୪ ବ୍ଦ ୦.୦୬ d୬୪.୬୮ ବ୍ଦ ୦.୦୮ c୬୩.୯୪ ବ୍ଦ ୦.୧୦ b୬୩.୦୨ ବ୍ଦ ୦.୦୩ a<0.001 Fat (%) ୧୦.୪୩ ବ୍ଦ ୦.୦୬ a୧୦.୭୭ ବ୍ଦ ୦.୧୭ b୧୦.୯୩ ବ୍ଦ ୦.୦୨ bc୧୧.୧୪ ବ୍ଦ ୦.୦୭ c<0.001 Total protein (%) ୧୯.୧୩ ବ୍ଦ ୦.୦୪ d ୧୮.୮୪ ବ୍ଦ ୦.୦୨ c୧୮.୬୦ ବ୍ଦ ୦.୦୯ b୧୮.୩୩ ବ୍ଦ ୦.୦୩ a<0.001 Ash (%) ୪.୨୯ ବ୍ଦ ୦.୧୪ a୪.୬୭ ବ୍ଦ ୦.୦୯ b୪.୮୯ ବ୍ଦ ୦.୦୫ bc୪.୯୪ ବ୍ଦ ୦.୦୬ c<0.001 Total carbohydrates (%) ୦.୪୨ ବ୍ଦ ୦.୦୬ a୧.୦୫ ବ୍ଦ ୦.୧୯ b୧.୬୪ ବ୍ଦ ୦.୧୪ c୨.୫୬ ବ୍ଦ ୦.୧୪ d<0.001 Energy value (kcal 100 g −1) ୧୭୨.୦୪ ବ୍ଦ ୦.୬୦ a୧୭୬.୪୬ ବ୍ଦ ୦.୮୧ b୧୭୯.୨୯ ବ୍ଦ ୦.୪୪ c୧୮୩.୮୬ ବ୍ଦ ୦.୨୪ d<0.001 Values are given as means ± Standard deviation from three repeated determinations. Means with different superscripts in a row orientation indicate significant differences ( p < 0.05) between samples determined using the Tukey test. Results for Warner–Bratzler shear forces, pH value and water activity of chicken sausage formulations. Data are expressed as mean ± standard deviation. Results for Warner–Bratzler shear forces, pH value and water activity of chicken sausage formulations. Data are expressed as mean ± standard deviation. Analyzed Parameter Samples p-Value CB0% CLS2% CLS4% CLS6% Shear force (N) ୩୦.୬୩ ବ୍ଦ ୧.୮୫ a୪୨.୭୬ ବ୍ଦ ୧.୯୯ b୪୬.୩୭ ବ୍ଦ ୧.୩୨ c୪୭.୫୬ ବ୍ଦ ୦.୯୬ c<0.001 Work of shear (mJ) ୩୬୨.୮୨ ବ୍ଦ ୧୨.୩୭ a୩୭୪.୮୦ ବ୍ଦ ୧୦.୯୨ a୪୧୫.୫୫ ବ୍ଦ ୭.୬୫ b୪୮୮.୨୨ ବ୍ଦ ୯.୨୭ c <0.001 pH ୬.୭୨ ବ୍ଦ ୦.୦୮ c୬.୬୩ ବ୍ଦ ୦.୦୧ bc୬.୪୪ ବ୍ଦ ୦.୦୯ ab୬.୨୩ ବ୍ଦ ୦.୧୧ a<0.001 Water activity ୦.୯୫୬ ବ୍ଦ ୦.୦୦୮ b୦.୯୪୯ ବ୍ଦ ୦.୦୧୧ ab୦.୯୪୦ ବ୍ଦ ୦.୦୦୫ ab୦.୯୩୨ ବ୍ଦ ୦.୦୦୭ a0.028 Values are given as means ± Standard deviation from three repeated determinations. Means with different superscripts in a row orientation indicate significant differences ( p < 0.05) between samples determined using the Tukey test. Colorimetric attributes of control and supplemented chicken sausages. Data are expressed as mean ± standard deviation. Colorimetric attributes of control and supplemented chicken sausages. Data are expressed as mean ± standard deviation. Color Parameters Samples L*(D65) a*(D65) b*(D65) C* h° ΔE Surface color CB0% ୪୧.୮୩ ବ୍ଦ ୦.୮୪ a୧୮.୯୮ ବ୍ଦ ୦.୧୬ b୧୪.୭୬ ବ୍ଦ ୦.୧୪ a୨୪.୦୫ ବ୍ଦ ୦.୧୦ a୩୭.୮୭ ବ୍ଦ ୦.୪୪ a- CLS2% ୪୩.୭୬ ବ୍ଦ ୦.୮୧ b୧୭.୭୦ ବ୍ଦ ୦.୨୫ a୧୭.୦୨ ବ୍ଦ ୦.୨୬ b୨୪.୫୬ ବ୍ଦ ୦.୩୬ a୪୩.୮୮ ବ୍ଦ ୦.୦୭ b୩.୨୮ ବ୍ଦ ୦.୬୮ aCLS4% ୪୪.୫୨ ବ୍ଦ ୦.୨୬ b୧୭.୫୨ ବ୍ଦ ୦.୧୨ a୧୯.୪୬ ବ୍ଦ ୦.୨୯ c୨୬.୧୯ ବ୍ଦ ୦.୨୧ b୪୭.୯୯ ବ୍ଦ ୦.୫୧ c୫.୬୪ ବ୍ଦ ୦.୮୫ bCLS6% ୪୪.୩୪ ବ୍ଦ ୦.୪୫ b୧୭.୭୯ ବ୍ଦ ୦.୧୦ a୧୯.୮୯ ବ୍ଦ ୦.୨୭ c୨୬.୬୯ ବ୍ଦ ୦.୧୭ b୪୮.୧୯ ବ୍ଦ ୦.୫୦ c୫.୯୧ ବ୍ଦ ୦.୭୮ bp-value 0.003 <0.001 <0.001 <0.001 <0.001 0.011 Section color CB0% ୪୮.୯୮ ବ୍ଦ ୦.୫୨ a୧୬.୯୩ ବ୍ଦ ୦.୧୧ b୧୧.୯୦ ବ୍ଦ ୦.୧୯ a୨୦.୭୦ ବ୍ଦ ୦.୧୯ a୩୫.୧୦ ବ୍ଦ ୦.୨୯ a- CLS2% ୪୯.୩୦ ବ୍ଦ ୦.୩୪ a୧୬.୨୫ ବ୍ଦ ୦.୧୪ a୧୪.୨୭ ବ୍ଦ ୦.୨୧ b୨୧.୬୩ ବ୍ଦ ୦.୧୬ b୪୧.୨୯ ବ୍ଦ ୦.୫୩ b୨.୫୨ ବ୍ଦ ୦.୩୪ aCLS4% ୪୯.୭୪ ବ୍ଦ ୦.୨୯ a୧୬.୧୫ ବ୍ଦ ୦.୨୨ a୧୭.୫୬ ବ୍ଦ ୦.୩୪ c୨୩.୮୬ ବ୍ଦ ୦.୩୩ c୪୭.୪୦ ବ୍ଦ ୦.୫୫ c୫.୮୦ ବ୍ଦ ୦.୩୯ bCLS6% ୪୯.୭୯ ବ୍ଦ ୦.୬୦ a୧୬.୧୫ ବ୍ଦ ୦.୨୩ a୧୮.୫୨ ବ୍ଦ ୦.୩୯ d୨୪.୫୭ ବ୍ଦ ୦.୪୪ c୪୮.୯୨ ବ୍ଦ ୦.୨୦ d୬.୭୩ ବ୍ଦ ୦.୨୨ cp-value 0.173 0.002 <0.001 <0.001 <0.001 <0.001 L*(D65)—lightness (ranging from 0 = black to 100 = white); a*(D65)—red–green component (positive values = red tones, negative values = green); b*(D65)—yellow–blue component (positive values = yellow tones, negative values = blue); C*—chroma (color saturation or intensity, higher values indicate more vivid colors); h°—hue angle (expresses the dominant color tone); ΔE—total color difference. Values are given as means ± Standard deviation from three repeated determinations. Different superscript letters within a column (for each section) indicate significant differences between samples according to Tukey’s HSD test ( p < 0.05). Sensory properties of chicken sausage formulations fortified with lupin flour. Data are expressed as mean ± standard deviation. Sensory properties of chicken sausage formulations fortified with lupin flour. Data are expressed as mean ± standard deviation. Sensory Attribute Samples p-Value CB0% CLS2% CLS4% CLS6% Appearance ୭.୪୦ ବ୍ଦ ୦.୬୦ b୭.୪୫ ବ୍ଦ ୦.୬୯ b୭.୦୫ ବ୍ଦ ୧.୪୭ ab୬.୮୦ ବ୍ଦ ୧.୨୦ a0.175 Section appearance ୬.୯୦ ବ୍ଦ ୧.୬୫ b୬.୪୫ ବ୍ଦ ୧.୩୬ b୬.୧୫ ବ୍ଦ ୦.୫୯ b୫.୦୦ ବ୍ଦ ୧.୩୮ a<0.001 Texture ୬.୮୫ ବ୍ଦ ୧.୩୫ b୬.୮୦ ବ୍ଦ ୧.୩୨ b୬.୫୫ ବ୍ଦ ୧.୦୫ ab୫.୭୫ ବ୍ଦ ୧.୧୨ a0.076 Flavor ୭.୩୫ ବ୍ଦ ୦.୮୧ b୭.୨୦ ବ୍ଦ ୦.୮୯ b୬.୮୫ ବ୍ଦ ୦.୯୯ ab୬.୮୦ ବ୍ଦ ୧.୦୧ a0.140 Taste ୭.୨୫ ବ୍ଦ ୦.୯୧ b୭.୧୫ ବ୍ଦ ୦.୮୮ b୬.୨୦ ବ୍ଦ ୧.୧୧ a୫.୯୫ ବ୍ଦ ୧.୧୫ a<0.001 Overall acceptability ୭.୨୦ ବ୍ଦ ୦.୭୭ c୬.୯୫ ବ୍ଦ ୦.୯୪ c୬.୦୦ ବ୍ଦ ୧.୧୨ b୪.୫୫ ବ୍ଦ ୧.୨୮ a<0.001 Values are given as means ± standard deviation. Different superscript letters within each sensory attribute indicate significant differences between samples according to Tukey’s HSD test ( p < 0.05). The p-values correspond to the overall one-way ANOVA results. Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). 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