3. Results and Discussion

3.1. Chemical Composition

The proximate composition of wet noodles, including moisture, ash, fat, protein, and carbohydrate contents, varied significantly with changes in the formulation ratio of wheat flour, mocaf, and pumpkin flour (Table 1).

Wheat flour: mocaf: pumpkin flour (w/w) | Moisture (%) | Ash (%) | Fat (%) | Protein (%) | Carbohydrates (%)
100:0:0 | 31.35 ± 0.18d | 1.09 ± 0.25e | 0.66 ± 0.05c | 12.78 ± 1.37a | 54.12 ± 1.09a
80:10:10 | 33.18 ± 0.11c | 1.35 ± 0.14d | 0.72 ± 0.09b | 9.64 ± 1.34b | 55.11 ± 2.54a
70:20:10 | 35.65 ± 0.80b | 2.66 ± 0.15c | 1.02 ± 0.14a | 8.84 ± 0.69c | 51.63 ± 1.30c
60:20:20 | 35.47 ± 0.19b | 2.95 ± 0.27b | 1.04 ± 0.09a | 7.58 ± 0.74d | 52.96 ± 2.91b
50:25:25 | 36.30 ± 0.07a | 3.20 ± 0.17a | 1.02 ± 0.15a | 6.85 ± 1.57e | 52.63 ± 1.74b

Table 1 shows that the moisture level of wet noodles rose significantly, increasing from 31.35% to 36.30% (p < 0.05). This increase can be attributed to the greater water‐binding capacity of amorphous starch and dietary fiber present in mocaf and pumpkin flour compared with wheat flour. Pumpkin flour contains dietary fiber and pectin that have been reported to enhance water retention [31] and water‐binding capacity in food systems [32].

The ash content showed a significant increase (p < 0.05), from 1.09% in control samples to 3.20% with higher incorporation of mocaf and pumpkin flour. This increase may be associated with the mineral composition of pumpkin flour reported in previous studies, including potassium, magnesium, and phosphorus [33]. These findings suggest that incorporating local ingredients can enhance the mineral content of wet noodles.

The fat content increased from 0.66% to around 1.02%–1.04% (p < 0.05) in formulations with a higher proportion of pumpkin flour [34]. The fat content increased from 0.66% to approximately 1.02%–1.04% as the proportion of pumpkin flour increased. This result suggests that pumpkin flour contributed to the lipid fraction of the noodle formulations.

Protein content decreased significantly (p < 0.05) with increasing proportions of mocaf and pumpkin flour, declining from 12.78% in the control (100:0:0) to 6.85% in the 50:25:25 formulation. This decrease was attributed to a reduction in gluten in the noodle dough [34]. Gluten is reduced when wheat flour is replaced with mocaf and pumpkin flour, both of which do not contain gluten. Previous studies have reported that mocaf generally contains lower protein levels than wheat flour, whereas pumpkin flour contributes dietary fiber rather than gluten‐forming proteins, which may contribute to the reduction in protein content observed in the noodle formulations.

The carbohydrate content ranges from 51% to 55%, with a slight decrease observed in formulations with the highest substitution. This is because an increase in water and ash content will proportionally reduce the carbohydrate content. Pumpkin contains both soluble and insoluble fibers, whose structure differs from that of wheat carbohydrates, which are primarily composed of starch. Mocaf has starch that binds water more easily, resulting in a decrease in the carbohydrate fraction [35].

3.2. Color

Changes in the color attributes of wet noodles, represented by L, a, and b* values, were consistently observed with increasing proportions of mocaf and pumpkin flour (Table 2). The L* value decreased significantly from 81.35 in the control to 72.78 in the 50:25:25 formulation, indicating a reduction in product brightness. This decrease reflects the dominance of carotenoid pigments derived from pumpkin, which absorb blue–green light, resulting in a darker color. Additionally, increasing the proportion of pumpkin flour contributed to a more intense yellow–orange color in the final product due to its carotenoid content. During cooking, interactions among starch, protein, and bioactive compounds can influence the product′s optical properties, leading to a darker color. A decrease in lightness (L*) following pumpkin flour incorporation into food products has been reported by Slamet et al. [36]. This reduction is mainly attributed to carotenoid pigments present in pumpkin flour, which impart a yellow–orange color and consequently decrease product brightness. In addition, the use of RS in noodle products has been reported to reduce lightness [37]. This effect may be associated with changes in starch matrix structure that alter light scattering properties within the product.

Wheat flour: mocaf: pumpkin flour (w/w) | L* | a* | b*
100:0:0 | 81.35 ± 3.77a | 2.08 ± 0.53d | 11.98 ± 1.01d
80:10:10 | 79.82 ± 4.24b | 4.47 ± 0.40c | 17.03 ± 1.89c
70:20:10 | 76.28 ± 3.46c | 5.38 ± 0.75b | 28.78 ± 2.75b
60:20:20 | 73.82 ± 4.60d | 6.59 ± 0.58a | 32.64 ± 2.68a
50:25:25 | 72.78 ± 3.53e | 6.75 ± 0.62a | 33.59 ± 2.70a

As the level of pumpkin flour increased, the a* and b* values of fresh noodles exhibited a consistent upward trend. The a* parameter increased from 2.08 in the control to 6.75 in the formulation containing a 50:25:25 ratio. The increase in the b* value from 11.98 to 33.59 indicates a stronger yellow–orange color intensity due to the β‐carotene content in the pumpkin flour. This trend indicates a positive relationship between carotenoid content and the product′s yellowness. Carotenoids are known to play a direct role in imparting the characteristic yellow color of pumpkin and are relatively stable under the processing conditions typically applied during fresh noodle production, which generally involve dough mixing and short cooking periods at temperatures close to 100°C. This compound contributes to the yellow–orange color in various pumpkin‐based food products [38]. In addition, the distribution of carotenoid pigments within the noodle dough matrix can influence the color intensity of the final product. During cooking, carotenoid pigments can disperse within the starch and protein matrix, thereby enhancing the yellow–orange color intensity of the resulting fresh noodles. This indicates that increasing the proportion of pumpkin flour not only boosts the content of bioactive compounds but also improves the product′s color characteristics, resulting in a more appealing appearance for consumers.

A progressive change in noodle color from pale yellow to deep orange–yellow was observed, as depicted in Figure 1. The 60:20:20 formulation produced the most uniform color, while the 50:25:25 formulation appeared darker and duller due to a decrease in L* value. This color change is beneficial because it gives functional noodles a distinctive visual characteristic without the addition of synthetic coloring. The orange–yellow color is produced by pumpkin carotenoid compounds [39].

Figure 1: Appearance of wet noodles formulated with different wheat flour: mocaf: pumpkin flour ratios.

3.3. Texture, Deformation, and Cooking Loss

Significant differences in hardness, deformation, and cooking loss were observed among wet noodle formulations prepared with varying proportions of wheat flour, mocaf, and pumpkin flour, as shown in Table 3.

Wheat flour: mocaf: pumpkin flour (w/w) | Hardness (N) | Deformation (%) | Cooking loss (%)
100:0:0 | 7.79 ± 0.79a | 11.35 ± 1.54a | 8.24 ± 1.01e
80:10:10 | 7.18 ± 1.05b | 10.60 ± 1.80b | 9.87 ± 0.97d
70:20:10 | 6.35 ± 1.87c | 8.86 ± 1.43c | 10.35 ± 1.53c
60:20:20 | 5.57 ± 1.41d | 8.75 ± 1.74c | 11.66 ± 1.49b
50:25:25 | 5.35 ± 0.97e | 6.03 ± 1.73d | 12.75 ± 1.63a

A significant reduction in fresh noodle hardness was observed, with values decreasing from 7.79 N in the control formulation to 5.35 N in the 50:25:25 formulation (Table 3). This decline was primarily associated with the reduced gluten content resulting from the substitution of a portion of the wheat flour with mocaf and pumpkin flour. Gluten plays a crucial role in forming an elastic, continuous protein network in noodle dough; thus, a reduction in gluten can weaken the protein–starch matrix, resulting in a softer noodle texture. Additionally, pumpkin flour may contribute to increased water retention within the dough matrix, which could weaken the protein–starch network and reduce noodle hardness. The incorporation of nonwheat ingredients into dough formulations has been reported to decrease noodle hardness by modifying the gluten network structure [40].

The deformation of wet noodles also decreased from 11.35% in the control formulation to 6.03% in the formulation with the highest substitution level. This decrease indicates a reduced ability of the dough structure to return to its original shape after being subjected to pressure. The reduction may be attributed to the partial replacement of wheat flour with mocaf and pumpkin flour, which weakens the gluten network responsible for maintaining the elasticity and structural integrity of the noodle matrix. This condition is characterized by weakened interactions between gluten chains, including reduced formation of disulfide bonds that help maintain the elasticity of the protein network. Additionally, new interactions between starch and protein via hydrogen bonding can modify the dough matrix structure, thereby affecting its elastic properties [41]. This phenomenon is common in food systems where the proportion of nongluten ingredients has increased.

Cooking loss increased from 8.24% in the control formulation to 12.75% in the 50:25:25 formulation. The high cooking loss value indicates weakening of the starch and protein matrix, leading to some of the solid components dissolving readily into the water during boiling [42]. The reduced gluten network and the incorporation of pumpkin flour may facilitate water penetration into the dough matrix, thereby promoting the release of soluble solids during cooking. Several studies have also reported that substituting wheat flour with nonwheat ingredients tends to increase cooking loss in noodle products [43]. This effect is generally attributed to the disruption of the gluten network, which reduces the ability of the dough matrix to retain starch granules and other soluble components during cooking. Nevertheless, the 60:20:20 formulation still yields cooking loss values within an acceptable range for fresh noodles, indicating that the ingredient balance in this formulation can maintain the product′s structural integrity. Overall, the findings suggest that increasing the proportion of mocaf and pumpkin flour leads to a softer noodle texture and increased cooking loss. However, the formulation with a moderate substitution level (60:20:20) still maintains relatively good structural integrity. This indicates that this formulation can balance textural characteristics and structural stability during cooking, making it a potentially optimal formulation for developing wet noodles from local ingredients.

3.4. Bioactive Compounds and Antioxidant Activity

The incorporation of higher amounts of pumpkin flour resulted in a significant enhancement of β‐carotene content in wet noodles (p < 0.05) (Table 4).

Wheat flour: mocaf: pumpkin flour (w/w) | ß‐carotene (μg/g) | Total phenolic content (mg GAE/g) | Antioxidant activity (%)
100:0:0 | 2.29 ± 0.82e | 0.14 ± 0.11e | 2.69 ± 0.84e
80:10:10 | 37.68 ± 3.61d | 2.36 ± 0.34d | 18.47 ± 2.42d
70:20:10 | 75.53 ± 5.87c | 3.43 ± 0.41c | 29.54 ± 3.58c
60:20:20 | 105.57 ± 6.70b | 3.92 ± 0.86b | 37.71 ± 3.76b
50:25:25 | 124.46 ± 6.95a | 4.94 ± 1.58a | 49.75 ± 3.04a

The β‐carotene content increased from 2.29 _μ_g/g in the control formulation (100:0:0) to 124.46 _μ_g/g in the formulation with a 50:25:25 ratio. The increase in β‐carotene content may be attributed to the incorporation of pumpkin flour, which has been reported as a rich source of carotenoids, particularly β‐carotene [44]. β‐Carotene is a carotenoid pigment that gives food its yellow to orange color. In addition, this compound exhibits biological activity as a provitamin A and acts as an antioxidant [45]. The incorporation of increasing amounts of pumpkin flour contributed to a greater presence of carotenoid pigments in the noodle matrix, thereby elevating β‐carotene content in the final product. These results indicate that partial substitution of wheat flour with pumpkin flour enhances bioactive compounds in fresh noodles, offering potential nutritional benefits and supporting the utilization of local ingredients in functional food development. In addition to β‐carotene, total phenolic compounds also contributed to the bioactive profile of the wet noodles, as evidenced by the significant increase in TPC from 0.14 to 4.94 mg GAE/g with increasing levels of mocaf and pumpkin flour substitution.

The incorporation of increasing proportions of mocaf and pumpkin flour resulted in a significant elevation of TPC (p < 0.05). The values increased from 0.14 mg GAE/g in the control formulation to 4.94 mg GAE/g in the 50:25:25 treatment. This enhancement reflects the contribution of substitute ingredients to the enrichment of phenolic compounds in the product matrix. Phenolic compounds are recognized as important secondary metabolites commonly found in plant‐based foods [46]. The antioxidant activity of these compounds is attributed to their capacity to neutralize free radicals by donating electrons or hydrogen atoms [47]. Within the wet noodle matrix, phenolic compounds can interact with starch and protein, which may influence their stability and biological activity during processing [48]. The increase in phenolic content at higher substitution levels reflects the contribution of mocaf and pumpkin flour to the bioactive profile of the wet noodles. Moreover, this enhancement contributes to the improved functional properties of wet noodles as a source of bioactive compounds.

The antioxidant activity of wet noodles increased from 2.69% to 49.75% (p < 0.05). This increase reflects a synergistic effect between β‐carotene and phenolic compounds in scavenging free radicals [49]. Carotenoid compounds, such as β‐carotene, are known to act as free radical scavengers via electron or hydrogen‐atom donation mechanisms, thereby playing a key role in suppressing oxidation in food systems [50]. The antioxidant activity of phenolic compounds is attributed to their capacity to donate protons and stabilize free radicals [51]. The interaction between these two groups of bioactive compounds can produce a synergistic effect, enhancing the overall antioxidant capacity of the fresh noodle product. The observed increase in antioxidant activity is consistent with the higher β‐carotene and TPCs observed in formulations containing greater proportions of pumpkin flour and mocaf. The β‐carotene content of pumpkin, along with the phenolic compounds present in the raw materials, contributes to the product′s increased antioxidant potential [10]. Overall, the increase in these bioactive components indicates that the incorporation of mocaf and pumpkin flour enhanced the functional properties of the wet noodles through increased β‐carotene content, TPC, and antioxidant activity. The use of local ingredients in noodle formulations facilitates food diversification and simultaneously contributes to the development of functional food products with potential health benefits.

3.5. Starch Digestibility and eGI

Starch digestibility fractions, including RDS, SDS, RS, and the eGI of fresh noodles prepared with varying proportions of wheat flour, mocaf, and pumpkin flour, are summarized in Table 5.

Wheat flour: mocaf: pumpkin flour (w/w) | RDS (%) | SDS (%) | RS (%) | eGI
100:0:0 | 64.69 ± 2.97a | 20.73 ± 1.02e | 5.76 ± 0.18e | 73.87 ± 1.90a
80:10:10 | 60.75 ± 2.04b | 22.42 ± 0.97d | 7.65 ± 0.95d | 70.93 ± 2.07b
70:20:10 | 57.86 ± 1.97c | 24.65 ± 1.53c | 8.71 ± 0.87c | 67.86 ± 1.86c
60:20:20 | 52.74 ± 1.86d | 26.86 ± 1.91b | 10.15 ± 0.42b | 63.74 ± 1.63d
50:25:25 | 49.08 ± 1.04e | 28.94 ± 1.74a | 12.62 ± 0.86a | 58.06 ± 1.07e

As presented in Table 5, increasing the proportions of mocaf and pumpkin flour significantly influenced the starch digestibility fractions and the eGI of fresh noodles (p < 0.05). The RDS value decreased gradually from 64.69% in the control formulation (100:0:0) to 49.08% in the formulation with the highest substitution (50:25:25). The reduction in the RDS fraction suggests that a portion of the starch becomes less susceptible to enzymatic hydrolysis during the initial phase of digestion [52]. Fiber and pectin may act as a physical barrier that limits the access of amylase enzymes to starch granules, thereby reducing the rate of starch hydrolysis [53]. In addition, interactions between starch and nonstarch components, such as fiber and phenolic compounds, can result in a more compact and stable matrix structure, ultimately reducing enzyme access to the starch substrate. This denser matrix structure can also limit the diffusion of water and enzymes during in vitro digestion, thereby reducing the fraction of RDS [54]. The reduction in RDS and the corresponding increase in SDS and RS may also be associated with starch–fiber interactions within the noodle matrix. Dietary fiber and pectin derived from pumpkin flour can form a physical barrier surrounding starch granules, thereby restricting enzyme accessibility during digestion. Furthermore, hydrogen bonding between starch molecules and nonstarch polysaccharides may contribute to the formation of a more compact matrix structure, resulting in slower starch hydrolysis and a lower estimated glycemic response.

The SDS value increased from 20.73% to 28.94%, whereas the RS value increased from 5.76% to 12.62% (p < 0.05). The observed changes indicate that substitution with mocaf and pumpkin flour influences the digestibility profile of starch in fresh noodles. Furthermore, the inclusion of pumpkin flour has been shown to enhance nutritional attributes, particularly by increasing dietary fiber and lowering glycemic response, supporting its application as a functional substitute ingredient [55, 56]. A decrease in the RDS fraction indicates that some of the starch has become less susceptible to hydrolysis by digestive enzymes [57]. Interactions between starch and other macromolecular components can enhance matrix compactness and stability, resulting in reduced enzyme penetration and slower starch hydrolysis [58].

[29] The increase in SDS and RS fractions suggests that starch hydrolysis occurred more gradually during digestion. RS is less susceptible to enzymatic degradation and may exert physiological effects similar to dietary fiber by escaping digestion in the small intestine and undergoing fermentation in the colon [59]. Therefore, the increased RS content may contribute to the enhanced functional properties of the developed fresh noodles.

Changes in the starch fraction were also reflected in the eGI values of the products. The estimated GI value decreased significantly from 73.87 in the control formulation to 58.06 in the formulation with the highest substitution. The decrease in GI value indicates that increasing the proportion of mocaf and pumpkin flour could yield noodles with a lower glycemic response. Changes in starch fractions, characterized by lower RDS and higher SDS and RS, are closely linked to the observed decrease in glycemic index [60]. Foods containing more SDS fractions tend to release glucose at a slower rate, resulting in a lower glycemic response [61].

The results indicate that alterations in starch fractions are consistently linked to corresponding changes in the eGI of fresh noodle products. A decrease in the RDS fraction, accompanied by increases in SDS and RS, contributes to a decrease in the eGI value [62]. The functional value of noodle products can be improved through the use of mocaf and pumpkin flour, as this combination alters starch composition, reduces glycemic response, and increases the fraction of SDS. It should be noted that the glycemic index values reported in this study were estimated from an in vitro digestion model and may differ from glycemic responses observed in vivo due to physiological factors affecting digestion, absorption, and glucose metabolism.

3.6. Spectrum FTIR

Figure 2 illustrates the FTIR spectra obtained from wet noodle formulations containing different proportions of wheat flour, mocaf, and pumpkin flour. All formulations exhibit relatively similar spectral patterns, indicating that the main components of the wet noodles remain dominated by carbohydrates and proteins. The absorption band at approximately 3274 cm−1 is associated with the stretching of hydroxyl (O–H) groups from water molecules, starch, and dietary fiber [63]. The band at approximately 2920 cm−1 is associated with the stretching of the C–H bond in the organic components of the material matrix [64]. The intensity of this band was higher in formulations with a higher proportion of mocaf and pumpkin flour, such as in the 60:20:20 and 50:25:25 ratios, suggesting a possible increase in hydrogen bonding within the matrix.

Figure 2: FTIR spectra of wet noodles formulated with different wheat flour: mocaf: pumpkin flour ratios.

The absorption band observed around 2922 cm−1 corresponds to C–H stretching vibrations of organic constituents. The peak at around 1653 cm−1 corresponds to the amide I region of wheat proteins, which are important for noodle matrix formation. Additionally, the fingerprint region (1200–900 cm−1) exhibits strong bands at 1076, 1022, and 995 cm−1, representing C–O and C–O–C vibrations of starch polysaccharides [65]. Interactions between starch, protein, and nonstarch components of mocaf and pumpkin flour are indicated by changes in band intensity in this region at higher substitution levels [66]. These interactions can modify starch molecular structure and affect its functional behavior and digestibility in the final noodle product.

3.7. Microstructure

Microstructural alterations in wet noodle formulations containing varying proportions of wheat flour, mocaf, and pumpkin flour were examined by SEM, as presented in Figure 3. In the control formulation (100:0:0), the noodle structure exhibited a relatively compact and continuous matrix with starch granules trapped within the gluten network.

Figure 3: SEM micrographs of wet noodles formulated with different wheat flour: mocaf: pumpkin flour ratios.

This structure reflects the ability of wheat flour to form a cohesive protein network, resulting in a more uniform dough matrix. However, increasing the proportions of mocaf and pumpkin flour led to a more irregular microstructure, characterized by the presence of pores and surface gaps. This effect is attributed to the reduction in gluten content caused by partial substitution with nonwheat ingredients. In addition, higher levels of fiber and other nonstarch components from mocaf and pumpkin flour may disrupt the formation of a continuous gluten network within the dough matrix [67]. In the 60:20:20 formulation, the microstructure still exhibits a relatively homogeneous matrix compared with formulations with higher substitution levels, indicating a better balance between starch and protein components in the dough system. The more open microstructure in formulations with higher substitution levels can enhance water diffusion during the cooking process and improve enzyme accessibility during in vitro starch digestion [68]. These conditions can affect the textural characteristics and digestibility fractions of the starch in the resulting fresh noodles.

3.8. Sensory Evaluation

Figure 4 demonstrates that variations in the proportions of wheat flour, mocaf, and pumpkin flour significantly affected sensory attributes, including color, aroma, taste, texture, and overall acceptance. Color preference scores increased with the addition of pumpkin flour up to a 60:20:20 formulation. The observed yellow–orange hue results from the presence of carotenoid pigments, notably β‐carotene, which enhance the visual attractiveness of the product to panelists. Carotenoids are known to give a characteristic yellow–orange color to pumpkin‐based products [36, 49].

Figure 4: Sensory acceptance profile of wet noodles formulated with different wheat flour: mocaf: pumpkin flour ratios.

The aroma score of the wet noodles also increased to a moderate level of substitution. The slightly sweet and distinctive aroma of pumpkin flour was considered to add character to the product. However, in the 50:25:25 formulation, there was a decrease in the aroma score, indicating that an excessively high proportion of pumpkin flour resulted in a stronger and less desirable sweet aroma. The aroma of wet noodles originates from pumpkin, which has a pleasant scent reminiscent of fresh fruit [69].

The flavor attributes of wet noodles show a similar trend. Adding moderate amounts of pumpkin flour can enhance the perception of natural sweetness and give the product a soft texture. This flavor is dominated by the addition of pumpkin flour. Pumpkin has a distinctive fresh fruit flavor [70]. The 60:20:20 formulation received the highest score because the panelists considered the balance of the flour flavor, the natural sweetness of the pumpkin flour, and the distinctive aroma to be in just the right proportions. The highest formulation (50:25:25) actually lowered the flavor score due to the overly strong pumpkin flavor.

The texture value of wet noodles decreased in the 50:25:25 formulation, in line with instrumental texture data showing a decrease in hardness and an increase in softness. Panelists preferred the texture of the 60:20:20 formulation, which exhibited moderate elasticity, a smoother surface, and a structure that remained fairly compact. This combination was consistent with the results of texture analysis and SEM, which showed that the noodle structure remained intact [35].

Overall, the 60:20:20 formulation had the highest likability score among the formulations. This formulation exhibited a more appealing color, a balanced aroma and flavor, and a texture that most closely matched the characteristics of fresh noodles expected by the panelists. The combination of wheat flour, mocaf, and pumpkin flour in that ratio produced fresh noodles with good sensory quality and high acceptance among the panelists. The sensory characteristics of the final product are strongly influenced by the balance of ingredient composition. Substituting wheat flour with mocaf and pumpkin flour at moderate levels improves color and sensory attributes while maintaining acceptable texture quality [71]. Conversely, an excessively high substitution rate can affect the starch and protein matrix structure in the dough, potentially reducing the noodles′ elasticity and chewiness. Therefore, the 60:20:20 formulation can be considered the most optimal for producing fresh noodles with balanced sensory characteristics that are well‐received by consumers.