Formulation and quality evaluation of quinoa-enriched functional spaghetti: Nutritional, antioxidant, cooking, color, and textural characteristics

Introduction

Food security and health are pressing global challenges, especially in developing nations, as the population is expected to rise to over 9 billion by 2050, increasing food demand by 70% to 100% (Godfray et al., 2010) [8] . Currently, nearly 1 in 8 people suffer from chronic undernourishment (FAO, IFAD, WFP, 2014) [6] , and metabolic diseases like diabetes and obesity are widespread (Standl et al., 2019) [19] . The aging population will further exacerbate these issues, with a higher incidence of age-related illnesses like osteoporosis and cardiovascular diseases (Song et al., 2024) [18] . Sustainable food production is crucial to address these challenges. Functional foods, which offer specific health benefits beyond basic nutrition, have become increasingly important. Spaghetti, a popular food staple due to its low cost, low glycemic index, and ease of preparation, is primarily composed of carbohydrates and protein but is deficient in essential nutrients like dietary fiber, vitamins, and minerals (Sissons et al., 2016) [17] . The addition of non-traditional, nutrient-rich ingredients is recommended to improve its nutritional profile (Bustos et al., 2015). Quinoa (Chenopodium quinoa Willd), a highly nutritious and climate-resistant pseudocereal, offers significant potential to enhance the nutritional value of spaghetti. Rich in bioactive compounds with health benefits, quinoa can thrive in adverse conditions, making it a valuable crop for sustainable food production (Ruiz et al., 2016) [14] . Incorporating quinoa into spaghetti could provide a functional, nutritious alternative, aligning with the growing demand for healthier food options.

Materials and methods

Quinoa flour was purchased from Keshav Global Exim, Ahmedabad, and Refined wheat flour was purchased from the local market of Varanasi, India. All chemicals, solvents, and reagents were analytical grade. Chemicals were obtained from HiMedia Laboratories Limited, Mumbai, India, and Sigma Aldrich Bengaluru, India.

Preparation of spaghetti

The production of quinoa spaghetti begins with the collection of high-quality quinoa seeds. These seeds are carefully sourced from reliable suppliers or cultivated under controlled conditions to ensure optimal quality and consistency. Once harvested, the quinoa seeds are thoroughly washed to remove any impurities, dust, or foreign particles. This cleaning process is essential to ensure that the seeds are free from contaminants before further processing. After washing, the quinoa seeds are subjected to a drying process. This is typically done by spreading the seeds out in a well-ventilated area or using specialized drying equipment. The drying process ensures that the seeds reach an appropriate moisture content, which is crucial for effective grinding and to prevent spoilage during storage. The dried quinoa seeds are then ground into a fine flour using a milling machine or other grinding equipment. The grinding process is critical in achieving the desired consistency and texture of the flour, which will form the base for the spaghetti dough. The quinoa flour is combined with additional ingredients, such as water, salt, or any other binding agents, depending on the recipe or desired product characteristics. The ingredients are mixed thoroughly to form a uniform dough. This step is essential to ensure proper texture and elasticity in the final product. The mixed dough is kneaded to develop the desired texture and consistency. Kneading is a crucial step in the spaghettimaking process, as it helps to activate the gluten-free binding agents, providing the dough with the necessary firmness and elasticity required for spaghetti shaping. After kneading, the dough is allowed to rest for a period of time. This resting phase helps to relax the dough, making it easier to roll and shape. It also allows the ingredients to fully hydrate and integrate, contributing to a more cohesive dough structure. Following the resting period, the dough is passed through a rolling machine to achieve a thin, even layer. The rolling process helps to standardize the thickness of the dough, which is critical for uniform cooking and texture in the final product. The rolled dough is then cut into the desired shapes using specialized cutters. For spaghetti, this typically involves cutting the dough into long, thin strands. The shape of the spaghetti can be adjusted depending on the product specification or consumer preference. Once the spaghetti has been cut, it is dried again to reduce its moisture content. The drying process helps preserve the spaghetti, ensuring it remains shelf-stable and ready for packaging. This step also helps maintain the spaghetti's texture and prevents it from becoming mushy during cooking. The dried quinoa spaghetti is then carefully packaged in low-density polyethylene (LDPE) bags. These bags are commonly used in food packaging due to their flexibility and ability to provide a moisture barrier, ensuring the product remains fresh and protected from contamination. Finally, the packaged quinoa spaghetti is stored in a cool, dry place to maintain its quality and prevent spoilage. Proper storage conditions are essential to prolong the shelf life of the product and ensure that it retains its texture and nutritional value until it reaches the consumer.

Fig 2: Flow chart of functional spaghetti

Proximate analysis of functional spaghetti

The moisture, protein, fat, fiber and ash contents of spaghetti samples were determined using the (AOAC method,1975) [2] . The carbohydrate content of the sample was determined by the difference method %carbohydrate = 100-(%Moisture + %Fat + %Protein + %Ash). Energy value in terms of Total calorie content was measured as per (Hailu Kassegn,2018) [9] . Total calorie content = (%carbohydrate × 3.87) + (%Fat×8.79) + (% Protein×4.27).

Cooking characteristics of functional spaghetti

Cooking quality characteristics of functional spaghetti, where cooking loss was determined according to AACC approved method (2000) [1] .

Swelling index and water absorption

Swelling index was determined according to (Devi & Sit, 2019) [5] . Water absorption was determined according to (Bianchi et al., 2021) [3] . This involved taking 25 grams of spaghetti and cooking it for the recommended 12 minutes; the cooking liquid was then drained and allowed to cool until it reached a temperature of 20°C. After that, an analytical scale (Precisa XB-220a) was used to record the weight of the cooked and dry spaghetti. The swelling index (SI) and water absorption index (IA) were calculated through the following formula:

Determination and extraction of antioxidant properties and total phenolics content of functional spaghetti

The DPPH scavenging ability of the sample extract was determined according to (Cervato et al., 2000) [4] with minor adjustments. 1 ml of the diluted extract was mixed with 3 ml of a 60 μM DPPH methanol solution. The mixture was then incubated in the dark at room temperature for 30 minutes. Afterward, the absorbance was recorded at 517 nm using a spectrophotometer (Jenway, 6405 UV/Vis, United Kingdom). A control sample containing methanol and DPPH solution was also tested. The DPPH inhibition percentage was calculated using the following equation:

Abs 517 (reference) -Abs 517 ( Sample) Abs 517 (reference) × 100

Where, Abs517 reference is the absorbance reading of the reference, and Abs517 sample is the absorbance reading of the sample The total phenolics content of the samples was determined using the Folin-Ciocalteu method as described by (Singleton et al., 1999) [16] . Briefly, 300 μL of the sample extract was mixed with 1.5 mL of Folin-Ciocalteu reagent and 1.2 mL of 7.5% Na2CO3 solution in a test tube. The mixture was then incubated in the dark at room temperature for 30 minutes. The absorbance was measured at 765 nm against a blank. The total phenolics concentration was calculated and expressed as gallic acid equivalent (GAE) in mg/g of the sample.

Colour analysis

The color of both uncooked and cooked spaghetti samples was measured using a colorimeter (Minolta CR-400, Inc., Japan). Readings were taken at various random points on the surface of the uncooked and cooked spaghetti. The measurements recorded included lightness (L*), redness (a), and blueness (b) values.

Textural profile analysis

Textural parameters of Functional spaghetti such as Hardness, Fracturability, Cohesiveness, Springiness, Gumminess, and Chewiness were analyzed using a Brookfield Ametex CT3 texture analyzer at 2.0 mm/s TA 75 Probe, United State (Padalino et al., 2017).

Results and discussion

Nutritional value of sphagetti

The results of nutritional analysis of quinoa flour-based sphagetti are shown in Table 1. The protein content increased from 10.56% in sample MS00 to 15.23% in sample QS00, demonstrating a significant rise as the proportion of quinoa flour increased. Meanwhile, fat content also showed an upward trend, increasing from 1.45% in MS00 to 6.87% in QS00. Conversely, carbohydrate content decreased from 77.89% in MS00 to 63.14% in QS00, indicating a shift in macronutrient distribution with the incorporation of quinoa flour. Moisture content rose from 3.22% in MS00 to 9.45% in QS00, while ash content saw a slight increase from 1.12% in MS00 to 2.61% in QS00.

Additionally, the crude fiber content increased from 0.98% in MS00 to 3.14% in QS00. These changes highlight how the nutritional composition of the sphagetti samples was influenced by the varying treatments. Similar trends were observed by (Torres et al., 2021) [20] , who reported increases in protein and fiber content and decreases in carbohydrate content when quinoa flour was incorporated into bakery products. This suggests that quinoa flour consistently enhances the nutritional profile of various food products by increasing protein and fiber content while reducing carbohydrate levels.

Cooking characteristics of sphagetti

The cooking quality characteristics of sphagetti including cooking loss, water absorption, and swelling capacity, are crucial for determining its overall quality and consumer acceptance. A lower cooking loss indicates higher quality sphagetti, as it signifies fewer soluble starches and other components leaching into the cooking water, which can otherwise make the water thick and less desirable. In the study by (Torres et al., 2021) [20] similar trend was observed as in this study, the cooking loss increased significantly (p<0.05) as the proportion of quinoa flour increased, with the lowest loss observed in the MS00 sample (2.53 g/100 g) and the highest in QS50 (7.44 g/100 g). This suggests that the control sample (MS00) retains its structure better during cooking, potentially due to a more robust gluten network, which is essential for maintaining the integrity of the sphagetti during the cooking process. Water absorption decreased as the quinoa flour content increased, with MS00 showing the highest absorption (3.78 ml/g) and QS00 the lowest (1.24 ml/g). This trend indicates that lower water absorption in higher quinoa content samples might be due to the absence of gluten, which typically aids in binding water. The ability of sphagetti to absorb water is vital for achieving the desired texture and mouthfeel, as it influences the final product's firmness and palatability. Similarly, swelling capacity, which indicates the amount of water absorbed by starch and proteins during cooking, decreased with increasing quinoa content, from 71.57% in MS00 to 39.14% in QS00. According to (Gaikwad et al., 2021) [7] , this reduction in swelling capacity suggests that the sphagetti may become less desirable in texture as quinoa flour replaces traditional wheat flour, which is known for its superior swelling properties.

Table2: Effect of different formulation treatments on the cooking characteristics of spaghettAntioxidant and total phenolic content in functional Sphagetti Values are expressed as mean± SD (n = 3). Different superscript letters within the same row indicate significant differences among treatments (P<0.05)

Samples

Antioxidant properties of sphagetti

The DPPH assay is widely used to evaluate antioxidant activity, which is based on the ability to donate hydrogen atoms (Scherer and Godoy, 2009) [15] . Antioxidant activity values above 0.5 indicate strong antioxidant properties. The table shows that all samples in this study demonstrated significant antioxidant activity, with the QS00 sample showing the highest DPPH free radical inhibition at 54.46%. This is notably higher than the MS00 sample, which had only 3.24% inhibition, indicating that the quinoa flour significantly boosted the antioxidant properties of the sphagetti. Phenolic compounds are known for their antioxidant properties, and the total phenolic content in the samples reflects this. The control sample MS00 had the lowest phenolic content (1.20 mg GAE/g), while the QS00 sample had the highest (6.71 mg GAE/g), suggesting that the increase in quinoa flour content directly contributes to the phenolic content. This finding is consistent with previous studies showing that phenolic-rich foods have strong antioxidant activity.

As indicated in other studies, the phenolic content and antioxidant activity can decrease after cooking due to thermal degradation and leaching of phenolic compounds into the cooking water (Verardo et al., 2011; Hirawan et al., 2010) [10,21] . This table, however, only shows the results before cooking, which suggests that incorporating quinoa flour into sphagetti could effectively enhance its antioxidant potential.

Textural profile analysis

Textural parameters of Functional spaghetti such as Hardness, Adhesiveness, Resilience, Cohesiveness, Springiness, and Chewiness were analyzed using Brookfield Ametex CT3 texture analyzer at 2.0 mm/s TA 75 Probe. The textural properties of spaghetti samples are analyzed here in the following Table 5 and Table 6. Comparing the control spaghetti to the spaghetti fortified with quinoa, a noteworthy rise was observed in every TPA measure. Likewise, comparable trends were seen in spaghetti fortified with quinoa and control, with hardness continuing to decrease in response to higher concentrations of quinoa flour. The hardness of the fortified spaghetti could be mostly determined by the strength of its gluten network (Ogawa and Adachi, 2017) [11] Springiness and chewiness show increasing values with higher concentrations of quinoa flour. There were no significant differences observed in the values of cohesiveness and resilience. However, the parameters of cohesiveness and springiness provided insights into how well the sample retained its structure during cooking, explaining the higher values observed for the quinoafortified spaghetti compared to the control sample.

Conclusion

The incorporation of quinoa flour into spaghetti formulations significantly improved the nutritional quality by increasing protein, dietary fiber, fat, ash content, and antioxidant properties, while reducing carbohydrate levels.

The enhanced phenolic content and DPPH scavenging activity confirm the potential of quinoa-based spaghetti as a functional food with added health benefits. However, the substitution of wheat flour with quinoa adversely affected cooking quality and structural properties, as evidenced by increased cooking loss and reduced water absorption and swelling capacity, primarily due to the absence of gluten.Color and textural characteristics were also altered, with quinoa-enriched samples exhibiting darker appearance and modified texture profiles. Despite these changes, the improved nutritional and functional benefits outweigh the minor compromises in cooking and sensory attributes. Therefore, quinoa-fortified spaghetti can be considered a promising alternative for developing nutrient-rich, functional food products that support health and sustainability goals.

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