Effect of Spirulina platensis enrichment on the physicochemical and sensory properties of pasta

Abstract

Spirulina platensis is a potential alternative food ingredient due to its bioactive compounds, nutritional composition, and a sustainable protein source. This study evaluated the effects of adding S. platensis powder (0, 0.5, 0.75, 1, 3, and 5%) to pasta on cooking properties, color, hardness and sensory assessment. The results showed that hardness decreased from 7.59 ± 0.14 N (control) to 4.58 ± 0.12 N (5% Spirulina powder). Cooking loss slightly improved from 6.88 ± 0.3% to 6.73 ± 0.7% and weight gain increased from 70.82 ± 3.1% to 98.28 ± 3.5%. The addition of Spirulina powder to the pasta resulted in a green hue, as indicated by the color measurement. Furthermore, the addition of 0.5, 0.75, and 1% Spirulina powder did not have a significant effect on the scores assigned to adhesiveness, firmness, aroma, taste, and color, but higher levels of Spirulina powder decreased the mentioned parameters. These results indicated that S. platensis powder was a suitable ingredient to enhance the nutritional value of pasta, by improving its cooking and texture properties, with an acceptable sensory properties.

Introduction

Pasta is a food product with a long historical tradition, typically produced with durum wheat semolina. It is widely consumed for several reasons, including its palatability, ease of transportation, long shelf life, low glycemic index, low cost, high digestibility, and ease of preparation¹. Durum wheat semolina is employed in the production of premium pasta, and it is coarser and exhibits a darker (more golden) hue compared to other wheat flours due to its elevated carotenoid content². Nevertheless, simple pasta products are unable to provide all the nutritional requirements of humans in isolation.

There is currently considerable interest in improving the nutritional value of pasta, particularly its protein and fiber content¹. Furthermore, consumers expect to be satisfied while providing their bodies with essential nutrients. They are also encouraged to adopt dietary habits that can help prevent nutrition-related diseases and improve their physical and mental well-being³. The growing popularity of pasta among consumers has the potential to drive the production of functional foods⁴. Recently, there has been a trend of incorporating various healthy ingredients into pasta production to enhance its nutritional profile or functional properties⁵. However, the quantity of raw material that can be used as a substitute for or combined with wheat flour must strike a balance between the enhancing nutritional value and achieving pasta with satisfactory sensory properties⁶.

Microalgae contain a variety of bioactive compounds with proven antioxidant properties, such as phycobiliproteins, carotenoids, and phenolic compounds⁷. Therefore, it is reasonable to deduce that microalgae have the potential to be used as natural sources of antioxidants. Some researchers postulate that microalgae can reduce the risk of cancer due to their antioxidant content⁸. Arthrospira platensis (commonly known as Spirulina) is a valuable source of bioactive compounds and serves as a pigment agent. Spirulina is a biomass of cyanobacteria (blue-green algae) that can be consumed by humans and other animals⁹. Due to its high nutritional value, S. platensis can be classified as a superfood. Its high phytonutrient content may make it a potential alternative to vitamin supplements¹⁰. It is renowned for its high protein content, and polyunsaturated fatty acids, such as linoleic acid and gamma-linolenic acid, as well as its polyphenols, carotenoids, essential amino acids, tocopherols, antioxidants, and phycocyanin¹¹. The protein content of Spirulina surpasses that of typical plant and animal protein sources, including soybeans (35%), peanuts (25%), cereals (8–14%), meat and fish (15–25%), eggs (12%), milk powder (35%), and whole milk (3%)¹². Spirulina contains all nine essential amino acids, as well as other amino acids and therefore, is a valuable source of both essential and non-essential amino acids, with the potential to enhance foods that have low protein content¹³. Spirulina also includes calcium, vitamins A, B12, B6, B2, H and K, as well as all essential minerals and enzymes, surpassing other food ingredients⁴. Furthermore, Spirulina is characterized by its green-blue color, which consumers in this product category, namely pasta, perceive positively. It is also a sustainable source of macronutrients and micronutrients and can be consumed by those following a vegan or vegetarian diet¹⁴. The antioxidant substances found in Spirulina consist of polyunsaturated fatty acids, phycocyanin, phenolics, and β-carotene, which is approximately 30 times more concentrated than in carrots. These elements are thought to contribute to the therapeutic benefits of Spirulina. The primary carotenoids present in Spirulina include β-carotene, canthaxanthin, astaxanthin, lutein, and zeaxanthin¹².

The environmental sustainability associated with Spirulina farming is another key factor. Spirulina requires fewer resources such as land, water, and energy in comparison to conventional livestock farming, and it produces reduced greenhouse gas emissions. This positions it as an environmentally friendly option that can lessen the ecological impact of food production, attracting environmentally aware consumers and businesses¹⁵.

Numerous researchers have documented the health-promoting effects of Spirulina, including its ability to alleviate immune system deficiencies, hyperlipidemia, hypertension, and cardiovascular, inflammatory infectious, metabolic, and cancereous diseases as well as pernicious anemia^9,16. Spirulina is also often used as an adjuvant therapy or as a complement to synthetic pharmaceutical treatments¹⁷. As a supplement, Spirulina can greatly lower the risk of many diseases due to its anti-inflammatory, antiviral, anticarcinogenic, and antioxidant properties¹⁸. In recent years, the medicinal and functional food properties of Spirulina have attracted increased interest from consumers.

Given the potential for more sustainable and high-protein materials, there is considerable scope for enriching pasta with Spirulina. This is due to the simplicity of the manufacturing process, its nutritional value, the low cost, and the high level of acceptance, including its green color¹⁹. Several studies have examined incorporating of the incorporation of S. platensis have been carried out with a view to incorporating this biomass into pasta^2,4,14,19,20. One such study demonstrated that incorporating microalgae biomass, specifically Arthrospira platensis, into fresh pasta produced an appealing and novel product. Furthermore, this addition significantly improved the pasta’s nutritional quality without affecting its cooking or texture properties, as evaluated through sensory analysis²¹. Rodríguez De Marco et al.¹⁶ incorporated Spirulina biomass into fresh pasta, improving its nutritional composition without affecting sensory, textural, or cooking quality. Additionally, S. platensis has the potential to be utilized as an ingredient in producing commercial unconventional dry pasta, as demonstrated by²². This approach has been shown to result in pasta products with acceptable sensory and technological characteristics. The main challenge of adding S. platensis to pasta is its significant negative impact on the sensory qualities. Considering current trends, the objective of this study was to produce an enriched pasta from durum semolina with various levels of S. platensis powder to determine the optimal amount of this microalgae for enhancing sensory properties. This study evaluated the effect of adding Spirulina on pasta quality parameters, such as cooking properties, hardness, color, and sensory properties. This study provided new insight into producing enriched pasta with S. platensis and improving its nutritional value.

Materials and methods

Materials

Semolina wheat flour was purchased from the Zar Macaron Company (Karaj, Iran). Salt was obtained from a local market. S. platensis microalgae powder was obtained from the Parsian microalgae company in Rasht, Iran. All other chemicals used in this study were of analytical grade and were purchased from Merck (Darmstadt, Germany).

Preparation of pasta samples

According to Table 1, semolina flour for pasta preparation was partially substituted with S. platensis powder. Pasta made without Spirulina powder was considered as the control (C). After mixing the semolina flour and Spirulina powder, 36% (w/w) distilled water and 0.5% (w/w) salt were added to the flour mixture and kneased for 10 min at 120 rpm using a mixer (Dierks and Sohne, Osnabrück, Germany). The dough underwent to a 20-min kneading process at 120 rpm, using a dough hook. Then the dough was extruded through an extruder (Anselmo, Italy) at 120 mmHg and 45 °C. The extruded pasta strands were subjected to two stages of drying. First, they were dried at a low temperature (50 °C, 55% relative humidity) for two hours. Then, they were dried at high temperature (75 °C, 25% relative humidity) for three hours. This process was undertaken to achieve a final moisture content of 10%. The dried pasta was stored in oriented polypropylene at 25 °C until needed²³.

Table 1.

Recipe ingredients of studied pastas (% content).

TreatmentsA	Semolina flour	Spirulina powder	Water	Salt
C	63.5	0	36	0.5
T1	63	0.5	36	0.5
T2	62.75	0.75	36	0.5
T3	62.5	1	36	0.5
T4	60.5	3	36	0.5
T5	58.5	5	36	0.5

^A Semolina flour for pasta preparation was partially substituted by Spirulina platensis microalgae powder.

Moisture, ash, and protein determination

The protein content of semolina wheat flour and Spirulina powder was analyzed using the Kjeldhal method with correction factors of 5.7 and 5.95, respectively, based on AACC method 46-11.02.02²⁴. One gram of each sample was placed in a Kaldal digestion flask. Then, 20 mL of concentrated sulfuric acid and one catalyst tablet (containing 96% sodium sulfate, 3.5% copper sulfate, 0.5% selenium dioxide) were added. A flask containing acid and catalyst but no sample was used as a control sample. Digestion continued for 140 min until the digestion solution cleared, indicating the breakdown of all organic compounds was complete. After cooling releasing the acid vapors, distillation step was performed using 32% sodium hydroxide and 2% boric acid. In the final titration step, the borate anion, proportional to the nitrogen content of the sample, was titrated with 0.1 normal hydrochloric acid in the presence of methyl red reagent. To obtain the protein percentage, the nitrogen percentage of the samples was multiplied by the sample’s correction factor, and the protein amount was expressed in terms of dry matter.

The moisture content of flour and Spirulina powder was determined using the drying method according to the AACC standard method 44-15.02.02²⁵. Briefly, 5 g of each sample was weighed and placed in a small metal dish; the weight was then recorded. The sample was then baked on an oven shelf at 100 °C for 24 h. Afterwards, the sample was cooled in a designated glass container to prevent moisture changes during cooling. Finally, the sample and its container were weighed again. The moisture content was expressed as a percentage.

The ash content was determined based on the AACC method 08-01.01.01²⁶. Place a 2-gram wet sample in a porcelain crucible and dry it in an oven at 60–105 °C for 8 h. Then, burn the dried sample on a hot plate until it produces no smoke, which takes approximately 20 min. Finally, ash the sample in a furnace at 600 °C for three hours and then weigh it.

% Ash Content = (ash weight/Sample weight) x 100.

Color measurement of pasta

The color values of the uncooked pasta samples were determined in triplicate using a Hunter Lab colorimeter (UltraScan PRO, Hunter Laboratory Inc., USA). The results were shown according to CIELAB system colour parameters (L*, a* and b*), where L* defines lightness-darkness (0 to 100), a* measures the degree of redness (0 to 60) or greenness (0 to −60), and b* the degree of yellowness (0 to 60) or blueness (0 to −60). The colorimeter was calibrated using a white standard plate (L* = 94.72, a* = −0.49, b* = 3.75) under artificial fluorescent light at 20 °C.

Cooking properties

The cooking properties of the pasta, including cooking loss and weight gain, were evaluated according to the AACC (2000) method 16–50 to determine cooking quality²⁷. Twenty-five grams of pasta samples were placed in 500 mL of boiling distilled water. The samples were removed after 15 min (the optimum cooking time), washed, and drained with cold distilled water for 2 min. The optimum cooking time is related to the variety of wheat used in flour production and pasta preparation²⁸. The resulting cooking water was collected in a volumetric flask and evaporated at 105 °C in an oven (Memmert, Germany) until a constant weight was achieved. The dry residue was weighed on an analytical balance. The following equation was to calculate the percentage of cooking loss:

Cooking loss (%) = [(Weight of dried residue)/(Weight of uncooked pasta)] × 100.

The cooked and drained pasta samples were weighed, and the following equation was used for reporting the weight gain of pasta (%):

Weight gain (%) = [(Weight of cooked pasta - Weight of uncooked pasta)/(Weight of uncooked pasta)] × 100.

Hardness evaluation

The hardness of the cooked pasta samples was analyzed using an Instron (Testo-metric, Japan) in accordance with the AACC (2000) method 41 − 30²⁷. A cutting test was conducted using a 1-mm diameter blade, a 100-N pressing weight, and a 10 mm/min speed. The amount of force required to cut the cooked samples was recorded as the hardness value (N).

Sensory evaluation

The sensory assessment of cooked pasta samples was evaluated based on their adhesiveness, firmness, aroma, taste, and color²³. The study involved human participants in the sensory analysis, and the authors state that the research was conducted ethically and approved by the institutional research ethics committee at the National Nutrition and Food Technology Research Institute. Before starting the sensory evaluation in research, we explained the methods and goals of the study to the assessors (1). We also obtained their approval (2), highlighting the importance of respecting participants’ autonomy and their right to withdraw at any time without facing negative consequences (3)^29,30.

The pasta samples were cooked in distilled water for 10 min. After 2 min of draining, the samples were served to the fifteen trained panelists. The pasta samples were assigned three-digit codes and served in a randomized order. Deionized water was provided between samples for mouth cleansing. Each panelist conducted the analysis individually, and sequentially under incandescent lighting within a laboratory setting. Panelists evaluated each sensory characteristic using a five-point hedonic scale, ranging from five (indicating a high level of liking) to one (indicating a high level of dislike). These evaluations will provide an estimation of the general consumer acceptance of the newly developed pasta, compared to a control pasta without Spirulina.

Statistical analysis

The investigations and sample analysis were carried out at least in triplicate. The results are presented as the mean ± standard deviation. An analysis of variance (ANOVA) was conducted, and the data were analyzed using Duncan’s test with the SPSS software (SPSS Institute, Cary, NC, USA). A 5% level of statistical significance was employed (P < 0.05).

Results and discussion

Chemical composition of semolina flour and Spirulina powder

Semolina flour showed a moisture content of 10.6% (under the 15% limit for microbial stability) and 0.68% ash, falling within the 0.4–2.0.4.0% wheat flour standard. S. platensis powder contained 9.9% moisture and significantly higher ash content (5.85%). Other studies reprted ash content of 7.9%³¹, 5.93%¹⁴, 13.11%⁶ and 13.65%³ for Spirulina. The protein content of the semolina flour used in this study was found to be 13.20%, which is consistent with other researchers’ findings¹⁴. Spirulina powder has an exceptionally high protein concentration of 55.14%, making it one of the most protein-rich plant-based materials. In our study, S. platensis powder was superior to the Spirulina used by El-Hameed et al.⁶ for spaghetti preparation; the latter contained 53.92% crude protein. Other studies have also reported high level of protein in Spirulina powder as 71.34%¹⁴ and 68.9%²¹ as well as 73.47% in fresh Spirulina biomass³². According to the FAO and WHO, Spirulina has the highest protein content due to its high essential amino acid content³³. Enriching wheat flour with Spirulina increases the chemical composition profile of the prepared pasta, including the ash and protein content. Therefore, the pasta prepared in this study can be considered a functional food source of protein. Studies have demonstrated that incorporating Spirulina into pasta products at levels between 2.5% and 10% enhances the protein and mineral content³.

Color of uncooked pasta

Color is a principal criterion for evaluating pasta and significantly influences the initial impression formed by consumers. Enriching pasta with a plant results in various color changes²⁸. According to the literature, these changes are not always accepted by consumers, who may reject them despite their increased nutritional value and associated health benefits³⁴. Nevertheless, the positive impact on consumers has led to increased interest in colored pasta products in recent years. This solution may not be applicable in other countries or cultures, however, due to differing consumer preferences³⁵. Nevertheless, given the growing resistance to synthetic colorants in food products, natural colorants are an appealing alternative because they are widely accepted by consumers, are perceived as safe, and lack a chemical composition⁴.

The results of the color measurements of raw pasta samples with varying Spirulina content are presented in Table 2. Increasing the Spirulina powder content in pasta samples significantly decreased the lightness (from 74.34 ± 0.1 to 44.79 ± 0.5, P < 0.05). Incorporating Spirulina resulted in a notable reduction in the b* color parameter (P < 0.05) (from 28.56 ± 0.2 to 5.78 ± 0.4). According to the results, adding Spirulina powder to the pasta samples produced an appealing green hue, likely due to the presence of chlorophyll in the powder. Increasing the amount of Spirulina in the pasta samples changed the product’s color from pale green to dark green (from − 1.79 ± 0.1 to −5.42 ± 0.2). The control sample (semolina pasta) showed the highest yellowness (29.45 ± 0.4), which can be attributed to the increased yellow pigment content in the semolina caused by β-carotenoid pigments.

Table 2.

Color analysis of pasta samples enriched with different levels of Spirulina platensis.

Treatment A	L*	a*	b*
C	75.51 ± 0.2a	−1.72 ± 0.3a	29.45 ± 0.4a
T1	74.34 ± 0.1a	−1.79 ± 0.1a	28.56 ± 0.2a
T2	72.50 ± 0.3ab	−1.86 ± 0.2a	26.84 ± 0.3ab
T3	69.15 ± 0.2b	−1.95 ± 0.1a	25.24 ± 0.5b
T4	56.28 ± 0.4c	−4.67 ± 0.3b	15.65 ± 0.2c
T5	44.79 ± 0.5d	−5.42 ± 0.2c	5.78 ± 0.4d

^A For treatment descriptions see Table 1.

Data are expressed as mean values. Values in the columns followed by different lowercase letters are significantly different (p < 0.05).

In recent years, various colored pasta products have been created using vegetable ingredients such as spinach, tomatoes, carrots, and beetroots. Developing vibrant and stable colors is a key innovation for these products. Microalgae offer a sustainable alternative to synthetic dyes as natural coloring agents, producing pasta similar to vegetable-based pasta and providing nutritional benefits³⁶. Similar results were found by Özyurt et al.⁴, Hussein et al.³, and Padalino et al.³⁷ for pasta enriched with microalgae. They claimed that Spirulinain pasta offered an attractive green hue. Messia et al.³⁸ also fortified pasta with Spirulina, pea protein isolate, and whey proteins. They concluded that adding Spirulina to pasta resulted in an eye-catching color. However, Raczyk et al.¹⁴ demonstrated that adding Spirulina to pasta negatively affected its color. Similarly, Ersyah et al.³⁹ reported that the color of noodles enriched with Spirulina was acceptable up to 5% and increasing the concentration decreased the acceptability as the color of noodles became darker. The high concentration of natural pigments, including chlorophylls, carotenoids, and C-phycocyanin, within S. platensis significantly affected the color of the pasta, resulting in increased color difference values.

Cooking properties of pasta

Empirical measurements such as cooking loss and weight gain are cooking quality parameters commonly used to provide important insights into pasta quality during cooking. Cooking loss is the total amount of solid matter that dissolves in the cooking water due to leaching from the pasta²⁸. Reducing cooking loss can help prevent nutrient loss⁴⁰. Elevated cooking loss indicates a reduction in gluten strength and a decrease in connectivity within the pasta structure. This phenomenon may be attributed to the leaching of starch and the partial dissolution of proteins, which occur as a result of gluten network disruption²³. Bustos⁴¹ highlighted that high-quality pasta depends on forming a continuous gluten network that traps starch granules, thereby limiting their swelling and leaching into the cooking water. This results in pasta with low water absorption, minimal cooking loss, and a reduced swelling index. However, producing pasta with unconventional ingredients like Spirulina is difficult because these ingredients dilute the gluten protein network¹⁴.

Table 3 shows the effect of Spirulina incorporation on pasta cooking quality. As shown, increasing the Spirulina content decreased the cooking loss of the pasta samples. This decrease could be due to the strengthening of the dough matrix by algae proteins, which trap starch in the created network. Spirulina polysaccharides increase water absorption into the gelatinized matrix structure of pasta during cooking, thereby reducing cooking loss. However, no significant differences in cooking loss were observed among the pasta samples (P < 0.05), indicating that adding Spirulina at these levels did not affect cooking loss. This result was in agreement with the findings of Hussein et al.³ and El-Baz et al.⁴². Ersyah et al.³⁹ also reported that the decrease in cooking losses and the increase in Spirulina concentration (6.5%) in dry noodles were due to the interaction between protein and starch. In contrast, Koli et al.³¹ reported that cooking loss increased from 4.13% in the control sample to 6.66% in pasta containing 12.5% (w/w) Spirulina. This increase was attributed to steric hindrance in the gluten-protein network, which is responsible for the product’s physical integrity during cooking. Raczyk et al.¹⁴ indicated that pasta with 3% Spirulina had the lowest cooking loss, and pasta with 10% Spirulina had the highest cooking loss (12%). This could be due to the combined effects of protein solubilization and the removal of the protein fraction, which weakens the gluten matrix. Zen et al.²⁸ and de Rijdt et al.³² reported that Spirulina did not affect pasta cooking loss. The authors observed that the cooking water thickens due to the partial leaching of soluble starch and other soluble ingredients, including non-starch polysaccharides, into the water during the cooking.

Table 3.

Cooking loss, weight gain, and hardness of pasta samples enriched with different levels of Spirulina platensis.

Treatment A	Cooking loss (%)	Weight gain (%)	Hardness (N)
C	6.88 ± 0.3a	70.82 ± 3.1e	7.59 ± 0.14a
T1	6.82 ± 0.5a	72.98 ± 2.5de	7.55 ± 0.10a
T2	6.80 ± 0.6a	75.74 ± 4.2cd	6.79 ± 0.13ab
T3	6.79 ± 0.2a	78.45 ± 5.6c	6.22 ± 0.11b
T4	6.76 ± 0.4a	91.58 ± 2.9b	5.46 ± 0.16c
T5	6.73 ± 0.7a	98.28 ± 3.5a	4.58 ± 0.12d

^A For treatment descriptions see Table 1.

Data are expressed as mean values. Values in the columns followed by different lowercase letters are significantly different (p < 0.05).

The weight gain observed in pasta during cooking is influenced by the quantity and quality of protein, as well as the starch amylose content. Gluten plays a key role in forming an internal network that retains the components of pasta²⁸. A compact protein structure traps starch granules, resulting in increased pasta weight after cooking. This structure also prevents the pasta from breaking apart on the surface²³. Adding Spirulina to semolina flour has been observed to enhance the resulting pasta samples’ water absorption capacity and increase their weight after cooking (Table 3). This may be due to Spirulina polysaccharides increasing water absorption and transferring it to the pasta’s protein-starch structure. These results are consistent with those of Koli et al.²⁹, who examined the nutritional and cooking quality of pasta fortified with Spirulina powder at doses ranging from 2.5% to 15%. Fragoso⁴³ also stated that the addition of microalgae biomass affected water absorption (P< 0.05), increasing it from 42.8% in control pasta to 54.9–64.5% in microalgae pasta. Similarly, Prabhasankar et al.⁴⁴ and Fradique et al.⁴⁵ reported that the higher weight of Spirulina-enriched pasta increased in weight upon cooking due to the starch’s high hydration, resulting in a weaker protein network. According to this study and others^21,31,45, semolina pastas enriched with S. platensis have high cooking quality.

Hardness of cooked pasta

The texture of pasta is an important factor in consumer acceptance and is influenced by various factors, such as the starch matrix network, gluten content, and the type and amount of fiber and proteins in the product³¹. The hardness value of pasta texture is an important parameter for determining pasta quality because it is related to the force required to compress pasta between the teeth⁴⁶. An increasing proportion of Spirulina in the matrix impedes gluten cross-linkages responsible for binding starch-protein complexes together. However, the reduction in firmness should not be so significant that the pasta loses its shape³¹.

Table 3 illustrates the requisite force to cut the pasta samples as the hardness value. In this study, the hardness of the pasta samples decreased as the level of Spirulina powder increased. This is likely due to an increase in protein and fiber content, as well as an increase in water adsorption during production, which decreases product texture hardness by increasing moisture content. Spirulina contains high amounts of protein and fiber, which bond with water molecules to maintain moisture in the product’s texture. Spirulina prokaryotic cells lack a hard cell wall, leading to rapid water absorption by their cell contents, particularly proteins. Additionally, the observed increase in pasta hardness may be attributed to the incorporation of protein-rich components that are likely to considerably influence the reinforcement of the gluten network⁶.

Fradique et al.⁴⁵ demonstrated that adding up to 5% Spirulina reduces bread hardness. Koli et al.³¹ found that pasta made with Spirulina was softer than control. The authors offered an explanation for these results, attributing them to changes gluten-starch structure following Spirulina incorporation. Similarly, Hernández-López et al.⁴⁷ claimed that crackers became less hard as the Spirulina concentration increased, ranging from 80 N at 1.5% to 26 N at 3.5%. Furthermore, Hussein et al.³ concluded that the lower hardness of the enriched pasta was related to its higher moisture content in compared to the control. In contrast, Rodríguez De Marco et al.¹⁶ stated that the addition of Spirulina increases the hardness of uncooked pasta. The authors of the study hypothesized that the increase in hardness was due to the pasta’s higher protein content. Zen et al.²⁸ also reported that control fresh pasta was less firm than pasta with Spirulina. These contradictory results may be due to differences in microalgae species, Spirulina powder particle size, type of semolina used, and gluten content of the flour used to prepare the pasta. High-gluten pasta is harder internally than low-gluten pasta after cooking.

Sensory properties of the cooked pasta

Table 4 illustrates the sensory evaluation scores of pasta samples enriched with different levels of S. platensis. In this study, the control sample was preferred by panelists. However, no significant differences were observed between the control samples and the samples T₁, T₂, and T₃. As the amount of Spirulina powder increased to 3% and 5%, however, all sensory indicators, including adhesiveness, firmness, aroma, taste, and color, decreased in the pasta samples. Spirulina powder interferes with the gluten network formation, resulting in a weaker structure. Gluten molecules cannot be fully hydrated because they compete with Spirulina powder. Additionally, Spirulina may hinder gluten network formation through steric hindrance. Incomplete hydration of starch and gluten likely causes the pasta to become more brittle, resulting in lower firmness. A weak gluten network also allows amylase to more easily diffuse toward the pasta surface³⁷.

Table 4.

Sensory analysis of cooked pasta samples enriched with different levels of Spirulina platensis.

Treatment A	Adhesiveness	Firmness	Aroma	Taste	Color
C	3.5 ± o.4a	3.7 ± 0.2a	3.5 ± 0.4a	3.5 ± 0.3a	3.3 ± 0.2a
T1	3.4 ± 0.3a	3.6 ± 0.3a	3.5 ± 0.2a	3.5 ± 0.2a	3.2 ± 0.4a
T2	3.5 ± 0.5a	3.5 ± 0.5a	3.4 ± 0.2a	3.4 ± 0.3a	3.1 ± 0.3a
T3	3.3 ± 0.3a	3.5 ± 0.4a	3.4 ± 0.5a	3.2 ± 0.4a	3.0 ± 0.2a
T4	2.5 ± 0.2b	2.9 ± 0.4b	3.0 ± 0.4b	2.5 ± 0.5b	2.5 ± 0.4b
T5	2.5 ± 0.4b	2.3 ± 0.3c	2.2 ± 0.5c	2.3 ± 0.3b	2.0 ± 0.5c

^A For treatment descriptions see Table 1.

Data are expressed as mean values. Values in the columns followed by different lowercase letters are significantly different (p < 0.05).

The findings of this study are consistent with those of Raczyk et al.¹⁴, who reported that the pasta with the addition of 3% Spirulina received the lowest scores for color, texture, and overall appearance. El-Hameed et al.⁶ also stated that spaghetti enriched with 1% S. platensis had the highest overall quality score, mainly due to improved resistance to breaking and improved color. However, they claimed that some panelists detected an unusual flavor in the spaghetti samples containing 2% Spirulina. Fradique et al.⁴⁵ demonstrated that incorporating up to 2% (w/w) Spirulina substantially enhances color scores, as evaluated by a panel of experts. Özyurt et al.⁴ reported that all pasta samples containing 0, 5, 10, or 15% Spirulina had a good overall acceptability score, but the samples with 10% Spirulina was the most preferred. A study by Zen et al.²⁸ found that the green color of microalgae negatively impacts consumers’ perception of pasta taste and quality. However, food acceptance depends on several factors, including health concerns, familiarity with food ingredients, and clean food production. The green color of food items may be perceived as a sustainability certification, and can therefore influence consumer perceptions and acceptance of food products. Saharan and Jood⁴⁸ reported that supplemented with 2% or 4% Spirulina powder had the highest organoleptic acceptability. Ersyah et al.³⁹ posited that panel assessments of dry noodle aroma and taste decreased with increasing Spirulina concentrations. This occurred because an increase in Spirulina concentration (6.5%) during cooking resulted in a more pronounced fishy odor emitted by the dry noodles. A total of 54 volatile compounds and 23 volatile carbonyl compounds have been identified in Spirulina. Heptanal and aromatic ketones have been shown to cause undesirable flavors.

A study by Koli et al.^3,19 found that pasta enriched with Spirulinaat concentrations ranging from 2% to 15% had superior appearance, color, and aroma compared to the control sample. Additionally, Mureșan et al.²⁰ demonstrated that incorporating Spirulina into pasta at concentrations of 2% and 5% markedly enhanced its nutritional value and sensory attributes. However, Raczyk et al.¹⁴ found that consumers preferred pasta without Spirulinacompared to enriched samples. Similar findings were reported by Padalino et al.³⁷, who found that incorporating Spirulinainto pasta reduced its overall acceptability due to its textural characteristics, including hardness. In a separate study, Fradinho et al.²¹ found that the sensory evaluation of gluten-free pasta fortified with Spirulina was more favorable than that of wheat and rice pasta. These discrepancies may be due to variations in Spirulina concentrations, species, and the chemical composition of the raw materials^{22,24–26,29,30,38,39,42,44,47}.

Conclusion

This study indicated that adding S. platensis powder to semolina pasta increased its nutritional value, particularly its protein content and improved cooking qualities, such as weight gain and decreasing hardnress for a better texture. However, obtaining a fortified pasta product of acceptable quality is often challenging, and the proportion of individual additives must be precisely determined according to consumer preferences. This study demonstrated that consumers preferred pasta with an enhanced nutritional profile. The findings suggested that integrating Spirulina powder did not hinder the development of novel food products and did not negatively impact acceptability due to its greenish hue and unpleasant odor. However, based on the sensory analysis findings, future research should focus on enhancing pasta’s sensory attributes by incorporating Spirulina powder at a higher level (> 1%) to provide enhanced nutritional value while ensuring consumer acceptance. Additionally, the bioactive compounds, antioxidant activity, essential minerals and amino acid profile in Spirulina -fortified pasta should be identified to clarify the nutritional enhancement and health benefits of Spirulina as a food enrichment ingredient. Fourier transform infrared spectroscopy (FTIR) analysis would be useful for identifying possible structural or molecular interactions between S. platensis components and the pasta matrix. While the enrichment with S. platensis significantly elevated total protein levels, future research should utilize in vitro or in vivo digestibility assessments to validate nutritional improvements. In light of these findings, Spirulina-enriched pasta shows significant potential for the industry to develop functional products.

Author contributions

P.Sh.: Writing, Methodology, Formal analysis, Investigation.F.F.: Writing, Validation, Project administration, Methodology.A.Z.: Writing, Review & editing, Investigation, Data curation. N.Kh.: Review & editing, Validation, Investigation. M.M.: Supervision, Investigation, Conceptualization, Review & editing.

Data availability

Data is provided within the manuscript.

Declarations

Competing interests

The authors declare no competing interests.