A total of 30 S. nudus specimens were collected in January 2024 using a purposive sampling method based on species presence. The sampling locations were two sites in coastal areas, namely Langara Tanjung Batu Village and Baho Bubu Village in the Konawe Islands Regency, Southeast Sulawesi Province, Indonesia. Langara Tanjung Batu Village was selected because it has a sandy-muddy substrate suitable for the burrowing behavior of S. nudus, while Baho Bubu Village was chosen because it represents an intertidal zone with high organic matter content, thereby supporting the availability of food sources for the species. Thus, the two locations together represent the natural habitat of S. nudus. Specimens were collected at low tide using a serampang, in accordance with the sampling procedure described by Nurhikma et al. (2017). Immediately following collection, the samples were transported to the laboratory under cool, oxygenated conditions to minimize stress and mortality. All individuals were thoroughly rinsed under running tap water to remove residual sediment, epibionts, and other external debris. Following cleaning, morphometric and yield analyses were performed on each specimen.

Samples of live and fresh peanut worms were prepared by immersion in ice water for 10-15 min to induce a state of immobility. The worm’s trunk (flesh), water content, and viscera were separated and cleaned with running water, according to the method described by Nurhikma et al. (2017). Some samples were sun-dried, around weather with temperatures of 27-37oC for two days, about 8 hours per day (Imbir et al., 2015). The fresh and dried peanut worm samples were then subjected to proximate analysis (water, ash, protein, fat, and carbohydrate content), mineral analysis, and fatty acid and phytochemical profiling.

Morphometric measurements of S. nudus were conducted following the methodology described by Ferdinandus et al. (2022), as follows. Each S. nudus specimen was measured for total body length (cm), body diameter (cm), and total body weight (g). Body length and diameter were measured to the nearest millimeter using a ruler, and body weight was determined using a digital analytical balance.

Yield analysis was performed by calculating the percentage ratio between the final component weight and the initial total body weight of each S. nudus specimen, following the standard procedures outlined by Nurhikma et al. (2017). This approach enables a quantitative assessment of the meat, viscera, and water content relative to the total mass of the organism. The yield (%) was calculated using the following formula:

The proximate analysis in this study was performed according to the modified AOAC (2005) method, which includes water, ash, protein, and fat. Moisture and ash contents were analyzed using an oven and furnace, respectively. Protein and fat contents were analyzed using the Kjeldahl and Soxhlet methods, respectively, while carbohydrates were tested using the diference method.

The analysis of calcium (Ca), potassium (K), sodium (Na), magnesium (Mg), and phosphorus (P) was performed using an atomic absorption spectrophotometer (AAS) in this study, referring to the method by modified AOAC (2005). The mineral content was determined using atomic absorption spectroscopy (AAS). Samples (approximately 1-2 g) were first dried, crushed, and transferred into a beaker that had been cleaned with 1 N HCl. Following the addition of 25 mL of 1 N HCl, the mixture was agitated on a shaker for 24 hours. The resulting extract was filtered through a Whatman No. 1 filter paper. A 1 mL aliquot of the filtrate was transferred to a volumetric flask, combined with 2 mL of lanthanum oxide solution and 1 N HCl to a volume of 10 mL, and then diluted with distilled water to a total volume of 50 mL. The absorbance was measured using AAS at specific wavelengths for each element: 422.7 nm (Ca), 766.5 nm (K), 213.9 nm (Na), 285.2 nm (Mg), and 248.3 nm (P).

Fatty acid analysis was conducted using gas chromatography, as described by the modified AOAC (2005) method. Samples were prepared via solvent extraction using a Soxhlet apparatus, yielding 0.02 g of liquid fat. Separately, a methanolic NaOH solution (5 mL) was prepared and heated at for 20 min before cooling to room temperature. This solution was added to the liquid fat sample and heated at for an additional 20 min. Subsequently, 2 mL of saturated NaCl and 5 mL of hexane were added and homogenized; the resulting hexane layer was then transferred to a reaction tube containing the pre-heated sample, and an aliquot of 2-5 μL was injected into a gas chromatograph (GC) equipped with a flame ionization detector (FID). The GC was operated under the following conditions: the column used was a Pico-Tag (3.9×300 mm) with a diethyl glycol succinate (DEGS) stationary phase and nitrogen as the mobile phase. The oven temperature was programmed with an initial temperature of increasing at a rate of to a final temperature of while the detector was maintained at . The flow rates of and were set at 2.5 kgf/cm2 and 50 kgf/ , respectively, with a pressure of 3,000 psi. Fatty acids were identified based on the FID response recorded in the chromatogram. The quantitative measurement of fatty acids was calculated using the following formula:

A = Sample concentration

B = Solvent concentration

Data obtained from the proximate composition (moisture, ash, protein, fat, and carbohydrate content), mineral composition (Ca, K, Mg, Na, and P), and fatty acid content of fresh and sun-dried S. nudus were determined in triplicates. The resulting data were statistically compared between the two treatment groups using an independent samples t-test. Statistical analyses were performed using IBM SPSS Statistics version 26.0, and diferences were regarded as statistically significant at p<0.05.

Morphometrics is a morphological measurement method using standardized body morphology adapted to the life phase of the pea worm S. nudus to measure length, weight, and physical scale (Figure 1). Morphological systematics of animals is determined by morphological measurements such as length and weight; therefore, it has valid evidence and is the easiest to identify (Gonzalez-Martinez et al., 2020; Labidi et al., 2021; Bhatkar et al., 2025; Currie et al., 2025). Morphometric observations of S. nudus peanut worm include measurements of total length, total weight, meat weight, viscera weight, water weight and yield (meat, viscera and water). The results of the morphometric observations and yield of peanut worms are presented in Table 1.

The morphometric measurements of S. nudus specimens in the present study yielded mean values of 12.36 cm in length, 2.97 cm in diameter, and 46.40 g total body weight. These findings indicate larger dimensions than those reported by Silaban (2018), who recorded average values of 10.04 cm in length, 1.81 cm in diameter, and 25.84 g in body weight for the same species. In contrast, when compared with the morphometric data from Nurhikma et al. (2017) on a diferent species, S. australe, our specimens were found to be shorter in length (17.07 cm) and lighter in body weight (49.77 g). However, they exhibited a greater body diameter than S. australe, which averaged 1.47 cm. These inter-study variations suggest that morphometric traits, such as length, diameter, and body mass, in peanut worms are influenced by a range of biological and ecological factors.

Growth in S. nudus, as with many marine invertebrates, is likely governed by both intrinsic species characteristics and extrinsic environmental conditions. Body length and diameter were closely correlated with body mass, indicating that morphometric parameters are reliable indicators of growth status. The growth dynamics of peanut worms appear to be analogous to those observed in teleost fish. Mounir et al. (2017), Dubuc et al. (2024), and Yang et al. (2024) outlined that fish growth rates are regulated by a combination of age, species, nutrition, physiological conditions, climatic factors, and genetic predispositions, all of which interact to influence the overall growth trajectory. Environmental conditions also play a pivotal role in shaping the morphometric outcomes. According to Marzouk et al. (2016), López-Rocha et al. (2018), and Maiorova and Adrianov (2018), variables such as salinity, habitat suitability, and availability of nutrientrich particulate matter significantly influence the growth of benthic marine invertebrates.

Yield, commonly expressed as a percentage, reflects the proportion of usable products derived from a given amount of raw material. It is a critical parameter for evaluating material eficiency, particularly in food processing and product development. In the present study, the yield analysis of S. nudus collected from Southeast Sulawesi revealed a composition of 34.62% edible meat, 18.33% ofal, and 47.03% water. These results indicate that water comprises the largest component of the organism by weight, exceeding the combined weights of meat and ofal. This finding is consistent with the existing literature, which consistently reports that peanut worms and related species exhibit high moisture content. For example, Cutler (1994) and Goto et al. (2016) noted that water typically accounts for 60% to 80% of the total body mass in similar marine invertebrates. The high-water content observed in S. nudus is not merely a compositional trait but also reflects its physiological importance. Water plays an essential role in maintaining osmotic balance, supporting metabolic processes, and preserving the structural integrity of organisms.

Nurhikma et al. (2017) reported that the yield of Siphonosoma australe collected from the coastal waters of Toronipa, Southeast Sulawesi, consisted of 67.25% meat and 32.39% of ofal. These data demonstrate that the proportion of edible meat significantly exceeds that of ofal, a pattern consistent with the yield composition observed in S. nudus specimens obtained from the waters of Konawe Kepulauan Regency. The comparability of the yield profiles between these two species suggests a potentially similar anatomical or ecological adaptation that favors higher meat content.

The rapid growth characteristics of juvenile peanut worms may also contribute to yield variability. According to Wati et al. (2021), S. nudus individuals aged between 0.08 and 2.50 months exhibit accelerated growth, with the most rapid increase in body length occurring at approximately 0.16 months of age. At this stage, worms reach an average length of 124.701 mm, suggesting a corresponding increase in biomass, including meat mass. This growth pattern may be influenced by their deposit-feeding behavior, which enables them to accumulate substantial quantities of organic matter and sedimentary particles within their bodies, thus supporting growth and nutrient assimilation.

Environmental conditions, particularly sediment dynamics, play a critical role in the growth and yield potential of these organisms. Huang et al. (2023) and Liu et al. (2023) observed that elevated hydrodynamic flow rates contribute to the aggregation of larger sand and mud particles, thereby enhancing food particle availability for deposit feeders, such as peanut worms. Increased food availability positively influences somatic growth, which subsequently afects the overall size, length, and meat yield of these marine invertebrates.

The proximate composition of fresh and sun-dried S. nudus was evaluated by determining the moisture, ash, protein, fat, and carbohydrate contents. Statistical analysis using an independent samples t-test revealed significant diferences in moisture, ash, protein, lipid, and carbohydrate contents between the two treatments (p<0.05). The proximate composition of fresh and sun-dried peanut worms is presented in Table 2.

The average water content of peanut worms was 79.01% (fresh) and 11.32% (sundried), as presented in Table 2. As Avila et al. (2022) explained, drying causes the release of water molecules from the product, thereby reducing the water content. Tapotubun (2018) stated that the drying process using sunlight tends to be slower because of the non-constant air temperature. The longer the drying process, the lower the water content trace and the higher the other chemical composition. Janetti and Janssen (2020) and Babiker et al. (2024) stated that the longer the drying time, the slower the moisture loss rate, but with much less water content remaining in the material. Tenyang et al. (2020) and Chibuezeh et al. (2022) observed that the loss of moisture content contributes to an increase in the relative concentrations of nutritional components, particularly ash, protein, and fat. Furthermore, Zhang et al. (2017) noted that the drying process significantly influences the nutrient profiles of materials. While an optimized drying process enhances nutrient stability by inhibiting enzymatic and microbial activities, improper methods, such as over-drying or high-temperature exposure, may lead to the degradation of heat-sensitive compounds, including specific amino acids and unsaturated fatty acids, thereby reducing the overall nutritional value of the product.

The moisture content of fresh S. nudus samples observed in the present study was comparatively higher than the values reported by Rahayu et al. (2019), who recorded a moisture content of 9.59% in fresh S. australe from the Wakatobi coastal region. Similarly, the values exceeded those reported by Fakhrurrozi (2011) for Xenisiphon sp. collected from the waters of Bangka Belitung, which had a recorded moisture content of 76.47% in fresh samples. Conversely, the moisture content of both fresh and dried peanut worms in this study was lower than that reported in several previously published studies. For instance, Salawati et al. (2024) reported a moisture content of 82.00% in fresh S. nudus specimens from North Minahasa, while Silaban and Rieuwpassa (2019) recorded 22.25% moisture content in dried peanut worms from Nusalaut. Likewise, Nurhikma et al. (2017) reported 82.25% moisture in fresh and 13.69% in freezedried S. australe collected from Konawe water. In a related study, Erliani (2021) found that fresh S. robustus specimens from Banda Naira contained 79.87% moisture content.

Variations in moisture content among species samples are attributed to diferences in habitat, environmental conditions, speciesspecific characteristics, and the drying mechanisms employed. Furthermore, Fitri et al. (2022) noted that the age at harvest plays a significant role, as younger organisms typically exhibit higher water content owing to elevated metabolic activity and greater tissue hydration compared to older individuals. However, this pattern may vary across species, and environmental conditions remain the predominant influencing factors. Binalshikh-Abubkr et al. (2021) stated that the diferences in the moisture content of marine biota are caused by the type and age of the biota, diferences in environmental conditions (such as temperature, pH of dissolved oxygen, salinity, and seasons), and the metabolism of the biota.

Fresh peanut worms had 1.74% ash content, whereas dried ones had 7.34% ash content (Table 2). The increase in ash content is thought to be caused by drying, which Hossain et al. (2017) and Majumdar et al. (2017) mentioned was due to significant water evaporation from the dried material. The drying process of a material increases the calculated ash content, which is influenced by the type of material, ashing, and drying method (including time and temperature).

The ash content of fresh S. nudus specimens in the present study was higher than the values reported by Salawati et al. (2024), who found 0.74% ash content in the same species from North Minahasa waters, and Rahayu et al. (2019), who reported 0.64% ash content in fresh S. australe from Wakatobi. In contrast, the ash content observed in both fresh and dried samples in this study was lower than that reported in several other studies. Nurhikma et al. (2017) recorded ash contents of 3.03% in fresh and 15.08% in freeze-dried S. australe from Konawe, Indonesia. Similarly, Silaban & Rieuwpassa (2019) reported 27.85% ash in dried S. nudus from Nusalaut. More extreme values were noted by Erliani (2021), who documented an ash content of 82.00% in fresh S. robustus from Banda Naira, and by Fakhrurrozi (2011), who found 79.87% in fresh Xenisiphon sp. from Bangka, Belitung. The diference in ash content in peanut worms is thought to be due to the diference in the type and nutritional habitat of their food. This is aligned with studies by Erniati et al. (2023) and Zhong et al. (2024), who stated that diferences in habitat, eating habits, geographic characteristics, or environmental substrate influence ash content.

The protein content of peanut worms is an important aspect of their nutritional value, recorded at 17.83% in fresh and 80.32% in sun-dried samples (Table 2). The increase in protein content in the dried samples does not indicate an absolute increase in protein content but rather a concentration efect due to the decrease in water content during the drying process. The loss of water content causes a higher proportion of dry matter components, including proteins, to be present in the total sample weight. Therefore, the percentage of protein measured in the dried samples increases as the water content decreases (Öztürk & Gündüz, 2018; Fitri et al., 2024). The high protein content is related to the eating habits of peanut worms, which consume sediment rich in organic matter as the main source of nutrients in their habitat. This finding is consistent with that of Leiwakabessy et al. (2017), who noted that proteins, carbohydrates, and fats are organic materials deposited in sediments and consumed by peanut worms, contributing to their high protein content.

The protein content of both fresh and dried S. nudus observed in the present study was higher than that reported in several previous studies across various regions in Indonesia. For example, S. nudus from North Minahasa waters exhibited a protein content of 12.80% in fresh samples (Salawati et al., 2024), whereas dried specimens from Nusalaut waters had 48.15% protein (Silaban & Rieuwpassa, 2019). Similarly, S. australe from Konawe waters contained 10.11% protein in fresh form and 56.35% when freeze-dried (Nurhikma et al.,2017). Other comparative data include fresh S. australe from Wakatobi waters, which showed 17.39% protein content (Rahayu et al., 2019), and S. robustus from Banda Naira, which contained 17.61% protein content in the fresh condition (Erliani, 2021). Additionally, Xenisifon sp. from Bangka Belitung waters demonstrated a relatively low protein content of 10.61% in fresh samples (Fakhrurrozi, 2011). These findings also highlight that diferences in protein content across various peanut worm species are influenced by biological and environmental factors such as diet, habitat characteristics, body size, and water content. Tamarit-Pino et al. (2019) and Liu et al. (2021) stated that variations in environmental conditions and nutrient availability can afect metabolic activity and protein assimilation eficiency, thus contributing to diferences in protein content between species and habitats. Kazangeldina et al. (2022) explained that metabolism causes diferences in protein levels in organisms, which are also afected by food types, habitats, species, body size, and moisture levels that vary between each type.

The fat content of fresh and dried peanut worms was 0.22% and 0.76%, respectively (Table 2). Dried peanut worms have a higher fat content than fresh peanut worms because drying is thought to be inversely proportional and simultaneously influences the decrease in moisture after drying (Silaban & Rieuwpassa, 2019), where the fat content increases during the drying process. The increase in lipid content after drying does not indicate an actual increase in lipid content but rather a concentration efect caused by the loss of water during the dehydration process. As moisture evaporates, the total weight of the sample decreases, resulting in a higher proportion of lipid components than the dry weight of the sample. Furthermore, the disruption of cellular structures during drying can enhance lipid extraction, making fat more readily detectable during proximate analysis (Bilgin & Tanrikulu, 2018; Banda et al., 2023).

The fat content of both fresh and dried S. nudus in the present study was generally lower than that reported in previous studies. Salawati et al. (2024) recorded a fat content of 1.56% in fresh S. nudus from North Minahasa waters, whereas Silaban & Rieuwpassa (2019) reported 1.12% in dried samples of the same species from Nusalaut. For S. australe, Nurhikma et al. (2017) found higher fat levels, with 3.03% in fresh and 15.08% in freeze-dried samples from Konawe waters, respectively. Similarly, Rahayu et al. (2019) reported a fat content of 1.28% in fresh S. australe from Wakatobi. Interestingly, the fat content of dried S. nudus in the present study was higher than that reported by Silaban & Rieuwpassa (2019) for fresh samples of the same species, which had a fat content of only 0.63%. The diference in fat content of peanut worm flesh is thought to be influenced by water content, nutrition, species, and habitat. Lestaluhu et al. (2020) stated that the nutritional content of a marine organism varies depending on its nutrition, age, and species. Sánchez-Solís et al. (2021) and Karapanagiotidis et al. (2024) explained that habitat factors such as sediment type, organic matter content, temperature, and salinity can influence feeding activity and lipid accumulation in peanut worms. Furthermore, diferences in metabolism, reproductive stage, body size, and nutrient assimilation eficiency contribute to variations in lipid content between species and habitats. The drying method also influences the measured lipid content, as a reduction in water content during the drying process increases the relative proportion of lipids in the sample.

The calculation results (by diference) of the carbohydrate content of fresh peanut worms were 1.20%, while the dried worms were 0.26% (Table 2). Changes in the moisture, ash, protein, and fat contents may influence the carbohydrate content of dry products. According to Rasul et al. (2021) and Kalita & Basumatari (2024), when the other nutritional content decreases, the carbohydrate content increases based on calculations using diferent methods. The lower the other nutritional components, the higher was the carbohydrate content, and vice versa.

The carbohydrate content of both fresh and dried S. nudus in the present study was lower than that reported in several previous studies. Salawati et al. (2024) reported a carbohydrate content of 2.30% in fresh S. nudus from North Minahasa waters, whereas Silaban & Rieuwpassa (2019) found 0.63% in dried samples of the same species from Nusalaut waters. In S. australe, Nurhikma et al. (2017) recorded a higher carbohydrate content of 5.06% in freeze-dried samples collected from Konawe, Indonesia. Likewise, Xenisifon sp. from Bangka Belitung showed a substantially higher carbohydrate level of 10.02% in fresh conditions (Fakhrurrozi, 2011). In contrast, the carbohydrate content of both fresh and dried S. nudus in this study was higher than that reported by Erliani (2021), who found only 0.37% fat in fresh S. robustus collected from Banda Naira waters. The species habitat, nutrient content, and diferent processing methods of peanut worms influence the diferences in carbohydrate content. Rasul et al. (2021) explained that the carbohydrate content is influenced by nutrients in the worm diet, species, habitat, and drying process. Birie et al. (2025) mentioned that diferences in the proportion of other nutritional contents, such as water, protein, fat, and ash, may also contribute.

The mineral composition of marine organisms is widely recognized as an important indicator of their nutritional value and plays a key role in assessing their potential as functional food resources (Mohanty et al., 2019). The results showed that dried peanut worms have a higher content of calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and phosphorus (P) compared to fresh peanut worms, showing that the drying process improves the mineral content of peanut worms. Statistical analysis using an independent samples t-test demonstrated that Ca, K, Mg, Na, and P difered significantly between fresh and sun-dried S. nudus (p<0.05). The mineral compositions of fresh and sun-dried peanut worms are presented in Table 3.

The analysis showed that sodium was the highest in both fresh (38,725 mg/kg) and dried peanut worms (56,820 mg/kg), whereas phosphorus was the lowest in both fresh (474 mg/kg) and dried peanut worms (3,8306 mg/ kg). The sodium content found in the samples in this study was lower than that reported by Nurhikma et al. (2017), where fresh S. australe had 43,700 mg/kg and its freeze-dried product had 127,334 mg/kg sodium. The phosphorus content in the previous study also varied, being higher in fresh (1,500 mg/kg) but lower in freeze-dried peanut worms (3,722 mg/ kg). The diference was due to diferences in the sampling areas and environmental conditions. According to Barzkar etal. (2017) and Rahul et al. (2024), mineral content can be influenced by habitat and environmental conditions. Each aquatic environment can provide diferent mineral intakes for aquatic organisms. Rahman et al. (2018) also stated that diferences in mineral levels in an organism can be caused by diferences in the types of food and environmental conditions in which they live.

Peanut worms, being marine animals, inhabit an environment rich in sodium and chloride minerals, which significantly contributes to their high sodium levels (Huong et al., 2019; Ba et al., 2022). Sodium, a mineral crucially bound to proteins, including enzymes involved in metabolic processes, plays a vital role in maintaining cell osmotic pressure, regulating cell membrane permeability, forming salts, and healing wounds (Manullang et al., 2016; Ardiansyah et al., 2020; Rodrigues et al., 2021).

Fatty acids are classified into three types: saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) (Guo et al., 2022; Irnawati et al., 2024). Statistical analysis using an independent samples t-test indicated significant diferences in lauric, myristic, pentadecanoic, palmitic, heptadecanoic, stearic, behenic, palmitoleic, oleic, nervonic, linolenic, and linoleic acids between the two treatments (p<0.05), whereas no statistically significant diference was detected in tridecanoic and arachidonic acids (p>0.05). The results of the fatty acid analysis are presented in Table 4. In fresh and dried peanut worms, 14 fatty acids were identified, including 8 SFA, 3 monounsaturated fatty acids (MUFA, and 3 polyunsaturated fatty acids (PUFA).

The highest amount of fatty acids in fresh and dried peanut worms was SFA at 1.82% and 3.29%, respectively, while the lowest was MUFA at 0.21% and 0.45%, respectively. However, a significant portion of the fresh and dried peanut worms, up to 97.69% and 95.78% of the total content, respectively, was unidentified. This high prevalence of unidentified fatty acids is thought to be due to the damage of several fatty acids during Soxhlet extraction, as suggested by Tonachella et al. (2025). Furthermore, Cascant et al. (2018) Zhukova (2022) reported that heating at high temperatures for a long time can damage unsaturated fatty acids, forming saturated fatty acids and various types of free radical groups.

Nurhikma et al. (2017) showed that the highest abundance of fatty acids in fresh S. australe is MUFA (35%), and the lowest is PUFA (2.4%). These diferences can influence habitat and feed nutrition. According to Künili & Çolakoğlu (2019) and Kandyliari et al. (2020), fatty acid variations in aquatic organisms can be influenced by seasonal changes, geographical location, nutrition, environmental salinity, and living conditions, such as being free in its natural habitat or being cultivated. Pratama et al. (2018) and Rahman et al. (2023) stated that the fatty acid content of fish can vary depending on feed, location, species, sex, and environmental conditions.

In this study, the highest SFA fatty acid in dried peanut worms was palmitic acid (1.76%), while the lowest was tridecanoic acid (0.01 %) in fresh peanut worms. Palmitate is the most abundant SFA in marine organism fats compared to all other fatty acids (Inguglia et al., 2020 & Irnawati et al., 2023). Generally, palmitic acid is the most abundant SFA in food, consisting of 15-50% of all fatty acids (Gomes et al., 2016). Nurhikma et al. (2017) showed that the highest fatty acid content in S. australe was palmitic acid in its fresh (1.96%) and freeze-dried (2.64) forms, while the lowest was tridecanoic acid in both fresh (0.04%) and freeze-dried (0.05%) forms. The diference in palmitic acid values can be caused by species, feed availability, age, and size (Wei et al., 2018). Palmitic acid is the primary fatty acid in the sn-2 composition of breast milk (Durmus, 2019) and is known to induce changes in hepatocytes to the proinflammatory cytokine interleukin-8 (Chen et al., 2016 & Truzzi et al., 2018).

The highest MUFA and PUFA contents of dried peanut worms were oleic acid (0.22%) and linoleic acid (0.21%), respectively. According to Silaban (2019), the highest MUFA and PUFA contents in fresh Sipunculus sp. in Titawai, Indonesia, are palmitoleate (15.80%) and linoleate (5.33%), respectively. Nurhikma et al. (2017) explained that the highest MUFA and PUFA content in S. australe is palmitoleic acid, both fresh (0.31%) and freeze-dried (0.27%), and arachidonic acid in fresh (2.80%) and oleic acid in freezedried (1.97%) marine worms.

Oleic acid is an essential fatty acid. According to Jóźwiak et al. (2020) & Szczepańska et al. (2023), oleic acid is beneficial to human nutrition as a source of energy and antioxidants to inhibit cancer, lower cholesterol levels, and act as a solvent for vitamins A, D, E, and K. Similarly, Adawyah et al. (2020) & Xia et al. (2024) mentioned the health benefits of linoleic acid, including cancer growth inhibition and a reduced risk of heart disease and diabetes, while stimulating immune and anti-inflammatory responses in body cells to maintain their functions. Linoleic acid also plays a vital role in fat transport and metabolism.