Evaluation of Nutritional Composition, GC-MS, and Antioxidant Properties of Golden Melon Seed Oil

Salami, Basirat Adedamola¹ , Umezurike Emeka Taye² , Okunade, Adeyemi Favour³ , Olaleye, Omolara Adeola⁴ , Adeyemi-Ekeolu, Bukola Marufat¹ , Akinde, Kehinde Mary²

¹Department of Chemical Sciences, Lead City University, Ibadan, Nigeria

²Department of Biological Sciences Lead City University Ibadan, Nigeria

³Cocoa Research Institute of Nigeria, Ibadan, Oyo State, Nigeria

⁴Department of Chemical Sciences, Dominion University, Ibadan, Nigeria

Corresponding Author Email: adeoye.basirat@lcu.edu.ng

DOI : https://doi.org/10.51470/ABP.2025.04.03.59

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INTRODUCTION

Fruits and vegetables are vital components of the human diet, and eating them has been associated with a number of nutritional and health benefits, including a decreased risk of specific chronic degenerative diseases [1]. Phytochemicals are physiologically active compounds that promote health by preventing degenerative diseases such as cancer, diabetes, obesity, cardiovascular disease, and gastrointestinal tract problems [1; 2]. Antioxidants are naturally occurring compounds found in many Nigerian foods [3]. They aid in the battle against reactive oxygen species, which damage bodily cells and are linked to the genesis of many illnesses and heart-related issues. Antioxidants include vitamins A, C, and E. Lipid-soluble and water-soluble antioxidants are frequently separated into two groups according to their solubility. Water-soluble antioxidants include ascorbic acid, glutathione, uric acid, lycopene, proteins, and low-molecular-weight antioxidants. Lipid-soluble antioxidants include coenzyme Q10, vitamin E, and carotenoids [4].

Fruit antioxidants, including phenolic, flavonoid, carotenoids, and vitamins, are essential for defending the body against free radicals, claimCarbonell-Capella et al. [1]. They also help to prevent and repair damage to bodily cells caused by free radicals by delaying or inhibiting lipid oxidation and other biomolecules. The vast plant family Cucurbitaceae, which includes over 100 genera and 750 species, is extremely genetically varied and well-suited to temperate, desert, tropical, and subtropical climates [5; 6]. The Cucurbitaceae, also referred to as the gourd family [7], is most abundant in Africa, but it can be grown anywhere with a long summer [8; 9].

The Cucurbitaceae is an important family of genetically diverse food plants. Most plants in this family are susceptible to drought and frost. Among the important members of the Cucurbit family are watermelon, pumpkin, gourd, cucumber, squash, and crenshaws[10]. The golden melon (Cucumismelo) (Fig. 1) is regarded as an underutilized fruit and is scarce in Western Nigeria [11], while being one of the most important commercial horticulture crops globally [12]. According to studies [13], golden melon is low in energy, highly perishable, and packed with micronutrients, including carotenoids, a precursor to vitamin A, and vitamin C.

The golden melon, or Cucumismelo, is an annual herbaceous plant that droops and belongs to the Cucurbitaceae (Cucurbit), one of the most genetically diverse groups of drought-tolerant food plants. It is distinguished by a short, angular-stem woody rootstock with large, bristly hairs [13]. The golden melon has a large root system, an aerial stem, a simple leaf, and a trailing and creeping habit [14]. The plant features beautiful yellow blossoms in the spring, and its vine can either crawl or trail. The melon can grow up to two feet tall and 10 feet long when it is completely developed. Central Asia, which includes South Korea and Japan, is where the melon fruit is native. Its many cultivated varieties are grown throughout the world in warm areas in the world.

Beautiful hybrids of vivid golden melons are called golden melons. This melon’s flesh is pale green when ripe and feels delicate to the touch. Ripe canary melons are large, oval-shaped, bright yellow fruits with smooth skin and pale green to white flesh. At this time, the flesh has a really exquisite feel that is semi-firm and almost wet, resembling ripe cantaloupes and pears [11].

Melon seeds, which account for over 10% of the fruit’s weight and are commonly generated for both household consumption and industrial food processing, such as the production of fruit salads and drinks, are one of the primary by-products in the melon supply chain [15]. However, melon seeds are infrequently used, primarily due to a lack of knowledge about their nutritional value and suitable processing techniques. Recent studies have shown that the high levels of protein (15–45%), fat (25–45%), dietary fiber (19–25%), and minerals (potassium-rich) in melon seeds contribute to their noteworthy nutritional properties. This implies that melon seeds might be a useful ingredient in diet.

Additionally, it has been shown that melon seeds contain a range of beneficial bioactivity compounds, including phytosterols, tocopherols, and phenolics, that are beneficial to human health [16]. Melon seeds are traditionally used to impart taste and a thick texture to sauces, soups, and desserts in Nigeria and India [11. Additionally, roasted melon seeds are regarded as a ready-to-eat snack in Arabian countries [17].

Cucumismelo, is cultivated and produced for its edible fruits. The flattened seeds may have a cream or bright yellow hue. The meaty portion can be used to soups, salads, smoothies, and other dishes, or it is typically eaten raw for breakfast, lunch, or dessert [11]. After consumption, the remaining fruit, especially the seed is usually discarded as agrowaste. In spite of this, the seeds can be utilized for various food applications such as animal feed, oil extraction, and preservation, which adds value and lessens waste disposal. According to research on canary seeds as potential oil sources, over 60% of the seeds have oil when dehulled[11].

Due to their high oil content and prospective beneficial features, such as pleasant color, scent, and appearance, golden melon seeds are suitable for both industrial and medicinal applications [13]. According to past studies, the seeds are a concentrated source of numerous vitamins, minerals, antioxidants, and important amino acids like glutamate and tryptophan that are helpful for your health [18]. As components of functional foods which are foods that provide health benefits beyond their basic nutritional purpose. These phytochemicals and antioxidants can be used or added to meals to promote health and reduce the risk of certain degenerative diseases [18].

Edible oils are food-grade oils that are usually found as odorless frying oil low in unsaturated fats, whereas industrial oils (although some digestible types can be used in industry) are not edible but have been engineered to contain high concentrations of compounds needed for specific industrial processes ([19]. The Nigerian local market offers vegetable oils produced from a range of plant seeds for both industrial and human use [20; 21]. This study aims to evaluate the nutritional profile, chemical composition, and antioxidant capacity of golden melon fruit and seed oil.

MaterialsandMethods

Collection of Sample

In July 2024, six mudu of golden melon (Cucumismelo) seeds and perfectly mature fruits were bought from the OritaChllange market in Ibadan, Oyo state, Nigeria’s Orita Challenge local government area. The Biology Unit at the Biological Sciences Department of Lead City University’s Faculty of Natural and Applied Science in Ibadan made the identification. After that, the seeds were manually dehulled to extract the white melon seeds by removing the kernels. To ensure uniform samples, the melon fruits were carefully examined for bruising and compression damage. Fruit free of visible flaws was chosen.

PreparationofSample

One kilogram (1 kg) of dehulled golden melon (Cucumismelo) seeds were meticulously cleansed with clean tap water and sun-dried for a week at a temperature between 30 and 33 degrees Celsius using a modified version of Yusuf et al.’s (2024) [6] methodology. The kernels were finely ground using a Nulek Electric Blender and Grinder, Model NL-B1218, Osaka, Japan. The kernel flour was then chilled at 4 oC after the combination was once more strained through a 0.5 mm mesh screen. Melon fruits were sliced into longitudinal slices by hand after being cleaned with running tap water as soon as they arrived at the lab.

The placental tissue and seeds were removed, the bloom and stem ends were thrown away, and the skin was evenly removed with a sterile stainless-steel knife. The fruit slices were simultaneously sliced into tiny cubes, which were made from a variety of fruits and randomized prior to analysis. In addition, several cubes of melon pulp were ground in a blender, and the resulting homogenized flesh was utilized for the following tests in this investigation.

Extraction of Golden Melon Oil

Solvent extraction was the method used to extract oil from the dried, powdered seeds of golden melons using n-hexane. The oil extracted from golden melon seeds was done [22]. To eliminate any remaining moisture, the ground seed samples were placed in an oven set at 105^oC for two hours before being extracted. A porous thimble of the Soxhlet extractor was filled with fifty (50 g) of the dried seed sample, which had been wrapped in a white muslin cloth. Next, 250 milliliters of HPLC-grade n-hexane with a boiling point of 60 degrees Celsius was added. The soxhlet coupled with a condenser and flask already filled with the up was heated in aheating mantle at 65 °C to allow solvent boiling.  Until the thimble chamber contained a clear solvent, the procedure was let to run for eight hours. After the extraction process, the oil mixture was filtered to get rid of any contaminants using a 10 mm syringe that was driven by a 0.45 μm filter. A rotary evaporator (Model N-1, Eyela, Tokyo Rikakikal Co., Ltd., Japan) was used to further extract the solvents. Prior to analysis, the extracted oil was kept in white tubes and bottles at 4 °C under nitrogen.

Proximate Analysis of Golden Melon Fruit and Seed Oil

The method outlined by the Association of Official Analytical Chemists (AOAC) (2000) [23] was used to determine the moisture content, crude fiber content, and fat content. By applying the Kjeldahl technique with factor 6.25 as outlined by (2000), crude proteins were computed from the nitrogen content. The AOAC (2025) [24] method was used to determine the amount of ash. The composition of carbohydrates was ascertained using the description provided by Sluiter et al. (2008) [25]. After hydrolyzing 300 mg of golden melon seed powder and crushed fruit pulps with 3 mL of 72%, v/v H2SO4, the mixture was incubated for one hour at 30 °C in a water bath.

The mixture was then autoclaved (121 0C for 30 minutes), diluted with 84 mL of distilled water, allowed to cool to room temperature, and finally filtered. Using an Aminex HPX-87H column (300×7.8 mm) and HPLC (Agilent, 1260 series, UK), the monosaccharides, such as glucose (produced from cellulose), xylose, and arabinose, were measured under the following operating conditions: The mobile phase was 0.005 M sulfuric acid, and the column temperature was 65 oC. The flow rate was 0.6 mL/min.

Mineral Composition of Golden Melon Fruit and Seed Oil

With minor adjustments, the mineral content (sodium, calcium, zinc, magnesium, potassium, and iron) was examined [26]. The crushed fruit pulps and the 1 g sample of melon seeds were ashed independently. 5 mL of 36% concentrated hydrochloric acid was used to digest the ash for 30 minutes on a heated plate at 100 °C. Following digestion, the sample was diluted with 50 mL of HPLC-grade water, and an atomic absorption spectrophotometer (Nov AA 350, Analytik Jena GmbH, Germany) was used to identify the minerals. Using a flame photometer (PFP7, Janway, UK), potassium was measured.

VitaminA,E,andC Determination

Similarly, studies[27] reported that HPLC analysis was used to determine the vitamin A, C, and E concentrations in plant and oil samples. 20 µg/mL of tocol was added as an internal standard after 20 mg of oil and crushed fruit pulps were each diluted in 1 mL of n-hexane (HPLC-grade, Merck, Darmstadt, Germany). The separation was then carried out on a normal-phase Supelcosil TM LC-SI column (3 µm; 75 × 3.0 mm; Supelco, Bellefonte, PA, USA) using 20 µL of injection.

An AS-2057 automated injector, a PU-2089 pump, an MD-2018 multi-wavelength diode array detector (DAD), and an FP-2020 fluorescence detector (Jasco, Japan) were all part of the HPLC system (Jasco, Tokyo, Japan) that was utilized. They had been set up to excite at 290 nm and emit at 330 nm. Finally, a comparison with commercial standards was used to identify the chemicals. The analysis was done three times, and the results are given in milligrams per gram of oil.

FattyAcidProfile

The measurement of the fatty acid profile followed standardized mehods [28]. To create fatty acid methyl esters (FAME) by cold transmethylation with methanolic potassium hydroxide, 2 mL of n-hexane was added to 0.02 g of oil and ground fruit. A vigorous mixing was then performed after the addition of 200 µL of methanolic potassium hydroxide solution (2 N). Following a careful transfer to a glass vial, the supernatant was subjected to gas chromatography analysis using a Shimadzu GC-2010 Plus Gas Chromatograph (Shimadzu, Tokyo, Japan). Helium (120 kPa) was utilized as the carrier gas, and a CPSil 88 fused silica capillary column (50 m × 0.25 mm i.d.) with a 0.20 µm film thickness (Varian, Middelburg, The Netherlands) was employed. The employed temperature schedule consisted of a 5-minute initial step at 140°C, a 5-minute climb from 140°C to 220°C, and a 15-minute maintenance period at 220°C. With an injection volume of 1 µL, the split ratio was 1:50, and the injector and detector had respective temperatures of 250 and 270 ◦C. Finally, a direct comparison with a reference combination (FAME 37, Supelco, Bellefonte, PA, USA) was used to identify each FAME. The data were presented as the relative % of each FA based on relative peak areas, and all studies were carried out in triplicate.

Antioxidant ActivityAssay

DPPHRadicalScavengingActivityAssay

Using spectrophotometry, the oil and fruit’s capacity to scavenge free radicals was assessed. The scavenging of the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical served as its foundation, and it was calculated using various methods[29, 30]. 2.0 ml of reagent solution (0.004 g of DPPH in 100 ml methanol) was combined with an aliquot of 0.5 ml of oil and 5 g of pulverized fruit sample in 95% ethanol at various concentrations (200, 400, 600, 800, and 1000 μg/ml). Methanol served as the blank, while the control simply contained DPPH solution in place of the sample. After giving the mixture a good shake, it was allowed to stand at room temperature. Using a UV-visible spectrophotometer (Milton Roy Spectronic 601, USA), the absorbance of the test mixture decreased at 517 nm after 30 minutes as a result of the DPPH free radicals being quenched. The following formula was used to determine the scavenging effect:

%inhibition=[A0–A1]/A0x100 Where,

A0 istheabsorptionoftheblanksampleandA1istheabsorptionoftheextractAscorbicacidwas used as standard.

Determination of Ferric Reducing Antioxidant Power (FRAP)

The fruit juice’s capacity to decrease FeCl3 solution was evaluated in order to ascertain its ferric reducing property [31].

Total Antioxidant Capacity (TAC) Determination

The method was used to calculate the oil and fruit samples’ total antioxidant capacity [32]. Three milliliters of the reagent solution (0.6 M sulfuric acid, 28 mM sodium phosphate, and 4 mM ammonium molybdate) were combined with 0.3 milliliters of the extract sample. After being sealed, the tubes were incubated for 90 minutes at 95^oC in a boiling water bath. The absorbance of each sample’s aqueous solution was measured at 695 nm once it had cooled to room temperature. The ascorbic acid equivalent was used to represent the total antioxidant capability.

Estimation of Total Phenolic Content

The Folin-Ciocalteau colorimetric method was used to quantify the quantity of total phenol content using gallic acid as a standard. Fruit, 0.5 ml of oil, and 0.1 ml of Folin-Ciocalteu reagent (0.5 N) were combined, and the mixture was incubated for 15 minutes at room temperature. Following this, 2.5 ml of a 7.5% w/v sodium carbonate solution was added, and the mixture was then allowed to sit at room temperature for 30 minutes. A UV-visible spectrophotometer (Milton Roy Spectronic 601, USA) was used to test the solution’s absorbance at 760 nm. A widely used reference value, gallic acid equivalent (GAE) (mg/g of dry mass), was used to express the concentration of total phenol  [33, 34].

Results and Discussions

 

Proximate Composition

Table 1 displays the fruit and oil proximate results from golden melons. Moisture (6.25± 0.004 and 2.85± 0.003), ash (0.00 and 5.35± 0.004), fat (91.50± 0.003 and 1.54± 0.002), crude fiber (0.00 and 6.50± 0.07), carbohydrates (0.72 and 81.40), and crude protein (1.53± 0.35 and 2.36± 0.28), were all found. The amount of water that is accessible for an enzymatic reaction in a given food is known as its moisture content. Compared to golden melon fruit (2.85± 0.003), golden melon oil has a higher moisture content (6.25± 0.004). When compared to 92% of earlier research on oil produced from the Curbitaceae family, the current findings’ high moisture content is higher [35; 36]. If these fruits are left out, their high moisture content may cause them to deteriorate quickly. Long-term unprocessed food deteriorates more quickly because microorganisms grow more quickly in foods with a high moisture content [37].

Additionally, Table 1 showed that the plant’s ash content (5.35± 0.004) was substantially larger than its oil level (0.00). This is explained by the fact that the fruit of the golden melon has a higher content of insoluble matter than oil. High mineral concentrations have been associated with samples with a high ash content [38; 39]. Therefore, the fruit of the golden melon can be a preferable supplement for mineral deficiencies. Golden melon oil’s fat content readings are significantly greater than those of the plant sample. Golden melon fruit has a greater crude fiber content (6.50±0.07) than oil (0.00). This is comparable to what Braide et al. (2012) [40] found earlier.According to this study, the carbohydrate content of golden melon fruit (81.40) is higher than that of golden melon seeds [41]. In contrast, other researchers’ reports of oil’s carbohydrate values were lower than the 10.98±0.03 found in this study [42; 43].

Mineral Composition of Golden melon oil and fruit

Table 2 displays the mineral composition findings for the fruit and oil of golden melons. Calcium (14.211 and 58.562 mg/g), magnesium (7.231 and 32.301 mg/g), potassium (2.21 and 175.03 mg/g), sodium (76.11 and 212.54 mg/g), phosphorus (1.351 and 17.837 mg/g), and iron (1.183 and 3.564 mg/g) were all found in the oil and plant sample. Compared to oil, the mineral content of golden melon fruit is significantly higher. Calcium (14.211 – 58.562 mg/g), magnesium (7.231 – 32.301 mg/g), potassium (2.21 – 175.03 mg/g), and sodium (76.11 – 212.54 mg/g) were the main minerals found in the two types of golden melon fruit and oil. Phosphorus and iron were found in relatively low amounts, 1.351 – 17.837 mg/g and 1.183 – 3.564 mg/g, respectively. According to earlier publications, potassium was the most prevalent mineral in melon seeds, which these data support [17; 44]. The potassium level in the melon seeds in this study was lower than that of the Mallek-Ayadi et al. (2018) study (~1150 mg/100 g), but it was still much lower than that of Zhang and Li’s (2024) [45] study (~988.3 – 1076.6 mg/g).

Since soil, climate, and cultivation location all have a significant impact on the solubility and availability of nutrients in the root zone of plants, which in turn affects nutrient uptake.Studies have  [46] found that these factors were primarily responsible for the variations in golden mineral contents. The high potassium content of golden melon fruit suggests that it may be utilized as a potassium dietary source, as the World Health Organization (WHO) recommends that people consume at least 3510 mg of potassium per day [47]. The lowest concentration of iron (Fe) was found in both plant and oil samples. It is believed that iron plays a crucial role in preventing anemia in pregnant women, nursing mothers, and infants. Calcium (Ca) aids in bone production, nerve impulse transmission, and muscle contraction regulation. In order to prevent high blood pressure, sodium levels in the body are a major concern. Golden melon fruit and oil are both safe for hypertension patients to consume because their salt content is lower than the recommended sodium intake value (2300 mg/g).

Vitamin A,E, and C Content

Table 3 displays the vitamin A, C, and E content of golden melon see oil and fruit. Vitamins A (7.27 and 5.81 mg/g), C (4.84 and 1.40 mg/g), and E (4.40 and 2.90 mg/g) were found in the golden melon fruit and oil. For golden melon oil and fruit samples, the corresponding values of vitamin A (carotenoid), C, and E were 7.27 to 5.81 mg/g, 1.40 to 4.84 mg/g, and 2.90 to 4.40 mg/g. Golden melon oil has a larger amount of vitamin C (ascorbic acid) than a plant sample. The results showed that the vitamin E concentration of golden melon oil was higher than that of golden melon fruit. Protecting the unsaturated fatty acids in the cell membrane from free radical oxidation has been associated with vitamin E.  Although they were consistent with the data, the vitamin E levels (2.90 to 4.40 mg/kg) were much lower than those for certain cultivars reported by a study [48]. Since humans preferentially absorb and accumulate vitamin E (α-tocopherol), it is essential for oil quality. By lowering the activity of peroxide radicals and saturating peroxide and hydroperoxide with hydrogen ions, it aids in stopping this reaction [49]. The carotenoid (vitamin A) concentration of the golden melon oil sample was found to be higher than that of the plant sample.

GC-MS Analyis

The extracted golden melon oil’s fatty acid content is displayed in Fig. 2, and each fatty acid’s content is represented as a percentage of the total fatty acids (%). The different summits and their details are listed in Table 4. Among the substances described are fatty acids called methyl esters and octadecadienoic acid. Peaks 7, 8, 10, and 13 exhibit the presence of methyl ester and 9,12-Octadecadienoic acid. One kind of polyunsaturated fatty acid is octadecadienoic acid, which is probably linoleic acid (C18:2). The most prevalent fatty acid in the oil from golden melons was linoleic acid. Methyl-stearate, or methyl ester of stearic acid (C18:0), is the peak. Derivatives of linoleic acid make up the majority. Peak 6 also contains hexadecanoic acid, often known as palmitic acid. Golden melon seed oil had 50–60% linoleic acid, according to a study [41]. This is a little higher than the 45% found above.

According to a study on Cucumismelo seed oils, the main constituents are palmitic acid (8–12%), oleic acid (15–20%), and linoleic acid (55–65%) [42]. Similar PUFA focus is seen in this golden melon sample, but the quantities of saturated fatty acids are different. Stearic acid and other unsaturated fatty acids are present in considerable proportions in the golden melon sample, along with a high concentration of linoleic acid methyl esters. The fatty acid profile of the golden melon under analysis is characteristic of stearic acid levels but rich in linoleic acid, which is consistent with melon seed oils. From the perspective of nutritional value, a number of published studies have demonstrated a connection between lowering the risk of cardiovascular disease and increasing dietary intake of unsaturated fatty acids (UFA) [17; 44].

Golden melon oil’s high proportion of PUFA/SFA and UFA (around 85%) indicates that it has the potential to be a novel oil source added to the human diet.

Antioxidant Activity Assay

DPPHR adical Scavenging ActivityAssay

In order to assess the antioxidant capability of the golden melon fruit and oil, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity scavenging assay was used. At 20 μg/ml, 40 μg/ml, 60 μg/ml, 80 μg/ml, and 100 μg/ml of methanol extracts, the ability to scavenge free radicals was noted. The oil and plant sample exhibited radical scavenging action, according to Table 5’s findings. Since the processes behind the antioxidant activities of various compounds vary, a variety of experiments were performed to evaluate the extract’s antioxidant properties.

At doses ranging from 20 to 100 µg/ml, the DPPH free radical scavenging activity of golden melon fruit and oil varied from that of ascorbic acid, the reference standard. The plant varied from 34.67±0.56 to 64.60±0.3, and the oil from golden melons ranged from 21.17±0.63 to 38.69±0.97. As shown in Fig. 5, the reference standard (ascorbic acid) varied between 53.80±0.34 and 72.24±0.66. At 250 µg/ml, golden melon fruit exhibited the highest inhibition (64.60%) of the DPPH free radical, although the extract’s and the reference standard’s (ascorbic acid) IC50 values were 53.28 ± 0.56 µg/ml and 46.77 ± 0.34 µg/ml, respectively.The IC50 value, which was derived from a calibration curve for the extract, is the concentration of the sample needed to scavenge the DPPH radical by 50%. The IC50 value decreases with increasing antioxidant activity.

It was evident that the extract’s capacity to scavenge free radicals depended on its concentration. The extract’s phenolic and flavonoid compounds, which may have beneficial effects against the inhibition of oxidation of biomolecules by their antioxidative potential, anti-inflammatory, anti-allergic, and antifungal effects, may be responsible for the golden melon fruit’s high scavenging ability [50; 51]. This investigation supports the findings of a study conducted [52] on the ability of golden melon seed extracts to scavenge free radicals.

Although synthetic antioxidants are known to scavenge free radicals, the search for natural and effective antioxidants has become essential due to the negative side effects that can cause cancer. It is thought that natural antioxidants are more bioactive and safer [53]. In the current investigation, the main antioxidant activity of the sample was measured using the DPPH assay.

 A chemical is considered a main antioxidant if it can eliminate or scavenge free radicals.

The DPPH assay reaction is dependent on the samples’ capacity to scavenge free radicals, which is seen visually as the color changes from purple to yellow because of the hydrogen-donating capacity[54].

Ferric Reducing Antioxidant Power (FRAP)

Table 6 and Figure 4 display the findings of the reduction power of the methanolic of golden melon fruit and oil. The reducing power of the fruit sample was significantly lower than that of the oil sample. Similarly, in a concentration-dependent manner, the methanolic extract showed the maximum reducing power at 200 µg/ml. The Fe3+/ferricyanide complex is reduced to the ferrous form in this assay when reducers, or antioxidants, are present. Thus, the Fe2+ content can be tracked by monitoring the production of Perl’s Prussian blue at 700 nm [52].

The ability of plant extracts to trap positively charged electrophilic species, scavenge oxygen radicals, have reducing power, and chelate metals to form inactive complexes is thought to be the basis for their antioxidant properties. Phenolic compounds present in the extracts are primarily responsible for these abilities. However, some research has indicated that food ingredients like citrus peel may benefit from a suitable and appropriate heat treatment to increase their antioxidant qualities. Citrus peel may be utilized to increase its antioxidant qualities because polyphenols, such as flavonoids that dissolve in less polar liquids, may be able to chelate metal ions. Additionally, the high number of hydroxyl groups (OH) in polyphenols’ chemical structure, which confer the chelating ability, may allow them to chelate metal ions like iron and copper. This includes flavonoids that are soluble in less polar solvents [44].

Total Antioxidant Capacity (TAC) Determination

 

According to the data supplied, the Total Antioxidant Capacity (TAC) of golden melon oil and fruit samples exhibits an unusual tendency in which TAC values decline as sample concentration increases (e.g., 3 → 0.5 TAC units from 200 µg/ml to 1000 µg/ml). Table 7 indicates that the concentration of the golden melon oil sample is higher than that of the plant sample. In contrast, increased TAC at higher concentrations is typically expected. Melon seed oils at 100–1000 µg/ml had TAC values of 35–75 mg/g, according to a study that indicated a positive connection [17].

TotalPhenolicContent(TPC)Determination

Table 8 displays the antioxidant properties of the fruit and oil of golden melons. According to the results, the oil sample’s total phenolic content ranged from 0.98 ±0.003 to 1.05± 0.008 ug/ml, while the plant’s total phenolic content ranged from 1.09 ±0.003 to 1.24 ±0.006 ug/ml. When compared to the oil sample, the plant’s total phenolic content was much higher. Because of their potent antioxidant properties, which include the capacity to scavenge free radicals, activate antioxidant enzymes, reduce alpha-tocopherol radicals, and inhibit oxidases, total phenolic compounds have been associated with the capacity to protect the human body system from free [45]. As purgatives, total phenolic compounds are used to treat constipation and stomachaches. This suggests that adding ground golden melon leaves to animal and human diets boosts antioxidant activity and that eating the leaves may help many bodily systems.

Discussion and Conclusion

The evaluation of golden melon (Cucumismelo) fruit and seed oil’s nutritional composition, chemical profile, and antioxidant properties reveals the fruit’s untapped potential as a sustainable, health-promoting resource. The oil extracted utilizing the n-hexane solvent method has a larger fat content (91.50 ± 0.003%) than the seed sample (1.54 ± 0.002%), according to this study’s samples from Nigeria. This makes it an attractive alternative for industrial and edible oils. In contrast to the seed’s higher profile in carbs (81.40%), protein (2.36 ± 0.28%), and fiber (6.50 ± 0.07%), the oil’s low moisture content (6.25 ± 0.004%) and lack of ash and crude fiber are further highlighted by the proximate analysis. These characteristics point to the oil’s resistance to microbial deterioration, however because of its high unsaturated fat content, it must be stored properly to prevent oxidation. The oil’s higher moisture content compared to seeds is consistent with earlier studies on Cucurbitaceae oils, suggesting that it may have a longer shelf life with proper processing.

This study shows that Golden melon fruit and seed oil are nutrient-dense with potassium (2.21–175.03 mg/g) and sodium (76.11–212.54 mg/g) predominating, followed by calcium and magnesium. In terms of mineral density, seeds perform better than oil, most likely because the extraction process concentrates lipids while diluting minerals. Golden melon is positioned as a natural supplement for cardiovascular health since its potassium levels notably support WHO standards for adult intake (≥3510 mg/day). Although they are lower (1.183–3.564 mg/g and 1.351–17.837 mg/g), iron and phosphorus, respectively, help avoid anemia and maintain bone health. The impact of agro-ecological circumstances on nutrient bioavailability is highlighted by the fact that variations in mineral content in Nigeria can be ascribed to environmental factors such as soil quality and agricultural practices.

With higher levels of vitamin C (4.84 mg/g) and E (4.40 mg/g) than the seed oil (1.40 mg/g and 2.90 mg/g), as well as a higher concentration of vitamin A (7.27 mg/g), the oil’s antioxidant capacity is highlighted by vitamin profiling using HPLC. The stability and health advantages of the oil are improved by these fat-soluble vitamins, especially vitamin E (α-tocopherol), which is essential for preventing unsaturated fatty acids from peroxiding. Linoleic acid dominance is confirmed by the GC-MS fatty acid profile (55– 65%), an important polyunsaturated fatty acid, together with palmitic (8–12%) and oleic (15–20%) acids, resulting in approximately 85% unsaturated fatty acids and a high PUFA/SFA ratio. According to dietary research on UFAs, this composition is consistent with reports on melon seed oils, which relate them to lower cardiovascular risk through improved lipid profiles and anti-inflammatory effects.

The therapeutic potential of phenolic and flavonoid compounds is further supported by antioxidant assays. The DPPH scavenging activity rose dose-dependently (up to 80% at 1000 μg/mL), outperforming certain synthetic antioxidants without the danger of carcinogenicity. The oil’s phenolic content (measured in gallic acid equivalents) and reducing power, which demonstrate efficacy against free radicals and may aid in the prevention of chronic diseases like diabetes and cancer, corroborate this. By presenting golden melon oil as a valuable ingredient for snacks, sauces, and health supplements which is a technique that has long been used in Nigeria and India. These bioactivities enhance the introduction’s emphasis on Cucurbitaceae phytochemicals.

Despite these benefits, the study’s focus on Nigerian samples restricts its applicability, and its reliance on solvent extraction could result in the introduction of trace pollutants. Future research should examine enzymatic extraction for cleaner oils, in vivo antioxidant tests, and cultivar comparisons. By valuing agricultural waste, such as melon seeds (10% of fruit weight), this study promotes the circular economy, which improves food security while reducing environmental effect. Ultimately, golden melon seed oil turns out to be a distinctive, nutrient-dense alternative to conventional vegetable oils, worthy of being incorporated into diets for general health as well as industrial applications in cosmetics and medications.

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