1. Introduction
The growing world population and the importance of health issues have increased the demand for healthy foods. The spotlight is increasingly on the pivotal role of dietary fats in human health, primarily as an indispensable source of energy. However, the stability and quality of dietary fats remain critical concerns, necessitating the development of effective preservation methods [1]. In this regard, the current research on dietary enhancements leans toward a paradigm shift in food systems, advocating for an increased reliance on functional foods and natural products. This shift is not only a response to growing health consciousness but also aligns with research emphasizing social health maintenance through improved dietary practices [2–5].
Sesame oil (Sesamum indicum) is widely recognized for its extensive applications in the food, pharmaceutical, and cosmetic industries [6]. One of its most notable characteristics is its oxidative stability, which makes it more resistant to auto-oxidation compared to other edible oils. However, external factors such as prolonged storage, high temperatures, and exposure to oxygen can still lead to quality deterioration. This study specifically investigates sesame oil due to its established role in preserving polyunsaturated fatty acid (PUFA)-rich oils and its need for further enhancement in long-term stability. The oil’s composition is rich in phytosterols, with beta-sitosterol accounting for approximately 60% of the sterol content, and gamma-tocopherol comprising over 90% of the total tocopherol content. Sesame oil also contains sesamin and sesamolin, which exhibit antioxidant effects, serum lipid-lowering properties, and protective roles against cardiovascular diseases, cancer, and aging, while improving metabolism and liver function [7].
In the food industry, the extraction of sesame oil primarily involves hot pressing or cold pressing, each with distinct advantages. Hot pressing heats the seeds to approximately 100°C and applies pressure to extract the oil, making it more economically viable due to its economic value. However, cold pressing preserves bioactive components and yields higher-quality oil without chemical additives or preservatives [8]. Despite its superior nutritional profile, cold-pressed sesame oil remains susceptible to oxidation, necessitating the incorporation of effective natural antioxidants to maintain its quality and extend shelf life [9]. Some products resulting from oil oxidation are considered harmful to health [10]. Free radicals contribute to degenerative disorders such as diabetes, cancer, and cardiovascular disease. Although endogenous antioxidants provide defense mechanisms, excessive free radicals lead to oxidative stress, reinforcing the necessity for dietary antioxidants [11]. Synthetic antioxidants like BHT, BHA, TBHQ, and propyl gallate are commonly used to prevent oxidation in edible oils, but their potential health risks have prompted a growing demand for natural alternatives [12].
The adverse health implications associated with synthetic antioxidants have catalyzed the search for natural alternatives. In this quest, marine organisms, including algae, have garnered researchers’ attention because of their rich supply of unique bioactive compounds [13–15]. Brown algae, particularly the Sargassum species, are recognized as potent sources of natural antioxidants due to their high phenolic content, polysaccharides, vitamins, beta-carotene, and fiber [2, 11, 16]. Among these, Sargassum bovianum has been selected in this study due to its well-documented antioxidant properties and availability in marine ecosystems, making it a promising candidate for oil preservation [17, 18]. To ensure its safe application in food products, this study employs an ethanol-based extraction process, a widely accepted method for obtaining bioactive compounds from edible marine sources. By evaluating the antioxidant potential of Sargassum bovianum extract and its effects on the physicochemical stability and sensory attributes of sesame oil, this study aims to enhance its oxidative stability and overall quality, contributing to the development of natural preservation strategies in the food industry.
2. Materials and Methods
2.1. Chemicals
All chemicals, standards, and solvents utilized in this study were purchased from companies Merck and Sigma (Germany).
2.2. Sampling and Preliminary Preparation
Due to the high density of these marine organisms in the area, 6 kg of Sargassum algae samples were first collected along the Lian Bushehr Coastal Park during high tide. After mixing the samples to obtain a homogeneous sample, they were initially washed with seawater to eliminate major impurities, debris, and other epiphytes [19].
After sample cleaning and species identification were completed, the samples were handed over to the Gulf Marine Biomedical Research Institute, Bushehr University of Medical Sciences, for targeted analysis. The samples were then dried for 4 days at ambient temperature in the shade of a clean-covered room. To increase the aeration of the algae, the algae were rotated every 6 h. The dried seaweed is then carefully ground using an electric blender. In addition, samples of sesame seeds from the city of Farashband in Fars province were purchased from six sales centers, each containing 500 g, for a total of 3 kg. The hand-processed sesame packs were cleaned, blended, and transported to an FDO-accredited oil extraction workshop in Bushehr (GB), where the oil was extracted using the cold press method. Finally, 1200 mL of oil was obtained.
2.3. Extraction and Determination of Lipid Percentage
Lipid extraction from the sargassum sample was performed using the Bligh and Dyer method [20]. Briefly, 100 mL of n-hexane solvent was added to 10 g of powdered algae sample and incubated at 25°C for 72 h with continuous stirring at 100 rpm for 72 h. The supernatant was collected, and the solvent was completely evaporated using a rotary evaporator under vacuum at 40°C. The total lipid content (percentage) was determined using the following equation:
(1)
2.4. Acid Value (AV)
The AV was measured using the ISO standard method [21]. AV is the amount of KOH (in mg) required for neutralizing the free fatty acids in 1 mg of fat [21]. To influence the time parameters, samples were tested for AV initially and after 120 days of storage. Briefly, 0.2 g of oil extracted from each sample was placed in an Erlenmeyer flask, and 5 mL of ethanol per sample was added, and heated. A few drops of phenolphthalein indicator were then added. The solution was neutralized with 0.1 N potassium hydroxide solution while the ethanol temperature was above 70°C. After transferring the neutralized ethanol to the arelen containing the test solution, the reagent was then titrated with 0.01 N potassium hydroxide. The AV of each sample was determined using the following equation.
(2)
where C: standard concentration of KOH (mol/L); V: standard volume of KOH (mL); and m: test weight (g).
2.5. Peroxide Value (PV)
PV is presented in milliequivalents of active oxygen present in 1 kg of oil sample. ISO Standard Method No. 3960 was used to measure PVs [22]. To influence the time factor, we evaluated the PV of the samples at the beginning of storage and after 120 days of storage. Briefly, 0.5 g of oil extracted from each weighed sample was added to 3 mL of chloroform: acetic acid solvent (2: 3) and mixed. Then, 0.5 mL of saturated potassium iodide was added and kept in the dark place, and after 1 min, 30 mL of distilled water was added. The solution was slowly titrated with 0.1 N sodium thiosulfate, using 1% starch binder as an indicator, until the blue color disappeared. The PV of each sample was calculated according to Equation (3). Findings were presented in milliequivalent of grams of oxygen per kg of oil.
(3)
where V: volume of sodium thiosulfate solution (mL); V0: volume of standard sodium thiosulfate solution used for control test (mL); Cs: concentration of sodium thiosulfate solution (mol/L); m: sample mass (gram); and F: solubility factor of sodium thiosulfate 0.010 N.
2.6. Refractive Index
The refractive index of each sample was measured according to ISO Standard Method No. 6320 using a Kruss refractometer (KRUSS DR201-95) at 25°C [23]. The RI measurement serves as an indicator of oil purity, composition, and degree of oxidation, providing valuable insights into the physicochemical properties of sesame oil.
2.7. Fatty Acid Methyl Ester (FAME) and Fatty Acid Analysis of the Samples
For FA methylation, 0.04 g of each extracted lipid was treated with 0.9 mL n-hexane, 1.8 mL methanol, and 1 mL concentrated sulfuric acid. The mixture was refluxed at 71°C for 2 h, allowed to cool, and washed three times with distilled water.
After separation and dehydration, a volume of 1 μL of the supernatant was introduced into a gas chromatograph equipped with a flame ionization detector (GC-FID). Fatty acids were analyzed using a Varian GC-FID instrument (CP-3800 series) equipped with a BPX-70 fused silica capillary column (SGE, Melbourne, Australia, 30 m × 0.22 mm i. d., 0.25 μm film thickness). Helium was utilized as the carrier gas at a pressure of 362.5 psi. The detector and injector temperatures were 255°C and 270°C, respectively, and the oven temperature was programmed at 60°C for 1 5°C min−1, up to 160°C at 10°C min−1, after then to 200°C at 5°C min−1, and isothermal for 70 min at 200°C. The flow rates of nitrogen, hydrogen, and air in the detector were 25, 30, and 300 mL/min, respectively. The retention time (RT) and peak area of each fatty acid were compared to each peak in a standard FA chromatogram to determine the type and amount of FA in the test sample [24]. The GC-FID Workstation Version 6.41 was used for device management.
2.8. Analysis of Secondary Metabolites by GC-MS Method
Ten g of each lyophilized sample was extracted with 60 mL of methanol: chloroform: n-hexane (1: 1: 1 v/v/v), and the supernatant was subjected to an Agilent 7890B gas chromatograph–mass spectrometer (Agilent GC-MS, Germany), to obtain the volatile chemical composition. Mass spectra were performed at 70 eV ionization energy, 0.5 mA filament emission, 0.5 s scan interval, and 50–500 Da m/z fragment. GC separation was performed using a HP-5MS UI capillary column (30 m × 0.25 mm ID × 0.25 μm i.d., 0.5 μm film thickness) with an injection volume of 1 μL, and a split ratio of 30:1. Helium was used as the carrier gas at a constant flow rate of 0.8 mL/min. The injection port, transfer line, and ion source temperatures were set at 240°C, 250°C, and 270°C, respectively. The oven temperature was initially held at 80°C for 3 min, then increased to 250°C at a rate of 5°C per minute, and maintained at this final temperature for 10 min. The total duration of GC run time was 37.66 min [25]. Identification of the isolated compounds was achieved by matching them with data from the National Institute of Standards and Technology Library (NIST MS database, 2014). The relative quantity (%) of components was calculated by comparing the average peak area with the total area [26].
2.9. Investigating the Antioxidant Activities (AAs) of the Extracts by DPPH Method
The AAs (%) of the lyophilized samples were conducted using the DPPH° radical scavenging method according to Marhamati et al. [27]. First, the radical scavenging effect of algae extract was investigated and compared with the antioxidants TBHQ, and ascorbic acid. Sesame oil samples were treated with seaweed extract, ascorbic acid, and TBHQ. For this purpose, 0.01 g sample was weighed and made up separately to a volume of 10 mL using methanol. Then, 2.5 mL of the resulting solution was then prepared to a volume of 25 mL (100 mg/kg). Concentrations of 5, 15, 25, 35, and 50 mg/kg were prepared to plot the calibration curve. Subsequently, 1.5 mL of each concentration was mixed with 1.5 mL of 0.1 mM methanol solution of DPPH. After 30 min at ambient temperature, the absorbance of the resulting mixture was read at 517 nm using a dual beam spectrophotometer (Cecil, The United Kingdom). DPPH inhibitory activity (%) was calculated using Equation (4) compared to standard samples of ascorbic acid and TBHQ. In the control group, methanol was used instead of the sample [27]:
(4)
where Ac represents absorbance of control; As denotes absorbance of the sample.
2.10. Sensory Evaluations
The sensory properties of the samples, including aroma, taste, color, and overall acceptability, were evaluated according to ISO 13299:2016 (Sensory Analysis—Methodology—General Guidance for Establishing a Sensory Profile) and the method of Khaki et al. [28]. A descriptive sensory analysis was performed by a trained panel of 10 individuals (5 women, 5 men, aged 20–50), following standardized procedures. Instead of the 5-point hedonic scale, we utilized the ISO-recommended scaling method for sensory profiling. The samples were coded with random three-digit numbers and presented in a controlled environment to ensure consistency and minimize bias. The panelists assessed the samples based on structured sensory descriptors with a defined intensity scale, ensuring a more objective and reproducible evaluation [28].
2.11. Statistical Analysis
Statistical analyses were carried out using SPSS fV.24. Each test was conducted in triplicate, and the results are reported as mean ± standard deviation (±SD) for each group. The results are reported using one-way analysis of variance (ANOVA) followed by Duncan’s test. A p value of less than 0.05 was considered statistically significant.
3. Results
3.1. Some Physicochemical Characteristics of Extracted Lipids
The total lipid contents in the n-hexane-extracted algal and sesame seed oil samples were 2.3 ± 0.05 and 40 ± 1.52%, respectively. Some physicochemical properties of S. bovianum lipid and its treatments at the time of collection and after 4 months of storage are presented in Table 1.
| Group | day | AV (mg/g NaOH) | PV (meq O2/Kg oil) | RI | |
|---|---|---|---|---|---|
| Control | 1 | 0.2165 ± 0.02 | 13.975 ± 0.08 | 1.4733 ± 0.08 | |
| 120 | 1.3425 ± 0.048 | 56.175 ± 0.45 | 1.4733 ± 0.08 | ||
| Treatment | 120 | Algae extract | 0.57 ± 0.042 | 30.925 ± 0.28 | 1.4723 ± 0.066 |
| TBHQ | 1.165 ± 0.056 | 19.75 ± 0.11 | 1.4724 ± 0.072 | ||
| Ascorbic acid | 0.4065 ± 0.41 | 25.325 ± 0.24 | 1.4726 ± 0.068 | ||
- Abbreviations: AV, acid value; PV, peroxide value; RI, refractive index.
According to Table 1, the peroxide and AVs of the control sample showed a further increase during the 120-day storage period compared to the other samples. This means that all three oil treatments significantly prevented the increase in peroxide and AVs compared to the control group (p < 0.05). The oxidation factors of the control sample showed that natural lignans with antioxidant properties, such as sesamol and sesamolin found in sesame oil, cannot provide long-term oxidative stability after 4 months of storage, indicating a need to supplement antioxidants. Considering the negative health effects of synthetic antioxidants and the inhibitory effect of seaweed extracts on the oxidation of sesame oil compared to control samples, the use of these marine organisms can be considered.
3.2. Comparison of Oil Stability Index (OSI) Among Treatments
Comparison of the OSI showed no significant difference between TBHQ, ascorbic acid, and seaweed extract treatments (p > 0.05). Algae treatments such as synthetic antioxidants can increase the oxidative stability of the oil (Figure 1).
3.3. Fatty Acid Profile of Sargassum bouvianum Algae
GC-FID analysis of the algal sample revealed a total of 18 fatty acids (Table 2).
| No. | Fatty acid | Chemical formula | RT∗ (min) | Amount (%) |
|---|---|---|---|---|
| 1 | Caproic acid | C6H12O2 | 2.880 | 31.88 ± 0.0184 |
| 2 | Enanthic acid | C7H14O2 | 3.471 | 8.24 ± 0.0042 |
| 3 | Caprylic acid | C8H16O2 | 4.332 | 0.207 ± 0.0014 |
| 4 | Nonanoic acid | C9H18O2 | 5.262 | 1.30 ± 0.0028 |
| 5 | Capric acid | C10H20O2 | 6.414 | 0.406 ± 0.0014 |
| 6 | Undecylic acid | C11H22O2 | 7.593 | 0.571 ± 0.0021 |
| 7 | Lauric acid | C12H24O2 | 8.855 | 0.561 ± 0.0014 |
| 8 | Tridecylic acid | C13H26O2 | 10.384 | 0.306 ± 0.0007 |
| 9 | Myristic acid | C14H28O2 | 11.887 | 11.990 ± 0.0113 |
| 10 | Pentadecylic acid | C15H30O2 | 13.693 | 0.964 ± 0.0014 |
| 11 | Palmitic acid | C16H32O2 | 15.609 | 32.534 ± 0.025 |
| 12 | Margaric acid | C17H34O2 | 17.262 | 1.346 ± 0.0042 |
| 13 | Stearic acid | C18H36O2 | 19.280 | 2.681 ± 0.0035 |
| 14 | Oleic acid | C18H34O2 | 18.947 | 1.334 ± 0.0028 |
| 15 | Linoleic acid | C18H32O2 | 18.735 | 1.463 ± 0.0028 |
| 16 | Nonadecylic acid | C19H38O2 | 20.920 | 1.054 ± 0.0021 |
| 17 | Arachidic acid | C20H40O2 | 23.082 | 1.079 ± 0.0028 |
| 18 | Heneicosylic acid | C21H42O2 | 25.714 | 2.092 ± 0.0035 |
| ∗∗SFA (%) | 97.233 ± 0.02 | |||
| ∗∗∗UFA (%) | 2.767 ± 0.006 | ω-3 | — | |
| ω-6 | 1.463 ± 0.0028 | |||
| ω-9 | 1.334 ± 0.0028 | |||
- ∗RT: retention time.
- ∗∗SFA: saturated fatty acids.
- ∗∗∗UFA: unsaturated fatty acids.
According to Table 2, 16 fatty acids with a value of 97.233 ± 0.02% belonged to saturated fatty acids (SFAs), and 2 fatty acids with a value of 2.767 ± 0.006% belonged to unsaturated fatty acids. Omega-6 and omega-9 values were 1.463 ± 0.0028 and 1.334 ± 0.0028%, respectively.
3.4. Fatty Acids Profile of Sesame Samples
Thirteen fatty acids were identified and quantified by GC-FID analysis of sesame oil (Table 3).
| No. | Fatty acid | Chemical formula | RT∗ (min) | Amount (%) |
|---|---|---|---|---|
| 1 | Myristic acid | C14H28O2 | 11.887 | 0.0195 ± 0.0007 |
| 2 | palmitic acid | C16H32O2 | 15.609 | 11.05 ± 0.0255 |
| 3 | Palmitoleic acid | C16H30O2 | 17.11 | 0.171 ± 0.0014 |
| 4 | Margaric acid | C17H34O2 | 17.262 | 0.051 ± 0.0007 |
| 5 | Heptadecenoic acid | C17H32O2 | 18.2 | 0.042 ± 0.0007 |
| 6 | Linoleic acid | C18H32O2 | 18.735 | 42.160 ± 0.0325 |
| 7 | Oleic acid | C18H34O2 | 18.947 | 39.951 ± 0.0601 |
| 8 | Stearic acid | C18H36O2 | 19.280 | 5.240 ± 0.0156 |
| 9 | Linolenic acid | C18H30O2 | 22.24 | 0.311 ± 0.0007 |
| 10 | Arachidic acid | C20H40O2 | 23.082 | 0.531 ± 0.0014 |
| 11 | Eicosanoic acid | C20H38O2 | 25.7 | 0.171 ± 0.0014 |
| 12 | Behenic acid | C22H44O2 | 29.1 | 0.132 ± 0.0007 |
| 13 | Lignoceric acid | C24H48O2 | 29.84 | 0.071 ± 0.0007 |
| ∗∗SFA (%) | 17.265 ± 0.011 | |||
| ∗∗∗UFA (%) | 82.634 ± 0.0245 | ω-3 | 0.311 ± 0.0007 | |
| ω-6 | 42.160 ± 0.0325 | |||
| ω-9 | 39.951 ± 0.0601 | |||
- ∗RT: retention time.
- ∗∗SFA: saturated fatty acids.
- ∗∗∗UFA: unsaturated fatty acids.
Based on the sesame oil analysis, unsaturated fatty acids, linoleic acid, and oleic acid were the two major fatty acids in the sample, followed by SFAs, linoleic acid, palmitic acid, oleic acid, and stearic acid. Omega-3, omega-6, and omega-9 fatty acids include linolenic, linoleic, and oleic acids, respectively.
3.5. Fatty Acid Profile of Sesame Sample Enriched With Sargassum Algae Extract
GC-FID analysis of sesame oil enriched with S. bovianum extract revealed 14 types of fatty acids with different contents (Table 4).
| No. | Fatty acid | Chemical formula | RT∗ (min) | Amount (%) |
|---|---|---|---|---|
| 1 | Nonanoic acid | C9H18O2 | 9.214 | 0.142 ± 0.0013 |
| 2 | Azelaic acid | C9H16O4 | 9.441 | 0.234 ± 0.0016 |
| 3 | Myristic acid | C14H28O2 | 10.602 | 0.077 ± 0.0007 |
| 4 | Hypogenic acid | C16H30O2 | 11.941 | 0.026 ± 0.0007 |
| 5 | Palmitoleic acid | C16H30O2 | 12.547 | 0.101 ± 0.0013 |
| 6 | E-8-Methyl-9-tetradecen-1-ol acetate | C17H32O2 | 14.854 | 0.147 ± 0.0013 |
| 7 | Palmitic acid | C16H32O2 | 15.28 | 10.573 ± 0.0361 |
| 8 | Heptadecanoic acid | C17H34O2 | 16.801 | 0.052 ± 0.0007 |
| 9 | Linoleic acid | C18H32O2 | 18.324 | 46.877 ± 0.0651 |
| 10 | Oleic acid | C18H34O2 | 18.741 | 37.952 ± 0.0552 |
| 11 | Stearic acid | C18H36O2 | 19.280 | 3.349 ± 0.0154 |
| 12 | gamma-Linolenic acid | C18H30O2 | 19.76 | 0.091 ± 0.0007 |
| 13 | Gondoic acid | C20H38O2 | 20.914 | 0.052 ± 0.0007 |
| 14 | Arachidic acid | C20H40O2 | 22.143 | 0.305 ± 0.0014 |
| ∗∗SFA (%) | 14.732 ± 0.021 | |||
| ∗∗∗UFA (%) | 85.099 ± 0.034 | ω-3 | — | |
| ω-6 | 46.968 ± 0.045 | |||
| ω-9 | 38.004 ± 0.034 | |||
- ∗RT: retention time.
- ∗∗SFA: saturated fatty acids.
- ∗∗∗UFA: unsaturated fatty acids.
Based on the results, the two main unsaturated fatty acids linoleic acid and oleic acid present in sesame oil enriched with Sargassum seaweed extract had values of 46.877 ± 0.0651 and 37.952 ± 0.0552%, followed by palmitic and stearic SFAs 10.573 ± 0.0361 and 3.349 ± 0.0154%, respectively. The defined fatty acid chromatogram of sesame oil enriched with Sargassum seaweed extract is shown in Figure 2.
3.6. Results of GC-MS Analysis of Sargassum Algae
GC-MS analysis revealed the presence of 53 compounds (SB1–SB53), in Sargassum extract with different and unique chemical structures, functional groups, and nuclei (Table 5).
| No. | Chemical formula | Chemical name | Molecular weight (gr/mol) | Peak area (%) |
|---|---|---|---|---|
| SB1 | C14H30O | 2-Hexyl-1-octanol | 214 | 0.167 ± 0.0018 |
| SB2 | C15H32O2 | 1,3-Propanediol, 2-dodecyl | 244 | 0.052 ± 0.0026 |
| SB3 | C15H27Cl | 4-Pentadecyne, 15-chloro- | 242 | 0.125 ± 0.0026 |
| SB4 | C12H26 | Dodecane | 170 | 0.284 ± 0.0009 |
| SB5 | C8H10O2 | 2-Phenoxyethanol | 138 | 0.537 ± 0.0053 |
| SB6 | C12H22 | Naphthalene, decahydro-1,6-dimethyl- | 166 | 1.023 ± 0.0024 |
| SB7 | C16H30O | 7-Hexadecenal, (Z)- | 238 | 0.165 ± 0.0032 |
| SB8 | C11H24O2 | Nonanal dimethyl acetal | 188 | 0.069 ± 0.0013 |
| SB9 | C10H20O2 | 5-Decanone, 6-hydroxy | 172 | 0.690 ± 0.0049 |
| SB10 | C14H30 | Tetradecane | 198 | 0.905 ± 0.0038 |
| SB11 | C15H24 | β -caryophyllene | 204 | 0.654 ± 0.0016 |
| SB12 | C18H38 | Octadecane | 254 | 2.549 ± 0.0090 |
| SB13 | C14H22O | Phenol, 2,4-bis(1,1-dimethylethyl)- | 206 | 0.729 ± 0.0035 |
| SB14 | C19H40 | Octadecane, 6-methyl | 268 | 0.106 ± 0.0016 |
| SB15 | C14H30O2 | Dodecanal dimethyl acetal | 230 | 0.217 ± 0.0032 |
| SB16 | C17H36 | Tetradecane, 2,6,10-trimethyl | 240 | 1.498 ± 0.0071 |
| SB17 | C15H23Br | Neoisolongifolene, 8-bromo- | 282 | 0.280 ± 0.0009 |
| SB18 | C18H37Cl | Octadecane, 1-chloro- | 288 | 0.291 ± 0.0027 |
| SB19 | C18H30 | Benzene, 1,3,5-tris(1-methylpropyl)- | 246 | 0.411 ± 0.0014 |
| SB20 | C16H32O3 | Methoxyacetic acid, 2-tridecyl ester | 272 | 0.333 ± 0.0035 |
| SB21 | C20H42 | Phytane | 282 | 1.751 ± 0.0025 |
| SB22 | C16H34 | Dodecane, 5,8-diethyl | 226 | 0.407 ± 0.0014 |
| SB23 | C12H20O2 | 9,10-Dimethyltricyclo [4.2.1.1(2,5)] decane-9,10-diol | 196 | 0.565 ± 0.0032 |
| SB24 | C19H40 | Octadecane, 2-methyl | 268 | 0.454 ± 0.0030 |
| SB25 | C14H28O2 | Myristic acid | 228 | 1.092 ± 0.0070 |
| SB26 | C20H40O | Phytol | 296 | 0.510 ± 0.0024 |
| SB27 | C18H36O | Phytone | 268 | 0.390 ± 0.0021 |
| SB28 | C16H22O4 | — | 278 | 2.265 ± 0.0015 |
| SB29 | C17H24O3 | 7,9-Di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione | 276 | 6.841 ± 0.0184 |
| SB30 | C18H28O3 | Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, methyl ester | 292 | 1.706 ± 0.0010 |
| SB31 | C16H32O2 | Palmitic acid | 256 | 13.187 ± 0.0128 |
| SB32 | C19H34O2 | 8,11-Octadecadienoic acid, methyl ester | 294 | 0.794 ± 0.0009 |
| SB33 | C19H36O2 | Methyl oleate | 296 | 1.444 ± 0.0043 |
| SB34 | C19H38O2 | Methyl stearate | 298 | 0.914 ± 0.0019 |
| SB35 | C17H32O2 | 7-Methyl-Z-tetradecen-1-ol acetate | 268 | 3.049 ± 0.0114 |
| SB36 | C18H34O2 | Oleic acid | 282 | 7.114 ± 0.0017 |
| SB37 | C18H36O2 | Stearic acid | 284 | 6.212 ± 0.0165 |
| SB38 | C34H70 | Tetratriacontane | 478 | 0.537 ± 0.0004 |
| SB39 | C17H34O4 | Tetradecanoic acid, 2,3-dihydroxypropyl ester | 302 | 0.429 ± 0.0029 |
| SB40 | C29H30O10 | 4,2-Cresotic acid, 6-methoxy-, bimol. ester, methyl ester, 4,6-dimethoxy-o-toluate | 538 | 0.325 ± 0.0020 |
| SB41 | C27H56 | Heptacosane | 380 | 0.681 ± 0.0034 |
| SB42 | C19H38O4 | 2-Palmitoylglycerol | 330 | 10.942 ± 0.0133 |
| SB43 | C24H38O4 | Diisooctyl phthalate | 390 | 1.964 ± 0.0072 |
| SB44 | C21H40O4 | 2-Monoolein | 356 | 1.187 ± 0.0007 |
| SB45 | C21H42O4 | 2-Stearoylglycerol | 358 | 19.266 ± 0.0651 |
| SB46 | C17H19NO3 | Piperine | 285 | 1.365 ± 0.0032 |
| SB47 | C19H26O5 | Androst-7-ene-6,17-dione, 2,3,14-trihydroxy-, (2. beta.,3. beta.,5. alpha.)- | 334 | 1.877 ± 0.0071 |
| SB48 | C30H52O | 2,2,4-Trimethyl-3-(3,8,12,16-tetramethyl-heptadeca-3,7,11,15-tetraenyl)-cyclohexanol | 428 | 0.262 ± 0.0009 |
| SB49 | C16H34O | 2-Hexadecanol | 242 | 0.189 ± 0.0025 |
| SB50 | C27H46O | 4alpha,5alpha-Epoxycholestane | 386 | 0.109 ± 0.0012 |
| SB51 | C16H30O | (Z)-7-Hexadecenal | 238 | 0.119 ± 0.0019 |
| SB52 | C20H18O6 | Asarinin | 354 | 0.754 ± 0.0022 |
| SB53 | C27H40O4 | Spirost-8-en-11-one, 3-hydroxy-, (3. beta.,5. alpha.,14. beta.,20. beta.,22. beta.,25R) | 428 | 0.214 ± 0.0025 |
Based on the results obtained, the compounds 2-stearoyl glycerol, palmitic acid, 2-palmitoyl glycerol, oleic acid, 7,9-Di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione, and stearic acid had the greatest abundance with values of 19.266 ± 0.0651, 13.187 ± 0.0128, 10.942 ± 0.0133, 7.114 ± 0.0017, 6.841 ± 0.0184 and 6.212 ± 0.0165, respectively.
3.7. Results of GC-MS Analysis of Sesame Sample
GC-MS analysis of sesame samples revealed a total of 52 compounds (SM1–SM52), in recent study (Table 6).
| No. | Chemical formula | Chemical name | Molecular weight (gr/mol) | Peak area (%) |
|---|---|---|---|---|
| SM1 | C10H22 | Decane | 142 | 0.136 ± 0.0019 |
| SM2 | C6H6O3 | Maltol | 126 | 0.156 ± 0.0016 |
| SM3 | C12H26O | 1-Octanol, 2-butyl | 186 | 0.054 ± 0.0007 |
| SM4 | C14H28O2 | 3-Acetoxydodecane | 228 | 0.024 ± 0.0007 |
| SM5 | C14H30 | Tetradecane | 198 | 1.066 ± 0.0013 |
| SM6 | C6H6O3 | 5-Hydroxymethylfurfural | 126 | 0.871 ± 0.0027 |
| SM7 | C10H18O | 2-Decenal | 154 | 0.018 ± 0.0007 |
| SM8 | C11H20O3 | 4-Hydroxy-4-methylhex-5-enoic acid, tert. -butyl ester | 200 | 0.020 ± 0.0007 |
| SM9 | C7H6O3 | Sesamol | 138 | 0.414 ± 0.0020 |
| SM10 | C12H20O2 | Isopulegol acetate | 196 | 0.034 ± 0.0007 |
| SM11 | C15H24 | β-Caryophyllene | 204 | 0.196 ± 0.0019 |
| SM12 | C17H36 | Tetradecane, 2,6,10-trimethyl- | 240 | 0.548 ± 0.0021 |
| SM13 | C18H32O16 | Melezitose | 504 | 0.049 ± 0.0008 |
| SM14 | C14H22O | Phenol, 2,4-bis(1,1-dimethylethyl)- | 206 | 0.051 ± 0.0007 |
| SM15 | C16H34 | Hexadecane | 226 | 0.209 ± 0.0011 |
| SM16 | C16H32O3 | Methoxyacetic acid, 4-tridecyl ester | 272 | 0.038 ± 0.0008 |
| SM17 | C11H13F2NO4 | Benzeneethanamine, 2,6-difluoro-3,4-methoxy-. beta. -hydroxy-N-formyl | 261 | 0.019 ± 0.0007 |
| SM18 | C30H48 | 24-Noroleana-4(23), 12-diene, 3-methyl-, (3. alpha.)- | 408 | 0.031 ± 0.0007 |
| SM19 | C18H36O3 | Methoxyacetic acid, 3-pentadecyl ester | 300 | 0.050 ± 0.0014 |
| SM20 | C20H42 | Hexadecane, 2,6,11,15-tetramethyl | 282 | 0.327 ± 0.0019 |
| SM21 | C17H34O2 | Tridecanoic acid, 4,8,12-trimethyl-, methyl ester | 270 | 0.065 ± 0.0008 |
| SM22 | C18H38 | Octadecane | 254 | 0.093 ± 0.0016 |
| SM23 | C16H22O4 | Diisobutyl phthalate | 278 | 0.195 ± 0.0011 |
| SM24 | C17H24O3 | 7,9-Di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione | 276 | 0.141 ± 0.0016 |
| SM25 | C34H70 | Tetratriacontane | 478 | 0.115 ± 0.0013 |
| SM26 | C16H32O2 | Palmitic acid | 256 | 4.065 ± 0.0094 |
| SM27 | C27H56 | Heptacosane | 380 | 0.909 ± 0.0034 |
| SM28 | C19H36O2 | Methyl oleate | 296 | 0.228 ± 0.0010 |
| SM29 | C19H34O2 | 8,11-Octadecadienoic acid, methyl ester | 294 | 0.316 ± 0.0019 |
| SM30 | C19H36O2 | Methyl 10-octadecenoate | 296 | 0.426 ± 0.0015 |
| SM31 | C18H32O2 | Linoleic acid | 280 | 2.909 ± 0.0049 |
| SM32 | C18H34O2 | Oleic acid | 282 | 42.062 ± 0.0912 |
| SM33 | C18H36O2 | Stearic acid | 284 | 6.939 ± 0.0092 |
| SM34 | C15H24N2O | Lupanine | 248 | 0.193 ± 0.0010 |
| SM35 | C24H50 | Tetracosane | 338 | 0.427 ± 0.0020 |
| SM36 | C20H40O2 | Arachidic acid | 312 | 0.047 ± 0.0006 |
| SM37 | C19H38O4 | 2-Palmitoylglycerol | 330 | 1.029 ± 0.0005 |
| SM38 | C30H42Cl2N4O3 | 9-(2′,2′-Dimethylpropanoilhydrazono) -3,6-dichloro-2,7-bis- [2-(diethylamino)-ethoxy] fluorene | 576 | 0.155 ± 0.0005 |
| SM39 | C21H40O4 | 2-Monoolein | 356 | 0.647 ± 0.0016 |
| SM40 | C21H42O4 | 2-Stearoylglycerol | 358 | 3.106 ± 0.0101 |
| SM41 | C19H36O | 12-Methyl-E, E-2,13 -octadecadien-1-ol | 280 | 0.052 ± 0.0006 |
| SM42 | C30H50 | Squalene | 410 | 0.244 ± 0.0018 |
| SM43 | C29H50O | Beta-sitosterol | 414 | 0.158 ± 0.0005 |
| SM44 | C28H48O2 | Tocopherols | 416 | 1.402 ± 0.0037 |
| SM45 | C20H18O6 | d-Sesamin | 354 | 15.900 ± 0.0124 |
| SM46 | C12H11NO4 | 3-Methyl-4-piperonyl -5-isoxazolone | 233 | 3.368 ± 0.0250 |
| SM47 | C28H48O | Campesterol | 400 | 1.281 ± 0.0068 |
| SM48 | C29H48O | Stigmasterol | 412 | 0.943 ± 0.0001 |
| SM49 | C29H50O | Gamma-sitosterol | 414 | 6.308 ± 0.0095 |
| SM50 | C29H48O | Fucosterol | 412 | 0.391 ± 0.0009 |
| SM51 | C27H40O4 | Spirost-8-en-11-one, 3-hydroxy-, (3. beta.,5. alpha.,14. beta., 20. beta.,22. beta.,25R)- | 428 | 0.065 ± 0.0008 |
| SM52 | C31H50P2 | Methylenebis(2,4,6-triisopropylphenylphosphine) | 484 | 1.547 ± 0.0207 |
According to Table 6, oleic acid followed by di-sesamin had the greatest abundance with values of 42.062 ± 0.0912 and 15.900 ± 0.0124, respectively.
3.8. GC-MS Analysis of Sesame Oil Containing Sargassum Algae Extract
GC-MS analysis of sesame oil containing sargassum extract identified 44 chemical compounds (SS1–SS44), with different structures and abundances (Table 7).
| No. | Chemical formula | Chemical name | Molecular weight (gr/mol) | Peak area (%) |
|---|---|---|---|---|
| SS1 | C11H22O | trans-2-Undecen-1-ol | 170 | 0.093 ± 0.0007 |
| SS2 | C7H10O2 | 2-Cyclopenten-1-one, 3-ethyl-2-hydroxy | 126 | 0.083 ± 0.0007 |
| SS3 | C8H10O2 | Ethanol, 2-phenoxy- | 138 | 0.122 ± 0.0014 |
| SS4 | C6H6O3 | 5-Hydroxymethylfurfural | 126 | 0.115 ± 0.0014 |
| SS5 | C10H18O | (Z)-2-Decenal | 154 | 0.612 ± 0.0021 |
| SS6 | C10H16O | 2,4-Decadienal | 152 | 1.009 ± 0.0021 |
| SS7 | C14H30 | Tetradecane | 198 | 0.241 ± 0.0014 |
| SS8 | C15H24 | β-Caryophyllene | 204 | 0.236 ± 0.0014 |
| SS9 | C14H20O2 | 2,6-Di-tert-butyl-P-benzoquinone | 220 | 0.164 ± 0.0007 |
| SS10 | C17H36 | Tetradecane, 2,6,10-trimethyl- | 240 | 0.590 ± 0.0014 |
| SS11 | C14H22O | Phenol, 2,4-bis(1,1-dimethylethyl)- | 206 | 0.117 ± 0.0007 |
| SS12 | C16H34 | Hexadecane | 226 | 0.346 ± 0.0014 |
| SS13 | C17H36 | Heptadecane | 240 | 0.114 ± 0.0007 |
| SS14 | C19H40 | Octadecane, 2-methyl- | 268 | 0.346 ± 0.0014 |
| SS15 | C20H42 | Hexadecane, 2,6,11,15-tetramethyl- | 282 | 0.103 ± 0.007 |
| SS16 | C14H28O2 | Myristic acid | 228 | 0.188 ± 0.0014 |
| SS17 | C18H38 | Octadecane | 254 | 0.119 ± 0.0007 |
| SS18 | C19H40 | Nonadecane | 268 | 0.094 ± 0.0007 |
| SS19 | C23H36O4 | Phthalic acid, butyl undecyl ester | 376 | 0.144 ± 0.0014 |
| SS20 | C16H22O4 | 1,2-Benzenedicarboxylic acid, bis(2-methylpropyl) ester | 278 | 0.437 ± 0.0014 |
| SS21 | C17H24O3 | 7,9-Di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione | 276 | 0.947 ± 0.0022 |
| SS22 | C16H32O2 | Palmitic acid | 256 | 8.194 ± 0.0158 |
| SS23 | C19H34O2 | Methyl linoleate | 294 | 0.501 ± 0.0014 |
| SS24 | C19H36O2 | Methyl 10-octadecenoate | 296 | 0.632 ± 0.0021 |
| SS25 | C18H32O2 | Linoleic acid | 280 | 2.313 ± 0.0114 |
| SS26 | C18H34O2 | Oleic acid | 282 | 33.469 ± 0.0313 |
| SS27 | C18H36O2 | Stearic acid | 284 | 5.520 ± 0.0172 |
| SS28 | C15H24N2O | Lupanine | 248 | 0.115 ± 0.0007 |
| SS29 | C17H34O | Hexadecanal, 2-methyl- | 254 | 0.128 ± 0.0007 |
| SS30 | C29H48O | Fucosterol | 412 | 2.597 ± 0.0110 |
| SS31 | C19H38O4 | 2-Palmitoylglycerol | 330 | 1.821 ± 0.0057 |
| SS32 | C24H38O4 | Diisooctyl phthalate | 390 | 0.316 ± 0.0014 |
| SS33 | C21H38O4 | 1-Monolinolein | 354 | 0.595 ± 0.0014 |
| SS34 | C21H40O4 | 2-Monoolein | 356 | 3.403 ± 0.0172 |
| SS35 | C21H42O4 | 2-Stearoylglycerol | 358 | 0.453 ± 0.0014 |
| SS36 | C31H50P2 | Methylenebis(2,4,6-triisopropylphenylphosphine) | 484 | 6.033 ± 0.0251 |
| SS37 | C20H18O6 | d-Sesamin | 354 | 12.590 ± 0.0278 |
| SS38 | C12H11NO4 | 3-Methyl-4-piperonyl-5-isoxazolone | 233 | 3.908 ± 0.0278 |
| SS39 | C28H48O | Campesterol | 400 | 1.219 ± 0.0086 |
| SS40 | C29H48O | Stigmasterol | 412 | 0.618 ± 0.0014 |
| SS41 | C29H50O | Gamma-sitosterol | 414 | 5.997 ± 0.0258 |
| SS42 | C19H26O5 | Androst-7-ene-6,17-dione, 2,3,14-trihydroxy-, (2. beta.,3. beta.,5. alpha.) | 334 | 3.230 ± 0.0114 |
| SS43 | C17H32O2 | E-8-Methyl-9-tetradecen-1-ol acetate | 268 | 0.102 ± 0.0014 |
The main compounds of sesame oil enriched with sargassum seaweed extract were, respectively, oleic acid, di-sesamin, palmitic acid, methylene bis-(2,4,6-triisopropylphenylphosphine), gamma-sitosterol, and stearic acid. The GC-MS chromatograms associated with the sargassum, sesame oil, and sesame samples enriched with algal extract and the overlap of the three chromatograms are shown in Figure 3.
3.9. Determining the Inhibitory Power of DPPH Free Radicals
Table 8 shows the DPPH test results of sesame oil treated with seaweed extract, ascorbic acid, and TBHQ after 120 days compared to the oil without additives. TBHQ, ascorbic acid, seaweed extract, and sesame oil showed the highest DPPH free radical inhibitory activity with significant differences (P < 0.005), respectively. After treating sesame oil with TBHQ, ascorbic acid, and Sargassum, the DPPH free radical inhibition effect increased in a dose-dependent manner (p < 0.05).
| Conc. (μg/mL) | DPPH radical inhibition (%) | ||||||
|---|---|---|---|---|---|---|---|
| TBHQ | Ascorbic acid | Algae oil | Sesame oil | Oil + BHQ | Oil + ascorbic acid | Oil + algae | |
| 5 | 82.21 ± 0.11 | 56.20 ± 0.1 | 38.61 ± 0.05 | 18.84 ± 0.05 | 57.18 ± 0.2 | 52.38 ± 0.07 | 37.20 ± 0.03 |
| 15 | 86.73 ± 0.13 | 63.40 ± 0.08 | 48.82 ± 0.06 | 24.92 ± 0.08 | 65.73 ± 0.17 | 57.63 ± 0.11 | 46.80 ± 0.05 |
| 25 | 90.60 ± 0.09 | 68.70 ± 0.09 | 57.46 ± 0.04 | 27.96 ± 0.05 | 77.35 ± 0.09 | 63.82 ± 0.08 | 53.73 ± 0.09 |
| 35 | 94.82 ± 0.11 | 76.80 ± 0.12 | 63.6 ± 0.06 | 29.89 ± 0.09 | 82.83 ± 0.08 | 68.78 ± 0.12 | 58.28 ± 0.12 |
| 50 | 97.26 ± 0.14 | 88.23 ± 0.13 | 72.75 ± 0.06 | 35.98 ± 0.08 | 90.27 ± 0.2 | 70.72 ± 0.09 | 63.48 ± 0.11 |
3.10. Sensory Tests
Sesame oil treatments with seaweed extract, ascorbic acid, and TBHQ and control samples on days 1 and 120 were evaluated by 10 trained assessors (5 male, 5 female) for sensory properties including taste, aroma, color, and overall acceptability (Table 9).
| Time (day) | Sample | |||
|---|---|---|---|---|
| Control oil | Oil + TBHQ | Oil + ascorbic acid | Oil + algae | |
| Aroma | ||||
| 1 | 4.70 ± 0.47 | 4.70 ± 0.47 | 4.60 ± 0.50 | 4.60 ± 0.50 |
| 120 | 1.20 ± 0.41 | 3.60 ± 0.50 | 3.20 ± 0.77 | 2.40 ± 0.50 |
| Taste | ||||
| 1 | 4.50 ± 0.15 | 4.50 ± 0.51 | 4.50 ± 0.51 | 4.50 ± 0.51 |
| 120 | 1.31 ± 0.31 | 3.70 ± 0.41 | 3.00 ± 0.92 | 2.80 ± 0.41 |
| Appearance color | ||||
| 1 | 4.80 ± 0.41 | 4.80 ± 0.41 | 4.50 ± 0.51 | 3.00 ± 0.65 |
| 120 | 4.40 ± 0.50 | 4.50 ± 0.51 | 2.80 ± 0.41 | 2.40 ± 0.50 |
| General acceptance | ||||
| 1 | 4.60 ± 0.50 | 4.50 ± 0.51 | 4.40 ± 0.50 | 3.80 ± 0.62 |
| 120 | 1.30 ± 0.50 | 3.90 ± 0.31 | 4.80 ± 0.41 | 2.50 ± 0.51 |
The results showed that there were no significant differences between the control and treated samples regarding the aroma and taste scores on the first day. At Day 120, a significant increase in the scores was observed compared to the control group, indicating the effectiveness of the treatment in maintaining the aroma and taste of the oil.
On the first day, there were no significant difference in color scores between the control and treatment, except for the algal oil treatment. At Day 120, the results of the different color treatments showed a significant decrease compared to the control group.
No significant differences in overall acceptability were observed between the control group and treatments on the first day, except for the algal oil treatment. Although the overall acceptance rate decreased compared to the first day, there was a significant difference compared to the control group at Day 120. Although the addition of algae to oil is generally not well received by inspectors, the beneficial nutritional and therapeutic effects of algae enrichment cannot be ignored.
4. Discussion
Many plant-based edible oils have many health benefits and are essential for a balanced diet. The composition and biological activities of these substances vary significantly between plant species [29]. Due to the harmful effects of synthetic preservatives in processed foods, natural bioactive compounds such as antioxidants, polyphenols, proteins, minerals, and vitamins are used as antibacterial, antiviral, anti-inflammatory, and anticancer agents [30]. Algal metabolites are biologically active compounds.
In the present study, total lipid analysis of Sargassum algae revealed 18 types of fatty acids (C6–C21). The most abundant fatty acid was palmitic acid (C16:0) followed by caproic acid (C6:0), myristic acid (C14:0), and enanthic acid (C7:0). In addition, the proportion of SFAs was higher than that of unsaturated fatty acids.
Various studies have investigated the fatty acids present in many species of algae from different areas of the world. Rocha et al. [1], studied the fatty acid profiles of red and brown seaweeds from the Portuguese coast, including Sargassum muticum, and identified 13 fatty acids that were C16:0, C20:5 (EPA), C18:1, C16:1 and C22:6 (DHA) fatty acids, respectively, with the following values of 20.89 ± 0.72, 13.83 ± 0.48, 7.84 ± 0.24, 7.43 ± 0.15, and 7.33 ± 0.72%. In their study, as well as in the present study, palmitic acid had the highest concentration. However, unsaturated fatty acids had a higher proportion than SFAs [1]. In a similar study, GC-MS analysis of Sargassum by Santos et al. revealed 20 fatty acids. Like the present study, the most abundant fatty acid was (C16:0). In their study, the ratio of SFAs, monounsaturated fatty acids (MUFA), and PUFAs were 32.62 ± 0.92, 16.36 ± 0.49, and 51.02 ± 4.79%, respectively [31]. In a study by Rocha et al. [1], algal biomass obtained in spring from the coast of Aguda (Porto) showed a more diverse lipid composition than in autumn. According to their results, the lipid composition of each algal species depends on different factors and conditions [1].
Geographical location and exposure to various factors such as temperature, salinity, pH, waves, light, and nutrients can influence different biochemical changes within a species, especially in fatty acid composition. Previous studies have shown that cold-water algae have higher levels of unsaturated fatty acids (PUFA) than similar warm-water species [1].
Therefore, the difference in algal fatty acid composition between the present study and the reviewed studies may be due to these factors.
Comparing the results of the present study with those of prospective studies shows that palmitic acid is the most abundant fatty acid. Palmitic acid has various biological activities, such as antibacterial and antioxidant effects [32].
GC-FID analysis of sesame oil identified and quantified 13 fatty acids.
Unsaturated fatty acids, linoleic acid, and oleic acid are the main fatty acids, followed by SFAs, palmitic acid, and stearic acid. In the study of Olasunkanmi et al. similar to our study, linoleic acid, oleic acid, and palmitic acid accounted for the largest amount of fatty acids in sesame oil, respectively [33]. Similar to our study, Almeida Vittori Gouveia et al. found that the C18:2, C18:1, and C16:0 had the highest fatty acids in the sesame oil contents with values of 47.62%, 35.32%, and 11.49%, respectively [34].
Sesame oil is highly unsaturated due to the presence of unsaturated fatty acids such as oleic acid and linoleic acid [35]. The comparison revealed that the most abundant fatty acid found in sesame oil is linoleic acid. This omega-6 fatty acid is mainly found in plant fats and algae and is one of the essential fatty acids essential for human and animal health [36]. Linoleic acid has antioxidant properties and scavenges free radicals [37].
Oleic acid was the second most abundant fatty acid in sesame oil analysis in the present study and the reviewed studies. Sesame oil is one of the rich sources of oleic acid [38]. This fatty acid plays an effective role in many body processes by changing the composition of cell membranes and receptors. It also reduces the absorption of in the small intestine by decreasing the production of cholesterol receptors. Daily intake of oleic acid improves metabolic control and effectively lowers fasting blood glucose levels in patients with type 2 diabetes [39]. Foods containing oleic acid reduce severe skin damage caused by sunlight [40]. Escrich et al. showed that oleic acid modulates the malignant behavior of cancer cells [41].
This study identified 14 fatty acids in sesame oil enriched with Sargassum seaweed extract.
The fatty acids with the highest content were linoleic acid, oleic acid, palmitic acid, and stearic acid. By adding algae to sesame oil, the proportion of linoleic acid increased compared to the original sesame oil. The amounts of oleic acid, palmitic acid, and stearic acid were slightly decreased. The contents of omega-6 fatty acids (linoleic acid, gamma-linolenic acid) and omega-9 fatty acids (oleic acid, gondoic acid) in the total fatty acids of Sargassum seaweed enriched oil were 46.968 ± 0.045% and 38.004 ± 0.034%, respectively. Furthermore, the enriched oil had an increased content of omega-6 and a decreased content of omega-9 compared to sesame oil.
The World Health Organization has consistently emphasized the importance of controlling saturated and trans-fat levels in food products to reduce the burden of disease in the population. However, since SFAs in food have special technical properties, replacing SFAs with vegetable oils with a high proportion of unsaturated fatty acids poses a great challenge.
Lipids rich in unsaturated fatty acids are susceptible to lipid oxidation, which can lead to decreased taste, texture, shelf life, and nutritional value of foods [42]. Although sesame oil is rich in unsaturated fatty acids, it is more oxidatively stable than other vegetable oils. The high oxidative stability of sesame oil is due to various factors such as the growing conditions of the sesame seeds, extraction methods, oil processing conditions, as well as the presence of lignans and trace element amounts [43].
By identifying the secondary metabolites of Sargassum extract and its biological and phytochemical properties, the stability effects of sesame oil enriched with seaweed extract can be predicted. In this study, Sargassum seaweed extract contained 53 metabolites. SB5 was also found. According to Travassos et al., 2-phenoxyethanol (SB5) is widely used as a preservative in cosmetics and pharmaceuticals as well as in the preservation of liquid protein concentrates [44].
This compound found in Sargassum extract acts as a natural additive in the product. Furthermore, β-caryophyllene compound (C15H24) was detected in the analysis of both sargassum (SB11) and sesame oil (SS8) samples. Recent studies have reported the biological activity of β-caryophyllene as a functional food ingredient. In addition to its therapeutic properties, β-caryophyllene has been approved by the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) as a food flavoring agent, and food and beverage preservative [45].
Antioxidant, antistress, and longevity properties provide the nutritional basis for using this unique compound to strengthen the immune system and prevent excessive oxidative stress, which causes excessive inflammation. SB11 may be a potential candidate or adjuvant for the prevention and treatment of novel coronavirus (COVID-19), especially due to its immunomodulatory, anti-inflammatory, and antiviral effects. This could be a promising nutraceutical approach to limit cytokine storm, a major cause of death in COVID-19 [46]. Given the surprising biomedical effects of β-caryophyllene and its presence in sesame and algae samples, as well as its increased amount in sesame oil samples enriched with algal extract, it may be beneficial due to its nutritional and antioxidant effects.
Phytol (SB26) was also identified in GC-MS analysis of sargassum extract. It is an unsaturated branched chain diterpene fatty alcohol, commonly extracted from medicinal plants, mosses, and edible algae. Due to its antioxidant properties, SB26 reduces oxidative stress in biological systems and inhibits inflammatory responses by reducing oxidative stress and cytokine production. This terpene molecule has antiradical activity against some radicals such as carbon dioxide anion radical (CO2 (−) •), methoxy radical (CH2OH•), hydroxyl radical (OH•), and DPPH radical. It can be used as an antioxidant, by neutralizing reactive nitrogen species (RNS) and reactive oxygen species (ROS) and chelating catalytic metals as an absorbent. This compound exhibits a variety of biological effects, including antibacterial, cytotoxic, sedative, and anti-inflammatory, antidiabetic, analgesic, antimutagenic, antitumor, antiteratogenic, antiepileptic, hypolipidemic, antispasmodic, and antiscratching behavioral effects [47]. When consumed, it is thought to have many beneficial effects.
At least part of the enhanced antioxidant properties of sesame oil may be related to the compound 7 SB29 detected in sargassum extract. Tatipamura et al. demonstrated the antibacterial and antiviral activities of this seaweed extract compound [48]. According to Sharif et al, this compound can treat skin diseases, gonorrhea, migraines, intestinal parasites, and warts [49]. Seaweed is one of the richest sources of natural antioxidants. Therefore, there is a strong relationship between the phenolic content and AA of seaweed extracts [50]. The phenol,2,4-bis(1,1-dimethylethyl) is one of the phenolic compounds observed in sesame (SM14) and sargassum (SB13) extracts and is present in high proportions in seaweed-rich oil. The potential of this phenolic compound as an effective antipathogen agent and its use in the combined treatment of persistent and drug-resistant infections and increased bacterial sensitivity to antibiotics has been demonstrated [51]. Rangel-Sanchez et al. demonstrated the antibacterial, antifungal, anticancer, and antioxidant properties of this compound [52].
The compound 2-monolein was identified in both analyses of sesame and sargassum algae. The amount of this compound in sesame oil enriched with seaweed extract was significantly increased compared to the original sesame sample. This compound has been shown to have antioxidant [53], anti-atherosclerotic, emulsifying, and surfactant [54], and antibacterial properties [55].
Alkaloid derivatives have strong biomedical activities and are considered as medicines for the treatment of various diseases [56]. Piperine alkaloid (SB46) was found in Sargassum extract. SB46 is an alkaloid amide with multifunctional properties such as antioxidant, anticancer, anti-inflammatory, hypotensive, hepatoprotective, neuroprotective, and bioavailability-enhancing as well as anti-inflammatory activities. It is effective for diabetes, obesity, arthritis, oral cancer, breast cancer, multiple myeloma, metabolic syndrome, high blood pressure, Parkinson’s disease, Alzheimer’s disease, stroke, cardiovascular disease, kidney disease, inflammatory disease, and nasopharyngitis. SB46 inhibits cytochrome P450 and UDP glucuronyltransferases [57]. There is a protective effect against lipid peroxidation in mice fed a high-fat diet that increases intracellular oxidative stress [58]. SB46 is a promising candidate as an antimalarial drug or as adjunctive therapy in combination with other drugs [59].
In this study, GC-MS analysis of sesame extract identified 52 compounds with different chemical groups. One of the major compounds was lipophilic d-sesamin lignan (SM45), which was enriched at 15.900 ± 0.0124%. In addition to inhibiting fatty acid synthesis in the liver and regulating blood lipids, it is often used in cancer, inflammation, neurological diseases, liver diseases, diabetes, eye diseases, cardiovascular diseases, and lung diseases [60]. The AA of SM45 and its protective role against alcohol and carbon tetrachloride-induced damage to the liver has also been demonstrated [61]. SM45 has been shown to have antioxidant and antistress effects. Overall, although sesamin does not exhibit strong AA in vitro, it is a powerful antioxidant in the body. SM45, after entering the biosome, is concentrated in the liver and its metabolites have specific antioxidant properties. It is therefore classified as an antioxidant [62].
Sesamol (SM9) is another phenolic compound identified in sesame sample in current study. SM9 has strong antioxidant effects. The high AA of sesame oil compared to other vegetable oils is due to this phenolic compound [62]. SM9 is a type of excipient used in foods and medicines that has antioxidant, anti-aging, and anti-inflammatory properties. SM9 protects the body from various diseases such as obesity, lipidemia, and diabetic foot ulcers, mainly by regulating lipid and energy metabolism and reducing inflammatory cell infiltration [63]. Due to the strong AA of SM9, it is possible that at least some of the AA of sesame oil is due to this lignan.
Sesame oil contains many unsaturated fatty acids and a small amount of free fatty acids but has better oxidative stability than other vegetable oils. This high oxidative stability is due to the inherent lignans and tocopherols and the excellent synergy between these components. Tocopherols are very powerful antioxidants found in sesame seeds and are very helpful in carrying out biological activities [62]. In addition, tocopherols play an effective role in increasing the oxidative stability of oils during storage in the presence of light [64].
The sesame samples in this study contained the sterols gamma-sitosterol (SM49), beta-sitosterol (SM43), campesterol (SM47), stigmasterol (SM48), and fucosterol (SM50). Phytosterols are plant steroids and biologically active molecules used for many health applications in the food, pharmaceutical, cosmetic, and healthcare industries. Humans cannot synthesize it, so it must be obtained from food. They have many pharmacological properties and biological effects, such as chemopreventive, antioxidant, anti-inflammatory, antidiabetic, anti-atherosclerotic, antibacterial, and cardioprotective effects. Phytosterols reduce lipid peroxidation in platelet membranes in the presence of iron. Their influence on oil stability at high temperatures has been shown to inhibit polymerization reactions. The antioxidant effects of phytosterols are related to their excellent ability to scavenge free radicals and stabilize cell membranes. They also act as antioxidant enzyme boosters. Furthermore, inflammation is increasingly associated with oxidative stress and overproduction of ROS. Therefore, these bioactive molecules with specific antioxidant properties have specific anti-inflammatory abilities [65]. Considering the high amount of SM50 and the increased amount of concentrated sesame oil contained in Sargassum seaweed extract, as well as the beneficial biomedical effects and significant antibacterial and antioxidant properties of these compounds, the addition of Sargassum seaweed extract can improve the nutritional and antioxidant properties of sesame oil.
The free radical scavenging activity of DPPH was used to evaluate its potential AA. The algal-containing sesame oil sample showed stronger inhibition with significant differences compared to the control sample at all concentrations. The free radical inhibitory ability of sargassum may be due to natural bioactive compounds found in seaweed and sesame oil.
The results of a study by Budhiyanti et al. [66] showed that the DPPH free radical scavenging activities of membrane and cytoplasmic extracts of Sargassum alga at a concentration of 0.45 mg/mL extract ranged from 14.61 to 48.71% and from 0.17%–44.05%, respectively. However, the AA of the extract was lower than that of the synthetic antioxidants BHT and EDTA, which is consistent with our results [66]. In Rajivgandhi et al. [13], S. wightii seaweed extract exhibited strong AA at a concentration of 200 μg/mL, due to the presence of phytochemical derivatives, biologically active compounds and rich polysaccharide content. Free radical inhibitory activity was directly related to phenol and flavonoid contents [13]. In the present study, the PV of the oil sample containing algae was significantly lower than that of the control sample, indicating the protective effect of algae extract on oil.
Additionally, PVs in all samples increased with increasing storage time (120 days). The control sample increased more than the other samples. In a study by Omidi et al. [67], the PV of sesame oil containing ethanolic spirulina extract was lower than that of oil containing synthetic antioxidants BHA and BHT after 16 days [67]. In our result, the sample containing seaweed extract showed a lower AV than the sample containing TBHQ, during the 120-day storage period. It may be due to the hydrolysis of triglycerides by temperature, bacterial, fungal, or vegetable lipase enzymes in crude oil [68]. This is probably due to the thermal and enzymatic hydrolysis of triglycerides present in the crude oil.
The chemical composition of algae potentially prevents triglyceride hydrolysis of free fatty acids and exhibits a higher potency than the synthetic compound TBHQ. In a study by Alavi and Golmakani [69], olive oil containing 0.5%, 1%, and 1.5% spirulina reduced the acidity index of samples during storage. This means that adding Spirulina algae can slow down the formation of secondary oxidation products [69]. The inflection point of the oxidation curve is determined as the degree of induction, and the Rancimet method is considered a direct measure of changes in oil quality and oxidative stability [7]. According to the oxidative stability results, the sesame oil sample enriched with Sargassum seaweed extract was more stable at a temperature of 110°C than the oil sample containing the synthetic antioxidants TBHQ and ascorbic acid and the control sample. This demonstrates the effectiveness of the valuable natural antioxidants and stabilizing compounds found in sargassum and sesame oils. Some of these were identified during the analysis of secondary metabolites. Adding algae to the oil not only increases its oxidative stability but also increases its nutritional value. Zanjani et al. [7] obtained the oxidative stability of sesame oil by cold press extraction using the Rancimat method in the range from 9.48 ± 0.1 to 7.35 ± 0.1 h. They attributed this stability to the presence of effective natural antioxidants such as lignans, phenolic compounds, tocopherols, and sterols, despite the high unsaturated fatty acid content [7]. The slight difference in oxidative stability of sesame oil in this study compared with other studies may be due to the variety of sesame seeds and processing methods. According to a study by Alavi and Golmakani [69], the induction times of original olive oil, olive oil with 0.5% spirulina extract, and synthetic antioxidant BHT were 22.85, 31.15, and 42.71 h, respectively. As shown in the current study, the addition of algae significantly increased the oxidative stability of original virgin olive oil [69].
The results of sensory evaluation during storage time showed that seaweed extract can control the loss of taste and aroma compared to the control group. The color changed from yellow to green due to adding seaweed extract to the oil on the first day, and the storage time did not change much compared to the first day. In a study by Alavi and Golmakani [69], the addition of spirulina extract to olive oil decreased the brightness index and increased the green color of the oil [69].
5. Conclusion
Chromatographic analysis revealed a variety of fatty acids with different chemical structures. The addition of algae to sesame oil significantly increased the DPPH inhibitory activity against free radicals in a concentration-dependent manner. Algae and synthetic antioxidants TBHQ and ascorbic acid increased the oxidative stability of the oil. After evaluating taste, aroma, and odor during 120 days of storage, we found that the seaweed extract was able to maintain these qualities. The antioxidant properties of Sargassum seaweed contributed to improving oil stability and protecting it from oxidation.
Conflicts of Interest
The authors declare no conflicts of interest.
Author Contributions
G.M. and A.D. participated in the conception and design of the study. M.M., T.K., G.M., N.B., and N.S. contributed to the data analysis and drafted the manuscript. M.M., A.B., and G.M. carried out the experiments and data analysis. All authors read and approved the final manuscript.
Funding
No funding was received for this research.
Acknowledgments
The authors have nothing to report.
Open Research
The data that support the findings of this study are available from the corresponding authors upon reasonable request.
