Effects of roasting conditions of sesame seeds on the oxidative stability of pressed oil during thermal oxidation

Chemical and structural transformations of lignin in sesame seed hull during roasting

To investigate the mechanism of lignin degradation during sesame roasting, structural transformations of milled wood lignin (MWL) from sesame seed hull samples roasted at 190-250 °C for 30 min were investigated. The findings revealed that, with increasing temperature, the degradation extent of carbohydrates from lignin carbohydrate complex in the fractions deepened, which reduced total sugar content (from 8.59 % to 0.45 %). Compared to that of the original sesame seed hull lignin (LSSH), the molecular weight of MWL fractions showed a tendency to decline (Mw 4377-2235 Da) with the rise of roasting temperature (210-250 °C). During roasting, lignins in the sesame seed hull underwent degradation and condensation. Due to demethoxylation, the H-type lignin proportion increased from 2.7 % to 26.1 %. Compared to G- and C-type lignin, S-type lignin was more stable. The β-O-4 linkages decreased from 5.8 to 1.2/100 Ar due to CO bond breaking, and β-β linkages from 26.3 to 9.6/100 Ar decreased due to condensation of CC. As the roasting temperature increased, more chemical bonds between lignin structural units were broken, resulting in the generation of more phenolic hydroxyl groups (1.80-2.53 mmol/g). This study helps to elucidate the contribution of lignin degradation during roasting to the oxidative stability of sesame oil.

Stability and Bioaccessibility of Lignans in Food Products

Lignans are a group of plant phenolic compounds with various technofunctional and health-promoting properties. They can be found in oilseeds (291.7-2513 mg/100 g), nuts, vegetables, fruits, and alcoholic and nonalcoholic drinks. The most common structural representative feature of lignans' backbone is a dimeric phenylpropanoid, which consists of two C6-C3 units joined by a central carbon. Compared to other phenolics, such as flavonoids, the literature on lignan stability and bioaccessibility is limited. This Mini-Review aims to present an overview of recent literature, draw connecting lines to the known regarding polyphenols, and suggest the main knowledge gaps. Processing methods and processing conditions influence the stability of lignans with several thermal treatments explored. Roasting, as a major studied processing step, displayed varying effects as a function of the lignan structure and matrix. The content of specific and even total lignans was shown to increase in some cases even after intense thermal treatment. Lignans were also reported to present a stabilizing effect against oxidation to oils when added externally. Different fermentation methods presented inconclusive outcomes on the content of lignans, likely stemming from the various matrices and microorganisms studied in a relatively limited pool of studies. The bioaccessibility of lignans in in vitro studies was usually low (from less than 1% in fermented flaxseed to 30% for microwaved artichokes). Yet, a clear conclusion regarding the digestive fate of lignans as a function of processing and structure cannot be currently suggested, and significant additional effort in this direction is needed.

The effects of superheated steam roasting on proximate analysis, antioxidant activity, and oil quality of black seed (Nigella sativa)

Nigella sativa, commonly known as the black seed, is a culinary spice therapeutic against many ailments. Common preparation practice of roasting or heating the seeds often deteriorates bioactive compounds, which can be remedied with superheated steam (SHS). With roasting temperatures of 150, 200, and 250°C and roasting times of 10, 15, and 20 min, convection and SHS roasting media were tested, and their effects on proximate analysis, antioxidant assays, and oil quality were evaluated. For proximate content, moisture significantly decreased from 9.08% in unroasted seeds to 4.18%-1.04% in roasted seeds, while fat increased to as high as 44.76% from 32.87% in unroasted seeds. Roasting only slightly increased ash content and had no significant impact on protein and carbohydrate content. SHS roasted black seeds had better DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging capacity (RSC) than convection roasted seeds. DPPH RSC decreased with elevated roasting time and temperature, conversely related to total phenolic content, which increased with increased roasting time and temperature. Oil of roasted seeds developed an increasingly intense brown color from an initial light, yellow, unroasted oil with better extraction efficiency in SHS roasting. For oil quality analysis, free fatty acid values were significantly lower in both roasted samples. Peroxide value was initially recorded at 84 in convection and 48 (meq O2/kg of oil) in SHS roasted samples. In contrast, p-anisidine values were initially recorded at 28.36 in convection roasted samples compared to 23.73 in SHS roasted samples. Based on all quality analyses, SHS showed better potential in black seed quality preservation.

Approaches of lipid oxidation mechanisms in oil matrices using association colloids and analysis methods for the lipid oxidation

Lipid oxidation is one of the key chemical reactions in foods containing fats and oils during production and storage. For several decades, many researchers have tried to understand the mechanisms of lipid oxidation and ways to control the rates of lipid oxidation. Theories of autoxidation or free radical chain reaction have been developed to successfully explain the phenomenon observed in oxidized lipids. Many studies have been conducted to explain the other factors that can affect the lipid oxidation such as food matrix, oxidation time and temperature, transition metal ions, pigments with sensitizing abilities, and surface-active compounds such as phospholipids, free fatty acids, monoacylglycerols, and diacylglycerols. Several strategies were developed to evaluate the degree of oxidation and oxidative stability. This review provides crucial information on the mechanism of lipid oxidation affected amphiphilic compounds and association colloids. This review article will extensively discuss about the methods for determining the oxidative stability.

Olive Oil Benefits from Sesame Oil Blending While Extra Virgin Olive Oil Resists Oxidation during Deep Frying

Fresh potatoes were deep-fried in olive oil (OO), extra virgin olive oil (EVOO), and their blends with 5%, 10%, and 20% v/v sesame oil (SO). This is the first report on the use of sesame oil as a natural source of antioxidants during olive oil deep frying. The oil was evaluated for anisidine value (AV), free fatty acids (FFAs), extinction coefficient (K₂₃₂ and K₂₇₀), Trolox equivalent antioxidant capacity (TEAC), and total phenols (TPs) until the total polar compounds (TPCs) reached 25%. Sesame lignan transformations were monitored through reversed-phase HPLC. While the TPCs in olive oils increased at a steady rate, the addition of 5%, 10%, and 20% v/v SO delayed TPCs' formation for 1, 2, and 3 h, respectively. The addition of 5%, 10%, and 20% v/v SO increased the olive oil frying time by 1.5 h, 3.5 h, and 2.5 h, respectively. The addition of SO to OO reduced the secondary oxidation products' formation rate. The AV for EVOO was lower than OO and all tested blends, even those with EVOO. EVOO was more resistant to oxidation than OO, as measured by the TPCs and TEAC, while the frying time rose from 21.5 to 25.25 h when EVOO replaced OO. The increase in frying time for OO but not for EVOO, after SO addition, points to a niche market for EVOO in deep frying.

Investigations on color and flavor formed by roasting sesame polysaccharide-protein mixtures

Roasting is an important operation to produce attractive colors and distinctive flavors during the production of sesame oil. To investigate the contributions of macromolecules to the color and flavor during roasting sesame seeds, water-soluble polysaccharides (WSP) and chelator-soluble polysaccharides (CSP) sequentially extracted from sesame hull were mixed with sesame protein isolate (SPI) at different ratios (1:1, 1:2, and 2:1, w/w), then the mixtures were roasted at 180 °C for 35 min. Results showed that WSP, CSP, and SPI degraded approximately at 150 °C and SPI had the highest thermal stability. According to monosaccharide/amino acid analysis, glucose and galacturonic acid showed the highest reduction rates, as well as lysine and arginine. CSP + SPI mixtures showed greater reactivity than WSP + SPI mixtures, resulting in a darker color and many more Maillard reaction products. The predominant volatiles of roasted WSP/CSP + SPI mixtures were aldehydes and heterocyclic compounds identified by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS). This work provides some new information about flavor and color development during roasting sesame seeds.

Application of Maillard Reaction Products Derived Only from Enzymatically Hydrolyzed Sesame Meal to Enhance the Flavor and Oxidative Stability of Sesame Oil

The low-temperature roasting of sesame oil has become increasingly popular because of its nutritional benefits; however, the flavor is reduced. In order to improve the quality of sesame oil without exogenous addition, sesame meal was hydrolyzed and further used to prepare Maillard reaction products (MRPs) while protease hydrolysis (PH) and glucoamylase-protease hydrolysis (GPH) were used, and their respective Maillard products (PHM and GPHM) were added in the oils for reducing sugar and total sugar content determination, free amino acid determination, and color and descriptive sensory analysis, as well as electronic nose, SPME-GC-MS, odor activity value, and oxidative stability analyses. Results showed that the MRPs could be produced using the enzymatically hydrolyzed sesame meal without exogenous addition, and the oil flavor blended with GPHM (GPHM-SO) was significantly (p < 0.05) improved with the best sensory quality. The composition of pyrazines (119.35 μg/mL), furans (13.95 μg/mL), and sulfur substances (6.25 μg/mL) contributed positively to sensory properties in GPHM-SO, and 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, and 2,3-dimethylpyrazine were characterized as the key flavor compounds with odor activity values of 7.01, 14.80, and 31.38, respectively. Furthermore, the oxidative stability of the oil was significantly improved with the addition of MRPs, and the shelf life of GPHM-SO was predicted to be extended by 1.9 times more than that of the crude oil based on the accelerated oxidation fitting analysis. In general, the MRPs derived only from sesame meal can enhance the flavor and oxidative stability of sesame oil and can be applied in the oil industry.

An Overview on the Use of Extracts from Medicinal and Aromatic Plants to Improve Nutritional Value and Oxidative Stability of Vegetable Oils

Oil oxidation is the main factor limiting vegetable oils' quality during storage, as it leads to the deterioration of oil's nutritional quality and gives rise to disagreeable flavors. These changes make fat-containing foods less acceptable to consumers. To deal with this problem and to meet consumer demand for natural foods, vegetable oil fabricators and the food industry are looking for alternatives to synthetic antioxidants to protect oils from oxidation. In this context, natural antioxidant compounds extracted from different parts (leaves, roots, flowers, and seeds) of medicinal and aromatic plants (MAPs) could be used as a promising and sustainable solution to protect consumers' health. The objective of this review was to compile published literature regarding the extraction of bioactive compounds from MAPs as well as different methods of vegetable oils enrichment. In fact, this review uses a multidisciplinary approach and offers an updated overview of the technological, sustainability, chemical and safety aspects related to the protection of oils.

Effect of Roasting on the Conformational Structure and IgE Binding of Sesame Allergens

Sesame can trigger a systemic allergic reaction. In the present study, we investigated the responses of the structure and IgE binding of sesame allergens to different roasting treatments (120, 150, and 180 °C for 5 to 30 min). We analyzed the tryptic digestion peptides using a label-free mass spectrometry method. The total amount of soluble proteins in sesame was significantly reduced by roasting at 180 °C, followed by 150 °C. Ses i 1 was the most stable protein during processing as it still possessed a higher protein abundance compared to other allergens after roasting under 180 °C. The most unstable allergens were Ses i 4 and Ses i 7, which suffered severe protein degradation at 180 °C. Roasting at 180 °C remarkably increased the secondary structure content of α-helices but decreased that of β-sheets, whereas roasting at 120 and 150 °C had a limited effect on the secondary structure of sesame proteins. Moreover, serum pool Western blot analysis showed that the main allergens were oleosin of Ses i 4 and Ses i 5. The IgE-binding ability of sesame allergens was significantly decreased under 180 °C roasting, as well as the solubility of sesame proteins, which showed remarkable congruence in changes. Relative quantification results indicate that individual sesame allergens respond differently to the roasting process. In general, sesame allergens are unstable under roasting treatment. Therefore, the allergenic potential of sesame allergens may be minimized by selecting appropriate parameters during processing.

Nutritional and Antioxidant Properties of Moringa oleifera Leaves in Functional Foods

Moringa oleifera is a tree cultivated originally in northern India, whose ancient use as a medicine has demonstrated its antioxidant and anti-inflammatory properties. Due to its richness in minerals and macronutrients, the antioxidant capacity and the mineral bioaccesibility were assessed. In addition, the chemical composition, amino acid, fatty acid, and mineral content were also evaluated. The performed analysis reported a high content of proteins and low content of lipids in the chemical composition. Regarding the mineral content, Ca and Fe presented high bioaccessibility; K, S, Ca, and Fe being the most concentrated elements. The obtained values using FRAP, ABTS, and ORAC methods showed high antioxidant capacity, directly related to the increased content of phenolic compounds. In view of the results, Moringa oleifera can be incorporated into the diet as a functional ingredient or as a fortifier of any kind of food. The important source of minerals, phenolics, proteins, unsaturated fats, and folates make it an excellent extract with beneficial properties.

Application of OXITEST for Prediction of Shelf-Lives of Selected Cold-Pressed Oils

Introduction: Due to the enhanced awareness of consumers concerning healthy foods, homemade expeller-pressed oils have become popular worldwide. However, an extended storage period may lead to oxidization of the oil and exposure to hazardous byproducts by consumers.

Methods: In this study, 10 pressed oil samples prepared from common oilseeds using a small-scale expeller oil press were analyzed by OXITEST with a sample amount of 5 g of oil and an oxygen pressure of 800 kPa under accelerated conditions for shelf-life projections. The oil properties were investigated, including the recovery, smoke point, acid value, iodine value, “fatty acid composition, and contents of pigments and tocopherols”.

Results: The autoxidation reaction of various expeller-pressed oils under an accelerated testing system followed zero-order Arrhenius kinetics (R² > 0.99). Shelf-lives of the pressed oils at 25°C were estimated by extrapolation to range 105~1,089 days. The obtained shelf-lives were significantly correlated with log induction period (IP) values (r > 0.81, p < 0.05) and unsaturated fatty acids (UFAs) (r < −0.69, p < 0.05), but not with the iodine value, acid value, or smoke point. Scatter diagrams between shelf-lives and UFAs suggested that these pressed oils could be grouped by two linear regression curves (r > 0.98, p < 0.05). The predictive equations using multiple linear regression are presented herein, with predictor variables of UFAs and an unspecified item involving potential influencing factors such as tocopherol contents (r > 0.88, p < 0.05).

Conclusions: Our findings first revealed that the UFA portion was partially correlated with the shelf-lives of selected expeller-pressed seed oils as estimated by the OXITEST. The derived equations can be applied for shelf-life predictions of expeller-pressed oils stored under dark ambient conditions based on the fatty acid profile.

Simultaneous Recovery of High Quality Black Sesame Oil and Defatted Meal by a New Aqueous Method: Optimization and Comparison with Other Methods

A method able to simultaneously obtain oil and defatted meal (rich in proteins) with high quality is preferable to others for processing black sesame seeds, which should also be green, healthy, highly efficient and sustainable. Methods including solvent extraction and hot-pressing currently available for the commercial production of oils are not able to meet all criteria just mentioned above. Therefore, development of new aqueous method of extracting black sesame oil has been promoted. In our study, we developed a new aqueous method using 1.95:10 aqueous salt solution-to-ground black sesame seed ratio which simultaneously recovered 96.54% black sesame oils and defatted meal with only 3.89% residual oils and 50.1% proteins (on dry weight basis). The oil produced had low acid value at 0.43 mgKOH/kg and peroxide value 3.37 mmol/kg and good other quality indexes. We found that proper amount of water added was essential for efficiently recover black sesame oils while other factors including temperature and time of baking raw materials to deactivate lipase activity, pore size of the sieve for ground black sesame seeds to pass through, addition of salt as well as temperature and time of agitating significantly affected the recovery efficiency. As compared with other methods, the new aqueous method had higher oil recovery rate or quality and was more environmentally friendly. No waste water was discharged during separation of oils. The experimental data can be applied to guide the design and manufacture of production line of black sesame oilseeds on a pilot or commercial scale.

Lipidomics reveals the changes in lipid profile of flaxseed oil affected by roasting

Roasting before oil extraction improves the oxidative stability and odor of flaxseed oil; however, the effect of roasting on lipid profile is still unclear. Herein, the changes in lipid profile in flaxseed oil during roasting were investigated based on lipidomic approach. 238 lipids including fatty acid (45 species), phospholipid (37 species), triacylglycerol (125 species), and oxidized fatty acid (21 species) were determined in unroasted and roasted flaxseed oils. After roasting, unsaturated fatty acids including oleic, linoleic, and lenolenic acid decreased. Triacylglycerols such as TAG(18:3/18:3/18:3) and TAG(18:2/18:3/18:3) had the same change trends with unsaturated fatty acids. However, phosphatidylcholines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidylinositols, lysophosphatidylcholines, lysophosphatidylethanolamines, and oxidized fatty acids firstly increased and then decreased during roasting. Cyclic phosphadic acids identified for the first time in flaxseed oils increased rapidly at high-temperature roasting. 23 lipids were determined as potential biomarkers to differentiate the light and dark roasted flaxseed oils. Our finding could provide useful information for flaxseed oil processing and lipidomics.

The chemical composition and heavy metal content of sesame oil produced by different methods: A risk assessment study

The oil was extracted from sesame seed with two extraction methods. Traditional (Ardeh oil) and industrial method (cold pressing method: virgin and refined sesame oil) oil extraction was studied to compare the quality and heavy metal content of extracted oils. The chemical properties (fatty acid composition, peroxide, anisidine, acid values, and TOTOX) and heavy metal contents were investigated. The Hazard Quotient (HQ) and Hazard Index (HI) of heavy metal intakes were calculated. The results demonstrated that the predominant fatty acid in oil samples was oleic, linoleic, palmitic, and stearic acids. It was indicated the peroxide, anisidine, acid values, and TOTOX of oil samples were as the order of Ardeh oil > virgin sesame oil > refined sesame oil. The reduction pattern of Pb > Zn >Cu > Cd >As was reported in sesame seed. Although the oil refining had been greatly reduced the Pb of oil sample, but it had yet been much higher than the permissible levels set by Codex Alimentarius. The HQ and HI of all heavy metals were less than one, but they were higher in Ardeh oil compared to others. It is necessary to monitor the presence of heavy metal contaminants and the quality of imported sesame seeds prior to oil preparation.

Reduction of Polycyclic Aromatic Hydrocarbons (PAHs) in Sesame Oil Using Cellulosic Aerogel

The effect of cellulosic aerogel treatments used for adsorption of four polycyclic aromatic hydrocarbons (PAHs)—benzo[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene [BaP]—generated during the manufacture of sesame oil was evaluated. In this study, eulalia (Miscanthus sinensis var. purpurascens)-based cellulosic aerogel (adsorbent) was prepared and used high performance liquid chromatography with fluorescence detection for determination of PAHs in sesame oil. In addition, changes in the sesame oil quality parameters (acid value, peroxide value, color, and fatty acid composition) following cellulosic aerogel treatment were also evaluated. The four PAHs and their total levels decreased in sesame oil samples roasted under different conditions (p < 0.05) following treatment with cellulosic aerogel. In particular, highly carcinogenic BaP was not detected after treatment with cellulosic aerogel. Moreover, there were no noticeable quality changes in the quality parameters between treated and control samples. It was concluded that eulalia-based cellulosic aerogel proved suitable for the reduction of PAHs from sesame oil and can be used as an eco-friendly adsorbent.

Effect of Roasting and Vacuum Microwave Treatments on Physicochemical and Antioxidant Properties of Oil Extracted from Black Sesame Seeds

Unroasted, roasted (at roasting temperatures of 100, 150 and 200 C and roasting times of 10, 20 and 30 min) and vacuum microwaved (at microwave watt powers of 800, 1440, 2400 and 3600 watts/kg black sesame seeds, for heating times of 10, 20 and 30 min) black sesame seeds were processed to extract oil using a single screw press at a constant pressing temperature of 50 C. The results revealed that different heat pre-treatments significantly affected yield and physiochemical and antioxidant properties of extracted oils. The extracted oil samples exhibited significantly different levels of total phenolic compounds, sesamin, sesamolin, and DPPH• and ABTS•+ scavenging activity. Additionally, it was found that these values of roasted and vacuum microwaved black sesame seed oils were significantly higher than those of unroasted oil. Sesamin, sesamolin, total content of phenolic compounds, and DPPH• and ABTS•+ scavenging activity of extracted black sesame oils increased when the roasting temperature and watt power increased. Black sesame oil obtained from unroasted, roasted and vacuum microwaved dried black sesame seeds contained linoleic and oleic acids as major fatty acids. Black sesame oil extracted from roasting and vacuum microwave treatments for 10 min at higher roasting temperature and microwave watt power had higher total phenolic content leading to a reduction of peroxide value and elevated stability of soybean oil when it was added during storage time at temperature of 65 °C.

Effect of conventional oven roasting treatment on the physicochemical quality attributes of sesame seeds obtained from different locations

The impacts of conventional oven roasting at different temperatures and for different times on the physicochemical attributes of sesame seeds obtained from different regions was assessed. The color characteristics (a*, b*, and L* values), ash, moisture, protein, oil, total phenolic, and antioxidant activity of raw sesame seeds and the peroxide value, p-anisidine, fatty acids, and tocopherols of sesame oil varied with source. Oven roasting temperature and time significantly affected the physicochemical properties and bioactive components of sesame seeds and the oil quality from different countries. Roasting variably increased the a* value, antioxidant activity, protein, oil, total phenolic, and tocopherol content, and p-anisidine and peroxide values, whereas it reduced b* and L* values, moisture, and linolenic acid content of sesame seeds from different countries. Roasting conditions and growing locations affected the physiochemical composition and bioactive compounds of seeds. Such factors can influence the quality attributes of sesame seeds and oil and should be considered during processing.

Profile of Volatile Aroma-Active Compounds of Cactus Seed Oil (Opuntia ficus-indica) from Different Locations in Morocco and Their Fate during Seed Roasting

Volatile compounds from oils extracted from cactus seeds (Opuntia ficus-indica) of five regions of Morocco were analyzed by dynamic headspace-GC/MS. Aroma active compounds were characterized by olfactometry. A total of 18 compounds was detected with hexanal, 2-methyl propanal, acetaldehyde, acetic acid, acetoin and 2,3-butanedione as most abundant. Olfactometric analysis showed that those compounds are aroma active; therefore, cactus seed oil flavor can be attributed to those compounds. Moreover, the effect of roasting of cactus seeds on the composition of volatile compounds in the oil was investigated. Especially the concentration of compounds known as products from the Maillard reaction increased significantly with roasting time such as furfural, furan, 3-methyl furan, 2-butanone, thiophene, 2, 3- dithiabutane, methyl pyrazine, 2-methyl pyrimidine, 2-metoxy phenol, dimethyl trisulfide and 5-methyl furfural.

Formation and Antioxidant Activity of Maillard Reaction Products Derived from Different Sugar-amino Acid Aqueous Model Systems of Sesame Roasting

This investigation was carried out to offer insight into the formation and antioxidant activity of Maillard reaction products (MRPs) derived from various sugar-amino acid model systems active in the roasting of sesame seeds. Reducing sugars (glucose, fructose, and xylose) and amino acids (serine, cystine, arginine, and lysine) present in sesame seeds were used to prepare the MRPs at various reaction times, and then the effect of reaction time on the MRPs derived from the various model systems was investigated. Within the first 15 min, the amounts of free amino groups decreased around 40% remaining amino groups of Lys-sugar model and around 75% remaining amino groups of Arg-sugar model. Results indicated that reducing sugar and free amino groups decreased obviously in Lys- and Arg-model systems. Based on correlation coefficient of antioxidant activities assessment and MRP formation in the Lys- and Arg-model systems above 0.978 and an extremely significant correlation in Pearson test exists, a conclusion could be made that these model systems are critical contributing factors in MRP formation during the roasting of sesame seeds. These findings offer insight into the formation and antioxidation of MRPs during the sesame seeds roasting.

Thermal Stability and Kinetic Study on Thermal Degradation of Vitamin D3 in Fortified Canola Oil

Nowadays, fortified vegetable oils with vitamin D₃ are widely available in different countries and are consumed daily. The reduction rate of added vitamin D₃ in fortified canola oil during heating process, the changes in oxidative status, and the thermal kinetic degradation of vitamin D₃ in the fortified oil were investigated. For this purpose, canola oil was fortified at two levels of vitamin D₃ with 5.625 µg/mL (low concentration or LC) and 13.585 µg/mL (a high concentration or HC). Samples were heated isothermally at 100, 150, and 180 °C for 30 min. The vitamin D₃ concentration was determined by the high-performance liquid chromatographic method. The retention of vitamin D₃ in samples treated at 100 °C for 30 min showed no significant reduction. Samples treated at 150 and 180 °C depending on the initial concentration showed the retention of 67.5% to 72.97% and 33.16% to 40.35% of vitamin D₃ , respectively. An inverse relationship was found between the increment of lipid oxidation products (peroxide and anisidine values) and the retention of vitamin D₃ . Kinetic parameters such as rate constant, activation energy, decimal reduction time, and quotient indicator were also calculated. An Arrhenius relationship was used for the assessment of temperature dependence of vitamin D₃ degradation. Activation energies for vitamin D₃ in LC and HC between 100 and 180 °C were found to be 44.01 and 38.77 kJ/mol, respectively. PRACTICAL APPLICATION: The oil can be fortified with vitamin D₃ at low cost and offers a good bioavailability. A high-temperature cooking method may not be appropriate for the fortified products containing high lipid content.

Investigations on the Maillard Reaction in Sesame ( Sesamum indicum L.) Seeds Induced by Roasting

This study investigated the formation of Maillard reaction products in sesame seeds under different roasting conditions. Sesame seeds were roasted at 150, 180, 200, and 220 °C for 10 min, and thermal process contaminants including 5-hydroxymethylfurfural, acrylamide, furan, and dicarbonyl compounds (1-deoxyglucosone, 3-deoxyglucosone, methylglyoxal, and diacetyl) together with glycation markers namely N-ε-fructosyllysine, N-ε-carboxymethyllysine, and N-ε-carboxyethyllysine, were monitored. Roasting induced the formation of 5-hydroxymethylfurfural, acrylamide, and dicarbonyl compounds, except furan, significantly ( p < 0.05). 5-Hydroxymethylfurfural and acrylamide content of roasted sesame seeds were found to vary as 3-40 mg/kg and 135-633 μg/kg, respectively. Dicarbonyl compounds were in the following order: methylglyoxal > 3-deoxyglucosone > 1-deoxyglucosone > diacetyl. On the other hand, N-ε-fructosyllysine concentration decreased while the roasting temperature increased; however, N-ε-carboxymethyllysine and N-ε-carboxyethyllysine formation was induced under those conditions. This is the first study reporting the formation of thermal process contaminants and glycation markers in sesame seeds through Maillard reaction during roasting.

Inhibition of Nitric Oxide Production, Oxidative Stress Prevention, and Probiotic Activity of Lactic Acid Bacteria Isolated from the Human Vagina and Fermented Food

In this study, lactic acid bacteria (LAB) with antioxidative and probiotic activities were isolated from the vaginas of Korean women and from fermented food. Among 34 isolated LAB strains, four strains (MG4221, MG4231, MG4261, and MG4270) exhibited inhibitory activity against nitric oxide production. The MG4221 and MG4270 strains were identified as Lactobacillus plantarum, and MG4231 and MG4261 were identified as Lactobacillus fermentum. These strains were able to tolerate pepsin and pancreatin, which is required for probiotic potential. The antioxidant effects of culture filtrates obtained from selected strains included 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity. Most of the culture filtrates had effective DPPH scavenging activity.In conclusion, the selected strains have significant activities and are potentially applicable to the development of functional foods. These strains might also contribute to the prevention and control of several diseases associated with oxidative stress, when used as functional probiotics.

Identification of key aroma-active compounds in sesame oil from microwaved seeds using E-nose and HS-SPME-GC×GC-TOF/MS

The study investigated the volatile compounds of sesame oil and the effects of microwave processing (0-8 min with 1-min intervals), mainly focusing on the integral flavor characteristics and individual aroma-active compounds. A total of 82 characteristic odors were identified using GC×GC-TOF/MS. Fifteen volatile compounds with the highest odor activity values (OAV > 100) were selected as the key odors contributing to the flavor profile of microwaved sesame oil, including 2-methyl-propanal (pungent, malt, green), 2-methyl-butanal (cocoa, almond), furaneol (caramel), 1-octen-3-one (mushroom), 4-methyl-3-penten-2-one (sweet), 1-nonanol (fat, citrus, green), 2-methyl-phenol (phenol), 2-methoxy-phenol (smoke, sweet), 2-methoxy-4-vinylphenol (clove, curry), 2,5-dimethyl-pyrazine (cocoa, roasted nut, roast beef), 2-furfurylthiol (coffee, roast), 2-thiophenemethanethiol (sulfur), methanethiol (gasoline, garlic), methional (cooked potato), and dimethyl trisulfide (fish, cabbage). The OAVs significantly increased with a longer microwave process. Meanwhile, PCA results based on E-nose and cluster analysis results based on GC×GC-TOF/MS were similar to distinguish flavor formation during the microwave process. PRACTICAL APPLICATIONS: Sesame oils were prepared by a microwave process. Aroma-active compounds with the highest OAVs in sesame oils were not clear. Identification of key aroma compounds of sesame oils could adopt a comprehensive assessment method in combination with E-nose and individual odors detection. Microwave pretreatment as a new processing technology for sesame oil extraction could reduce the time consumption and produce a unique fragrant flavor compared to the traditional roasting process.

White Sesame Seed Oil Mitigates Blood Glucose Level, Reduces Oxidative Stress, and Improves Biomarkers of Hepatic and Renal Function in Participants with Type 2 Diabetes Mellitus

OBJECTIVES

The study was designed to investigate the impact of white sesame seed oil (WSSO) consumption on fasting blood glucose (GLU), insulin (INS), glycosylated hemoglobin (HbA1c), and hepatic antioxidant enzymes. A secondary aim was to check the influence on serum biochemistry, hepatic, cardiac, and renal functions.

METHODS

Forty-six participants with type 2 diabetes were recruited and randomly divided into two equal groups: diabetic control (DCON) and diabetic sesame oil (DSO). At baseline and 30, 60, and 90 days, blood samples were drawn and analyzed. Two-way repeated-measures analysis of variance was used to evaluate the difference between groups and across time.

RESULTS

In both groups, GLU, INS, and HbA1c were not significantly different at baseline (mean 187.07 ± 5.63 mg/dl, mean 12.12 ± 1.03 μU/ml, and mean 7.55 ± 0.37%, respectively). At 90 days, GLU was significantly (p < 0.05) decreased in DSO (137.83 ± 3.16 mg/dl) when compared with DCON (218.13 ± 5.92 mg/dl), while INS was significantly increased in DSO (23.13 ± 1.15 μU/ml) as compared to DCON (7.93 ± 0.38 μU/ml). At 90 days, HbA1c was significantly lower (p < 0.05) in DSO as compared to DCON. Thiobarbituric acid reactive substances were significantly lower (p < 0.05) in DSO (1.08 ± 0.05 [MDA] nmol/ml) as compared to DCON (2.26 ± 0.07 [MDA] nmol/ml). In DSO, activities of hepatic antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) increased while in DCON these activities decreased significantly (p < 0.05) across the time period. Biomarkers of liver, cardiac, and renal functions improved significantly in DSO as compared to DCON.

CONCLUSION

WSSO as a functional food may play an important role in GLU regulation and against deleterious effects of diabetes in humans with type 2 diabetes.

Effect of Roasting Temperatures on the Properties of Bitter Apricot (Armeniaca sibirica L.) Kernel Oil

Volatile compounds and quality changes of bitter apricot (Armeniaca sibirica L.) kernel oil (AKO) with different roasting conditions were determined. Bitter apricot kernels were roasted at 120, 130, 140 and 150°C for 15 min. Unroasted bitter apricot kernel oil was used as the control. Quality indicators included color, acid value and peroxide value, fatty acids, total phenols and oxidative stability. Peroxide values of the tested oils were 0.46-0.82 meq/kg, acid values were 0.60-1.40 mg KOH/g, and total phenol contents were 54.1-71.5 μg GAE/g. Oleic acid was the major fatty acid, followed by linoleic, palmitic, stearic and palmitoleic acids. Roasting increased the oxidative stability of bitter AKO. Volatile compounds were tentatively identified and semi-quantified. Among the 53 volatiles identified, benzaldehyde and benzyl alcohol were the major components. These two aroma compounds increased significantly during roasting and contributed sweet and almond flavors. Pyrazines were also prevalent and significantly increased with roasting. Sensory evaluation showed that roasted, nutty, sweet and oily aromas increased as roasting temperature increased.Practical applications: Bitter apricot kernels cannot be consumed directly, thus it is potentially beneficial to find uses for them, especially in China where bitter apricot processing is a significant industry. Roasted bitter AKO with a pleasant aroma could be prepared and might find use as an edible oil. The roasting process gave the bitter AKO a pleasant flavor. This study provided preliminary information on production parameters and potential quality control parameters.

The effect of microwave pre-treatment of rapeseed on the degradation kinetics of lipophilic bioactive compounds of the oil during storage

This study examined the storage stability of tocochromanols and carotenoids in the oils prepared from microwave pre-treated (MV) rapeseeds (2-10 min, 800W) during storage at 20 °C for 12 months. In line with lipophilic antioxidant degradation throughout the storage period, changes in the antioxidant capacity of the oil were monitored. Microwaving significantly affected the concentration of lipophilic antioxidants in the oil. After 10 min of MV pre-treatment the highest content of total tocochromanols (76.64 mg/100g) was achieved, whereas a maximum carotenoid concentration (861.28 μg/100g) was obtained following 6 min seed MV pre-treatment. The degradation kinetics for the tocochromanols and carotenoids followed a zero-order kinetic model. From the kinetic analysis, it was shown that the degradation rate constant (k) of both tocochromanols and carotenoids decreased with longer seed exposure to MV radiation. The kinetics of antioxidant capacity degradation during the storage of oils followed a zero-order reaction. The rate of antioxidant capacity degradation in the control oil was higher (k=9.1 x 10-2 mmol TEAC/l/month) compared with oils prepared from MV pre-treated seeds (k=6.8-8.0 x 10-2 mmol TEAC/l/month).

Effects of Hydrogen-Donating or Metal-Chelating Antioxidants on the Oxidative Stability of Organogels Made of Beeswax and Grapeseed Oil Exposed to Light Irradiation

To enhance the oxidative stability of organogels made from grapeseed oil, the antioxidant effects of sesamol, α-tocopherol, β-carotene, ethylenediaminetetraacetic acid (EDTA), and citric acid were determined in beeswax-based organogels stored under light or in the dark conditions at 25 °C. Without the addition of antioxidants, the organogels rapidly oxidized under light irradiation but not during storage in the dark. Sesamol showed the highest antioxidant activity at concentrations of 10 to 40 ppm, whereas the other compounds exhibited no antioxidant activity at 10 ppm. α-Tocopherol and β-carotene improved the oxidative stability of organogels at concentrations above 40 and 100 ppm, respectively. The addition of sesamol yielded better oxidative stability than the addition of EDTA or a mixture of sesamol and citric acid. Sesamol can improve the oxidative stability of organogels, which could lead to economic benefits for the food industry.

PRACTICAL APPLICATION

Recently, interest in organogels has increased due to their properties of maintaining a solid state at room temperature and composition of trans-free and highly unsaturated fatty acids. However, the addition of antioxidants is necessary due to the high degree of unsaturation in organogels. The results of this study showed that the addition of sesamol significantly enhanced the oxidative stability of organogels under light irradiation. Therefore, the use of sesamol-supplemented organogels could prolong the shelf-life of bakery or meat food products.

Biochemical and Antioxidative Properties of Unprocessed and Sterilized White and Black Sesame By-product from Northern Thailand

The objectives of this research were to determine the effects of sterilization on storage stability of white and black sesame by-products. Results showed that sterilization at 120 ºC for 10 min had no effect on proximate compositions and mineral contents of both sesame seed cakes, but the significant reductions of thiamine, riboflavin, sesamin, sesamolin, total phenolic compounds and antioxidant capacity (DPPH and FRAP assays) were observed. During the storage at 37 ºC, all bioactive components and antioxidant properties apparently tended to decrease when the storage time rose. At the end of storage, PV (peroxide value) and TBARS (thiobarbituric acid-reactive substances) values of stored black sesame seed cakes were shown to be significantly lower than that in white sesame seed cakes. This study may suggest the application of black and white sesame seeds cakes as functional food ingredients in the future production.

Manufacture of low-benzo(a)pyrene sesame seed (Sesamum indicum L.) oil using a self-designed apparatus

The aim of this study was to lower benzo(a)pyrene (BaP) contents in sesame seed oil (SSO) during manufacture by using a self-designed apparatus, to determine its optimal conditions, and to analyze antioxidants in SSO which might be related to BaP content reduction. Washing and spin-drying steps reduce exogenous BaP contamination, and the reduced moisture in seeds lowered BaP content in final SSO. A ventilation system in the roasting step inhibits BaP formation and reabsorption, followed by a controlled compression step. The optimal condition, a single washing cycle with 2-min spin-drying, 1350-rpm ventilation, and a single compression cycle, reduced the BaP content in SSO to 2.93 μg/kg, where the raw seeds had been spiked with 10-μg/kg BaP. Total phenolic contents showed a reversal pattern to the distribution of BaP contents. Sesamol and sesamolin were quantified by a high performance liquid chromatography-ultraviolet detector, and it was suggested that sesamol which is a strong antioxidant might have prevented BaP formation during the roasting step. This study enabled the commercial production of low-BaP SSO, and the data could be used in further investigations of the BaP content reduction mechanism with quantitative chemical analysis of the SSO composition.