To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular me...To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.展开更多
Troxerutin fatty acid esters were prepared using troxerutin and fatty acid vinyl esters as substrates in pyridine through enzymatic route. The structures of as-prepared compounds were identified by FT-TR, NMR, and ESI...Troxerutin fatty acid esters were prepared using troxerutin and fatty acid vinyl esters as substrates in pyridine through enzymatic route. The structures of as-prepared compounds were identified by FT-TR, NMR, and ESI-HRMS. Using alkaline protease(≥30 mg/mL) as enzyme, maximum yields reached 58% at 3:1(vinyl hexanoate to troxerutin) in pyridine(water content ≤1%). The yields gradually declined as chain length of acyl donors rose. The antioxidation abilities of the as-obtained compounds were confirmed by both DPPH free radical scavenging and potassium ferricyanide reduction methods. The antioxidation ability of troxerutin fatty acid esters was found lower than that of troxerutin. However, the logP values of troxerutin fatty acid esters varied from 0.15 to 1.94, suggesting that troxerutin fatty acid esters had better lipophilicity than troxerutin(logP =-2.12) when compared to their oil-water distribution coefficients. Overall, these findings look promising as reference for further development of future troxerutin.展开更多
Wheat germ is a by-product derived from the wheat milling industry. Defatted wheat germ is the main by-product of the wheat germ in the oil extraction process. This study aims at development of efficient and low cost ...Wheat germ is a by-product derived from the wheat milling industry. Defatted wheat germ is the main by-product of the wheat germ in the oil extraction process. This study aims at development of efficient and low cost processing methods to transform these residues in added value co-product. In this study, wheat germ was analysed for its proximate composition, fatty acid composition, physical and chemical characteristics of wheat germ oil. The basic chemical composition analyses revealed high values of dry matter (87.37 g/100g FW), significant amounts of total protein and fat (27.69 and 8.99 g/100g FW, respectively) content and low ash content (3.08 g/100g FW). The quality of the extracted oils was assessed in terms of acid value, iodine value, saponification value, peroxide value, refractive index, and unsaponifiable matter. The fatty acid profile was found to be made up of linoleic followed by palmitic and oleic as the major fatty acids. Antioxidant properties and in vitro antibacterial activity of defatted wheat germ (DWG) extract were also determined. DWG, as a source of natural antioxidants and antibacterial, could be used to formulate nutraceuticals with potential applications to reduce the level of oxidative stress. The antioxidant potency of the DWG extracts could be the basis for its health promoting potential. The results showed that these by-products could be used as a source of bioactive compounds beneficial for health.展开更多
The antioxidative properties of four antioxidants such as rosemary extracts (RE), <span style="font-family:Verdana;">tert</span><b><span style="font-family:Verdana;">-</s...The antioxidative properties of four antioxidants such as rosemary extracts (RE), <span style="font-family:Verdana;">tert</span><b><span style="font-family:Verdana;">-</span></b><span style="font-family:Verdana;">butylhydroquinone</span><b> </b><span style="font-family:Verdana;">(TBHQ), ascorbyl palmitate (AP), citric acid (CA) and their mixtures were investigated on the formation of 4-hydroxy-2-transnonenal (HNE) in commercial corn oil heated at 185</span><span style="font-family:Verdana;">°</span><span style="font-family:;" "=""><span style="font-family:Verdana;">C</span><span style="font-family:Verdana;"> for up to 6 hours. Among the antioxidants 100 ppm RE and a mixture of 200 ppm tertiary butylated hydroquinone (TBHQ) + 100 ppm ascorbyl palmitate (AP) + 50 ppm citric acid (CA) exhibited excellent antioxidative activity, as determined by the thiobarbituric acid reaction (TBARS) assay, measuring the formations of the secondary lipid oxidation products and by high-performance liquid chromatography (HPLC), measuring the formation of the toxic </span></span><span style="font-family:Verdana;"><i></i></span><i><i><span style="font-family:Verdana;">α</span></i><i><span style="font-family:Verdana;"></span></i></i><span style="font-family:Verdana;">, </span><span style="font-family:Verdana;"><i></i></span><i><i><span style="font-family:Verdana;">β</span></i><i><span style="font-family:Verdana;"></span></i></i><span style="font-family:Verdana;">-unsaturated hydroxyaldehyde HNE after heat treatment of corn oil at 185</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C up to 6 hours. TBHQ, AP and CA alone did not show much protective properties. The synergistic effects of TBHQ + AP + CA mixture shown to reduce the formation of HNE after 6 hours heat-treated corn oil by 27%. RE 100 ppm was also found to be a very effective antioxidant, reducing the formation of HNE after 6 hours heat-treated corn oil in the same condition by 29%.</span>展开更多
Protection of frying oil from deterioration by adding plant phenolic extracts to guarantee the quality of fried foods becomes the primary approach to promote the sustainable development of deep frying.Therefore,source...Protection of frying oil from deterioration by adding plant phenolic extracts to guarantee the quality of fried foods becomes the primary approach to promote the sustainable development of deep frying.Therefore,sources,antioxidant effects,and mechanisms of plant phenolic extracts recently applied in the quality protection of frying oil as well as challenges for the actual use of these extracts are comprehensively reviewed in this study.Spices,herbs,berries,tea leaves,and fruit and vegetable wastes are common sources for preparing phenolic extracts showing comparative antioxidant capacity referring to the synthetic antioxidants.The general effect of using these natural antioxidants is the improvement of thermal stability to extend the shelf life of frying oil and thus the modification of edible quality of fried foods.Specifically,the increases in common quality attributes and amount of hazardous products and the oxidative reduction of unsaturated triacylglycerols without negatively influencing the sensory quality are inhibited when suitable plant extracts are applied.The incorporation of plant phenolic extracts other than synthetic counterparts in frying oil has been demonstrated as a potential method to improve the frying performance of oils.However,challenges for the scale application of plant phenolic extracts,such as the purity,thermal stability,and antioxidant timing,are still needed to be further investigated.展开更多
Palm oil consumption and its effects on serum lipid levels and cardiovascular disease in humans is still a subject of debate. Advocacy groups with varying agenda fuel the controversy. This update intends to identify e...Palm oil consumption and its effects on serum lipid levels and cardiovascular disease in humans is still a subject of debate. Advocacy groups with varying agenda fuel the controversy. This update intends to identify evidence-based evaluations of the influence of palm oil on serum lipid profile and cardiovascular disease. Furthermore, it suggests a direction for future research. The sources of information were based on a Pub Med, Google Scholar, African Journal online and Medline search using key words including: palm oil, palmitic acid, saturated fatty acids and heart disease. Published animal and human experiments on the association of palm oil and its constituents on the serum lipid profile and cardiovascular disease were also explored for relevant information. These papers are reviewed and the available evidence is discussed. Most of the information in mainstream literature is targeted at consumers and food companies with a view to discourage the consumption of palm oil. The main argument against the use of palm oil as an edible oil is the fact that it contains palmitic acid, which is a saturated fatty acid and by extrapolation should give rise to elevated total cholesterol and low-density lipoprotein cholesterol levels. However, there are many scientific studies, both in animals and humans that clearly show that palm oil consumption does not give rise to elevated serum cholesterol levels and that palm oil is not atherogenic. Apart from palmitic acid, palm oil consists of oleic and linoleic acids which are monounsaturated and polyunsaturated respectively. Palm oil also consists of vitamins A and E, which are powerful antioxidants. Palm oil has been scientifically shown to protect the heart and blood vessels from plaques and ischemic injuries. Palm oil consumed as a dietary fat as a part of a healthy balanced diet does not have incremental risk for cardiovascular disease. Little or no additional benefit will be obtained by replacing it with other oils rich in mono or polyunsaturated fatty acids.展开更多
Chia seed oil (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:""><span style="font-family:Verdana;">Salvia ...Chia seed oil (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:""><span style="font-family:Verdana;">Salvia </span><span style="font-family:Verdana;">hispanica</span></span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;"> L.) contains polyunsaturated omega-3 fatty acids and natural antioxidants that have many health effects. Consequently, the chief purpose of the present study was the outcome of various attentiveness of chia seed oil on </span><span style="font-family:Verdana;">quality</span><span style="font-family:Verdana;"> and sensory evaluation of ice milk. In treatments T</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">, T</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, T</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">, and T</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">, the milk fat was moderately swapped with chia seed oil at 10%, 20%, 30%, and 40%, respectively, and compared with the control treatment (100% </span><span style="font-family:Verdana;">milk fat</span><span style="font-family:Verdana;">). All treatments were stored at </span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">18</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C for 30 days. Samples were analyzed fortnightly and monthly to determine the shelf life during the storage period by acidity and peroxide value. Physicochemical properties of fatty acids, total polyphenols, and total flavonoids of chia seed oil and ice milk samples were determined. Also, the overrun and sensory evaluation of ice milk samples were studied. Results indicated an increase in the absorption of omega-3 fatty acids (linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic “in the samples of” ice milk supplemented with chia seed oil compared with control. Furthermore, there has been an increase in natural antioxidants (total phenolic and total flavonoid contents) levels in the supplemented ice milk samples as compared to control. Furthermore, an increase in the shelf life of the supplemented ice milk samples was also noticed. Generally, fortification of ice milk with chia seed oil increased the concentration of omega-3 fatty acids and also improved the antioxidant properties of ice milk.展开更多
The main aim of this study was to explore the effects of microwave pre-treatment on quality of kenaf seed oil by observing the changes in oil yield, oxidative stability, fatty acid components, tocopherols, antioxidant...The main aim of this study was to explore the effects of microwave pre-treatment on quality of kenaf seed oil by observing the changes in oil yield, oxidative stability, fatty acid components, tocopherols, antioxidant activities and color intensity of kenaf seed oil. Microwave pre-treatment on kenaf seeds did affect the quality of the extracted oils. Microwave pre-treatment increased the extracted oil yields significantly (P 〈 0.05). Moreover, the roasted oils showed a significant increase in oxidative stability, antioxidant stability and colour of kenaf seed oils. In terms of fatty acids composition, microwave roasting had greater effect on oleic acids (C18:1) and linoleic acids (C18:2), as roasting increased the oleic acid content but decreased linoleic acid. There was no significant difference in the palmitic acids (C16:0) and stearic acids (C18:0) (P 〉 0.05). A significant decrease (P 〈 0.05) in the iodine value of the oils was found. In conclusion, kenaf seed oil roasted for 2 min had better oil quality if compared to the unroasted oil, as microwave pre-treatment improved the oil yield, oxidative stability and antioxidant activities of kenaf seed oil.展开更多
文摘To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.
基金financially supported by Science and Technology Department of Henan Province (No. 132102310028)the Program for Innovative Research Team from Zhengzhou (No. 131PCXTD605)
文摘Troxerutin fatty acid esters were prepared using troxerutin and fatty acid vinyl esters as substrates in pyridine through enzymatic route. The structures of as-prepared compounds were identified by FT-TR, NMR, and ESI-HRMS. Using alkaline protease(≥30 mg/mL) as enzyme, maximum yields reached 58% at 3:1(vinyl hexanoate to troxerutin) in pyridine(water content ≤1%). The yields gradually declined as chain length of acyl donors rose. The antioxidation abilities of the as-obtained compounds were confirmed by both DPPH free radical scavenging and potassium ferricyanide reduction methods. The antioxidation ability of troxerutin fatty acid esters was found lower than that of troxerutin. However, the logP values of troxerutin fatty acid esters varied from 0.15 to 1.94, suggesting that troxerutin fatty acid esters had better lipophilicity than troxerutin(logP =-2.12) when compared to their oil-water distribution coefficients. Overall, these findings look promising as reference for further development of future troxerutin.
文摘Wheat germ is a by-product derived from the wheat milling industry. Defatted wheat germ is the main by-product of the wheat germ in the oil extraction process. This study aims at development of efficient and low cost processing methods to transform these residues in added value co-product. In this study, wheat germ was analysed for its proximate composition, fatty acid composition, physical and chemical characteristics of wheat germ oil. The basic chemical composition analyses revealed high values of dry matter (87.37 g/100g FW), significant amounts of total protein and fat (27.69 and 8.99 g/100g FW, respectively) content and low ash content (3.08 g/100g FW). The quality of the extracted oils was assessed in terms of acid value, iodine value, saponification value, peroxide value, refractive index, and unsaponifiable matter. The fatty acid profile was found to be made up of linoleic followed by palmitic and oleic as the major fatty acids. Antioxidant properties and in vitro antibacterial activity of defatted wheat germ (DWG) extract were also determined. DWG, as a source of natural antioxidants and antibacterial, could be used to formulate nutraceuticals with potential applications to reduce the level of oxidative stress. The antioxidant potency of the DWG extracts could be the basis for its health promoting potential. The results showed that these by-products could be used as a source of bioactive compounds beneficial for health.
文摘The antioxidative properties of four antioxidants such as rosemary extracts (RE), <span style="font-family:Verdana;">tert</span><b><span style="font-family:Verdana;">-</span></b><span style="font-family:Verdana;">butylhydroquinone</span><b> </b><span style="font-family:Verdana;">(TBHQ), ascorbyl palmitate (AP), citric acid (CA) and their mixtures were investigated on the formation of 4-hydroxy-2-transnonenal (HNE) in commercial corn oil heated at 185</span><span style="font-family:Verdana;">°</span><span style="font-family:;" "=""><span style="font-family:Verdana;">C</span><span style="font-family:Verdana;"> for up to 6 hours. Among the antioxidants 100 ppm RE and a mixture of 200 ppm tertiary butylated hydroquinone (TBHQ) + 100 ppm ascorbyl palmitate (AP) + 50 ppm citric acid (CA) exhibited excellent antioxidative activity, as determined by the thiobarbituric acid reaction (TBARS) assay, measuring the formations of the secondary lipid oxidation products and by high-performance liquid chromatography (HPLC), measuring the formation of the toxic </span></span><span style="font-family:Verdana;"><i></i></span><i><i><span style="font-family:Verdana;">α</span></i><i><span style="font-family:Verdana;"></span></i></i><span style="font-family:Verdana;">, </span><span style="font-family:Verdana;"><i></i></span><i><i><span style="font-family:Verdana;">β</span></i><i><span style="font-family:Verdana;"></span></i></i><span style="font-family:Verdana;">-unsaturated hydroxyaldehyde HNE after heat treatment of corn oil at 185</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C up to 6 hours. TBHQ, AP and CA alone did not show much protective properties. The synergistic effects of TBHQ + AP + CA mixture shown to reduce the formation of HNE after 6 hours heat-treated corn oil by 27%. RE 100 ppm was also found to be a very effective antioxidant, reducing the formation of HNE after 6 hours heat-treated corn oil in the same condition by 29%.</span>
基金the National Natural Science Foundation of China(Grant No.32101981)。
文摘Protection of frying oil from deterioration by adding plant phenolic extracts to guarantee the quality of fried foods becomes the primary approach to promote the sustainable development of deep frying.Therefore,sources,antioxidant effects,and mechanisms of plant phenolic extracts recently applied in the quality protection of frying oil as well as challenges for the actual use of these extracts are comprehensively reviewed in this study.Spices,herbs,berries,tea leaves,and fruit and vegetable wastes are common sources for preparing phenolic extracts showing comparative antioxidant capacity referring to the synthetic antioxidants.The general effect of using these natural antioxidants is the improvement of thermal stability to extend the shelf life of frying oil and thus the modification of edible quality of fried foods.Specifically,the increases in common quality attributes and amount of hazardous products and the oxidative reduction of unsaturated triacylglycerols without negatively influencing the sensory quality are inhibited when suitable plant extracts are applied.The incorporation of plant phenolic extracts other than synthetic counterparts in frying oil has been demonstrated as a potential method to improve the frying performance of oils.However,challenges for the scale application of plant phenolic extracts,such as the purity,thermal stability,and antioxidant timing,are still needed to be further investigated.
文摘Palm oil consumption and its effects on serum lipid levels and cardiovascular disease in humans is still a subject of debate. Advocacy groups with varying agenda fuel the controversy. This update intends to identify evidence-based evaluations of the influence of palm oil on serum lipid profile and cardiovascular disease. Furthermore, it suggests a direction for future research. The sources of information were based on a Pub Med, Google Scholar, African Journal online and Medline search using key words including: palm oil, palmitic acid, saturated fatty acids and heart disease. Published animal and human experiments on the association of palm oil and its constituents on the serum lipid profile and cardiovascular disease were also explored for relevant information. These papers are reviewed and the available evidence is discussed. Most of the information in mainstream literature is targeted at consumers and food companies with a view to discourage the consumption of palm oil. The main argument against the use of palm oil as an edible oil is the fact that it contains palmitic acid, which is a saturated fatty acid and by extrapolation should give rise to elevated total cholesterol and low-density lipoprotein cholesterol levels. However, there are many scientific studies, both in animals and humans that clearly show that palm oil consumption does not give rise to elevated serum cholesterol levels and that palm oil is not atherogenic. Apart from palmitic acid, palm oil consists of oleic and linoleic acids which are monounsaturated and polyunsaturated respectively. Palm oil also consists of vitamins A and E, which are powerful antioxidants. Palm oil has been scientifically shown to protect the heart and blood vessels from plaques and ischemic injuries. Palm oil consumed as a dietary fat as a part of a healthy balanced diet does not have incremental risk for cardiovascular disease. Little or no additional benefit will be obtained by replacing it with other oils rich in mono or polyunsaturated fatty acids.
文摘Chia seed oil (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:""><span style="font-family:Verdana;">Salvia </span><span style="font-family:Verdana;">hispanica</span></span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;"> L.) contains polyunsaturated omega-3 fatty acids and natural antioxidants that have many health effects. Consequently, the chief purpose of the present study was the outcome of various attentiveness of chia seed oil on </span><span style="font-family:Verdana;">quality</span><span style="font-family:Verdana;"> and sensory evaluation of ice milk. In treatments T</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">, T</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">, T</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">, and T</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">, the milk fat was moderately swapped with chia seed oil at 10%, 20%, 30%, and 40%, respectively, and compared with the control treatment (100% </span><span style="font-family:Verdana;">milk fat</span><span style="font-family:Verdana;">). All treatments were stored at </span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">18</span><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C for 30 days. Samples were analyzed fortnightly and monthly to determine the shelf life during the storage period by acidity and peroxide value. Physicochemical properties of fatty acids, total polyphenols, and total flavonoids of chia seed oil and ice milk samples were determined. Also, the overrun and sensory evaluation of ice milk samples were studied. Results indicated an increase in the absorption of omega-3 fatty acids (linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic “in the samples of” ice milk supplemented with chia seed oil compared with control. Furthermore, there has been an increase in natural antioxidants (total phenolic and total flavonoid contents) levels in the supplemented ice milk samples as compared to control. Furthermore, an increase in the shelf life of the supplemented ice milk samples was also noticed. Generally, fortification of ice milk with chia seed oil increased the concentration of omega-3 fatty acids and also improved the antioxidant properties of ice milk.
文摘The main aim of this study was to explore the effects of microwave pre-treatment on quality of kenaf seed oil by observing the changes in oil yield, oxidative stability, fatty acid components, tocopherols, antioxidant activities and color intensity of kenaf seed oil. Microwave pre-treatment on kenaf seeds did affect the quality of the extracted oils. Microwave pre-treatment increased the extracted oil yields significantly (P 〈 0.05). Moreover, the roasted oils showed a significant increase in oxidative stability, antioxidant stability and colour of kenaf seed oils. In terms of fatty acids composition, microwave roasting had greater effect on oleic acids (C18:1) and linoleic acids (C18:2), as roasting increased the oleic acid content but decreased linoleic acid. There was no significant difference in the palmitic acids (C16:0) and stearic acids (C18:0) (P 〉 0.05). A significant decrease (P 〈 0.05) in the iodine value of the oils was found. In conclusion, kenaf seed oil roasted for 2 min had better oil quality if compared to the unroasted oil, as microwave pre-treatment improved the oil yield, oxidative stability and antioxidant activities of kenaf seed oil.