抗氧化剂之间相互作用对食用植物油氧化稳定性影响的研究进展

由于含有丰富的不饱和脂肪酸，食用植物油在储存和热加工过程中会发生氧化变质。添加抗氧化剂是提高食用植物油氧化稳定性的有效措施，复配抗氧化剂可以提升抗氧化效果、降低抗氧化剂的成本等，研究发现，复配的抗氧化剂之间存在相互作用。本文综述了抗氧化剂之间相互作用的类型、机理、研究方法以及在食用植物油中应用的研究进展，为抗氧化剂在食用植物油中的深入研究提供参考。     

Antioxidants in lipid foods and their impact on food quality

This paper reviews the antioxidant properties of tocopherols and ascorbic acid in edible oils, and the impact of interfacial phenomena on their activities in emulsions and the effects of edible oil processing. Tocopherols are the most important natural antioxidants found in vegetable oil-derived foods. These antioxidants can interrupt lipid autoxidation by interfering with either the chain propagation or the decomposition processes. α-Tocopherol at high concentrations inhibits hydroperoxide decomposition but promotes hydroperoxide formation. The effect of antioxidants in inhibiting hydroperoxide decomposition may thus be critical in preserving food quality by reducing rancidity due to aldehyde formation. Ascorbic acid can regenerate α-tocopherol, inactivate metal initiators and reduce hydroperoxides. The activity of natural antioxidants is greatly affected by complex interfacial phenomena in emulsions and multi-component foods. In an oil-in-water emulsion system, the lipophilic antioxidants α-tocopherol and ascorbyl palmitate are more effective than in bulk oil, while the opposite trend is found for the hydrophilic antioxidants Trolox and ascorbic acid. The methodology to evaluate natural antioxidants must be carefully interpreted depending on whether oxidation is carried out in bulk oils or in emulsions, and what method is used to measure lipid oxidation.     

食用植物油抗氧化的研究进展

食用植物油能够为机体生长和代谢提供能量,补充人体必需脂肪酸和多种微量营养素。植物油中丰富的不饱和脂肪酸在加工和贮藏过程中易受环境因素影响而发生氧化酸败,产生一系列有害氧化产物,食用后对机体生理健康造成一定威胁。因此,本文简述了食用植物油氧化诱因、主要氧化途径-自动氧化机制及油脂氧化的危害,具体从低温储藏、气调储藏和添加单一或复配抗氧化剂方面综述了食用植物油抗氧化研究进展,并对目前食用植物油氧化和抗氧化措施等研究领域存在的问题进行了深入探讨,以期为食用植物油氧化稳定性相关研究提供一定参考。     

食用油脂中合成抗氧化剂的检测分析研究进展

向油脂中添加合成抗氧化剂是防止食用油脂在使用过程中发生氧化酸败的最有效方法之一,国家规定油脂中合成抗氧化剂添加的最大限量标准为200 mg/kg,因此建立准确、快速和高效的分析方法检测食用油脂中合成抗氧化剂的含量保证油脂以及含油食品的质量安全具有十分重要的意义。食用油脂中抗氧化剂的检测方法较多,最常用的有高效液相色谱法、气相色谱法、高效液相色谱-串联质谱法、气相色谱-串联质谱法等。本文主要综述了近年来食用油脂中合成抗氧化剂检测分析方法的研究进展,总结了不同分析方法之间的差异,并对今后的发展趋势加以展望。     

不同食用油氧化稳定性比较研究

为了比较不同食用油的氧化稳定性,选取紫苏油、亚麻籽油、核桃油、菜籽油和芝麻油5种食用油为原料,以烘箱法为对照,分别采用涂膜法和模拟法以过氧化值和酸值为考察指标对其氧化稳定性进行评价,并对其氧化过程中的脂肪酸组成变化进行探讨。结果表明:5种食用油氧化稳定性从高到低依次为:芝麻油菜籽油核桃油亚麻籽油紫苏油;在氧化初期,多不饱和脂肪酸含量减少,单不饱和脂肪酸含量和饱和脂肪酸含量有不同程度的增加,多不饱和脂肪酸含量对食用油氧化稳定性具有明显的影响,特别是亚麻酸含量;在评价氧化稳定性的方法中,烘箱法操作简便但无法反映氧化实际情况,涂膜法检测过程高效且实时,模拟法可反映食用油在使用中的实际氧化过程。     

Green tea extract as food antioxidant. Synergism and antagonism with α-tocopherol in vegetable oils and their colloidal systems

The antioxidant effects of α-tocopherol (TOH) in combination with green tea extract (GTE), the green tea polyphenol (−)-epicatechin (EC) or the isomeric (+)-catechin (C), were investigated using different lipid systems based on high linoleic sunflower oil: bulk oil, o/w-emulsion and a phosphatidylcholine-based liposome system. Both polyphenols as well as TOH were efficient antioxidants in all systems when used alone, as detected by the formation of free radicals and conjugated dienes and by oxygen consumption. Strong synergistic effect was found for the combination of TOH and GTE in a methyl linoleate o/w-emulsion and in the pure bulk oil, while only an additive effect was observed in a liposome system. The synergism was already evident for the tendency for radical formation in the bulk oil as detected by electron spin resonance (ESR) spectroscopy. On the contrary, combinations of TOH with either EC or C showed clear synergistic effects in both heterogeneous systems, but antagonistic or additive effects in bulk oil. GTE may accordingly be used to protect both vegetable oils and their emulsions against oxidation through enhancement of the activity of their endogenous antioxidants, while GTE is less efficient in the protection of phospholipids as in liposomes.     

HEALTH PROMOTING CONSTITUENTS IN PLANT DERIVED EDIBLE OILS

Of all the edible oils, only that produced from olives has had its health attributes studied in detail. For maximum nutritional benefit, an edible oil should contain minimal levels of saturated fats, especially lauric and myristic acids and minimal levels of trans fatty acids. If the oils are not to be heated repeatedly and if they contain high levels of antioxidants, they should contain omega-3 and possibly omega-6 polyunsaturated fatty acids. The fatty acid profile should be dominated by monounsaturated fatty acids. Secondary products which act as antioxidants including polyphenols, proanthocyanidins, tocopherols and carotenoids increase the shelf-life of oils, reportedly reduce cardiovascular disease and provide some anticarcinogenic properties. More research is also required, but there is evidence that phytosterols and squalene are also beneficial components of edible oils. Selection and breeding can be used to increase the desirable components of edible oils. Geographic, culture and environmental factors can influence the properties of the oil produced by crops, and methods of processing can greatly reduce the levels of health promoting components. Despite the current anti-GMO sentiments, biotechnology should be used both in the development of plant cultivars which produce nutritional oils and in processing to maximize the desirable components.     

Singlet Oxygen‐Related Photooxidative Stability and Antioxidant Changes of Diacylglycerol‐Rich Oil Derived from Mixture of Olive and Perilla Oil

Abstract: This study investigated the oxidative stability and antioxidants changes in diacylglycerol (DAG)‐rich oil under singlet oxygen. DAG‐rich oil was derived from triacylglycerol (TAG) oil of extra virgin olive and perilla oil mixture by hydrolysis and re‐esterification using lipases. The oxidation of oils was performed at 25 °C for 48 h under singlet oxygen produced with chlorophyll b under light, and was evaluated by headspace oxygen consumption and peroxide value (POV). The oxidation of DAG‐rich oil was higher and faster in the co‐presence of light and chlorophyll than in their single presence. DAG‐rich oil was more oxidation‐susceptible than TAG oil. There was no significant change in fatty acid and lipid subclass compositions in DAG‐rich oil during the photooxidation. Tocopherols were degraded, whereas polyphenols weren't during phootooxidation of DAG‐rich oil. The oxidation of DAG‐rich oil was well‐correlated with tocopherol contents, not with polyphenol contents, indicating that tocopherols were effective antioxidants in the singlet oxygen‐related phootooxidation of DAG‐rich oil. The results suggested that the oxidative stability of DAG‐rich oil under singlet oxygen be improved by a precise control through retention of tocopherols. Practical Application: The results of this study can be applied to the utilization of diacylglycerol oils to the area of functional edible oils with good oxidative stability.     

Synergistic effect of 3,4-dihydroxyphenylglycol with hydroxytyrosol and α-tocopherol on the Rancimat oxidative stability of vegetable oils

The current work evaluated the ability of pure 3,4-dihydroxyphenylglycol (DHPG) and hydroxytyrosol (HT) in combination with a commercial phenolic extract from Olea europaea rich in HT to prevent the oxidation of edible vegetable oils. The commercial phenolic extract was highly soluble in all matrices and significantly improved the oxidation stability and delayed the onset of rancidity of oils compared to a control (with no antioxidant). The combinations of DHPG with other natural antioxidants, such as HT and α-tocopherol, showed that it can be a useful supplement to increase the shelf life of sunflower oil. Synergism was observed when DHPG and HT were added in combination. The synergistic effect was directly related to the concentration ratio between both antioxidants. The mixtures containing DHPG/α-tocopherol and DHPG/HT/α-tocopherol also showed effectiveness in delaying oxidation.     

食用油使用过程中存贮条件对其氧化稳定性的影响研究

研究了大豆油、菜籽油、棕榈油等几种食用油在使用过程中不同存贮条件下的氧化稳定性。将食用油启封,放置在不同的环境里,检测其过氧化值和酸值的变化。结果表明:避光存贮31 d,食用油的过氧化值均低于8 mmol/kg,酸值(KOH)达到0.26~0.35 mg/g;而在室内日光直接照射的条件下存贮31 d,各食用油的过氧化值均高于10 mmol/kg,酸值(KOH)达到0.35~0.45 mg/g。实验表明,启封后的食用油,存贮于避光处可以连续使用30 d以上,而置于室内日光直接照射条件下,其连续使用期只有3周。对比实验中,棕榈油氧化稳定性优于其他油脂。     

Gallic Acid Grafted Chitosan Has Enhanced Oxidative Stability in Bulk Oils

Gallic acid (GA) was grafted in chitosan and the effects of GA grafted chitosan (GA‐g‐CS) on the oxidative stability in bulk oil was tested at 60 and 140 °C. To text oxidative stability in oils, headspace oxygen content, conjugated dienoic acid (CDA) value, p‐anisidine value (p‐AV), and acid value were determined. Chitosan itself did not show antioxidative or prooxidative effects in oils at 60 °C. However, GA‐g‐CS and GA acted as antioxidants at 60 °C. At 140 °C heating with moisture supplied condition, different results were observed. GA‐g‐CS acted as antioxidants based on the results of CDA and p‐AV. However, chitosan showed the highest oxidative stability based on results of acid value and brown color formation at 140 °C. This could be due to reduction of moisture content by chitosan. GA was continuously released from GA‐g‐CS in bulk oil. This might have provided extra antioxidant activities to oils.     

Comparative Effect of Bunium persicum and Rosmarinus officinalis Essential Oils and Their Synergy with Citric Acid on the Oxidation of Virgin Olive Oil

The objective of this study was to evaluate the effect of Bunium persicum and Rosmarinus officinalis essential oils on the oxidation of virgin olive oil during accelerated storage. The synergistic effect between citric acid and antioxidants of natural and synthetic types was investigated. The B. persicum and R. officinalis essential oils significantly retarded the oxidation of virgin olive oil. Their antioxidant capacity was comparable to butylatedhydroxytoluene and better than β-carotene. Here we show that when natural and synthetic antioxidants are combined with citric acid, they produce an extra antioxidant effect, hence the manifestation of synergy. Generally, the essential oils of B. persicum and R. officinalis can be applied to increase the oxidative stability of virgin olive oil.     

甘草总黄酮对油脂抗氧化作用研究

以过氧化值(POV)为指标,采用Schaal烘箱法研究了甘草总黄酮对油脂的抗氧化性能。结果表明:甘草总黄酮对四种食用油脂均有良好的抗氧化效果,且对猪油具有较强的抗氧化作用,其作用具有剂量效应关系;VC、柠檬酸、酒石酸对甘草总黄酮的抗氧化作用均有协同增效作用;甘草总黄酮与合成抗氧化剂混合使用时,其抗氧化能力均好于只添加单一抗氧化剂的效果。     

微波加热对食用油品质及脂肪酸成分的影响

研究微波加热对食用油品质及脂肪酸成分影响,为家庭健康烹调提供理论依据。用家用微波炉的不同加热档位,对菜籽油、大豆油等8种常用食用油加热不同时间,用滴定法测定加热后油脂的酸价和过氧化值,GC-MS测定油脂的脂肪酸成分,并以这些指标评价微波加热对食用油品质的影响。在实验所用加热条件下,8种食用油的酸价和脂肪酸成分均未发生明显改变。不同食用油的过氧化值变化曲线有所不同,菜籽油、大豆油、花生油、芝麻油、调和油的过氧化值随着微波功率和时间增加而上升,玉米油、橄榄油和葵花籽油的过氧化值随着微波功率和时间增加先上升后下降。微波加热虽然改变了食用油的过氧化值,但酸价尚未发生改变,认为油脂尚未发生酸败,微波加热也没有破坏食用油原有的脂肪酸组成。从微波加热对食用油的品质和脂肪酸成分影响的结果看,可以认为微波加热是日常生活中安全和健康的加热方式。     

Conjugated Linoleic Acid (CLA) Formation in Edible Oils by Photoisomerization: A Review

Conjugated linoleic acid (CLA) that is commonly found in dairy and ruminant fats, is geometrical and positional isomer of linoleic acid (LA). Edible oils are not good sources of CLA. Attempts have been made to generate CLA in edible oils through photoisomerization procedures. CLA isomers have several proven health benefits. This article reviews procedures for producing CLA containing edible oils by photoisomerization approach and applications of photoisomerized oils for food uses. The article reviews (1) the photoisomerized production of CLA containing oils on lab scale, with customized equipment, at pilot plant scale; (2) the effects of iodine content, photoisomerization time, refining, interference from minor components of oils, efficacy of different edible oils containing LA, interference from antioxidants; (3) the chemical kinetics, oxidative stability; and (4) photoisomerized oils for frying oils and as drying oils.The review also briefly covers methods of measurement of CLA.     

食用植物油营养功能成分及检测技术的研究进展

食用植物油是人体生命活动和机体代谢过程中不可或缺的物质,不仅为人体提供能量、必需脂肪酸,还含有植物甾醇、维生素E、多酚、角鲨烯和类胡萝卜素等多种营养功能成分。研究表明,植物甾醇具有降低胆固醇水平、抗动脉粥样硬化和抗肿瘤等功能;维生素E可以抑制油脂过氧化,增加机体免疫能力,预防和治疗心血管疾病等;多酚具有消炎、预防冠心病等功能;角鲨烯具有促进血液循环、活化机体细胞等功能。本文主要对植物油中的营养成分及相应检测技术进行了简要综述,旨在促进植物油营养成分的深入研究,挖掘食用油潜在营养成分和价值,为指导消费者合理使用食用油提供科学依据。     

Chemical stabilisation of oils rich in long-chain polyunsaturated fatty acids during homogenisation,microencapsulation and storage

The aim of this study was to systematically investigate the impact of chemical stabilisation on the autoxidation of microencapsulated oils rich in long-chain polyunsaturated fatty acids. During the microencapsulation process, the fish oil undergoes multiple changes of its physical properties: bulk oil, dispersed oil in aqueous phase, and dispersed oil in dry matrix. Autoxidation already occurred in the first stages of the microencapsulation process itself during emulsification and spray-drying. An efficient stabilisation was achieved using a ternary combination of lipophilic antioxidants, synergistic compounds and a trace metal chelator, e.g. a combination of tocopherols, rich in the δ-derivative and low in the α-derivative, with ascorbyl palmitate and lecithin. Trace metal chelation by, e.g. Citrem or lecithin in combination with ascorbyl palmitate proved to be of particular importance in the emulsion, but not during the storage of the microencapsulated oil. In the microencapsulated oil, the addition of rosemary extract rich in carnosic acid to ternary blends of tocopherols, ascorbyl palmitate and lecithin or Citrem significantly retarded autoxidation.     

辅酶Q_(10)食用油的开发应用

从辅酶Q10(CoQ10)食用油的稳定性,人体吸收利用效果,食用安全性及其推荐量,CoQ10与食用油的协作关系,以及与油中伴随物维生素E产生的协同抗氧化作用等方面进行综述。论述了开发CoQ10食用油的重要意义,介绍了CoQ10食用油的制作工艺,并就CoQ10添加前后对食用油色泽、酸值和过氧化值影响以及传统的煎炸、清炒方式对CoQ10食用油质量指标影响进行实验验证;最后分析展望了辅酶Q10食用油的适宜人群及其应用前景。     

Comparison of Oxidative Stability among Edible Oils under Continuous Frying Conditions

The stability of camellia oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 1:7:1) after frying potatoes was compared with palm oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 4:4:1) and peanut oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 2:4:4). Oil samples were evaluated for acid value, iodine value, peroxide value, p-anisidine value, total oxidation value, tocopherols content, and fatty acids composition. There was the least change in fatty acid composition in camellia oil among the three edible oils. The α-tocopherol was more vulnerable to heat degradation than γ-tocopherol and δ-tocopherol, and α-tocopherol was completely degraded before the whole frying process was done for palm and peanut oils. The oxidative stabilities of the three edible oils were in the order of camellia oil > palm oil > peanut oil. The oxidative stability was mainly determined by the calculated oxidizability value related to fatty acid composition, and when calculated oxidizability values were similar, the tocopherol contents of edible oils would be a key factor in affecting their oxidative stabilities.     

Role of physical structures in bulk oils on lipid oxidation

Lipid oxidation is important to food manufacturers especially when they increase unsaturated lipids in their products to improve nutritional profiles. Unfortunately, the number of antioxidants available to food manufacturers to control oxidative rancidity is limited and the approval of new antioxidants is unlikely due to economic barriers in obtaining government approval for new food additives. Therefore, new antioxidant technologies are needed for food oils. This paper reviews the current knowledge of lipid oxidation in foods with emphasis on how physical properties of food systems impact oxidation chemistry. In particular, the role of association colloids in bulk oils on lipid oxidation chemistry is discussed in an attempt to understand mechanisms of oxidation. Increasing the understanding of how physical properties impact lipid oxidation could lead to the development of novel antioxidant technologies that not only protect the oil against oxidation and increase shelf-life but also allow food manufacturers to include more nutritionally beneficial fatty acids in their products.