Evaluation of Fatty Acid Composition,Tocols Profile,and Oxidative Stability of Some Fully Refined Edible Oils

Present study includes evaluation of fatty acid composition, tocols profile, and oxidative stability of some fully refined edible oils. Fully refined sunflower, soybean, corn, hazelnut, peanut, and canola oils were analyzed for fatty acids by capillary gas liquid chromatography, tocols by normal phase-high performance liquid chromatography and oxidative stability by rancimat. Free fatty acid, peroxide value, and iodine value of investigated oils were determined by titrimetric methods. Saturated, mono-, and polyunsaturated fatty acids were found to be in the ranges between 2.03–18.58, 23.39–77.26, and 14.39–58.52%, respectively. Tocols and oxidative stability of the investigated oils were found to be in the ranges between 488.88–913.51 mg kg^?1 and 3.05–4.99 h, respectively.     

Fatty Acid Composition and Oxidative Stability of Cold-pressed Edible Seed Oils

ABSTRACT: This study was conducted to determine the fatty acid (FA) compositions and oxidative stabilities of cold-pressed cranberry, carrot, hemp, and caraway seed oils. The cold-pressed cranberry and hemp seed oils exhibited higher α-linolenic acid (18:3n-3) contents with levels of 22 and 19 g/100 g fatty acids, respectively. Cold-pressed carrot seed oil contained about 82% oleic acid and had the lowest total saturated fatty acids among all tested oils. Cold-pressed caraway seed oil had the greatest oxidative stability with an OSI value of 150 hours. In addition, cold-pressed carrot seed oil had the lightest color while hemp seed oil was the darkest among all the oils tested.     

Quality Evaluation of Edible Film-Coated Chicken Strips and Frying Oils

ABSTRACT: Methyl cellulose (MC) and hydroxypropylmethylcellulose (HPMC) edible film materials were applied to marinated whole chicken strips either prior to breading, after breading, or were incorporated in the breading. Subsequently, the influence of an edible film's location relative to the crust on fried food product quality and the quality of the frying oil were determined. Films applied to chicken strips prior to the breading had fried crusts with higher fat and lower moisture levels. Decreased degradation of frying oils was recorded when product coated with HPMC (food grade E4M) films had been fried compared to non-coated product. It is postulated that these edible films hindered the migration of moisture and acetic acid into the frying oil and this activity was responsible for reduced free fatty acid generation in those oils used to fry the coated products.     

没食子酸酯类抗氧化剂对不同植物油氧化稳定性能影响的研究

没食子酸酯类抗氧化剂是优化植物油脂氧化稳定性能主要添加剂,本论文制备了7种不同酯基结构的没食子酸酯类抗氧化剂并进行了红外光谱表征,分别研究了此7种抗氧化剂对21种植物油脂和地沟油的抗氧化效果。研究结果表明,21种植物油脂和地沟油的氧化稳定性能不同,且差别较大,其中蓖麻子油的氧化稳定性能最好,诱导期时间达到39.19h,最差的是牡丹籽油,诱导期时间为1.03 h,两者相差达到38倍。7种不同酯基没食子酸酯类抗氧化剂对21种植物油脂和地沟油的抗氧化效果十分明显,其中酯基不同的没食子酸酯类抗氧化剂对植物油脂的抗氧化效果不同,且差别较大,其中没食子酸丙酯(PG)对植物油脂的抗氧化效果最好。同一种没食子酸酯类抗氧化剂对不同植物油脂的抗氧化效果有所不同,差别也较大,如没食子酸甲酯(MT)使亚麻籽油抗氧化效果提高了8.23倍,而使蓖麻子油的抗氧化效果提高了1.5倍。支链酯基的没食子酸酯类抗氧化剂与直链酯基的没食子酸酯类抗氧化剂对植物油脂的抗氧化效果相差不大。     

油脂氧化稳定性的研究

用Ｒａｎｃｉｍａｔ仪器测定了油脂氧化稳定性。结果表明,温度的高低,脂肪酸不饱和度,抗氧化剂和增效剂的使用,均与油脂氧化稳定性有着密切的关系。     

10种小宗植物油的脂肪酸组成及氧化稳定性

考察山茶籽油、乳木果油、亚麻籽油、牡丹籽油、核桃油、葡萄籽油、玫瑰果油、紫苏籽油、石榴籽油和甜杏仁油10种植物油的脂肪酸组成、酸价、过氧化值（POV）、硫代巴比妥酸（TBA）值和油稳定性指数（OSI）。结果显示：10种植物油中,除乳木果油不饱和脂肪酸含量偏低,为50.41%（质量分数）,其余植物油不饱和脂肪酸含量均较高（84.34%～92.47%,质量分数）。亚麻籽油和牡丹籽油的主要脂肪酸为α-亚麻酸,山茶籽油和乳木果油主要脂肪酸含量为油酸>亚油酸>α-亚麻酸,剩余6种植物油则为亚油酸>油酸>α-亚麻酸。根据酸价,山茶籽油、玫瑰果油与紫苏籽油品质最好,亚麻籽油则相反,新鲜度最低。综合POV和TBA值两个指标,亚麻籽油主要处于深度氧化阶段,核桃油虽已深度氧化但仍主要为初级氧化产物,乳木果油与葡萄籽油更易发生深度氧化,剩余植物油氧化程度不高。乳木果油的OSI最高,核桃油最低,且10种植物油的OSI与多不饱和脂肪酸质量分数、不饱和脂肪酸质量分数呈显著负相关,与饱和脂肪酸质量分数、饱和脂肪酸/不饱和脂肪酸比例呈显著正相关。研究结果为进一步开发我国植物油产品提供依据。     

Comparison of Oxidative Stability of Sesame (Sesamum Indicum), Soybean (Glycine Max) and Mahua (Mee) (Madhuca Longifolia) Oils Against Photo-Oxidation and Autoxidation

Lipid oxidation is one of the major causes of food spoilage. This study was conducted to evaluate and compare the oxidative stability of sesame (Sesamum indicum), soybean (Glycine max) and mahua (Madhuca longifolia) against photooxidation and autoxidation. Stability of oils against photo-oxidation and autoxidation was determined by exposing the oils to florescent light over 28 days and storing the oils at an elevated temperature (60 °C) for 28 days, respectively. The level of oxidation was determined by measuring peroxide value (PV), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and conjugated trienes (CT). Sesame oil exhibited the strongest oxidative stability against both photo-oxidation and autoxidation while Mahua oil exhibited the least stability highest both photo-oxidation and autoxidation as measured by primary oxidative products. However, Mahua oil showed the strongest stability against both photo-oxidation and autoxidation as measured by secondary oxidative products. In conclusion, higher oxidative stability was shown by the Mahua oil than sesame and soybean oils for photooxidation and autoxidation.     

Physico-Chemical Properties,Composition, and Oxidative Stability of Olive and Soybean Oils Under Different Conditions

Commercial olive and soybean oils have been analyzed periodically in order to evaluate the influence of storage conditions on quality. The following parameters were determined every 10 days of storage: peroxide, saponification and acid values, absorption coefficients K₂₇₀ and K₂₃₂, phenols, chlorophylls and carotenoids contents, DPPH scavenging ability, and total antioxidant activity. Edible oils were exposed to daylight and stored at room temperature in different containers with the same surface area of exposure to air either in clear glass or opaque glass bottles. Changes in oils properties were also examined after the addition of Vit-E as an antioxidant in oil samples. The results showed a gradual loss of quality during storage, especially in clear glass bottles. The addition of the antioxidant, however, significantly reduced the deterioration and oxidation rate in the oil. The best containers for commercial packing of oil were opaque glass bottles containing antioxidant products.     

Effect of Natural Extracted Antioxidants from Eriobotrya japonica (Lindl.) Fruit Skin on Thermo Oxidative Stability of Soybean Oil During Deep Frying

The effects of ultrasound-assisted, supercritical CO₂ and solvent extraction techniques on antioxidant activity of Eriobotrya japonica (Lindl.) skin extracts were investigated using 2, 2-diphenyl-1-picrylhydrazyl, β-carotene, and Rancimat assays. Solvent extract of skin at 400 ppm had the highest antioxidant activity. Solvent extraction was the most effective method on extraction of phenols and tocopherols. Protective effects of extracts in stabilization of soybean oil during frying were determined by measuring its peroxide value, total polar compounds, carbonyl value, free fatty acids, conjugated dienes, and trienes. Results indicated that solvent extract of skin at 400 ppm exhibited stronger antioxidant activity in oil than tertiary butylhydroquinone.     

薏苡仁油在不同存放条件下的氧化与氧化稳定性

薏苡仁油富含不饱和脂肪酸,具有较高的营养与药用价值。以酸价和过氧化值为指标对不同温度、光线、空气和抗氧化剂存放条件下的薏苡仁油进行氧化稳定性研究。结果表明：温度、光线和空气均可加速薏苡仁油的氧化,其中温度对薏苡仁油的氧化影响最大;添加抗氧化剂可明显提高薏苡仁油的稳定性,其抗氧化效果VE 强于TBHQ。     

Oxidative Stability of Cooking Oil Blend Stabilized with Leaf Extract of Eucalyptus citriodora

The present study was conducted to assess the effects of Eucalyptus citriodora (E. citriodora) leaf extract on the oxidative stability of blend of canola, rapeseed, and sunflower oils (45:20:35 v/v, respectively) under accelerated storage. The blended oil was stabilized with 300 mg/L ethanolic extract (source of total phenolic content and total flavonoid content [5.23 ± 0.19 and 1.18 ± 0.04 g/100 g d.wt. of extract]) of E. citriodora leaves. The oxidative stability was measured on the basis of parameters such as free fatty acid contents, peroxide value, sponification value, iodine value, color, cloud point, and refractive index. After a 100 day incubation period, the increase in refractive index, free fatty acid, and peroxide, and sponification values in stabilized and non-stabilized oil blends were 0.0028 and 0.0047, 0.20 and 2.37% as oleic acid, 12.54 and 21.12 meq/kg of oil and 10.04 and 17.01 meq of KOH/g of oil, respectively, as compared with initial values. However, a decrease of 10.0 and 16.9 g of iodine/100 g of oil was recorded in oil iodine values of both stabilized and non-stabilized blended vegetable oils. Results showed that E. citriodora leaf extract was found effective to maintain the oxidative stability of blended vegetable oils for long duration (6 months) as compared with control oil samples. Therefore, it can be concluded that E. citriodora leaf extract is a cheap rich source of natural antioxidants that can be easily used for the stabilization of vegetable oils in the food processing industries.     

澳洲坚果仁油的品质特性及其氧化稳定性的研究

为研究浸出澳洲坚果仁油(MNO)加热时的氧化稳定性,在测定其酸值(AV)、过氧化值(PV)、碘值(Ⅳ)、脂肪酸组成后,测定其在100、110、120、130、140、150℃下的氧化诱导期(IP)。结果表明:MNO的AV、PV和IV分别为0.089 mgKOH/g、0.019 mmol/kg和62 gI_2/100 g;其脂肪酸组成以油酸(69.81%)和棕榈油酸(14.90%)为主。在110~150℃范围内,MNO氧化的平均温度系数Q_(10)=2.24,其不同温度(T)下的IP符合方程IP=324 510e~(-0.081T)。MNO氧化的Arrhenius公式和过渡态理论反应速率常数热力学表达式分别为lnk=29.617-12 789(1/T)和In(k/T)=14.444-12 392(1/T),MNO氧化反应的表观活化能(E_a)、活化焓(△H_≠~θ)和活化熵(△S_≠~θ)分别为106.3 kJ·mol~(-1)、103.0 kJ·mol~(-1)和-77.5 J·K~(-1)·mol~(-1)。这些结果有助于评价MNO的质量和预测其贮存期。     

深度油炸对食用油中反式亚油酸含量的影响

选用我国消费最普遍的压榨大豆油和三级浸提大豆油为试验材料,研究不同大豆油经反复油炸对反式亚油酸含量的影响及其含量随油炸次数增加的变化规律。试验分为2组,反复油炸40次,每炸5次采集1次油样,每组测定3个重复。薯条油炸温度为180～185℃,油炸时间为32 h。试验结果表明,压榨大豆油和三级浸提大豆油中总反式亚油酸含量分别为0.18 g/100 g和0.08 g/100 g,前者极显著高于后者(P=0.001),9-cis,12-trans C18:2和9-trans,12-cis C18:2是2种大豆油中主要的反式亚油酸。深度油炸极显著提高大豆油中反式亚油酸含量(P=0.000),在反复油炸40次后,压榨大豆油和三级浸提大豆油中总反式亚油酸含量分别为1.11 g/100 g和0.68 g/100 g,且前者极显著高于后者(P=0.008)。压榨油反式亚油酸经油炸增加幅度高于三级浸提大豆油。     

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.     

A Chemometric Approach to Assess the Frying Stability of Cottonseed Oil Blends During Deep-Frying Process: Fatty Acid Composition and Tocopherol Analyses

The aim of the present study was to determine impacts of different additives on fatty acid composition and total tocopherol content of cottonseed oil during deep-frying process using a chemometric approach. A quarter-fractional factorial design with two levels and five factors was used for preparing the frying cottonseed oil blends. In the experimental design, additives were such as ascorbic palmitate, mixed tocopherols, dimethylpolysiloxane, lecithin, and sesame oil were used as factors. The effect of additives on fatty acid composition and tocopherol content were evaluated with normal distribution (ND) graphs during ten hours frying at 170 ± 5°C. The data were statistically assessed by one-way analysis of variance at a significance level of p < 0.05. The analysis of variance test results were in good agreement with ND graphs and data indicated that the interaction between ascorbic palmitate and dimethylpolysiloxane (A × C factor) showed a significant and protective effect on fatty acids. Meanwhile, the sesame oil (E factor) and A × C factor were showed a significant effect on level of tocopherols. The results of study indicated that present approach could be used to assess and improve the frying stability of any oil with respect to fatty acid composition and tocopherols.     

微波加热与常规加热对植物油温度和氧化稳定性影响的对比

鉴于微波加热和常规外加热方式作用的内要机理完全不同,研究了两种加热方式对植物油温度和氧化稳定性影响的情况,发现植物油的温升速率受加热方式的影响较大,而其品质方面却没有太显著的关别。     

三种脱胶处理对水代法提取的核桃油氧化稳定性的影响

水代法提取的核桃油,通过盐析、８５％磷酸及２０％明矾溶液三种脱胶处理后,添加抗氧化剂维生素Ｅ和２,６二叔丁基对甲酚（ＢＨＴ）于其中,在３７℃恒温下避光储存。测定其过氧化植（ＰＯＶ）和酸值（ＡＶ）,比较它们的氧化稳定性。结果表明,８５％磷酸脱胶处理的核桃油氧化稳定性优于盐析及明矾脱胶处理的样品;同时,维生素Ｅ在三种脱胶油中的抗氧化效果均优于２,６－二叔丁基对甲酚（ＢＨＴ）。     

紫外光谱结合BP神经网络算法建立食用油掺伪煎炸油的快速鉴定模型

为建立一种快速食用油掺伪煎炸油检测方法,采用紫外光谱法鉴别其掺伪,本研究选取大豆油、玉米油和葵花籽油为代表分别煎炸,在纯油中掺入相应煎炸时间0~6 h及掺假梯度0~90%的煎炸油制备掺伪油样,进行紫外光谱及二阶导数预处理,经处理后的光谱特征峰与BP（Backpropagation,BP）神经网络算法结合建立食用油掺伪煎炸油模型,对掺入煎炸油类别、煎炸时间和煎炸油含量进行鉴别分析。结果表明二阶导数预处理后掺伪煎炸油的光谱特征峰中大豆油为446和462 nm、玉米油为268和274 nm、葵花籽油为280和288 nm,根据其特征峰位与峰值建立Levenberg–Marquardt算法（LMA）、动量梯度下降法（MGD）及弹性梯度下降法（EGD）掺伪模型识别率分别为98.15%、91.67%和95.52%。     

Assessment of the Antioxidant Capacity and Oxidative Stability of Esterified Phenolic Lipids in Selected Edible Oils

The research work was aimed at the determination of the antioxidant capacity (AOC) and the oxidative stability of phenolic lipids (PLs), obtained by lipase‐catalyzed transesterification of phenolic acids (PAs) with selected edible oils (EOs), including flaxseed (FSO), fish liver (FO), and krill (KO) oils. The statistical analyses (Tukey's test at P < 0.05) revealed that the difference in AOC between that of the esterified FSO (EFSO) and the esterified krill oil (EKO) containing PLs and their control trials of EOs was significant (P < 0.05). To evaluate the storage stability, the EOs and their esterified products were subjected to 2 oxidation treatments. The experimental findings showed that the esterified EOs had higher oxidative stability when they were subjected to light, oxygen, and agitation at 50 °C as compared to that of the EOs; however, only the esterified fish oil (EFO) showed a significant difference in its peroxide value, when the esterified EOs were placed in the dark at 25 °C. Overall, the phenolic mono‐ and diacyglycerols present in the EOs have shown to be potential antioxidants in improving the oxidative stability of the oil and enhancing its AOC.