The effect of commercial refining steps on the rancidity measures of soybean and canola oils

The effect of commercial refining steps on the peroxide value (PV), acid value (AV), carbonyl value (CV), total polar compounds (TPC) content, polar compounds distribution, and oil/oxidative stability index (OSI) of soybean and canola oils was studied. The PVs were changed during the different refining steps. The AVs significantly decreased after the neutralisation step. The CVs continuously increased during the refining steps. The marked decrease observed in the TPC contents after the neutralisation step was mainly due to the decrease in the content of free fatty acids (FFA) and oxidised triglyceride monomers (oxTGM) than in the content of the other polar compounds. On the contrary, the study showed more significant changes in diglycerides (DG) and triglyceride dimers (TGD) contents than in the FFA and oxTGM contents during the deodorisation step. The OSIs significantly decreased after the neutralisation step and indicated no considerable changes during the further refining steps.     

Performance of two immobilized lipases for interesterification between canola oil and fully-hydrogenated canola oil under supercritical carbon dioxide

The performance and stability of Lipozyme RM IM and TL IM for the interesterification between canola oil and fully-hydrogenated canola oil (FHCO) in the presence of SCCO₂ were studied using a high pressure batch stirred reactor at 65 °C/17.5 MPa. The influence of exposure time (4, 8, and 12 h) in SCCO₂ and pressurization/depressurization cycles of up to 12 times on the enzyme's resultant activity were studied. There was no significant difference (p > 0.05) in the performance of the two enzymes over reaction time, reaching a constant degree of interesterification of about 23% after 2 h. Although FE-SEM images illustrated some morphological changes on the surface of the enzymes after 4 cycles of 7 h each, similar degrees of interesterification were achieved after each cycle. However, the amount of reaction intermediates decreased by 50–60% in the product obtained by using SCCO₂-treated enzymes after 12 pressurization/depressurization cycles compared to untreated enzymes, while there were no significant changes in the conformational and morphological structure of the treated enzymes based on FTIR and FE-SEM analysis. Findings enhance our understanding of enzymatic conversions of lipids under high pressure CO₂, targeting production of base-stock for zero-trans margarines.     

Production of set yoghurt analogue through replacement of milk fat with canola and sesame oil

The aim of this study was to determine the effect of fat level and composition on chemical, textural, microbial and sensory properties of set yoghurt analogue. The best fat level for production of yoghurt analogue was found to be 2% (w/v). Studies on the effect of fat composition (canola‐to‐sesame oil ratios of 2.0/0, 1.3/0.7, 0.7/1.3, 2.0/0) indicated the superior performance of pure sesame oil. Increasing the canola‐to‐sesame oil ratio generally resulted in an inferior product. Replacement of milk fat by vegetable oils yielded yoghurts with a lower saturated fatty acid content and less firmness.     

The effect of palm oil or canola oil on feedlot performance,plasma and tissue fatty acid profile and meat quality in goats

Twenty-four entire male Kacang kid goats were fed diets containing 3% canola (n = 12) or palm oil (n = 12) supplements for 16 weeks. The goats had an initial live weight of 14.2 ± 1.46 kg and were fed a mixed ration ad libitum (10.4 MJ/ME and 14% crude protein). There was no difference in feedlot performance due to diet. Inclusion of canola oil reduced (P < 0.05) kidney fat weight and increased (P < 0.05) linolenic acid (18:3n − 3) concentration in the blood plasma, m. longissimus lumborum (LL), liver, and kidney. The palm oil diet increased (P < 0.05) myristic (14:0) and palmitic (16:0) acid content in the blood, but this did not alter these fatty acids in the LL muscle. Lipid oxidative substances in the liver and LL from palm oil fed kids were higher (P < 0.05) than those from canola supplemented kids. The incorporation of canola oil into the goats' diet increased muscle omega-3 fatty acid content, but lipid oxidation was lowered in the blood and muscle LL.     

Acrylamide formation in a cookie system as influenced by the oil phenol profile and degree of oxidation

The purpose of this study was to investigate the effect of the olive oil phenolic compounds as well as of thermoxidised oil on the formation of acrylamide in a cookies system. Three virgin olive oils having different phenolic profile and a thermoxidised sunflower oil were selected. Cookies were baked at 190 °C for different times (8–16 min) following a basic recipe where type of oil was the variable. Additionally to acrylamide (AA), other parameters such as colour, moisture, antioxidant activity (AOA), and hydroxymethylfurfural (HMF) were measured. Results showed that concentration and composition of phenolic moiety of virgin olive oil significantly affect the acrylamide formation, particularly at prolonged baking time. Virgin olive oil with a higher dihydroxy/monohydroxy ratio was more efficient in the AA mitigation and AA was reduced up to 20%. Colour and AOA were not significantly different among the three types of oils. However, AA is dramatically increased when thermoxidised oil is used with a parallel increase of browning and HMF. It was concluded that lipid oxidation products should be considered as an important factor in acrylamide formation during baking of fat-rich products.     

大豆油食用期氧化稳定性的研究

以过氧化值、酸值和p-茴香胺值为评价指标,模拟大豆油家庭食用条件,研究充氮气、添加抗氧化剂(TBHQ)的大豆油(2.5L/桶)在3个月(6、7、8月)食用期内的品质变化规律.结果表明:在3个月的食用期内,2种处理方式下大豆油的过氧化值、酸值和p-茴香胺值均随着时间的延长逐渐增加,其中,过氧化值分别在第70、50 d达到质量安全值5.0 mmol/kg,酸值均小于质量安全值0.2 mg KOH/g,p-茴香胺值变化不大.与添加抗氧化剂相比,氮气储藏同样提高了大豆油的稳定性,氮气储藏可以成为大豆油的一种绿色储藏方法.     

Comparison of the stability of palm olein and a palm olein/canola oil blend during deep‐fat frying of chicken nuggets and French fries

Stability of palm olein (PO) and a blend 50% palm olein/50% canola oil (POC) during deep‐fat frying at 180 °C of French fries (FF) or chicken nuggets (CN) was studied through the determination of physical and chemical parameters in the fresh and used oils. Degradation at the end of the study resulted in total polar compounds of 12–13.5% for PO and 11.5–14.5% for POC and viscosity of 65–123.3 cP for PO and 63–72.8 cP for POC. Lower peroxide values (5.33–6.32) were obtained for the blend (PO had 5.21–8.55). Food type affected colour parameters and p‐anisidine value of the oils. For CN, the lowest fat content and higher hardness were obtained when they were fried in PO. CN caused a faster deterioration in the oils, in comparison with FF, especially in POC. Gas chromatography allowed to observe differences in fatty acids composition for both used oils.     

Evaluation of SIMCA and PLS algorithms to detect adulterants in canola oil by FT-IR

Adulteration of canola oil with four potential edible oils was analysed using FT-IR and chemometric methods. The adulterants (corn, peanut, soya bean and sunflower oils) were studied in four different proportions (canola oil + adulterant oils: 90 + 10, 95 + 5, 98 + 2 and 99 + 1 in volume). Excellent classification results were obtained when multi-class approaches were performed with a maximum error of 3%, using 1630 or 16 wavenumbers as variables. In the case of one-class approaches, the selection of variables (16 wavenumbers) was necessary, improving the classification error to 5%. The differences observed using the different methods were related to the nature of each model depending on how the boundaries are set in each of them, responding either to a PCA-based or PLS-based algorithm.     

野生香薷籽油脂肪酸组成及氧化稳定性研究

采用气相色谱对野生香薷籽油的脂肪酸组成进行分析测定,通过Rancimat氧化稳定性测定仪测定香薷籽油氧化稳定性,并分析比较不同抗氧化剂对香薷籽油的抗氧化效果。结果表明:香薷籽油中不饱和脂肪酸含量超过90%,其中亚麻酸含量达到58.65%;诱导期的对数与温度之间呈线性相关,香薷籽油在20℃时货架期为52.8 d,在抗氧化剂添加量相同的情况下,TBHQ的抗氧化效果最好;柠檬酸具有很好的增效作用,添加0.02%TBHQ+0.01%柠檬酸作为香薷籽油的抗氧化剂,在20℃时货架期为334.9 d,货架期延长282.1 d,抗氧化效果显著。     

Extraction of canola seed (Brassica napus) oil using compressed propane and supercritical carbon dioxide

This study aimed to investigate the extraction of canola seed (Brassica napus) oil using supercritical carbon dioxide and compressed propane as solvents. The extractions were performed in a laboratory scale unit at temperatures and pressures of 40, 50 and 60 °C and 20, 22.5 and 25 MPa for carbon dioxide and 30, 45 and 60 °C and 8, 10 and 12 MPa for propane extractions, respectively. The results indicated that pressure and temperature were important variables for the CO₂ extraction, while temperature is the most important variable for the extraction yield with propane. The extraction with propane was much faster than that with carbon dioxide. The characteristics of the extracted oil, that is, the oxidative stability determined by DSC and the chemical profile of fatty acids determined by gas chromatography, were similar for the two solvents. The overall extraction curves were well described by the Sovová model.     

Oxidative stability of olive oil during the thermal process: Effect of Pistacia khinjuk fruit oil

The oxidative stability of refined olive oil with incorporated Pistacia khinjuk fruit oil (PKFO; 0.5%, 1%, 2%, 5%, and 10%) during thermal processing at 170ºC for 8 h was evaluated. The conjugated diene values, carbonyl values, acid values, oil/oxidative stability indices, and total tocopherol content were measured during thermal processing. Olive oil containing 0.5% PKFO was identified as the most oxidative stable oil followed by oils containing 100 ppm TBHQ and 1, 5, 10, and 2% PKFO. No significant difference between samples of olive oil containing 100 ppm TBHQ and 1% PKFO was observed. Thus, it was concluded that PKFO at levels lower than 1% could provide stronger antioxidation activity in comparison with TBHQ (the strongest syntactic antioxidant used in the food industry). Moreover, reduction in tocopherol compounds during thermal processing was higher in olive oil containing TBHQ as compared to those in pure olive oil.     

高阻气性软包装袋对花生油氧化稳定性的影响

为了延长花生油的保质期,测定了4种不同复合材料对花生油的抗氧化性能,筛选合适的包装材料制作花生油软包装保鲜袋,并评价其对花生油的抗氧化效果,在9周贮藏期内,对每周花生油的POV值进行检验。结果表明：流延聚乙烯/尼龙/流延聚丙烯膜（CPE/PA/CPP）复合材料抗氧化性能较好,采用比表面积小的CPE/PA/CPP制作的软包装袋用于包装花生油,可以显著提高花生油氧化稳定性。     

牡丹籽油微胶囊的释放动力学和氧化稳定性研究

为深入了解微胶囊化技术对牡丹籽油储藏稳定性和货架期的影响,采用Avrami’s公式分析牡丹籽油微胶囊的油保留率,考察牡丹籽油微胶囊在储藏期间的释放动力学;通过监测过氧化值(POV)的变化,对牡丹籽油微胶囊进行氧化动力学研究。结果表明:牡丹籽油微胶囊的释放反应介于扩散限制动力学和一级释放动力学之间;经过微胶囊化,牡丹籽油的POV上升速率降低,25℃储藏条件下货架期显著延长,45℃储藏条件下仍然可保持较高不饱和脂肪酸含量。研究表明微胶囊化可有效降低牡丹籽油的氧化速度,提高牡丹籽油的储藏稳定性,延长货架期。     

Kinetic study of canola oil and tocopherol extraction: Parameter comparison of nonlinear models

In this work a statistical method of comparison was used in order to compare the parameters of a modified diffusion model representing the kinetics of canola oil and tocopherol extraction. The model takes into account an initial stage where solvent removes the oil from the surface of the ground seed by washing. Kinetic tests were carried out in a batch extractor at different temperatures (from 25 to 60 °C) using hexane as solvent. Tocopherol concentration in the extracted oil was determined by HPLC.     

Cytooxidative effects of α‐tocopherol and ascorbyl palmitate on thermal oxidation of canola oil

Canola oil, with and without added α‐tocopherol and ascorbyl palmitate, was used to deep‐fat frying potatoes once per day for 10 day or once per week for 10 weeks. Changes in chemical and physical properties were monitored. Refractive index, free fatty acids and absorbance at 232 and 270 nm increased with frying time. Smoke point, ‘L’ color index, iodine value and the C_18 : 2/C_16 : 0 ratio in the oil decreased with the frying time. According to smoke point, which shows the time of the oil should be discarded, canola oil without antioxidant (control) can be used safely 8 times daily or 7 times weekly. For canola oil with antioxidant (oil + α‐tocopherol + ascorbyl palmitate( the smoke point did not decrease below 170°C in both daily and weekly fryings. This showed that canola oil with antioxidant could be used safely at least 10 times for both frying intervals. In both daily and weekly fryings, the addition of 200 ppm α‐tocopherol and 200 ppm ascorbyl palmitate increased the oxidative stability of canola oil.     

冷榨胡麻油在加速氧化过程中品质变化的研究

以冷压榨法提取的胡麻油为研究对象,通过Schaal烘箱法加速氧化试验,分析冷榨胡麻油的理化性质、脂肪酸组成及含量、生育酚与甾醇的组成及含量、角鲨烯含量。结果表明：冷榨胡麻油在加速氧化的前20 d内,过氧化值(5.85 mmol/kg)和酸价(1.6 mgKOH/g)均符合GB 2716—2018标准;而α-亚麻酸和生育酚的含量则显著下降(P<0.05),分别减少了16.28%和79.65%,其中α-生育酚的含量在加热8 d后则无法检出。为综合评价冷榨胡麻油的品质变化规律,采用主成分分析法可将其氧化过程可分为3个阶段：第1阶段(0～8 d),第2阶段(12～20 d),第3阶段(24～28 d)。由此可知,冷榨胡麻油在加速氧化20 d内具有良好的氧化稳定性,但从有益伴随物的角度分析其在氧化8 d内适合贮藏。此研究结果可以用于预测冷榨胡麻油的货架期,为冷榨胡麻油的储藏提供数据支持。     

内外源因子对花生油氧化稳定性的影响

本文首先研究花生油中的维生素E组成,共检测出8种维生素E的同分异构体,总量为281.78μg/g,其中α-生育酚占53.7%。以此为基础,以过氧化值、p-茴香胺值、DPPH自由基清除能力为评价指标,考察内源物质（α-生育酚）及外界因素（氧气、温度）对花生油氧化稳定性的影响。结果表明:在贮藏期内,低浓度（0.01%）的α-生育酚有效延缓了花生油的初级氧化进程,但在次级氧化阶段并未表现出抗氧化效果;高浓度（0.02%）的α-生育酚反而产生了促氧化作用,需要严格控制其添加量。相较于抗氧化剂α-生育酚及BHT的添加,低温、密封、充氮处理更能有效延缓花生油的氧化进程,不失为一种方便、有效且安全的保存措施。      

迷迭香的抗氧化活性及对藻油氧化稳定性影响的研究

在对迷迭香的DPPH自由基清除能力和还原力与合成抗氧化剂BHT对比研究的基础上,采用Schaal烘箱法,以POV(过氧化值)、TBA(丙二醛值)和DHA含量为氧化稳定性指标,研究了迷迭香在藻油中的抗氧化作用,并探究了增效剂对迷迭香的协同增效作用。结果表明:DPPH自由基清除能力和还原力依次为迷迭香粉BHT迷迭香精油;迷迭香粉和迷迭香精油对藻油都具有较强的保护作用,抗氧化能力依次为0.02%迷迭香粉0.02%BHT0.02%迷迭香精油0.02%VE;0.02%迷迭香粉与0.01%VC棕榈酸酯在藻油中有很强的增效作用。     

核桃内源性多酚的体外抗氧化能力及对核桃油 氧化稳定性的影响

为促进核桃加工副产物的综合利用,探究副产物中多酚对核桃油氧化稳定性的影响,测定了槲皮素、没食子酸、儿茶素、绿原酸、鞣花酸5种核桃内源性多酚对DPPH和ABTS+自由基的清除能力及氧自由基吸收能力（ORAC）以评价其体外抗氧化能力,并将5种内源性多酚分别加入核桃油中,进行18 d的加速氧化试验,以酸值、过氧化值、共轭二烯值、共轭三烯值、同步荧光光谱、色泽及感官品质（透明度、气味、滋味）作为考察指标,分析其对核桃油氧化稳定性的影响。结果表明：槲皮素、没食子酸和绿原酸的体外抗氧化能力较强;5种多酚均能有效减缓核桃油酸值、过氧化值、共轭二烯值和共轭三烯值的升高,其中没食子酸、绿原酸和儿茶素在维持核桃油感官品质方面优于其他2种多酚。综上,在开发核桃油相关产品时,可以考虑通过添加没食子酸、儿茶素和绿原酸提高产品的氧化稳定性。