微波和脱皮处理菜籽对油中活性成分的影响

以高、中、低芥酸和硫甙含量菜籽为原料,微波和脱皮预处理后分别冷榨制油。结果表明,不同处理方式对同一品种菜籽的基本品质并无影响,但油中植物甾醇和维生素E含量均存在明显差异,且含量大小依次为低芥酸低硫甙菜籽〉中芥酸中硫甙菜籽〉高芥酸高硫甙菜籽。利用SPSS（统计产品与服务解决方案,Statistical Productand Service Solutions）方差分析,探讨4种不同处理方式与3种不同原料对菜籽油中维生素E和植物甾醇的影响。结果表明,不同处理方式对双低菜籽油中α、γ维生素E和△5-燕麦甾醇影响差异显著,对菜籽甾醇、菜油甾醇和β-谷甾醇影响不显著;同一种处理方式下,不同原料对维生素E和植物甾醇都存在显著差异。微波处理后油中维生素E和植物甾醇含量最高,且低芥酸低硫甙菜籽更适宜通过微波处理提高油的品质。     

制油工艺对菜籽油微量成分和氧化稳定性的影响

以不同制油工艺制得的菜籽油为原料,比较研究了菜籽油的酸值、过氧化值、脂肪酸和甘三酯的组成及微量营养成分。结果表明:制油工艺对菜籽油的脂肪酸和甘三酯组成无显著性影响;水酶法制得菜籽油的酸值(KOH)相对较高,为0.995 mg/g,但富含β-胡萝卜素、植物多酚,含量分别为5.40 mg/kg和152.08 mg/kg;浸出菜籽毛油富含生育酚和植物甾醇,含量分别为833.74 mg/kg和6 607.35 mg/kg;精炼菜籽油的酸值(KOH)最低,仅为0.233 mg/g,但精炼菜籽油的微量营养成分相对较少。分别以氧化诱导时间和DPPH自由基清除能力为指标,评价了不同制油工艺制得菜籽油的氧化稳定性,结果发现5种菜籽油的氧化稳定性大小是:水酶法菜籽油最强,精炼菜籽油最弱,而浸出菜籽毛油、热榨菜籽油和冷榨菜籽油介于其间,这一性质和油中的植物多酚和β-胡萝卜素含量呈显著正相关。     

Effect of pretreatment with microwaves on mechanical extraction yield and quality of vegetable oil from Chilean hazelnuts (Gevuina avellana Mol)

The effect of microwave (MW) radiation on hazelnut seed (Gevuina avellana Mol) was studied as a substrate pretreatment prior to oil extraction by pressing. Samples were MW-treated at a frequency of 2450 MHz using a microwave oven. Six MW pretreatments were established, combining two potencies (400 W and 600 W) and three times of pretreatment (120, 180 and 240 s). Extraction oil yield increased with MW pretreatments of hazelnut seed with respect to untreated seeds, as a control. Conditions of 400 W and 240 s were selected (45.3% of extraction oil yield). Observations under light microscopy showed that the microstructure of treated samples to 400 W and 240 s, was modified comparing with that of untreated samples, thereby improving the extraction efficiency. The quality characteristics (e.g. acid value, peroxide value), oil composition (e.g. fatty acids, α-tocotrienol content) and oil oxidative stability (e.g. induction time) were measured. These results were compared to those of an untreated oil sample. MW pretreatment had a positive effect on oxidative oil stability (induction time of 23.9 h) with respect to untreated oil (8.8 h).

Industrial relevance

Chilean hazelnut (Gevuina avellana Mol) is the southernmost Macadamieae species of the family Proteaceae that grows mainly in the southern part of Chile and Argentina. The oil is composed mainly of unsaturated fatty acids, which represent 93% of the total. Its main components are oleic and palmitoleic acids, which represent 70% fatty acids. Conventional vegetable oil extraction is carried out by pressing or solvent extraction. Solvent oil extraction is the most efficient method; however, its application presents some industrial disadvantages such as plant security problems, emissions of volatile organic compounds into atmosphere, high operation costs and poor quality products caused by high processing temperatures. Mechanical pressing oil extraction is technically less extensive and less labor-intensive than the extraction solvent method . The safety and simplicity of the whole process is advantageous over the more efficient solvent extraction equipment. Furthermore, materials pressed out generally have better preserved native properties, end products are free of chemicals and it is a safer process. However, extraction by just pressing the seeds is relatively inefficient. It is advisable to research new methodologies for pretreating substrates that also allow for better retention and availability of desirable plant metabolites. Within these pretreatments, the radiation microwave is included. There is not much information in the literature about the application of microwave radiation as a pretreatment for Chilean hazelnut and its effect on the microstructure of the substrate, extraction yield and quality of oil. The aim of the present study was to investigate the impact of pretreatment by microwave radiation prior to the oil extraction by pressing on the microstructure, recovery of oils and oil quality of Chilean hazelnut seeds (G. avellana Mol).     

基于微波预处理油菜籽的压榨油和浸出油理化品质比较

微波预处理油菜籽可显著提高压榨出油率,但压榨后的饼粕中仍残留油脂,可采用浸出法提取饼中残油。为比较压榨油和浸出油的主要理化品质,在2450MHz、800W的微波条件下,分别对油菜籽预处理0～7min,冷却至室温后压榨制油,继而对饼粕中残油用正己烷萃取。结果表明,微波处理时间、压榨和浸出的制油方式对菜籽油酸价、过氧化值、p-茴香胺值、水分含量均有显著影响（P〈0.05）。压榨油和浸出油的酸价、p-茴香胺值随微波时间的延长而增加,过氧化值呈先增加后减少的趋势,浸出油酸价、过氧化值和p-茴香胺值高于压榨油。压榨油水分含量随微波时间的延长而增加,而浸出油的则减少,压榨油水分含量高于浸出油。压榨油和浸出油的色泽（罗维朋比色）随微波时间的延长逐渐变深,浸出油色泽更深;加热试验（至280℃）中压榨油无析出物,而浸出油产生絮状析出物。由此可见基于微波预处理油菜籽的压榨油仅需水洗、过滤或离心分离即可满足国家标准,浸出油则需要进行脱胶、脱酸、脱色等精炼处理。     

3种抗氧化剂对菜籽油氧化稳定性的影响

为探究抗坏血酸棕榈酸酯、迷迭香提取物和茶多酚棕榈酸酯及其复合物对菜籽油氧化稳定性的影响,采用Schaal烘箱加速氧化实验法对菜籽油进行氧化稳定性评价,并采用响应面实验优化复配抗氧化剂的配方。结果表明：3种抗氧化剂均能显著提高菜籽油的氧化稳定性（P＜0.05）,其中茶多酚棕榈酸酯抗氧化效果最为理想,添加量为0.01%和0.05%时,菜籽油过氧化值比空白对照分别降低了61.76%和68.79%;响应面实验得到最优复配抗氧化剂配方为0.02%抗坏血酸棕榈酸酯、0.03%迷迭香提取物、0.03%茶多酚棕榈酸酯,在此配方下加速氧化13 d时菜籽油过氧化值为6.017 mmol/kg。该复配抗氧化剂能有效减缓菜籽油的氧化速度,且能够保护菜籽油不易受高浓度抗氧化剂的促氧化作用。     

姜酮酚复配脂质伴随物对菜籽油氧化稳定性的影响

为了促进天然抗氧化剂的开发与利用,以脱除脂质伴随物多酚、甾醇和生育酚的菜籽油(空白油样)为研究对象,以DPPH自由基清除率为指标,采用正交试验优化甾醇、α-生育酚与姜酮酚复配抗氧化剂的配方。随后通过Rancimat法测定添加最优配方复配抗氧化剂的油样(简称添加姜酮酚的油样)的氧化诱导时间,并通过Schaal烘箱法考察添加姜酮酚油样的酸值、过氧化值、茴香胺值、丙二醛含量、共轭二烯含量(K₂₃₂)、共轭三烯含量(K₂₇₀)、总酚含量、DPPH自由基清除率和脂肪酸组成的变化,并与添加BHT的油样(以0.2 g/kg BHT代替姜酮酚)和空白油样进行了对比。结果表明：复配抗氧化剂最优配方为0.4 g/kg甾醇、0.05 g/kg α-生育酚和0.05 g/kg姜酮酚;与空白油样相比,添加姜酮酚的油样与添加BHT的油样其氧化诱导时间均延长;随着加速氧化储藏时间的延长,菜籽油的各项理化指标均发生一定程度的劣变,各油样的氧化稳定性排序为添加BHT的油样>添加姜酮酚的油样>空白油样。综上,姜酮酚复配脂质伴随物对于提高菜籽油的氧化稳定性有一定效果。     

冷榨核桃油氧化稳定性研究

选择了不同温度、光照及加入TBHQ抗氧化剂的条件下,以冷榨核桃油储存期间过氧化值和酸值变化为评价指标,对其氧化稳定性进行评价,结果表明:经50d储存,冷榨核桃油酸值和过氧化值都有不同程度的升高,不同温度下过氧化值、酸值升高变化趋势为:50℃>室温25℃避光>5℃;见光条件下的过氧化值、酸值升高变化趋势为:室温25℃见光>室温25℃避光;不同温度下加入抗氧化剂的过氧化值、酸值变化趋势为:50℃>室温25℃避光>5℃;采用Rancimat仪评价几种抗氧化剂提高核桃油的氧化稳定性值结果为:TBHQ>VE>BHT>空白样。     

菜籽油加工技术研究进展

菜籽油是我国主要食用油之一,富含油酸、亚油酸、维生素E、植物甾醇、胡萝卜素和菜籽多酚等功能性物质,营养价值高,因其独特的风味备受欢迎,但不同的加工技术对菜籽油品质具有较大影响。本文综述了国内外常用的菜籽油加工技术研究进展,着重阐述了加工技术对菜籽油品质的影响机制,旨在为进一步优化菜籽油加工技术,提高油品质量和促进菜籽油的适度加工提供一定的参考。     

Physical and oxidative stability of pre-emulsified oil bodies extracted from soybeans

Soybeans contain oil bodies that are coated by a layer of oleosin proteins. In nature, this protein coating protects the oil bodies from environmental stresses and might be utilised by food manufacturers for the same purpose. In this study, an aqueous extraction method was developed to increase the yield of oil bodies extracted from soybean. This method involved a two-step procedure: (i) blending, dispersion, and filtration of soybeans; (ii) homogenisation, suspension, and centrifugation of the filter cake. Using this extraction method about 65% of the oil bodies could be obtained. The mean particle diameter (d₄₃) and sedimentation of the resulting oil bodies increased during storage, suggesting they were prone to aggregation. Heat treatment (90 °C, 30 min) of the oil body suspensions immediately after extraction improved their storage stability, which was attributed to deactivation of endogenous enzymes such as lipase and lipoxygenase. Heat treatment did not adversely affect the oxidative stability of the oil body suspensions at pH 3 or 7 during storage at 37 °C. These results suggest that this aqueous extraction method can be used to prepare oil body suspensions with improved long-term stability.     

Evaluation of oxidative stability of sweet and bitter almond oils under accelerated storage conditions

This study aimed to investigate the oxidative stability of cold-pressed bitter and sweet almond oil under accelerated aging conditions. The oxidative stability of both oils was analyzed using as physicochemical metrics: fatty acid (FA) composition, sterol content, chlorophyll and carotenoid level, tocopherol level, iodine index, free fatty acid, Peroxide value and specific extinction coefficients K232–K270. The variations of these parameters were evaluated over four weeks at 60 °C. The results showed that carotenoid, total sterol, and tocopherol levels were decreased, the free fatty acid, Peroxide value, K232 and K270 parameters increased slightly for both oils, while, FA profiles and Iodine value did not significantly vary over four weeks. After four weeks, sweet almond cold-pressed oil still presents an excellent physicochemical profile. Bitter almond oil presents after the same delay much less satisfactory properties.     

Oxidative stability of olive oil after food processing and comparison with other vegetable oils

The use of olive oil showed an important protection of meat and potatoes when compared with other vegetable oils, with sunflower oil samples being oxidised after 60 min of processing at 180 °C. Olive oil samples were not oxidised, independently of the olive oil quality used. Shelf life was longer for extra-virgin olive oil containing samples and this fact was positively correlated with their higher phenolic content. The radical-scavenging activity of extra-virgin olive oil was higher than for other olive oil samples and was also positively correlated with the phenolic content of the oil. Seed oil antioxidants showed little capacity in delaying the oxidative degradation of seed oils and meat processed with them. However, tocopherol content and the identity of tocopherols present in the oil were shown to have a more important role in the oxidative stability of seed oils than the fatty acid composition.     

Effect of refining on the lignan content and oxidative stability of oil pressed from roasted sesame seed

Oxidative stability of pressed and refined sesame oils during seven consecutive months of storage at room temperature was studied comparatively. Lignans, peroxide value (PV), p‐anisidine value (AV) and total oxidation value (TOTOX) were determined as evaluation indices. PV, AV and TOTOX of sunflower, corn and peanut oils were simultaneously monitored to compare their oxidative storage stabilities with the sesame oils. The total amount of lignans in the pressed and refined sesame oils were 1103 and 790 mg per 100 g respectively. The contents of sesamin and sesemolin in the pressed sesame oil were 734 and 369 mg per 100 g respectively. Sesamin and sesamolin content were reduced by 256 and 159 mg per 100 g, respectively, after refining. Nearly 40% of the sesamin epimerised to asarinin after oil refining. The results indicate that sesame oils pressed from roasted seed have far superior storage stability to oxidation than the other vegetable oils. This difference may be due to much higher sesamin and sesamolin contents in the pressed sesame oils. The results suggest lignan compositions and levels could be used as key indicators for evaluating the oxidative storage stability of sesame oil products as well as to differentiate between pressed and refined sesame oils.     

加速氧化条件对大豆油氧化稳定性的影响

本研究采用同批油料提取的水酶法大豆油、溶剂浸提大豆油与一级大豆油进行室内储藏实验。不同温度（25⁸0℃）下储存一定天数（0⁶0d）测定样品过氧化值、共轭二烯值、共轭三稀值、p-茴香胺值以及脂肪酸组成。实验结果表明:在相同温度条件下,3种植物油的过氧化值有显著区别,一级大豆油的过氧化值显著高于水酶法大豆油和溶剂浸提大豆油;对于同一油脂在不同温度下,温度越高,氧化反应的活化能越小,大豆油氧化越快;油脂储藏稳定性为溶剂浸提大豆油>水酶法大豆油>一级大豆油。      

微波预处理压榨茶叶籽油及其氧化稳定性

采用微波预处理压榨法提取茶叶籽油,与烘烤后压榨法在提取率、理化性质和氧化稳定性进行了比较.结果表明,微波预处理压榨茶叶籽油得率比120℃烘烤后压榨得油率高9.6％,为21.81％,油脂提取率为77.5％;微波预处理压榨茶叶籽油的理化性质与60、80℃烘烤后压榨茶叶籽油无明显差异;微波预处理压榨茶叶籽油氧化稳定性高于60℃烘烤后压榨的茶叶籽油,适当升高烘烤温度,压榨茶叶籽油的氧化稳定性升高,当烘烤温度达到120℃时,其氧化稳定性下降.     

微波预处理对亚麻籽油得率及其贮藏稳定性的影响

对亚麻籽进行微波预处理,并采用微波辅助溶剂法提取亚麻籽油。以亚麻籽油得率为指标,对微波预处理亚麻籽工艺条件进行优化,同时比较了经微波预处理和未经微波预处理提取的亚麻籽油得率、贮藏稳定性和多酚含量。结果表明:微波预处理最佳工艺条件为原料水分含量6%、微波功率65 W、微波时间3 min,在此条件下亚麻籽油得率为46. 60%,比未经微波预处理的提高了8. 05个百分点;在105℃贮藏8 d内,经微波预处理和未经微波预处理提取的亚麻籽油的过氧化值增加量分别为4. 38 mmol/kg和18. 16 mmol/kg,K_(232)的增加量分别为2. 53、9. 04,K_(270)的增加量分别为0. 09、0. 35;与未经微波预处理相比,微波预处理可将亚麻籽油中的多酚含量提高14. 9%。微波预处理能提高亚麻籽油得率和多酚含量,同时可延缓亚麻籽油氧化的速率,进而提高其贮藏稳定性。     

亚麻籽烘烤预处理对亚麻籽油得率 及贮藏稳定性的影响

以亚麻籽油得率为指标,对烘烤预处理亚麻籽工艺进行优化,并研究烘烤预处理对亚麻籽油贮藏稳定性及多酚含量的影响。结果表明：亚麻籽烘烤预处理最佳工艺条件为烘烤时间40 min、烘烤温度100?℃、粉碎粒度0.250 mm（60目）,以此条件下的亚麻籽为原料提取油脂,亚麻籽油得率为44.46%,比未预处理提取的亚麻籽油得率高7.91个百分点,多酚含量高12.61个百分点;贮藏8 d,烘烤预处理提取的亚麻籽油过氧化值、K232、K270的增幅均小于未预处理提取的亚麻籽油。研究表明烘烤预处理不仅能提高亚麻籽油得率,同时可延缓亚麻籽油氧化,进而提高亚麻籽油的贮藏稳定性。     

低水分酶法预处理高效提取菜籽油工艺研究

采用对油菜籽细胞物理破碎和酶处理相结合方法,建立一种低水分酶法预处理油菜籽提取菜籽油新工艺;并采用响应面分析(RSA)法对实验工艺条件进行优化,得到最佳工艺条件为:以木瓜蛋白酶为处理酶,酶解时间2h、酶解温度48.45℃、加酶量1.27%,在此工艺条件下菜籽油提取率可达93.65%。     

Heat-oxidation stability of palm oil blended with extra virgin olive oil

Rancimat induction time of palm oil (PO), several extra virgin olive oils (EV) and their binary blends have been determined at three different temperatures (120, 130 and 140°C). Analytical composition and oxidation stability of PO/EV blends were found to be a linear combination of the oil partners. Induction time of pure PO was always higher than those of EV oils and blends, in which induction time increased proportionally with the percentage of PO. However, induction time of 80% PO blend was similar to that of pure PO. Fatty acid composition appeared to be the most important factor affecting heat-oxidation stability and a saturated/unsaturated ratio near 1 was the optimally stable composition. Conversely, total phenols had a zero or negative role on the oxidative stability of the blends. Finally, in heat-oxidised oils significant losses of polyunsaturated fatty acids and formation of short-chain fatty acids were recorded.     

不同贮存条件对海藻油氧化稳定性影响

以过氧化值为指标,考察空气、温度、光照等环境条件对海藻油稳定性影响,然后采用Schall烘箱加速氧化法,以POV和DHA含量为指标,通过L9(34)正交试验,从抗氧化剂TBHQ、VE、Vc棕榈酸酯优选海藻油复合抗氧化剂;及研究充N2保护、充N2保护结合添加抗氧化剂对海藻油稳定性影响。结果表明:空气,高温及光照均可显著加速海藻油氧化,降低海藻油稳定性;抗氧化剂TBHQ、VE、Vc棕榈酸酯能明显延缓海藻油氧化,影响顺序为Vc棕榈酸酯TBHQVE,最佳抗氧化剂组合为0.01%Vc棕榈酸酯+0.02%TBHQ+0.50%VE;充N2保护也能提高海藻油氧化稳定性,但效果比最佳复合抗氧化剂为差;充N2保护结合添加抗氧化剂能有效提高海藻油氧化稳定性。     

Enzymatic hydrolysis and pressing conditions effect on borage oil extraction by cold pressing

Borage seed oil extraction using cold pressing produces a good oil quality, but it has a low-yield. In a previous study on a borage oil extraction process by cold pressing using commercial enzymes, the oil yield was enhanced in comparison to the control without enzymes. The aim of this work was to further evaluate the effect of temperature, moisture and time of enzymatic hydrolysis; and the effect of this treatment under selected conditions on the pressing stage and on product qualities. The best treatment condition with Olivex–Celluclast was 45 °C, 20% moisture over 9 h of treatment. When the extraction of the pre-treated borage meal was carried out by double pressing (20 min each) on preheated matter, 95% of the oil was recovered. The enzymatic treatment did not affect the oil quality and the residual meal was more valuable due to its lower fibre content.