热加工过程中棕榈油理化特性、脂肪酸与自由基的变化研究

以棕榈油（24℃）为原料,采用国标法测定棕榈油在不同温度（160、180、200℃）下常规理化指标（酸价、过氧化值、丙二醛值、p-茴香胺值和总氧化值）随时间的变化,在此基础之上,分别采用GC-MS法与电子自旋共振（ESR）法对180℃下棕榈油脂肪酸组成和自由基含量变化进行测定。结果表明,加热温度越高和加热时间越长棕榈油理化指标值越大,其中过氧化值呈现先上升后下降趋势。脂肪酸组成结果表明,棕榈油中饱和脂肪酸与不饱和脂肪酸比例约为1∶1,且随着加热时间延长,比例基本不变。ESR实验表明,加热时间越长,2-苯叔丁基硝酮（PBN）捕获的自由基量越多,棕榈油氧化程度越深。      

蓖麻油的理化性质及脂肪酸组成分析

对一级蓖麻油的理化性质进行了测定,并利用气相色谱-质谱联用仪（GC—MS）对蓖麻油的脂肪酸组成进行了分析和鉴定。     

乌榄仁油的理化性质与脂肪酸组成分析

目的：从开发新油脂和提高经济价值角度出发,研究乌榄仁油的理化性质与脂肪酸组成。方法：采用气相色谱质谱联用法对不同压榨温度下提取的油脂进行脂肪酸组分测定。结果表明：乌榄仁的含油量高（65.71%）;其各项理化指标符合国家的相关规定,随着压榨温度的升高,色泽加深,气味更加愉悦;脂肪酸组成共有10种,主要成分为棕榈酸、硬脂酸、油酸、亚油酸,不饱和脂肪酸总量为63.47-67.15%,随着压榨温度升高,除亚油酸外其他脂肪酸成分均无显著性差异,与其他油脂脂肪酸的对比中发现其优点是亚油酸含量高;结论：乌榄仁的含油量高,脂肪酸成分好,亚油酸含量略有优势,具有开发前景,可为乌榄仁油的进一步加工利用提供科学依据。     

油松籽油理化性质及脂肪酸组成研究

本文对油松籽油理化性质和脂肪酸组成进行了分析研究。结果表明,油松籽含油率为30.37%,酸值1.6（KOH）/（mg/g）,皂化值188.7（KOH）/（mg/g）,碘值93.1I_2g/100g,乙酰值26.3（KOH）/（mg/g）,羟基值3.7（KOH）/（mg/g）。油中主要含有棕榈酸4.59%、硬脂酸2.07%、油酸21.20%、亚油酸42.92%、亚麻酸0.36%。     

华山松籽油脂肪酸组成及其理化性质研究

通过气相色谱(GC)分析了华山松籽油的主要脂肪酸组成。结果表明华山松籽含油率为56.5%,其中主要含有亚油酸63%,油酸26%,棕榈酸5%,硬脂酸2%,花生酸1%,芥酸1%,不饱和脂肪酸总量达90%。理化测定结果表明华山松籽油相对密度为0.915,折光率为1.4778,酸价为5.1,皂化价为190.8,碘价为142.6,过氧化值为0.04305%。     

栀子果油的脂肪酸组成及其主要理化性质分析

以栀子为原料提取栀子果油,对其理化性质及脂肪酸组成等进行了测定分析。结果表明,油脂主要成分为亚油酸（43．47％）、棕榈酸（22．72％）、硬脂酸（9．98％）,此外,还含有反式角鲨烯（1．20％）。可见,栀子油脂具有很高的食用价值,可作为一种新的食用油源加以开发利用。     

诃子油的理化性质及脂肪酸组成分析

测定了黑诃子、金诃子和毛诃子的粗脂肪含量及相应油脂的酸值、皂化值和脂肪酸组成,结果发现毛诃子的含油率最高,为3.50%。三种诃子油的酸值为7.95、6.27、9.07 mg KOH/g;皂化值为267.0、222.8、261.1 mg KOH/g;均含有棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸和三十碳酸,不饱和脂肪酸含量超过60%,主要为油酸和亚油酸,具有降低血脂的作用,使诃子油成为一种极具开发价值的保健油脂。     

谷子油的理化性质及脂肪酸组成分析

对谷子的基本组成和谷子油的理化性质及脂肪酸组成进行了分析。结果表明,谷子中粗蛋白质、粗脂肪、总糖和淀粉含量分别为13.9%、5.6%、66.5%和63.7%。谷子油的酸值(KOH)为11.9 mg/g,碘值(I)为132.9 g/100 g,过氧化值为30.9 mmol/kg,皂化值(KOH)为194.4 mg/g,不皂化物含量为2.73%。谷子油主要由10种脂肪酸组成,其中饱和脂肪酸含量占16.81%,主要为棕榈酸(7.87%)、硬脂酸(6.17%)和花生酸(2.03%);不饱和脂肪酸含量达83.26%,其中以亚油酸含量(65.30%)最高,其次为油酸(14.20%)和亚麻酸(2.93%)。因此,谷子油是一种极具开发价值的营养保健油脂。     

文冠果种子油理化性质及脂肪酸组成

利用索氏抽提法提取文冠果种子油,对文冠果种子油理化性质进行测定,用气相色谱法分析脂肪酸组成及相对含量.结果表明:文冠果种子含油率为56.4%,相对密度(d20)0.912 4,折光率(n20)1.466 5,水分及挥发物含量10.13%,酸值0.93mg/g(以KOH计),皂化值167.46mg/g(以KOH计),碘值101.32g/100g (以I计).油中主要含有棕榈酸7.87%、硬脂酸5.25%、油酸33.93%、亚油酸48.34%、亚麻酸4.6l%.     

鸵鸟油理化性质及脂肪酸组成分析

采用索氏提取法提取了在陕西养殖的鸵鸟油,室温分离得到液体油和固体脂.采用化学方法和气相色谱仪测定了两者常规理化指标和脂肪酸组成.结果表明,鸵鸟液体油和固体脂除碘值外其他理化指标稍有不同,其中脂肪酸组成及含量也有差异.液体油主要含有棕榈酸、油酸和亚油酸等,不饱和脂肪酸含量为63.96%,其中油酸含量最高,达到42.23%;固体脂主要含有棕榈酸、硬脂酸和油酸等,饱和脂肪酸含量为55.93%,其中棕榈酸含量最高,为45.23%.     

烟台大樱桃仁油理化性质及脂肪酸组成分析

初步分析烟台大樱桃仁油的理化性质及脂肪酸组成,旨在为开发新型功能性油脂——烟台大樱桃仁油以及樱桃仁的综合利用提供理论依据。采用气相色谱对烟台大樱桃仁油的脂肪酸组成进行了分析,并对该油脂的理化性质进行了研究。结果表明:从该油脂中分离出10种脂肪酸,主要为亚油酸(39.14%),油酸(36.09%),棕榈酸(7.79%),硬脂酸(2.96%),花生酸(1.49%),不饱和脂肪酸质量分数达76.2%,属于高油酸-亚油酸型油脂;烟台大樱桃仁油含油率为27.8%,其主要理化指标为:酸价1.87 mg KOH/g,过氧化值8.95 mmol/kg,碘值118 g I/100 g,皂化值184 mg KOH/g,不皂化物1.67%。烟台大樱桃仁油作为油料新品种进行开发,必将产生很高的经济效益和社会效益。     

Extraction and physicochemical properties of low free fatty acid crude palm oil

Response surface methodology was applied to optimize the pre-treatment of oil palm (Elaeis guineensis) fruit spikelets before oil extraction. The treatment applied was drying at different times and temperatures. The dried spikelets were then subjected to mechanical processes and crude oil was extracted. A central composite design was employed to study the responses, namely percentage of free fatty acids (FFA) and oil yield, and the optimum conditions for minimum FFA and maximum oil yield were identified from their respective contour plots. It was concluded that the pre-treatment should be carried out for 12.8 h at 66.8 °C. Under the optimum conditions, the corresponding response values for FFA and oil yield were 1% and 33.6%, respectively. Some of the physicochemical properties of the extracted oil were then determined. The low free fatty acid crude palm oil exhibited good physicochemical properties and could be useful for industrial applications.     

烘烤条件对奇亚籽油理化性质及脂肪酸组成的影响

对奇亚籽进行烘烤、压榨取油,测定不同烘烤条件(温度、时间)下奇亚籽油的理化性质及脂肪酸组成,探讨烘烤温度和时间的影响。结果表明:随着烘烤温度的升高和烘烤时间的延长,奇亚籽油色泽加深,酸价、过氧化值、K_(232)、K_(268)均呈现上升趋势,且180℃烘烤50 min以上较其他条件下显著升高(p0.05);烘烤条件对脂肪酸组成无影响。故烘烤奇亚籽不宜在高温下进行,若采用180℃烘烤时,则时间不应超过50 min。     

超声处理对红花籽油理化性质及脂肪酸组成的影响

研究了不同超声条件下,红花籽油过氧化值、酸值、皂化值及脂肪酸组成的变化规律。结果表明:超声温度控制在50℃以下,超声功率小于等于600 W,超声时间短于60 min时,超声处理对红花籽油的过氧化值、酸值无明显影响,当超声功率高于600 W时,过氧化值、酸值随超声时间的延长而增加;超声温度控制在50℃以下,超声功率小于等于900 W,超声时间短于60 min时,超声处理对红花籽油脂肪酸组成没有影响,对脂肪酸含量和皂化值有较小的影响。     

不同干燥方式对山桐子油理化性质、脂肪酸组成及微量营养成分含量的影响

通过测定山桐子果含水率、含油率以及山桐子油酸价、过氧化值、皂化值、脂肪酸组成、维生素E、总酚、角鲨烯和β-谷甾醇,研究了阴干、晒干和烘干3种不同干燥方式对山桐子油理化性质、脂肪酸组成和微量营养成分含量的影响,并采用主成分分析综合评价3种油的品质。结果表明:山桐子油酸价和皂化值由高到低的干燥方式依次为阴干>晒干>烘干;山桐子油过氧化值和β-谷甾醇含量由高到低的干燥方式依次为晒干>烘干>阴干;山桐子油角鲨烯含量由高到低的干燥方式依次为烘干>阴干>晒干;VE含量由高到低的干燥方式依次为晒干>烘干≈阴干;总酚含量3种干燥方式没有显著差异。综合比较,晒干得到的山桐子油的理化性质较好,微量营养成分损失最小。     

Effect of lauric acid and coconut oil on ruminal fermentation, digestion, ammonia losses from manure, and milk fatty acid composition in lactating cows

This experiment (replicated 3 × 3 Latin square design) was conducted to investigate the effects of lauric acid (LA) or coconut oil (CO) on ruminal fermentation, nutrient digestibility, ammonia losses from manure, and milk fatty acid (FA) composition in lactating cows. Treatments consisted of intraruminal doses of 240 g of stearic acid/d (SA; control), 240 g of LA/d, or 530 g of CO/d administered once daily, before feeding. Between periods, cows were inoculated with ruminal contents from donor cows and allowed a 7-d recovery period. Treatment did not affect dry matter intake, milk yield, or milk composition. Ruminal pH was slightly increased by CO compared with the other treatments, whereas LA and CO decreased ruminal ammonia concentration compared with SA. Both LA and CO decreased protozoal counts by 80% or more compared with SA. Methane production rate in the rumen was reduced by CO compared with LA and SA, with no differences between LA and SA. Treatments had no effect on total tract apparent dry matter, organic matter, N, and neutral detergent fiber digestibility coefficients or on cumulative (15 d) in vitro ammonia losses from manure. Compared with SA, LA and CO increased milk fat 12:0, cis-9 12:1, and trans-9 12:1 content and decreased 6:0, 8:0, 10:0, cis-9 10:1, 16:0, 18:0, cis 18:1, total 18:2, 18:3 n-3 and total polyunsaturated FA concentrations. Administration of LA and 14:0 (as CO) in the rumen were apparently transferred into milk fat with a mean efficiency of 18 and 15%, respectively. In conclusion, current data confirmed that LA and CO exhibit strong antiprotozoal activity when dosed intraruminally, an effect that is accompanied by decreases in ammonia concentration and, for CO, lowered methane production. Administration of LA and CO in the rumen also altered milk FA composition.