Lipase-catalysed interesterification between canola oil and fully hydrogenated canola oil in contact with supercritical carbon dioxide

The processing parameters in enzymatic reactions using CO₂-expanded (CX) lipids have strong effects on the physical properties of liquid phase, degree of interesterification, and physicochemical properties of the final reaction products. CX-canola oil and fully hydrogenated canola oil (FHCO) were interesterified using Lipozyme TL IM in a high pressure stirred batch reactor. The effects of immobilised enzyme load, pressure, substrate ratio and reaction time on the formation of mixed triacylglycerols (TG) from trisaturated and triunsaturated TG were investigated. The optimal immobilised enzyme load, pressure, substrate ratio and time for the degree of interesterification to reach the highest equilibrium state were 6% (w/v) of initial substrates, 10 MPa, blend with 30% (w/w) of FHCO and 2 h, respectively. The physicochemical properties of the initial blend and interesterified products with different FHCO ratios obtained at optimal reaction conditions were determined in terms of TG composition, thermal behaviour and solid fat content (SFC). The amounts of saturated and triunsaturated TG decreased while the amounts of mixed TG increased as a result of interesterification. Thus, the interesterified product had a lower melting point, and broader melting and plasticity ranges compared to the initial blends. These findings are important for better understanding of CX-lipid reactions and for optimal formulation of base-stocks of margarine and confectionary fats to meet industry demands.     

Enzymatic interesterification of palm and coconut stearin blends

Hard fractions of palm oil and coconut oil, blended in the ratios of 90:10, 85:15, 80:20 and 75:25, were interesterified for 8 h using Lipozyme TL IM. Major fatty acids in the blends were palmitic acid (41.7–48.4%) and oleic acid (26.2–30.8%). Medium‐chain fatty acids accounted for 4.5–13.1% of the blends. After interesterification (IE), slip melting point was found to decrease from 44.8–46.8 °C to 28.5–34.0 °C owing to reduction in solids content at all temperatures. At 37.5 °C, the blends containing 25% coconut stearins had 17.4–19% solids, which reduced to 0.4–1.5% on IE, and the slip melting point (28.6 and 28.8 °C) indicated their suitability as margarine base. The reduction in solid fat index of the interesterified fats is attributed to the decrease in high‐melting triacylglycerols in palm oil (GS₃ and GS₂U type) and increase in triolein (GU₃) content from 1 to 9.2%. Retention of tocopherols and β‐carotene during IE was 76 and 60.1%, respectively, in 75:25 palm stearin and coconut stearin blend.     

Characterisation of zero‐trans margarine fats produced from camellia seed oil,palm stearin and coconut oil using enzymatic interesterification strategy

Zero‐trans interesterified fats were produced from camellia seed oil (CSO), palm stearin (PS) and coconut oil (CO) with three weight ratios (CSO/PS/CO, 50:50:10, 40:60:10 and 30:70:10) using Lipozyme TL IM. Results showed that the interesterified products contained palmitic acid (34.28–42.96%), stearic acid (3.96–4.72%), oleic acid (38.73–47.95%), linoleic acid (5.92–6.36%) and total medium‐chain fatty acids (MCFA)s (∑MCFAs, 5.03–5.50%). Compared with physical blends, triacylglycerols of OOO and PPP were decreased and formed new peaks of equivalent carbon number (ECN) 44 in the interesterified products. The product CPC3′ showed a slip melting point of 36.8 °C and a wide plastic range of solid fat content (SFC) (45.8–0.4%) at 20–40 °C. Also, the major β′ form was determined. These data indicated that the zero‐trans interesterified fats would have a potential functionality for margarine fats. Subsequently, the antioxidative stabilities of interesterified products with the addition of α‐tocopherol (α‐TOH) and ascorbyl palmitate (AP) were investigated. The results indicated that AP had a dose‐dependent effect at concentrations of 100, 200 and 400 ppm.     

The effects of enzymatic interesterification on the physical-chemical properties of blends of lard and soybean oil

The main goal of the present research effort was to evaluate the physical-chemical properties of blends of lard and soybean oil following enzymatic interesterification catalyzed by an immobilized lipase from Thermomyces lanuginosa (Lipozyme™ TL IM). Lipase-catalyzed interesterification produced new triacylglycerols that changed the physical-chemical properties of the fat blends under study. Solid fat content (31.3 vs 31.5 g/100 g), consistency (104.7 vs 167.6 kPa), crystallized area (0.6 vs 11.8) and softening point (31.8 vs 32.2 °C) of lard increased after interesterification, and this was mostly due to the increase of SSS (saturated) + SSU (disaturated-monounsaturated) triacylglycerols. These contents (SSU + SSS) increased in lard after interesterification from 42.9 to 46.7 g/100 g. The interesterified blends exhibited lower values for the physical properties when compared with their counterparts before enzymatic interesterification. The interesterification of blends of lard with soybean oil increased the amounts of UUU (triunsaturated) and SSS triacylglycerols and reduced the amounts of UUS (diunsaturated-monosaturated) triacylglycerols. The interesterified blends of lard and soybean oil demonstrated physical properties and chemical composition similar to human milk fat and they could be used for the production of a human milk fat substitute.     

Effects of chemical interesterification on solid fat content and slip melting point of fat/oil blends

Fat/oil blends, formulated by mixing fully hydrogenated palm oil stearin or palm oil stearin with vegetable oils (canola oil and cottonseed oil) in different ratios from 30:70 to 70:30 (w/w %), were subjected to chemical interesterification reactions on a laboratory scale. Fatty acid (FA) composition, iodine value, slip melting point (SMP) and solid fat content (SFC) of the starting blends were analysed and compared with those of the interesterified blends. SMPs of interesterified blends were decreased compared to starting blends because of extensive rearrangement of FAs among triacylglycerols. These changes in SMP were reflected in the SFCs of the blends after the interesterification. SFCs of the interesterified blends also decreased with respect to the starting blends, and the interesterified products were softer than starting blends. These interesterified blends can be used as an alternative to partial hydrogenation to produce a plastic fat phase that is suitable for the manufacture of margarines, shortenings and confectionary fats.     

Effect of model heat treatment conditions on selected properties of milk fat

In this study, the effect of diverse thermal treatments on the physical characteristics of anhydrous milk fat was monitored with the use of scanning calorimetry, firmness analysis, electron microscopy and image analysis. The optimal properties of milk fat were achieved for the thermal treatment taking into account its composition as well as melting and solidification points of the main triacylglycerol fractions (temperatures: 6/20.5/14 °C). Unfavourable results were obtained for the one‐stage system (10 °C/13 h). These results may be helpful in optimising parameters of milk fat crystallisation in high‐fat products, and the fractal analysis has proven to be useful in the evaluation of fat crystallisation.     

Enzymatic interesterification of anhydrous butterfat with flaxseed oil and palm stearin to produce low-trans spreadable fat

Lipase-catalysed interesterification was performed to produce low-trans spreadable fat (LTSF) with anhydrous butterfat (ABF), flaxseed oil (FSO), and palm stearin (PS) using biocatalysts (Lipozyme RM IM and Novozym SP435). The reaction was carried out for 24 h at 60 °C in a shaking water bath (180 rpm). Seven substrate blends for the production of LTSF were prepared: 12:6:2, 10:6:4, 9:6:6, 8:6:6, 6:6:8, 6:6:9, and 4:6:10 (ABF/PS/FSO, by weight). After 24-h interesterification, decreased saturated fatty acid (SFA) contents in LTSFs were observed with ranges from 67% to 41%. LTSFs exhibited low atherogenic index (AI) with ranges from 2.8 to 0.8, compared with 3.3–4.7 AI of butter fat. Equivalent carbon number (ECN) 42–46 in the newly produced triacylglycerol (TAG) increased according to rearrangement of FAs on TAG backbone. The α-linolenic acid contents (mol%) of each LTSF were 5.6% (12:6:2), 10.7% (10:6:4), 15.1% (9:6:6), 15.8% (8:6:6), 20.8% (6:6:8), 22.4% (6:6:9) and 26% (4:6:10). The trans fatty acids in the LTSFs was not more than 2%. Melting point ranges of LTSF were from 37 (9:6:6) to 32 °C (4:6:10).     

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。     

驴脂组成成分及其油脂的品质指标分析

研究了驴脂的元素谱库、营养成分组成,测定了驴脂提取分离产物驴油的品质指标。以电感耦合等离子体质谱技术(ICP-MS)对驴脂中37种金属元素进行扫描分析,形成样本的元素谱库,结果表明驴脂中各金属元素均未达到检出限。以多质量分析器组合式质谱仪对驴脂进行MSn级扫描,最终获得驴脂中主要成分信息,发现驴脂主要成分中包含16种氨基酸及其衍生物类、11种有机酸、46种脂质以及糖类、维生素类等多种成分。采用超声辅助溶剂提取法得到的驴油相对密度为0. 908,水分含量为0. 68%,酸价(KOH)为0. 58 mg/g,过氧化值为0. 018 g/100 g,碘值(I)为85g/100 g。研究储存温度对驴油过氧化值的影响,结果表明驴油常温下即可储存。驴脂可作为食品、化妆品的研发原料,具有广阔的应用前景。     

火麻仁油组分含量及理化性质的研究

采用气相色谱、高效液相色谱等方法,对火麻仁油的脂肪酸组成、维生素E含量和理化性质进行了测定分析。试验结果表明:火麻仁油中不饱和脂肪酸含量为89.83%,其中油酸、亚油酸和亚麻酸含量分别为10.93%、58.79%和20.11%,亚油酸和亚麻酸搭配的比例更为合理,且维生素E总含量高达537 mg/kg,是一种重要的营养保健油脂资源,极具开发潜力。     

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。     

Effect of blending and lipase catalyzed interesterification reaction on the cholesterol lowering properties of palm oil with rice bran oil in rats

The effect of feeding blended and interesterified oils containing palm oil (PO) and rice bran oil (RBO) on serum and liver lipids was evaluated in rats. The PO and RBO were blended to contain saturated, monounsaturated and polyunsaturated fatty acids in the proportion of 1:1.5:1. The blended oil was subjected to transesterification reaction using immobilized lipase, lipozyme IM‐RM. Rats were fed a diet containing blended or interesterified oils for 8 weeks. Rats fed PO showed significantly higher levels of cholesterol in serum and liver as compared to those given RBO, blended oil of PO with RBO or interesterified oil. Rats fed blended oils showed a significant decrease in serum cholesterol by 51% compared to rats fed PO. Feeding interesterified oil to rats resulted in decrease in serum cholesterol by 56% compared to rats fed PO, which was 10% lower compared to that observed in rats given blended oil. The present study indicated that a combination of PO with RBO can significantly lower serum lipids in rats as compared to those given diet containing PO alone.     

[1]酶法制备芝麻粗油体及其相关理化性质的研究

目的 利用果胶酶与纤维素酶所组成的复合酶对芝麻进行粗油体提取,探究酶法提取粗油体内在稳定机制。方法 研究在不同总酶量与复合酶配比下芝麻粗油体的提取率,比较分析了粗油体的组成成分,粒径与电位,微观结构及核磁成像、流变学特性。结果 结果表明,相比于碱法,复合酶法可显著提高粗油体的提取率,当总酶量为5%,果胶酶与纤维素酶质量比为2:1时粗油体的提取率可达68.07%,且粗油体中蛋白质与多糖的含量较高;受组成成分的影响,酶法制备粗油体的粒径较大,Zeta电位较低,粗油体中存在聚集体,且水分分布的均匀性也较差;流变特性分析则表明,酶法制备粗油体的G’和G”值普遍大于碱法制备粗油体,说明酶法制备的粗油体具有较好的网络结构。结论 为合理设计酶法提取工艺和制备应用于食品、化妆品体系的粗油体胶体体系提供了一定的参考价值。     

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。     

脂肪酶对油脂体外降解及消化的研究

以大豆油、菜籽油、棕榈油、鸭油和猪油的乳化油脂为原料,测定添加脂肪酶后油脂的水解效果,并进行体外模拟猪胃肠道消化试验,观察乳仔猪料添加脂肪酶后消化率的变化。结果表明:乳化油脂中添加脂肪酶反应4 h即可达到降解峰值,当脂肪酶酶活剂量达到200 U/mL(以原始油脂体积计)时,不同油脂产生的脂肪酸量均可达到饱和;在添加不同剂量脂肪酶阶段,棕榈油和猪油乳化油脂产生的脂肪酸量始终大于大豆油和鸭油乳化油脂的,菜籽油乳化油脂的最低,组间差异显著(P0.05);与空白不加酶组相比,所有乳化油脂加酶(酶活剂量为260 U/mL)后产生的脂肪酸总增加量均超过1.50 mmol/L,总增加率均超过300%,其中以菜籽油的提升最高,达到了810.5%。模拟乳仔猪消化过程也发现,当脂肪酶(酶活80 000 U/g)添加量为125 g/t(以饲料质量计)时,饲料干物质消化率和能量消化率可提高0.86个百分点和0.83个百分点,鉴于饲料中其他组成原料也含有一定的脂肪,故脂肪酶添加量略高于125 g/t或与其他酶进行搭配使用效果可能更佳。     

Effect of oil content and processing conditions on the thermal behaviour and physicochemical stability of oil-in-water emulsions

The destabilisation mechanism of oil-in-water (o/w) emulsions was studied as a function of oil content (20% and 40% o/w), homogenisation conditions and crystallisation temperatures (10, 5, 0, −5 and −10 °C). A mixture of anhydrous milk fat and soya bean oil was used as the lipid phase and whey protein isolate (2 wt%) as emulsifier. Crystallisation and melting behaviours were analysed using differential scanning calorimetry. Physicochemical stability was measured with a vertical scan macroscopic analyser. Emulsions with 20% oil were found to be less stable than those with 40% oil. For 20% o/w emulsions, the crystallisation was delayed and inhibited in emulsions with smaller droplets and promoted in emulsions with larger droplets when compared with 40% o/w emulsions. Depending on the droplet sizes in the emulsion, the formation of lipid crystals (in combination with the emulsifier) either stabilises (small droplets) or destabilises (big droplets) the emulsion.     

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。      

Effect of glycerol and vegetable oil on physicochemical properties of Arabic gum-based beverage emulsion

The effect of two emulsion components namely glycerol (0.5, 1 and 1.5% w/w) and vegetable oil (2, 3 and 4% w/w) on ζ-potential, conductivity, pH, apparent viscosity, fluid behavior, turbidity and cloud stability of orange beverage emulsion was investigated. The negatively charged ζ-potential significantly (p < 0.05) increased with increasing glycerol content. A slight increase in ζ-potential was observed by adding 2% (w/w) vegetable oil to the emulsion formulation, while it was slightly decreased when vegetable oil content was increased up to 4% (w/w). Apparent viscosity, pH and turbidity of orange beverage emulsions significantly (p < 0.05) increased when the concentration of glycerol or vegetable oil was increased. All prepared beverage emulsions behaved as non-Newtonian (i.e., pseudoplastic or shear thinning) fluids. The addition of different concentration levels of both supplementary emulsion components except for 0.5% (w/w) glycerol significantly (p < 0.05) improved the cloud stability of orange beverage emulsions.     

油脂营养成分及其对肠道健康影响的研究进展北大核心CSCD

油脂是人体最主要的营养物质之一,其消化吸收主要发生在肠道,而肠道内存在种类繁多的菌群,可以直接参与人体的消化吸收、脂质代谢、能量供应等。油脂的消化吸收可能与多种代谢紊乱和肠道疾病、糖尿病、肥胖等慢性疾病存在联系,而食用油脂摄入不平衡会影响肠道菌群组成和代谢,破坏肠道稳态,进而可能导致上述疾病的发生。综述了油脂的脂肪酸组成、功能性伴随成分及其对人体健康的影响,分析了近年来油脂对肠道菌群组成及其代谢产物影响的研究,并对未来的研究方向进行了展望,这对进一步开展油脂营养特性及其对肠道健康影响的研究以及合理膳食保障人体健康具有积极意义。