米糠固脂与棕榈硬脂混合应用于起酥油的研究

米糠固脂是米糠油冬化或分提获得的副产物。以3种具有不同固体脂肪含量(SFC)曲线的米糠固脂(RBS1、RBS2及RBS3)、棕榈硬脂(PS)为原料,按照米糠固脂与棕榈硬脂质量比40∶60进行二元混合制备起酥油,并以市售起酥油为参考,对混合体系的SFC、晶型、脂肪酸组成、微量营养素含量进行了分析。结果表明:由不同米糠固脂组成的二元混合体系差异不大,且与市售起酥油具有相似的SFC曲线;其棕榈酸、亚油酸含量较市售起酥油高,硬脂酸含量较市售起酥油低;体系表现为β'晶型;此外,二元混合体系中含有丰富的谷维素、植物甾醇,可丰富起酥油的营养特性。     

Production of trans‐free margarine stock by enzymatic interesterification of rice bran oil,palm stearin and coconut oil

BACKGROUND: Trans‐free interesterified fat was produced for possible usage as a spreadable margarine stock. Rice bran oil, palm stearin and coconut oil were used as substrates for lipase‐catalyzed reaction. RESULTS: After interesterification, 137–150 g kg^?1 medium‐chain fatty acid was incorporated into the triacylglycerol (TAG) of the interesterified fats. Solid fat contents at 25 °C were 15.5–34.2%, and slip melting point ranged from 27.5 to 34.3 °C. POP and PPP (β‐tending TAG) in palm stearin decreased after interesterification. X‐ray diffraction analysis demonstrated that the interesterified fats contained mostly β′ polymorphic forms, which is a desirable property for margarines. CONCLUSIONS: The interesterified fats showed desirable physical properties and suitable crystal form (β′ polymorph) for possible use as a spreadable margarine stock. Therefore, our result suggested that the interesterified fat without trans fatty acid could be used as an alternative to partially hydrogenated fat. Copyright © 2010 Society of Chemical Industry     

棕榈油硬脂和大豆油酶法酯交换的研究

进行了固定化脂肪酶Lipozyme TL IM催化棕榈油硬脂和大豆油酶法酯交换的研究,考察了酶法酯交换分批操作的反应动力学曲线,发现5%的加酶量、70℃下反应,反应3 h内达到平衡,反应温度在70~90℃对反应速度无明显影响。采用填充床式反应器进行连续反应,结果表明通过装有10 g脂肪酶柱子的最佳流速为30 g/h。对化学酯交换和酶法酯交换产品性质的比较发现,二者SFC无明显差异。采用填充床式反应器对40∶60和30∶70的棕榈油硬脂和大豆油的混合物进行酶法酯交换反应,测定了反应产物的SFC曲线,为将来的应用开发提供参考数据。     

Structured lipids obtained by chemical interesterification of olive oil and palm stearin

Interesterification of palm stearin (PS) with liquid vegetable oils could yield a good solid fat stock that may impart desirable physical properties, because PS is a useful source of vegetable hard fat, providing β′ stable solid fats. Dietary ingestion of olive oil (OO) has been reported to have physiological benefits such as lowering serum cholesterol levels. Fat blends, formulated by binary blends of palm stearin and olive oil in different ratios, were subjected to chemical interesterification with sodium methoxide. The original and interesterified blends were examined for fatty acid and triacylglycerol composition, melting point, solid fat content (SFC) and consistency. Interesterification caused rearrangement of triacylglycerol species, reduction of trisaturated and triunsaturated triacylglycerols content and increase in diunsaturated-monosaturated triacylglycerols of all blends, resulting in lowering of melting point and solid fat content. The incorporation of OO to PS reduced consistency, producing more plastic blends. The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of palm stearin and olive oil.     

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.     

Application of hydrogenated palm kernel oil and palm stearin in whipping cream

Non-dairy creams made from hydrogenated palm kernel oil (HPKO) are generally more stable than dairy creams. However, in summer the emulsion tends to separate. This paper outlines some steps that were taken to modify the HPKO with the intention of increasing the stability without affecting whipping performance. This was achieved by blending HPKO with palm stearin (POs). Interesterification was employed to eliminate the increase in solid fat content at 37°C and 40°C. Results of the experiment showed that an interesterified HPKO: POs 66:34 blend proved to have satisfactory whipping performance when compared to creams made with HPKO alone.     

猪油与棕榈硬脂酶法酯交换制备零反式脂肪酸起酥油的研究

研究了固定化脂肪酶Lipozyme RM IM催化猪油和棕榈硬脂酯交换制备起酥油的工艺,考察了反应温度、酶添加量、反应时间对酯交换反应的影响.并以反应后体系在20℃下的固体脂肪含量(SFC)为指标,确定了理想的工艺条件:反应温度60℃,酶添加量8％,反应时间1h.利用等温曲线和X-射线衍射技术研究了混合体系酯交换前后的相容性和晶体形态,结果表明:经酯交换后,混合体系的相容性得到显著改善,晶型由β型转变为β’型,适宜用作焙烤起酥油.     

米糠油中谷维素的研究进展及在食品中的应用

对米糠油中谷维素的研究现状进行了综述,包括谷维素的定义、理化特性、生理功能、制备方法及国内外谷维素在食品领域的开发和应用。     

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.     

米糠深加工技术的分析与评价(Ⅱ) --米糠油精炼及其副产品的利用

米糠油是一种营养价值很高的植物油,但它含有较复杂的和数量较多的油溶性物质如游离脂肪酸、蜡质、色素等,大大增加了米糠油精炼难度,制约了米糠油的深度开发和利用.对几种典型米糠油精炼技术如化学精炼、物理精炼及混合油精炼、生物精炼、再酯化脱酸、膜技术脱酸等进行了介绍,并对其应用情况进行了评述;同时对米糠油副产品的利用技术如米糠油提取谷维素技术、植物甾醇的制取技术、天然维生素E的提取技术、糠蜡制取技术等作了较详细地论述和评价,以期为米糠油的综合开发利用提供参考.     

脱臭工艺条件对米糠油中反式脂肪酸含量的影响

研究了脱臭温度和脱臭时间对米糠油中反式脂肪酸含量的影响。结果表明,脱臭温度和脱臭时间对米糠油中反式油酸含量的影响很小;脱臭温度对米糠油中反式亚油酸含量影响显著,脱臭时间对其影响的显著性次之;在一定的脱臭时间下,不同脱臭温度下米糠油中总反式脂肪酸含量最多的约为最少的30-40倍,在250℃以下米糠油中总反式脂肪酸的形成速度缓慢、相对含量低;在一定的脱臭温度下,不同脱臭时间时米糠油中总反式脂肪酸含量最多约为最少的8倍,且在250℃和270℃时,脱臭时间在40 min以下米糠油中总反式脂肪酸的形成速度缓慢、相对含量低。     

Lipase-catalyzed production of solid fat stock from fractionated rice bran oil,palm stearin,and conjugated linoleic acid by response surface methodology

Solid fat stock was produced from the fractionated rice bran oil (solid phase, S-RBO) and palm stearin (PS) through lipase-catalyzed reaction, in which conjugated linoleic acid (CLA) was intentionally incorporated. For optimizing the reaction, response surface methodology (RSM) was employed with four reaction variables such as water activity, reaction temperature, reaction time, and mole ratio of S-RBO to PS. The predictive model was adequate due to no significant lack of fit and satisfactory level of coefficient of determination (R² = 0.95). The melting point of solid fat stock was affected by reaction time and substrate mole ratio, whereas water activity and reaction temperature had no significant effect. Based on ridge analysis, the combination of A_w (X₁; 0.32), reaction temperature (X₂; 65.3 °C), reaction time (X₃; 28.9 h), and substrate mole ratio (X₄; 1:1.1) was optimized for producing solid fat stock with target melting point of 43.8 °C. The solid fat stock (SFS) contained 39.9% palmitic, 31.3% oleic, 13.2% linoleic acid, and 10.9% CLA isomers. Solid fat contents were 23.4, 10.9, and 2.5% at 20, 30, and 40 °C, respectively. These results suggested that RSM can be used to optimize the lipase-catalyzed production of a solid fat stock.     

碱炼脱酸工艺条件对高酸值米糠油碱炼效果的影响

以高酸值米糠毛油为原料,分别采用一次碱炼脱酸和两次碱炼脱酸工艺,以油脂碱炼得率、脱色率、谷维素损失率、甾醇损失率为考察指标,研究碱液浓度对碱炼效果的影响,并对两种碱炼脱酸工艺效果进行比较。结果显示:两次碱炼脱酸与一次碱炼脱酸相比,相同碱液浓度条件下,油脂碱炼得率平均提高4.89%,谷维素损失率平均降低5.87%,甾醇损失率在碱液浓度较低(12°Bè~20°Bè)时,两次碱炼甾醇损失率明显比一次碱炼低(平均低12.64%),但在碱液浓度超过24°Bè之后,两次碱炼的甾醇损失率比一次碱炼高,也即在高浓度碱液条件下,减少碱炼次数对减少甾醇损失是有利的。米糠毛油两次碱炼脱酸时,一道碱炼的碱液浓度为28°Bè,二道碱炼的碱液浓度为12°Bè时谷维素损失率最低,16°Bè时甾醇损失率最低,碱液浓度对碱炼得率和脱色率的影响不显著。     

米糠油脱酸工艺的选择和产品方案的设计

针对米糠油的特点,对物理精炼和化学精炼的脱酸工艺进行了比较并设计了化学精炼联产方案.指出米糠油精炼工艺必须要考虑毛米糠油中游离脂肪酸和谷维素的综合利用,米糠油的产品需要强化营养油这个特征,而不能削弱这个特征.并提出了一级油和四级油的联产设计方案,使米糠油营养价值和经济效益最大化.     

Production of zero trans Iranian vanaspati using chemical transesterification and blending techniques from palm olein, rapeseed and sunflower oils

Chemical transesterification and blending techniques were used for producing zero trans fats suitable for use as Iranian vanaspati. Triple blends of palm olein (POo), rapeseed (RSO) and sunflower oil (SFO) were subjected to two different treatments: (i) blending and then transesterification (BT) and (ii) transesterification of pure POo before blending with RSO and SFO (TB). The changes in slip melting point (SMP), solid fat content (SFC), carbon number (CN) triacylglycerol (TAG) composition, induction period (IP) of oxidation at 120 °C and IP of crystallisation at 20 °C of blends before and after treatments were investigated. Both BT and TB methods resulted in an increase in the CN48 TAG molecules, SMP and SFC, and a decrease in the IP of oxidation and crystallisation of initial blends. Samples made by TB method had higher CN48 TAG content, SMP, SFC and IP of oxidation, and lower IP of crystallisation than those made by BT method. Correlation between SFC at 20 °C and saturated fatty acid (SFA) content of the treated blends indicated that the SFA must be higher than 33.1% and 26.8% for BT and TB methods, respectively, to obtain fats suitable for use as vanaspati.     

Innovative production of multistrain synbiotic product using Thai-pigmented rice and rice bran oil

This study found that the isolated probiotics Lactobacillus paracasei KUKPS6201, L. acidophilus KUKPS6107, L. reuteri KUKPS6103, L. rhamnosus KUKPS6007, L. salivarius KUKPS6202, Bacillus coagulans KPSTF02 and Saccharomyces boulardii KUKPS6005 had high potential for probiotic properties. All strains had antibacterial activity and high antioxidant activity of 1.654 ± 0.017 mg Trolox mL⁻¹ probiotic extract. The selected strains could survive in a simulated gastrointestinal tract under anaerobic conditions and showed no haemolytic activity. Furthermore, the probiotic strains were strongly auto-aggregated and also showed co-aggregated ability with pathogenic bacteria. The probiotic microorganisms demonstrated high ability to adhere to Thai-pigmented rice grains. The results of analysis of these probiotics showed that Riceberry rice bran oil was an excellent prebiotic. A synbiotic product containing Thai-pigmented rice grains (cultivar Riceberry, Luem Pua and Black Jasmine) and rice bran oil was produced. After 8 weeks of storage, the viability of the probiotics in terms of multistrains was 7.36 ± 0.04 log CFU g^–1 (85.78% survival rate). Microbiological safety testing indicated that the amounts of contaminants were acceptable. This study provided the first scientific report on the feasibility of applying Thai-pigment rice, rice bran oil and mixed-culture probiotics as a novel functional synbiotic product.     

煎炸米糠油营养成分及煎炸油条品质分析

利用米糠油连续煎炸油条32 h,通过对煎炸米糠油中谷维素、维生素E、植物甾醇含量,以及煎炸油条含油率、酸值、过氧化值、羰基值检测和感官指标评价,分析研究米糠油在煎炸过程中营养成分的变化及煎炸油条的品质。结果表明:经过32 h的连续煎炸,煎炸油条中米糠油的酸值(KOH)从0.73 mg/g逐渐增加至1.32 mg/g,过氧化值呈现波动增长的变化趋势(由0.05 g/100 g增大至0.08 g/100 g),羰基值从12.50 meq/kg逐渐增加至61.72 meq/kg;煎炸米糠油中谷维素含量相对稳定,植物甾醇含量有所降低(从1.67%降低至1.23%),维生素E含量从57.04 mg/100 g显著降低至1.18 mg/100 g;煎炸油条的平均含油率为12.38%;煎炸油条的含油率低、感官效果好。     

以樟树籽仁油、油茶籽油、全氢化棕榈油 为原料的起酥油基料油的表征

采用专一性脂肪酶Lipozyme TL IM,将樟树籽仁油、油茶籽油和全氢化棕榈油按4个质量比(2∶2∶4, 2∶2∶5, 2∶2∶6, 2∶2∶7)进行sn-1,3位随机酯交换制备起酥油基料油,以物理混合物(PB)为对照对酯交换反应后产品(IP)的脂肪酸组成及熔点、多晶形式、微观结构、甘油三酯(TAG)的组成进行测定。结果表明:酯交换反应后仍有12.21%～16.91%的中链脂肪酸(MCFA)被保留;从DSC熔融曲线发现,相较于PB, IP只产生了一个响应值较弱的峰形,SFC曲线则表现一直陡峭下降的趋势,具有狭窄的塑性范围,是理想的高稳定起酥油基料油;微观结构上表现为更小(约20μm)球状晶体;IP中生成了新型的TAG种类(CPO, LaOP, LaPP, COS, CPS等)。总体而言,合成的起酥油基料油在能保证正常膳食长链脂肪酸(LCFA)摄入的同时,还能提供一定量MCFA的摄入,被人体快速吸收,具有一定的营养功能。     

近红外光谱结合偏最小二乘法快速检测米糠油过氧化值和酸价

研究旨在建立近红外光谱法快速测定米糠油中过氧化值和酸价的方法。以化学滴定法测定米糠油中过氧化值和酸价为参比方法,采用近红外分析技术结合偏最小二乘法,建立了米糠油中过氧化值和酸价的近红外定量分析模型。过氧化值和酸价定量分析模型的决定系数分别为99.11%和99.72%,预测标准差分别为0.436 7%和0.044 78%,交叉验证标准差分别为0.452 2%和0.046 69%。利用78个验证集样品对定标模型进行外部独立验证,过氧化值及酸价的绝对误差分别在–0.78%～0.82%和–0.142%～0.139%之间,相对误差分别在–13.21%～14.44%和–14.85%～12.46%之间。表明所建立的定量分析模型及方法可对米糠油中过氧化值和酸价进行简便、快速测定。