米糠油精炼及糠蜡的制取技术

米糠油是国际上公认的营养油,其油酸与亚油酸含量之比大致符合国际卫生组织所推荐的最佳比例1∶1。由于毛米糠油的特殊性,米糠油的精炼存在一定的困难。针对米糠油的特殊性,对米糠油的化学精炼和物理精炼以及糠蜡制取工艺,各个工序进行了较为详细的叙述,以期为米糠油的开发利用提供参考。     

米糠蜡对大豆油凝胶特性的影响研究

在大豆油中添加米糠蜡以制备凝胶油。考察了米糠蜡添加量和冷却温度对凝胶油的影响。结果表明:米糠蜡添加量为8%时,在常温下能形成凝胶油且口感较好,具有一定的塑性。随着米糠蜡添加量的增加,米糠蜡凝胶油在硬度增加的过程中,胶着度下降,弹性和咀嚼度也随之下降,回复性基本不变。此外,在弹性以及黏聚性方面,米糠蜡凝胶油和人造黄油接近。随着米糠蜡添加量的增加,凝胶油的熔融温度和结晶温度升高。     

米糠油低温浸出条件的优化

采用低温溶剂法浸提米糠油。以提油率和蜡含量为指标,通过正交实验,确定最佳的提取工艺条件。并对最佳浸提条件下获得的毛油进行理化性质的检测并与高温最佳浸提条件下获得的毛油对比。结果表明,低温浸提米糠油的最佳工艺参数为:浸提温度20℃、料液比1∶3、浸提时间2h,按此工艺条件提取米糠毛油,重复3次,取平均值,提取率为16.70%,蜡含量为0.79%。低温浸出工艺浸提出的米糠毛油蜡含量比高温低约1.83%。      

乳化剂对米糠蜡凝胶油理化特性的影响

将单硬脂酸甘油酯、硬酯酰乳酸钠、聚甘油脂肪酸酯分别与米糠蜡复配制备凝胶油,研究乳化剂添加量对凝胶油持油率、晶体形态、热学性质、分子间作用力、晶型和流变学的影响。结果表明：乳化剂的复配质量比对凝胶油的微观结构和宏观特性都会产生影响,但对持油率和总焓变却不呈浓度依赖。随着单硬脂酸甘油酯含量的增加,α、β和β3种晶型共存,晶体形态从针状转变为簇状,且表现出较好的流变性质。当单硬脂酸甘油酯与米糠蜡复配质量比为5:2时,持油率高达87.94%。分子间作用力表明单硬脂酸甘油酯和聚甘油脂肪酸酯依靠氢键的键合作用增加液态油的束缚力和粘弹性质。     

米糠一次浸出及米糠油物理精炼

米糠作为中低含油量的一种特殊油料,很适于通过一次浸出提取毛糠油.米糠一次浸出需经历米糠预处理和米糠浸出两个阶段,米糠预处理的方法有3种:蒸炒、造粒、膨化,其中膨化又分为千式膨化和湿式膨化两种方式;米糠的浸出制油工艺过程具有与其他大宗油料不尽相同的工艺、设备要求,主要体现在物料浸出与湿粕脱溶两道工序上.米糠浸出所得到的毛糠油为一种高酸值毛油,采用物理精炼工艺在提高油脂精炼率和经济效益方面具有明显的优势.米糠油物理精炼工艺过程包括脱胶、脱色、脱酸、脱蜡、脱脂,关键工序是蒸馏脱酸,脱胶、脱色是其至关重要的前处理工序.米糠油物理精炼工艺在实际生产应用中可根据毛糠油的原料情况和精糠油的成品质量等级要求,结合化学精炼工艺进行综合精炼或进行各种档次成品油的生产调节,取得物尽其用的效益.     

三元共沸物法提纯米糠蜡工艺条件的优化

以米糠油加工的副产物蜡糊为原料,乙酸乙酯-乙醇-水三元共沸物为溶剂,以提取率和丙酮不溶物（纯度）为指标,经萃取[溶剂∶原料（v∶m）,6∶1]、离心分离、旋转蒸发、低温干燥制得米糠蜡;通过响应曲面法优化米糠蜡提取工艺条件。结果表明,最佳提纯条件为:料液比6∶1,提取温度65℃,提取时间45min,冷却温度20℃,此时,模型预测米糠蜡提取率为89.65%,丙酮不溶物为64.30%。验证实验得米糠蜡提取率为89.17%,丙酮不溶物为63.67%,与预测值基本吻合。      

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.     

超声辅助水酶法提取米糠油的研究

研究了超声辅助水酶法对米糠油提取的影响,并利用响应面法对米糠油提取工艺进行了优化。结果表明,复合酶(纤维素酶、中性蛋白酶和淀粉酶质量比1∶1∶1)和超声辅助处理有利于米糠油的提取。提取米糠油的最佳条件为:复合酶添加量1.5%(占米糠质量),料液比1∶6,酶解时间3 h,酶解温度39.5℃,pH 5.4,超声功率198 W,超声时间15 min。在最佳条件下,米糠油提取率可达88.3%,所得米糠油中谷维素含量为2.2%。     

米糠油制取工艺的研究

对米糠油的制取和精炼工艺进行了研究。结果表明,米糠油浸出的最佳工艺条件是:米糠含水量7%,粉碎至50目,浸出溶剂异丙醇,浸出温度60℃,pH 6.0,料液比1∶5,浸出时间2 h。米糠油精炼的最佳工艺条件为:碱炼初温45℃,KOH浓度18.5%,超碱量0.4%;采用二次脱色工艺,第1次活性白土加量4%,脱色时间30 m in,脱色温度90℃;第2次活性白土加量3%,脱色时间15 m in,温度85℃,真空度0.1 MPa;在真空度0.08 MPa、温度180℃、脱臭时间1.5 h条件下,可以脱除米糠油中的臭味成分,保持米糠油的固有味道。     

山稻米糠油营养成分分析与比较

分别对江南地区栽培较广的3个山稻品种进行了米糠含油率、脂肪酸组成、不皂化物含量与组成、γ-谷维素含量的分析,并与水稻和旱稻米糠油进行对比。结果表明,3个山稻品种米糠含油率均高于水稻和旱稻,最高的是山稻18号,含油率达(23.08±2.20)%;脂肪酸组成最丰富的是山稻14号,共检出14种脂肪酸,必需脂肪酸质量分数最高的是山稻5号,仅次于旱稻,达35.83%,最低的是14号,为28.31%;米糠油不皂化物中含量最高的是甾醇类化合物,3个山稻品种中植物甾醇质量分数均超过总不皂化物的50%;山稻18号角鲨烯含量最高,仅次于旱稻,达1 168.91mg/kg; 5种米糠油中γ-谷维素含量从高到底分别为山稻18号、山稻5号、旱稻、山稻14号和水稻,γ-谷维素质量分数分别为(20.74±0.08)、(18.26±0.08)、(16.68±0.88)、(14.72±0.31)、(12.61±0.11) mg/g, 5个品种间γ-谷维素含量差异极显著(P<0.01)。山稻米糠含油率较高,脂肪酸组成丰富,油中植物甾醇和γ-谷维素等含量均高于传统栽培的水稻和旱稻,是一种极具潜力的食用油。     

米糠蜡添加量对亚麻籽油基油凝胶结构及性质的影响

为探究亚麻籽油基油凝胶作为替代传统塑性脂肪的潜力,以米糠蜡为凝胶剂,探究不同米糠蜡添加量对亚麻籽油基油凝胶外观形态、微观结构、持油率、理化性质及热力学性质的影响。结果表明：在室温条件下,米糠蜡添加量不小于6%时才会使亚麻籽油凝胶化;随着米糠蜡添加量的增加,油凝胶的结晶网络结构由簇状逐渐转变为针状,结晶密度增大;油凝胶的持油率、酸值以及熔融峰/结晶峰峰值温度均随着米糠蜡添加量的增加而增大;油凝胶的过氧化值随着米糠蜡添加量的增加呈现先增后减的趋势。综上,在亚麻籽油中添加适量的米糠蜡可形成热塑性好、结构稳定、理化性质良好、持油率高的油凝胶。     

Simultaneous rice bran oil stabilization and extraction using sub-critical water medium

Sub-critical water technique was used for simultaneous inactivation of lipase enzyme existing in rice bran and extraction of its oil in order to obtain the stabilized edible rice bran oil. Sub-critical water treatment was carried out in the temperature range between 120 and 240 °C for 10 and/or 20 min residence time in a batch reactor. The quality of the extracted oil was evaluated with respect to its total free fatty acids concentration over a 12 week period, and compared with the oil obtained by conventional extraction methods. Without sub-critical water treatment, the concentration of total free fatty acids in the rice bran significantly increased from 5.6% to 36.0%. In contrast, no increase was observed in the total free fatty acids concentration in the samples treated by sub-critical water. Experimental evidence showed that total free fatty acids concentration increased somewhat in the oils treated by conventional methods. Considering no change was observed in total free fatty acid concentration in the treated oils by sub-critical water, it was found that sub-critical water not only could efficiently extract oil from rice bran in a short residence time but also completely stabilized the extracted oil. Oil extraction yields generally increased with increases in sub-critical water treatment temperature and residence time. The highest extraction yield of oil was 249 (mg/g dry matter) obtained at 240 °C and 10 min residence time. Oil extraction by sub-critical water could be conducted in a very short residence time (10 and/or 20 min). Also, the kinetics of free fatty acids formation in untreated rice bran was investigated and developed which successfully describes the concentration of total free fatty acids in the course of rice bran storage.     

米糠油谷维素提取方法研究进展

谷维素是从米糠油或胚芽油等谷物油脂中提取的一种天然混合物,是米糠油深加工过程中产生的极有价值的副产品。本文从谷维素的组成、提取和纯化方法进行综述,重点阐述不同提取工艺的特点和优缺点,分析实验中遇到的实际问题并且提出解决的办法。      

米糠油脱酸工艺研究进展

米糠油是一种营养价值丰富的植物油,其富含多种生理活性物质。米糠中富含高活性脂肪酶,这使得米糠毛油的酸价很高,因此采用满足高脱酸率以及高生理活性物质保留率的脱酸工艺显得尤为重要。不同的脱酸工艺对米糠油的品质油具有显著性影响。本文详细的介绍了近些年国内外米糠油现有的脱酸工艺,对蒸馏法脱酸、膜分离技术脱酸、超声波辅助精炼技术脱酸、溶剂萃取脱酸、化学碱炼脱酸、酶催化酯化脱酸等方法进行归纳总结,旨在为米糠油脱酸的研究提供依据。     

有机溶剂法提取米糠油工艺的研究

以市售米糠为原料优化米糠油提取工艺,考察提取过程中的不同有机溶剂、提取温度、提取时间、液料比和干燥时间等因素对米糠油提取率的影响。在单因素试验的基础上,选定提取温度、提取时间、液料比进行响应面分析试验,建立二次回归方程,通过响应面分析得到提取米糠油的优化组合条件。结果表明：以混合溶剂（正己烷/环己烷=4∶1,V/V）为提取溶剂,提取温度70 ℃、提取时间2.0 h、液料比为20∶1（mL∶g）时,米糠油提取率为79.81%。     

Extraction of policosanols from hydrolysed rice bran wax by high-intensity ultrasound

This study provided a detailed method for extraction and purification of policosanols from hydrolysed rice bran wax (RBW) by high‐intensity ultrasound (HIU), where the hydrolysis of RBW under HIU was focused. The optimised operating conditions for hydrolysis were as the following: 20 kHz, 100 W, 1:2 of wax to 4% sodium hydroxide (w:v) and 50 min at ambient temperature, under which the hydrolysis rate of 94.3% was obtained. Thereafter, policosanols were extracted and purified from the hydrolysed RBW. With the analysis by GC, it was shown that even‐numbered aliphatic alcohols were the major components of the policosanols, accounting for 95% or so, where triacontanol (C₃₀) was the predominant component with 26.95%, followed by octacosanol (C₂₈) with 17.04%, dotriacotanol (C₃₂) with 16.01%, tetracosanol (C₂₄) with 11.13%, hexacosanol with 10.90%; however, the odd‐numbered alcohols only accounted for about 5% and they were non‐acosanol (C₂₉) with 2.92%, heptacosanol (C₂₇) with 1.57% and pentacosanol (C₂₅) with 0.65%.     

米糠微波灭酶及提油工艺研究

以新鲜米糠为原料,利用工业化连续微波灭酶设备进行灭酶处理,然后对灭酶米糠的提油工艺进行了研究。实验结果表明,微波辐射具有很好地降低米糠中解脂酶活性的作用,并且得到最佳处理厚度为0.9cm,处理时间为4min,每小时处理量达到36kg。米糠油浸出的最佳工艺条件是:浸出温度55℃,浸出时间2h,料液比1∶6,在此条件下米糠油得率达到90.04%,较未灭酶米糠油得率有明显提高。      

超临界CO2流体萃取米糠油研究

通过超临界CO2流体萃取米糠油研究,总结萃取压力、萃取温度、萃取时间和物料水分含量对米糠出油率影响。结果表明,最适宜萃取条件为:萃取压力30 MPa、萃取温度45℃、萃取时间80 min、物料水分含量为5％～6％,出油率达14．32％;同时测定超临界CO2流体萃取米糠油中脂肪酸甘油酯组成,得出油酸甘油酯、亚油酸甘油酯和棕榈酸甘油酯占总脂肪酸甘油酯90％以上,其中,油酸甘油酯和亚油酸甘油酯占总脂肪酸甘油酯70％以上;通过超临界CO2法与压榨法比较,超临界CO2流体法萃取米糠油不饱和脂肪酸含量较高,理化指标也优于压榨法,因萃取温度低,防止提取过程中油脂氧化,因此超临界CO2流体萃取是一种较好提取米糠油方法。     

Optimization of enzymatic degumming process for rice bran oil using response surface methodology

Response surface methodology was used to determine the optimum processing conditions for enzymatic degumming of rice bran oil. Reaction time, enzyme dosage, level of water added and temperature were the factors investigated with respect to phosphorus and free fatty acids contents. A D-optimal design, with four variables and two response functions, was employed to study the effect of the individual variables on the response functions. For each response, second-order polynomial models were developed using multiple linear regression analysis. Applying desirability function method, optimum operating conditions were found to be reaction time of 4.07 h, enzyme dosage of 50 mg/kg, added water of 1.5 ml/100 g and temperature of 49.2 °C. At this optimum point, phosphorous and free fatty acids contents of degummed oil were found to be 8.86 mg/kg and 2.01 g/100 g as oleic acid, respectively.