【作者】 刘贺；

【导师】 王兴国；

【作者基本信息】 江南大学 ， 粮食油脂及植物蛋白工程， 2009， 硕士

【摘要】 谷维素(Oryzanol)具有抗氧化、降血脂、促进皮肤微血管循环等作用,可用于食品、医学、化妆品等领域,已引起国内外广泛重视。本文研究了从米糠混合油提取谷维素的工艺,并对其抗氧化性进行研究。本研究从米糠混合油出发,经过两次碱炼后,谷维素富集到二道碱炼皂脚中;再将皂脚溶解到甲醇溶液中,过滤后,以柠檬酸析出,将析出液抽滤即得谷维素粗品;精制得谷维素成品。通过单因素实验优化确定一道碱炼工艺为:NaOH溶液浓度5%(w/v),油与正已烷比例为1:2,反应温度55℃,反应时间60min,一道碱炼降低6个酸价,谷维素损失率仅为3.6%;二道碱炼工艺为:NaOH溶液浓度为11%(w/v),反应温度60℃,反应时间120min,二道碱炼谷维素捕集率达到84.9%,精炼率为90.8%。利用响应面法对影响二道碱炼工艺条件进行了优化,结果如下:NaOH溶液浓度10.64%,反应温度59.2℃,反应时间106.7min,谷维素捕集率为86.8%。研究了二道碱炼条件对米糠油品质的影响,并对优化条件下二道碱炼后米糠油品质进行了评价,二道碱炼后米糠油谷维素残留率为8.1%,比市售米糠油谷维素含量高。酸价为0.36mg KOH/g油,色泽Y33R3.0,均符合三级米糠油标准。将二次皂脚溶解在甲醇溶液中,然后用柠檬酸析出,通过单因素实验优化确定酸析条件为:pH 6,柠檬酸浓度20%,酸析温度60℃,酸析时间30min,养晶温度20℃。对主要因素进行正交实验,得优化条件为:柠檬酸浓度20%,酸析温度65℃,酸析时间30min,最终谷维素得率为64.6%,纯度为99.6%。采取两种方法脱除皂脚中的残留溶剂,一种为真空加热法,另外一种为常压加热法。均可以取得很好效果,溶剂残留可降到安全水平。更多还原

【Abstract】 Oryzanol in rice bran oil can be used in food, medicine, cosmetics and other fields. In this paper, a new enrichment process of oryzanol in rice bran miscella was systematically studied, and its anti-oxidation ability was tested.Extraction method in this paper is as follows: rice bran oil blended with hexane refined twice, oryzanol trapped into the soapstock of the second alkali refining; the soapstock dissolved in methanol prior to filtration; then the solution precipitated by citric acid and vaccum filtrated to give crude oryzanol. Final products is obtained by further purification.Through single factor experiment, the optimal refining process was established:1) the first alkali refining: acid value reduction 6, NaOH concentration 5%(w/v), oil to hexane ratio 1:2, reaction temperature 55℃, reaction time 60min, under this condition, the loss rate of oryzanol is only 3.6%; 2) the second alkali refining: NaOH concentration 11%(w/v), reaction temperature 55℃, reaction time 60min, after treating under the best condition, the trapping rate of oryzanol can reach 84.9% and oil refining yield is 90.8%. The optimum preparation conditions optimized by RSM were as follows: NaOH concentration 10.64%(w/v), reaction temperature 59.19℃, reaction time 106.7min. Under these conditions, the trapping rate of oryzanol was 86.60%.After the second alkali, the quality of the rice bran oil was evaluated. The retention of oryzanol in the oil was 8.13%, acidity value 0.3(KOH)(mg/g) and colour Y33R3.0, which has reached Grade 3 requirement of rice bran oil.The soapstock dissolved in methanol was subjected to filtration followed by precipitation using citric acid. Through single factor experiment, the optimal conditions were determined as follows: Acid precipitation pH 6, citric acid concentration 20%, acid precipitation temperature 60℃, acid precipitation time 30min and crystal growing temperature 20℃.Orthogonal experiments were performed to determine the optimal condition: citric acid concentration 20%, acid precipitation temperature 65℃, acid precipitation time 30 min. Under this condition, oryzanol yield was 64.6%, purity was 99.6%. Oryzanol obtained were characterized with HPLC and IR spectroscopy.Two methods, i.e. heating in vaccum under stirring and heating in normal pressure under stirring,were adopted to remove solvent. The former gives samples no-detectable of solvent. While when heating temperature was 70℃, strring for 5 min in the other method, the solvent residual can be reduced to industrially acceptable level.更多还原