【作者】 刘政；

【导师】 郭玉蓉；

【作者基本信息】 甘肃农业大学 ， 农产品加工及贮藏工程， 2007， 硕士

【摘要】 燕麦(Avena sativa L.)一直以来都被认为是一种保健型食物资源,最新的观点认为,燕麦中所含有的特殊成分更具有较高的营养价值,通过提取、分离、纯化出来的功能成分可作为食品添加剂添加到食品中,提高食品的营养。本研究以裸燕麦为原料,采用不同的方法分离其中淀粉、燕麦油和β-葡聚糖,通过单因素和正交方法筛选其最佳提取工艺条件,并对不同分离成分进行相关性质和功能试验研究,结果表明:燕麦淀粉的最佳分离条件为pH11、反应时间1.5h、料水比1:10。在此条件下,燕麦淀粉得率为76.8%,纯度为96.4%;和马铃薯淀粉、玉米淀粉和豌豆淀粉相比:燕麦淀粉的溶解度、膨润力显著高于玉米淀粉和豌豆淀粉,蓝值显著高于玉米淀粉和马铃薯淀粉,而与马铃薯淀粉相比,冻融稳定性和透明度较差,这与燕麦淀粉的分子结构和组成有关。燕麦油超临界萃取的最佳分离条件为萃取压力为45MPa;萃取温度为40℃;夹带剂为石油醚;采用最佳提取工艺燕麦油的得率为6.266﹪;超临界所得燕麦油的主要理化性质为,酸价9.8KOHmg/g、碘价117.8Ig/100g、皂化值188.7KOHmg/g、不皂化值1.87%,折光指数1.4740,熔点11.5℃,色度黄35红3.4,无明显异味,外观色浅淡,常温下少许沉淀物。通过GC-MS分析,燕麦油的主要成分有豆蔻酸、棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸、二十碳一烯酸。燕麦油脂中不饱和脂肪酸的含量达80.1%,同时含有一定比例的饱和脂肪酸,其饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸的比例为0.5:1:1。燕麦油及其皂化物、不皂化物具有一定的抗氧化和清除羟自由基(·OH)的能力,三种成分的抗氧化能力的大小依次为,皂化物>不皂化物>燕麦油,其抗氧化的能力显著优于(P<0.05)对照组;三种成分在不同浓度下,其清除羟自由基的能力与其浓度成正比。并通过清除羟自由基能力及抑制猪油氧化能力的测定综合评价了燕麦油及其皂化物,不皂化物的抗氧化性能。燕麦β-葡聚糖分离的最佳工艺为50℃、3h、pH11、料液比1:20,最高得率为2.77%。β-葡聚糖流变特性与β-葡聚糖溶液浓度和温度密切相关,浓度在0.4%-0.5%时,粘度呈直线上升趋势;温度在25-65℃之间β-葡聚糖溶液粘度下降迅速。燕麦β-葡聚糖对正常小鼠的血脂、体重具有显著地调节作用,对STZ诱变的糖尿病小鼠具有显著的降血糖、降血脂的功效,同时燕麦β-葡聚糖组小鼠体重下降(P<0.05)。燕麦β-葡聚糖能显著降低高血糖小鼠的血清TC和LDL-C,显著升高HDL-C。:燕麦β-葡聚糖对小鼠糖尿病有显著的治疗作用。总之,燕麦中淀粉、油脂和β-葡聚糖具有显著的特点,可在食品生产中有选择地利用,燕麦油脂有较强的抗氧化、抗自由基作用,其β-葡聚糖对小鼠的血糖和血脂有显著地调节作用。更多还原

【Abstract】 Oat (Avena sativa L.) has long been considered a healthy source. And an alternative view is to consider oat as a potential source of specific compounds that can be extracted, purified, and marketed as food complement or incorporated into other food products. From the perspective of the human diet, oat should be regarded as a source of a spectrum of active phytochemicals, which may act in various combinations, perhaps synergistically.Nake oat was used as material to separated its components (starch, oat oil andβ-glucan) according to single-factor and orthogonal experimental. Meanwhile, relative properties and function of extracted components were researched.The results were showed as follows:The best seperation technology condition of oat starch were pH value in 11, time in 1.5 hours, the solid-liquid ratio 1:10. The yield of oat starch was 76.8%, and the purity reached 96.4% with the optimal extracting conditions. Compared with potato starch, corn starch and pea starch, oat starch is higher in solubility and distensibility than corn starch and pea starch, is higher in blue value than potato starch and corn starch, but lower in freezing-thawing stability and transparency than potato starch. Those properties were related to the molecule structure.The optimal extracting conditions of oat oil were extraction pressure in 45MPa, extraction temperature in 40℃, carrying solvent was petroleum ether. The yield of oat oil was 6.266﹪with the optimal extracting conditions. The physicochemical properties of oat oil extracted by supercritical CO2 were shown that acid value was 9.8KOHmg/g, iodic value 117.8Ig/100g, sopanificable value 188.7KOHmg/g, unsopanifcable value 1.87%, refractive index 1.4740, melting point 11.5℃, yellow color(35), red color (3.4), no special odor and taste, and had a slight precipitation. The result of analysis by GC-MS was shown that fatty acid constituents of oat oil were myristic, palmitic, stearic, oleic, linoleic, linolenic and eicosenoic acids. The unsaturated fatty acid was accounted for 80.1% of total oil. The ratio of the saturated, unsaturated and polyunsaturated fatty acid was approximately 0.5:1:1. The effects of oat extracts on hydroxyl radical scavenging and activities of oat extracts were shown that the highest scavenging ability was exhibited by sopanificable matter, then unsopanifcable matter, and the oat oil showed the lowest scavenging ability. For the three samples, their scavenging abilities were positively related to their concentration. The antioxidation of oat oil, sopanificable matter and unsopanifcable matter was valued by the ability to inhibit the lard oxidation and the to scavenge·OH.The optimal extracting conditions ofβ-glucan were temperature in 50℃, time in 3 hours, pH value in 11 and the solid-liquid ratio 1:20. The yield of oat oil was 2.77﹪with the optimal extracting conditions. The rheological property ofβ-glucan had the remarkable relation with concentration ofβ-glucan and the temperature. The viscosity ofβ-glucan remarkably increased with concentration ofβ-glucan in 0.4%-0.5%, and quickly reduced with the temperature 25-65℃.β-glucan had the remarkable effection on blood sugar and weight of normal rats and so did for blood sugar and blood lipid of STZ diabetes rats.β-glucan had the function to reduce weight, TC and LDL-C for diabetes rats, and increase HDL-C.β-glucan had the remarkable treatment against diabetes.In a word, the starch, oil andβ-glucan of oat had its unique properties which were used to selectively in food production. Oat oil had the powerful effect of hydroxyl radical scavenging and antioxidation, andβ-glucan of oat had the remarkable effect on blood sugar and blood lipid of rats.更多还原