【作者】 张美莉；

【导师】 胡小松；

【作者基本信息】 中国农业大学 ， 农产品加工及贮藏工程， 2004， 博士

【摘要】 荞麦具有很高的营养价值和药用价值。荞麦类黄酮和蛋白质是其最主要的生物活性成分，赋予荞麦降血压、降血脂、降血液胆固醇和降血糖等多种生理功能。荞麦抗营养因子的存在是影响荞麦蛋白质消化性的主要因素。发芽处理可以降低或消除抗营养因子的含量。全文以萌发荞麦为材料，研究了不同荞麦品种萌发后主要营养成分和生物活性物质的动态变化以及荞麦类黄酮提取物和蛋白提取物清除自由基和对大鼠红细胞膜损伤的保护作用。主要结论如下： 1．荞麦萌发24h后可溶糖含量呈上升趋势，不同品种荞麦在萌发72h后可溶糖含量增加了2.0～3.4倍。脂肪酸总量无明显变化，单不饱和脂肪酸(MUFA)含量增加，多不饱和脂肪酸(PUFA)含量下降。矿物元素含量无明显变化。 2．建立了HPLC法测定萌发荞麦中芦丁、槲皮素含量的方法：选择反相C-18分离柱，流动相以甲醇：水=50∶50，在362nm波长、1.0ml／min流速的条件下，确定出芦丁的保留时间为3.517′，槲皮素为6.303′。 3．苦荞和甜荞类黄酮总量随萌发时间的增加呈现先略有下降而后升高的趋势。四川苦荞在萌发72h时比萌发初提高了33％(P＜0.01)。而山西甜荞增加59％(P＜0.01)。表明延长发芽时间可以提高荞麦中的类黄酮含量。荞麦萌发后芦丁含量变化与类黄酮总量变化趋势相一致，而槲皮素含量呈下降趋势。萌发处理是降低苦荞苦味的有效方法之一。在萌发过程中苯丙氨酸解氨酶(PAL)活力变化与总黄酮含量变化较一致。苦荞在萌发的各个时期PAL活力均高于甜荞。 4．苦荞萌发后蛋白质总量无明显变化，而甜荞蛋白质总量有所下降。萌发苦荞清蛋白和球蛋白含量下降，而谷蛋白和醇溶蛋白含量增加。甜荞除清蛋白含量有所下降外，其它三种蛋白含量增加。苦荞和甜荞萌发后蛋白质消化率均增加了近10个百分点，但与酪蛋白相比仍然较低。在萌发初期胰蛋白酶抑制(TI)活性较强，萌发后TI活性下降，但萌发84h后仍然存在33％—41％的抑制率。TI含量与蛋白消化率之间呈极大的负相关关系。 5．荞麦萌发的各个时期以谷氨酸含量最高，其次是精氨酸、天冬氨酸。甜荞氨基酸总量在萌发72h时比萌发前提高了11.2％(P＜0.05)，而苦荞则有所下降。甜荞在萌发72h时苯丙氨酸等5种必需氨基酸AAS值有所增加，必需氨基酸总量明显升高。苦荞除蛋氨酸和苯丙氨酸在萌发72h时的AAS值有所下降外，其余氨基酸的AAS值均无明显变化。 6．荞麦类黄酮提取物和蛋白质提取物清除(?)的能力均高于·0H。荞麦萌发后类黄酮提取物仍然具有明显的清除(?)和·0H的能力。苦荞蛋白清除(?)作用强于甜荞蛋白，而清除·0H效果则相反。萌发处理不改变荞麦蛋白提取物清除(?)的能力，而清除．0H能力有所增强。 7．荞麦及其萌发后的类黄酮提取液和蛋白质提取液在一定浓度范围内可剂量依赖性地抑制过氧化特丁烷(TBHP)引发的大鼠红细胞溶血和抗细胞膜脂质过氧化的作用，降低TBHP引起的大鼠红细胞MetHb生成率。更多还原

【Abstract】 Buckwheat has high nutritional and pharmaceutical value. Its extensive physiological functions such as reducing blood pressure, blood lipids, blood cholesterol and blood sugar are found to due to its main bioactive ingredients, buckwheat flavonoids and protein extracts. However, buckwheat also has some inherent anti-nutrients, which have key roles in reducing the digestibility of buckwheat proteins. Germination can reduce the content of anti-nutrients of buckwheat or even remove them. Therefore, comprehensive studies including the dynamic changes of main nutrients and bioactive ingredients in buckwheat after germination, the free radical scavenging activities of buckwheat flavonoid and protein extracts, and the protective effects of buckwheat flavonoid and protein extracts on red cell of mice against oxidative damage were carried out. The main results of this paper are as follows.The content of soluble sugar of buckwheat began to increase after 24 h of germination, and could increase to 2.0~3.4 times of its original content after 72 h of germination. There was no obvious change in content of fatty acids. However the content of mono-unsaturated fatty acids (MUFA) increased, while the content of poly-unsaturated fatty acids (PUFA) decreased. Additionally, the content of mineral elements had hardly any change after germination.The method to determine the content of rutin and quercetin in germinated buckwheat by HPLC (high performance liquid chromatography) was developed. The separating column was C-18 reverse phase column. The flowing phase was methanol and water with volume ratio of 50 against 50. The retention time of rutin and quercetin was 3.517 min and 6.303 min at 362 nm of wavelength and 1.0 ml/min of flowing velocity respectively.The content of flavonoids of F.tartaricum Gaerth and F.esculentum Moench reduced slightly and then increased with the time of germination. At 72 h of germination, the content of flavonoids of Sichuan F.tartaricum Gaerth and Shanxi F.esculentum Moench was 33% and 59% higher than its original content (P<0.01) respectively, indicating that the content of buckwheat flavonoids could be raised by prolonging the time of germination. The same situation was also found in the change of the content of rutin during germination. However, the content of quercetin decreased gradually. Making seeds germinate is one of effective methods to reduce the bitterness of buckwheat. During germination, the activity of PAL(Phenylalanine Ammonialyase) took the same situation as the change of flavonoidscontent. Moreover, the PAL activity in F.tartaricum Gaerth was higher than in F.esculentum Moench through the whole period of germination.The total content of protein had hardly any change in F.tartaricum Gaerth and obviously decreased in F.esculentum Moench after germination. In F.tartaricum Gaerth, the content of albumin and globulin was reduced while the content of prolamine and glutelin was raised by germination. In F.esculentum Moench, the content of albumin decreased while the content of other three proteins such as globulin, prolamine, and glutelin increased. The digestibility rate of protein in both F.tartaricum Gaerth and F.esculentum Moench was raised by nearly 10% after germination. The content of TI (Trypsin Inhibitors) was 0.72u/mg and 0.68u/mg in Sichuan F.tartaricum Gaerth and Shanxi F.esculentum Moench respectively. The activity of TI was higher at the early period of germination and was reduced later. For example, the inhibiting rate of TI was 40.8% and 33.4% in Sichuan F.tartaricum Gaerth and Shanxi F.esculentum Moench respectively at 84 h of germination. There was an obvious negative relationship between TI content and protein digestibility.As for amino acids, the content of glutamic acid was the highest through the whole period of germination while the content of arginine and aspartic acid was secondly and thirdly highest respectively. The content of total amino acids increased by 11.2% in F.esculentum Moench but decreased in F.tartaricum Gaerth at 72h of germinatio更多还原