葛根渣功能产品固态发酵菌株的筛选

提取淀粉后的葛根渣中富含葛根异黄酮和膳食纤维,但没有得到充分的利用,研究旨在从10株食药用真菌中筛选获得1株高效菌株,以通过葛根渣固态发酵获得功能产品。研究发现,在所选择的10株食药用真菌中,菌株DS1和EN2通过发酵葛根渣可实现发酵物中膳食纤维含量的提升,并具备形成产品的良好品质,其中菌株DS1在发酵葛根渣后也大幅提升了葛根渣中异黄酮的相对含量。发酵结束,菌株DS1发酵物中膳食纤维含量提升了8.8%,而葛根异黄酮含量提升了30.3%,为优选的葛根渣固态发酵获取功能产品的菌株。     

由大豆浓缩蛋白(SPC)乳清制备高纯度异黄酮苷元的研究

以价格低廉、易污染环境的大豆浓缩蛋白(SPC)乳清为原料,采用等电点结合盐析法沉淀蛋白质、活性炭脱色、离子交换树脂脱盐、HPD-100型非极性大孔树脂吸附纯化、盐酸水解等工艺,制备高纯度的大豆异黄酮苷元产品。经高效液相色谱(HPLC)等方法分析,大豆异黄酮的纯度为(58.4±2.5)%(w/w),总回收率为(78.3±2.6)%;异黄酮苷元的相对含量≥95%(w/w),其中染料木素(Genistein)与大豆甙元(Daid-zein)的含量分别为(23.4±0.8)%和(31.2±0.9)%,而黄豆黄素(G lycitein)的含量极低。产品纯度和附加值高,既能克服当前异黄酮提取工艺中原料成本高、预处理方法繁琐、产品纯度低等缺点,又能实现废物利用,具有良好的推广应用与产业化前景。     

青方腐乳发酵过程中大豆异黄酮的转化研究

本文比较了青方、红方、白方和低盐红腐乳中大豆异黄酮组成和含量差异,并对青方腐乳发酵过程中大豆异黄酮含量和构型变化规律进行研究。结果表明,四种类型腐乳中大豆异黄酮基本以苷元形式存在,青方腐乳大豆异黄酮含量明显低于其他类型腐乳,仅为红方腐乳的33.01%,从单一异黄酮来看,大豆苷元和染料木素在四种类型腐乳中的含量明显高于黄豆黄素;青方腐乳发酵过程中大豆异黄酮转化研究发现,白坯中大豆异黄酮以糖苷型为主,染料木苷含量高于大豆苷和黄豆黄苷,前酵过程中糖苷型大豆异黄酮转化为苷元型大豆异黄酮,盐腌过程中糖苷型大豆异黄酮含量有轻微降低,发酵过程中苷元型大豆异黄酮总量在后酵前30 d显著下降,其中大豆苷元可能部分转化为雌马酚,导致青方腐乳大豆异黄酮含量明显低于其他类型腐乳,对其转化物质需进一步鉴定。     

超高效液相色谱-串联质谱法测定大豆中异黄酮素含量

目的 以染料木黄酮、大豆苷元和黄豆黄素的含量为指标,建立超高效液相色谱-串联质谱测定大豆中异黄酮素总量的方法。方法 样品用乙醇-水(3+1,V/V)提取,经过β-葡萄糖苷酶水解后,用Acquity UPLC?BEH C18柱(2.1 mm×100 mm, 1.7μm)分离,以甲醇和0.1%甲酸溶液(含5 mmol/L乙酸铵)作为流动相进行梯度洗脱,电喷雾负离子模式(ESI-)电离,多反应监测模式进行检测。结果 染料木黄酮、大豆苷元在5.0～500μg/L范围内线性关系良好(r>0.995),方法的检出限分别为2.7、4.0 mg/kg,在300.0、600.0、1 200 mg/kg添加水平的平均回收率为89.4%～102.2%,相对标准偏差(n=6)为1.5%～4.6%;黄豆黄素在0.5～50.0μg/L范围内线性关系良好(r>0.995),方法的检出限为0.6 mg/kg,在30.0、60.0、120.0 mg/kg添加水平的平均回收率为85.7%～104.0%,相对标准偏差(n=6)为1.3%～2.8%。结论 该方法简单、灵敏、准确可靠,适用于大豆中异黄酮素含量的测定...     

异黄酮衍生物的合成研究进展

本文从异黄酮侧链化学修饰出发综述了该类化合物衍生物的合成研究。     

UVB-Protective Effects of Isoflavone Extracts from Soybean Cake in Human Keratinocytes

It has been shown by chromatography that aglycone, glucoside, acetylglucoside and malonylglucoside isoflavone extracts prepared from soybean cake showed better antioxidant activities than isoflavone standards. Consequently, the aim of this study was to evaluate the protective effects of these isoflavone extracts against ultraviolet B (UVB)-induced keratinocyte damage. Our results demonstrated that these soybean cake isoflavone extracts could inhibit UVB-induced keratinocyte death. Moreover, they could inhibit UVB-induced intracellular release of hydrogen peroxide (H₂O₂) Furthermore, these isoflavone extracts differentially inhibited UVB-induced MAPK phosphorylation. The ERK1/2 and p38 phosphorylation was not inhibited by all tested isoflavone extracts, whereas JNK phosphorylation was inhibited by group I to group III isoflavone extracts. Since these isoflavone extracts are relative stable and easily obtained than the isoflavone standards, we suggest that soybean cake may be a useful potential source for developing effective skin care agents in against photoaging.     

Effects of Plant Flavonoids on Fecundity, Survival, and Feeding of the Formosan Subterranean Termite

Fecundity, mortality, and food consumption of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were evaluated in response to five plant flavonoids (genistein, biochanin A, apigenin, quercetin, and glyceollin). Apigenin fed at 50 g/primary reproductive pair proved to be the most toxic flavonoid. Biochanin A was most effective in reducing fecundity. Subsequently, these two flavonoids were tested through oral feeding and topical application at 100-g dose. Significant reduction in the numbers of progeny was evident for biochanin A in both treatment methods. Choice feeding tests with termite workers showed that initially termites were attracted to filter paper treated with biochanin A, but over a period of 72 hr, consumed significantly less material when compared to controls. Biochanin A is a promising phytochemical with ability to reduce fecundity in primary reproductives of the Formosan subterranean termite, but it does not elicit phagostimulant activity.     

加热预处理对大豆胚芽风味及其异黄酮存在形式的影响

大豆胚芽含有大量异黄酮化合物,天然异黄酮存在形式主要丙二酰型糖苷,此类异黄酮化合物是大豆胚芽的苦涩、豆腥味的主要呈味物质。研究显示采用加热处理可较大程度地降低大豆胚芽的苦涩味,从而改善胚芽的风味。采用HPLC分析显示,加热处理可使丙二酰型异黄酮糖苷转换为乙酰型糖苷,甚至糖苷化合物,后者的呈味显著低于丙二酰型异黄酮糖苷化合物。     

大豆中主要活性成分的开发和利用

研究了大豆中五种主要活性成分的功能、应用及提取工艺。