Biological Availability and Preliminary Selenium Speciation in Selenium-Enriched Mycelium of Lentinula edodes (Berk.)

Our goal is to obtain a new food supplement — a chemopreventive preparation derived from selenium (Se)-enriched Lentinula edodes mycelium. In the present study the bioavailability of selenium from Se-enriched mycelium preparations was tested in vitro and in vivo. Three different preparations of selenated mycelium were compared: dried mycelium, lyophilized mycelium, and lyophilized-autolyzed mycelium. In vitro, estimated Se bioavailabilities were 60%, 82%, and 98%, respectively. In vivo bioavailability was determined in rats. As reference, sodium selenite and Se yeast formulations were used at an Se-equivalent dose. The pharmacokinetic data for tested mycelial preparations suggest a rapid but incomplete Se absorption, and rapid elimination, without risk of accumulation. The speciation of selenium in Se-enriched mycelial cultures was carried out by specific oxido-reduction reactions. For tested mycelium the main part of Se was in the 0 and IV oxidation states in inorganic form or combined in a lipid or carbohydrate structure, about 47% was in the –II state in Se-amino acids or in other undefined water- or alcohol soluble organic compounds. Differences in pharmacokinetic data for Se yeast and L. edodes mycelial formulations probably arise from differences in Se speciation. Our data suggest that formulations of selenized Lentinula edodes mycelium could be used in chemoprevention as food supplements.     

Optimization of Selenium-Enriched Mycelium of Lentinula edodes (Berk.) Pegler as a Food Supplement

Our goal was to optimize the growth conditions of submerged mycelial cultures of Lentinula edodes (Shiitake mushroom) in order to obtain a new dietary supplement enriched in selenium We designed a process technology in which mycelial cultures were cultivated in media composed of beet molasses, 10%; liquid stillage, 5%; corn steep liquor, 0.15%; and KH₂PO₄, 0.3%, enriched with selenium in concentrations ranging from 0 to 100 μg/mL by the addition of sodium selenite of selenic acid. Se concentrations in mycelial dry mass rose from 0.001 mg/g (mycelia cultivated in media containing no selenium) to 50 mg/g (mycelia cultivated in medium containing 100 μg Se/mL). The highest mycelial specific growth rate (0.46/day) was recorded when the concentration of selenium in the medium was lower than 20 μg/mL. In vitro, estimated Se bioavailabilities from selenized mycelium strongly depended on its preparation in a proper manner and were 60% and 82% for dried mycelium and mycelial lyophilizate, respectively. Our results suggest that these optimized culture conditions could be applied to obtain a new Se-enriched dietary supplement.     

香菇EST资源的SSR信息分析

对来源于NCBI 公共数据库的12144 条香菇(Lentinus edodes)EST 序列进行简单重复序列SSR 搜索。结果表明：在这些香菇EST 序列中共有359 个SSR 位点,46 种SSR 的重复单元,其中2 碱基重复243 条(67.69%),3 碱基重复114 条(31.76%),5 碱基重复1 条(0.28%),6 碱基重复1 条(0.28%)。平均33.8 条EST 序列中有1 个SSR。SSR的碱基总数达7727kb,约占整个EST 序列碱基数的2.94%。本实验还根据搜索结果设计了100 条香菇EST-SSR 引物,并随机合成了20 对引物。以4 个野外采集的香菇DNA 为模板,对引物进行了筛选与评价,有16 对引物有较清晰且稳定的目标扩增产物,其中11 对引物的产物存在遗传多态性。结果表明本实验设计开发的香菇的EST-SSR标记是可行且有效的。     

香菇、茶叶抗类可可脂巧克力起霜花的动力学研究

用差示扫描粉析法分别对添加了香菇和茶叶的乌柏类可可脂巧克力的ＶＩ（β）晶型在２８℃、３０℃和３２℃下的等温结晶动力学进行了研究,结果表明,结晶速率常数（Ｋｎ）值,随温度的升高而减少,半结晶时间（ｔ１／２）随温度升高而延长,含有香菇和茶叶巧克力的ＡＶｒａｍｉ指数（ｎ）平均值分别为２．２和２．３,明显小于空白对照样（ｎ－２．６）,而且在各曙结晶温度下二者的半结晶时间的均大于对照样。从动力学角度说明香菇     

天然人体免疫调节剂——香菇多糖

概述了香菇多糖的营养价值和开发动态。简要讨论了香菇多糖的提取分离、化学结构、免疫作用机理、毒性试验和应用前景。     

香菇膳食纤维挤压改性的研究

采用挤压改性方法处理两种不同工艺制备的香菇膳食纤维 ,在不同的挤压处理条件下 ,香菇膳食纤维的总膳食纤维的量均未改变 ,水溶性膳食纤维的含量分别提高 6%～ 1 5%和 2 %～ 8% ,被改性的物质主要是不溶性纤维中的半纤维素。     

香菇多糖的提取工艺比较

本实验以香菇为原料,应用酶解法提取香菇多糖。考察了影响实验的因素即酶用量、酶制剂作用时间、作用温度和pH值对酶解法提取率的影响。并将酶解提取方法与传统提取方法进行分析比较。利用红外光谱和紫外吸收光谱分析浸提物。混合酶解提取法香菇多糖最高提取率为12.90%,比传统水浴浸提法高出6.26%,在时间上仅用了传统方法的1/3。其产品在紫外吸收时,粗产品杂质含量少,比传统浸提方法更接近标准品。研究结果表明,混合酶解法提取香菇多糖的方法优于传统水浴浸提法。     

香菇风味成分的研究

采用水蒸汽蒸馏法提取香菇中挥发性成分,然后用色谱/质谱联用分析鉴定,用GC/MS总离子流色谱峰面积进行分析其风味成分。香菇的挥发性成分主要是一些含硫和八碳的化合物。其中二甲基二硫醚、二甲基三硫醚、甲硫基二甲基三硫醚、1,2,4-三硫杂环戊烷、香菇精是香菇的特征风味成分。其中以含硫的的杂环化合物最为重要,他们是香菇风味最重要的组成部分。     

乌桕类可可脂及其巧克力结晶性质的研究(II)

为探索乌桕类可可脂(CTCBE)巧克力调温工艺操作困难的原因与机理,采用差示扫描量热法(DSC)、X-射线衍射(XRD)对添加天然生物乳化剂(香菇粉)的CTCBE巧克力(LC)和空白CTCBE巧克力(CC)在调温过程中结晶行为进行研究分析。并采用粘度法、升温破乳法对两种巧克力浆料在调温过程中的流散性及乳化稳定性进行对比研究。DSC和XRD结果均表明添加香菇粉明显促使CTCBE巧克力形成高熔点稳定晶型,LC比CC酱料的粘度降低近20%,乳化稳定性提高100倍以上,有效地改善了CTCBE巧克力调温工艺操作条件,提高产品产量及质量(具有良好热稳定性、抑制霜花效果及抗氧化性)。