谷物β-葡聚糖研究进展

该文综述谷物β-葡聚糖结构、理化特性、生理功能、测定方法、提取纯化及开发应用等方面研究进展,并对谷物β-葡聚糖研究存在问题及今后研究方向进行探讨。     

不同碳、氮源对猴头菌菌丝体多糖含量的影响

目的:明确培养猴头菌菌丝体时不同碳、氮源对多糖含量的影响。方法:用不同碳、氮源液体培养基对猴头菌进行液体浅层静置培养,用苯酚-硫酸法测定菌丝体中的多糖含量。结果:从菌丝体多糖含量角度考虑最佳碳源为淀粉,最佳氮源为豆腐渣;在淀粉用量为4.0%、豆腐渣用量为1.5%时得到的猴头菌菌丝体多糖含量高达162.17mg/g。结论:淀粉和豆腐渣能比常用碳、氮源大幅度提高液体培养猴头菌菌丝体的多糖含量,而且价格低、来源广,在生产上有着很好的推广应用前景。     

Fe~(3+)配位对水溶性大豆多糖性质的影响

以柠檬酸三钠-三氯化铁法合成水溶性大豆多糖-铁(Ⅲ)配合物,采用邻菲罗啉分光光度法测得其含铁量为18.1%,表明Fe3+与水溶性大豆多糖基本形成了稳定的配合物,在pH值1～14内不沉淀。对其抗氧化活性的研究表明,水溶性大豆多糖与铁配合后,对羟基自由基、亚硝酸盐的清除活性及对脂质抗氧化的活性均比水溶性大豆多糖好。在浓度为10 mg/mL时,水溶性大豆多糖对羟基自由基的清除率为16.0%,对亚硝酸盐的清除率为53.9%,对脂质体氧化的抑制率为34.9%,而相同条件下水溶性大豆多糖-铁(Ⅲ)配合物对羟基自由基的清除率为29.6%,对亚硝酸盐的清除率为67.5%,对脂质体氧化的抑制率为77.9%。     

青钱柳多糖降血糖活性的研究

为了研究青钱柳多糖降血糖活性,从青钱柳水提取物中分离、纯化得到青钱柳多糖,然后用其对实验性糖尿病小鼠进行灌胃,观察糖尿病小鼠的血糖及其体质量的变化。实验结果表明青钱柳多糖高、中、低剂量组与模型组血糖值有极显著性差异,青钱柳多糖可以显著提高小鼠对葡萄糖、淀粉的糖耐量,但对蔗糖的影响不显著。     

Modification of pectin polysaccharides during ripening of postharvest banana fruit

Pectin is one of the major components of the primary cellular walls and middle lamella in plant tissues. In this study, water-soluble pectin (WSP) and acid-soluble pectin (ASP) fractions were isolated from pulp tissues of banana fruit at various ripening stages. Their monosaccharide compositions, glycosyl linkages and molecular mass distributions were evaluated. As ripening progressed, fruit firmness decreased rapidly, which was associated with the increase in the WSP content and the decrease in the ASP content. Meanwhile, the molecular mass distributions of WSP and ASP fractions exhibited a downshift tendency, indicating the disassembly of pectin polysaccharides. Moreover, galactose and galacturonic acid as the major monosaccharide compositions of pectin polysaccharides increased in WSP fraction but decreased in ASP fraction during fruit softening. GC–MS analysis further revealed that pectin polysaccharide had a 1,4-linked galactan/galacturonan backbone with different types of branching and terminal linkages in WSP and ASP fractions. During banana fruit ripening, the amount of 1,4-linked Galp residues of ASP fraction decreased significantly whereas 1,3,6-linked Galp, 1,2-linked Manp and 4-linked Araf residues disappeared, which was related to depolymerization of pectin polysaccharides. Overall, the study indicated that the modifications in polysaccharide compositions and glycosyl linkages, reduced molecular mass distributions and enhanced depolymerization of pectin fraction during banana ripening were responsible for fruit softening.     

碱溶性米糠多糖的提取及其免疫调节功能研究

本文研究了不同提取温度、提取时间和碱摩尔浓度对碱溶性米糠多糖提取得率的影响。采用响应面分析的方法得到碱溶性米糠多糖的最佳提取条件为：温度44．5℃，时间2．13h，NaOH浓度0．53mol/L。并在此基础上，采用动物试验证明碱溶性米糠多糖具有免疫活性增强作用。     

樟芝真菌发酵培养基优化研究

以麸皮、蛋白胨、MgSO4·7H2O、VB1、葡萄糖、酵母膏、KH2PO4。7种为影响樟芝真菌液体培养的影响因素,分别以菌丝体和胞外多糖为目的产物进行L18（3^7）正交试验,综合以胞外多糖和菌丝体为目的产物进行樟芝真菌液体培养的正交试验分析后得出,樟芝真菌液体培养时的适宜培养基为：麸皮40g／L、葡萄糖25g／L、蛋白胨4g／L、MgSO4·7H2O 0．4g／L、酵母膏2．0g／L、KH2PO4 0．6g／L、VB10．01g／L。     

柳小皮伞深层发酵培养基的筛选

采用Plackett-Burman设计对影响柳小皮伞（Marasmius salicicola）AS5．166发酵胞外多糖培养基的组成成分进行了筛选，所选取的10个相关因素为：葡萄糖、蔗糖、酵母膏、蛋白胨、K2HPO4、KH2PO4、CaCl2、FeSO4、MgSO4、VB1。结果表明，影响柳小皮伞（Marasmius salicicola）AS5．166胞外多糖含量的主要因素为葡萄糖、蔗糖、酵母膏、KH2PO4、MgSO4和FeSO4。     

富含香菇多糖的山楂功能性饮料的研制

为了得到一种风味良好、营养丰富的新型复合功能性饮料,该实验以香菇和山楂浓缩清汁为主要原料,优化提取工艺,得到最优的香菇粗多糖提取工艺参数为料液比为1∶25、pH=8.5、提取时间2h、温度45℃、加酶量0.5%,此时香菇多糖提取率达到6.25%。通过配方筛选正交试验,得到最优配比为香菇粗多糖0.3%、山楂浓缩汁12%、安赛蜜0.012%、柠檬酸0.3%、白砂糖8%、香精0.002%、色素0.002%。实验所得到的山楂复合饮料,实现了风味和营养的互补。     

猴头菇多糖的纯化工艺

对猴头菇子实体多糖进行纯化研究。采用树脂吸附法对猴头菇多糖脱色并利用超滤法进行分级除杂。结果表明：猴头菇多糖适宜采用HD-3树脂进行脱色;静态脱色工艺为pH4.5、每100mL添加树脂量15.0g、脱色2.5h,脱色率和多糖得率分别达到84.9%和83.2%;动态脱色工艺控制流速为5BV/h时,脱色率和多糖得率都较高,平均达83.9%和82.3%;最佳超滤工艺为选择截留分子质量为10kD 和100kD的两种膜对猴头菇多糖进行超滤,超滤温度45℃、压力0.16MPa、溶液pH7～9。此工艺适合工业化生产的需要,得到的猴头菇多糖纯度达74.2%。