玉米须总黄酮提取工艺及其降血糖作用研究

[目的]研究玉米须总黄酮提取工艺及降血糖作用。[方法]以玉米须为材料,通过正交设计考察乙醇浓度、料液比、提取时间对玉米须总黄酮提取率的影响,确定最佳工艺条件;并以四氧嘧啶所致糖尿病小鼠为动物模型,研究玉米须提取物的降血糖作用。[结果]玉米须总黄酮提取最佳条件为16倍70%乙醇,回流2次,每次浸提2 h。动物试验表明,玉米须提取物高剂量组能显著抑制四氧嘧啶所致糖尿病小鼠模型血糖的持续升高(P0.05)。[结论]玉米须提取物具有辅助降血糖作用。     

玉米须类胡萝卜素的提取及其稳定性

为进一步开发玉米须资源,以废弃的玉米须为原料,探讨不同萃取剂、超声时间、表面活性剂、温度、提取时间、液料比、搅拌转速对类胡萝卜素提取量的影响,同时研究光照、pH、营养元素、超声时间对玉米须类胡萝卜素稳定性的影响。结果表明,玉米须类胡萝卜素最适提取工艺条件:以丙酮为萃取剂,超声预处理6 min,十二烷基硫酸钠(SDS)用量1.6%,提取温度35℃,提取时间45 min,液料比13m L·g~(-1),搅拌转速125 r·min~(-1),此条件下的提取量为311.21 mg·kg~(-1),与理论预测值(313.96 mg·kg~(-1))相近。玉米须类胡萝卜素对光照,提取温度,酸碱环境,Ca~(2+)、Mg~(2+)、Fe~(2+)、Fe~(3+)、Zn~(2+)元素和超声处理较为敏感,而在避光、中性环境、Na~+和K~+元素条件下有利于其储存,适度的超声处理在提高玉米须类胡萝卜素提取率的同时对其稳定性无显著影响,节约时间成本。综上,高效利用玉米须中的类胡萝卜素对玉米须深加工具有重要意义。     

Heat stress effects around flowering on kernel set of temperate and tropical maize hybrids

Final kernel number in the uppermost ear of temperate maize (Zea mays L.) hybrids is smaller than the potential represented by the number of florets differentiated in this ear, and than the number of silks exposed from it (i.e., kernel set <1). This trend increases when stressful conditions affect plant growth immediately before (GS₁) or during (GS₂) silking, but the magnitude of change has not been documented for heat stress effects and hybrids of tropical background. In this work we evaluated mentioned traits in field experiments (Exp₁ and Exp₂), including (i) two temperature regimes, control and heated during daytime hours (ca. 33-40 °C at ear level), (ii) two 15-d periods during GS₁ and GS₂, and (iii) three hybrids (Te: temperate; Tr: tropical; TeTr: Te × Tr). We also measured crop anthesis and silking dynamics, silk exposure of individual plants, and the anthesis-silking interval (ASI). Three sources of kernel loss were identified: decreased floret differentiation, pollination failure, and kernel abortion. Heating affected all surveyed traits, but negative effects on flowering dynamics were larger (i) for anthesis than for silking with the concomitant decrease in ASI, and (ii) for GS₁ than for GS₂. Heat also caused a decrease in the number of (i) florets only when performed during GS₁ (−15.5% in Exp₁ and −9.1% in Exp₂), and only among Te and TeTr hybrids, (ii) exposed silks of all GS × Hybrid combinations, and (iii) harvestable kernels (mean of −51.8% in GS₁ and −74.5% in GS₂). Kernel abortion explained 95% of the variation in final kernel numbers (P < 0.001), and negative heat effects were larger on this loss (38.6%) than on other losses (≤11.3%). The tropical genetic background conferred an enhanced capacity for enduring most negative effects of heating.     

中国茧丝绸出口贸易研究现状

茧丝绸是我国具有垄断地位的少数出口商品之一。茧丝绸行业从上世纪90年代陷入低谷后,近十年不断恢复增长。在加入WTO后茧丝绸贸易的国际环境发生了巨大变化,如何在新的国际规则下加强茧丝绸产品的国际竞争力,保持茧丝绸贸易的持续增长成为一个重要的研究内容,本文在总结前人的研究基础上对茧丝绸出口贸易的健康发展也提出一些建议。     

搅拌型丝素酸奶的研制

以丝素作为辅料研发搅拌型丝素酸奶,通过正交试验确定丝素酸奶的优化配方为:每1L乳液含奶粉15%,丝素0.75%,白糖7%,接种量4%。制得的酸奶稠度大、光泽好、酸甜适中、细腻润滑、风味浓郁。与未添加丝素的对照酸奶相比,搅拌型丝素酸奶pH值变化不大,保水性显著增强,乳酸菌含量显著提高。     

GB/T 1797—2008生丝标准对生丝分级的影响

GB/T1797—2008生丝标准对生丝质量提出了新要求,笔者以2009年安徽检验出口的20/22D规格生丝为例,进行GB1797—2001、GB/T1797—2008标准间试套,借此分析GB/T1797—2008标准带来的影响,以期为优化缫丝工艺提供借鉴。     

广西桑蚕原料茧解舒率与茧层丝胶初期溶解速度的关系探讨

本文通过对不同品种、不同庄口与季节原料茧茧层丝胶性能研究,结果表明广西的桑蚕原料茧,春茧和秋茧5min、10min两个处理水平的茧层丝胶初期溶解速度与蚕茧解舒率之间都存在着良好的正相关关系,茧层丝胶初期溶解速度越大,蚕茧的解舒率越大。庄口和季节是影响广西桑蚕原料茧茧层丝胶初期溶解速度的重要因素。而茧层丝胶初期溶解速度与蚕茧解舒率在品种水平上则没有相关关系,也就说明茧层丝胶初期溶解速度在品种间虽然有差异,但蚕品种并不是主要制约或影响蚕茧茧层丝胶初期溶解速度的直接因素。     

用高温高压水精练蚕丝及冻结解冻法回收丝胶的研究

以粗纤度生丝及普通纤度生丝为材料 ,采用高温高压水精练蚕丝 ,丝胶的平均分子量随温度的增加逐步降低 ,10 0℃时丝胶分子量为 2 0万～ 6 5万 ,130℃时 ,为 13万～ 4 3万以下。蚕丝经 12 0℃精练 1h后脱胶干净 ,且练液无污染 ,利于丝胶的回收利用。采用冻结解冻法回收其丝胶 ,可使 110℃精练的丝胶回收率达 80 %以上 ,温度增高回收率降低 ,冻结次数增多回收率提高。     

蚕丝及Ⅱ型胶原凝胶支架负载软骨细胞构建组织工程类软骨

观察软骨细胞在蚕丝及胶原凝胶2种支架上生长状态,为软骨组织工程支架选择提供依据。将体外第2代兔关节软骨细胞接种于蚕丝和Ⅱ型胶原凝胶,倒置显微镜下观察软骨细胞在支架内的生长增殖状况,并对细胞-支架复合物进行组织切片观察。结果显示,经胶原包被后的蚕丝对软骨细胞表现出良好的吸附作用,并有利于软骨细胞的生长增殖。在培养初期,蚕丝内细胞生长增殖较胶原凝胶内的慢,但随后随着胶原支架的缀陵降解细胞增殖速度减慢,而蚕丝上的细胞数量仍在增加。该研究表明软骨细胞在蚕丝和胶原凝胶两种支架上都能维持正常生长状态,但蚕丝作戈、软骨组织工程支架在长期效果优于胶原凝胶。     

Fast response photochromic textiles from hybrid silica surface coating

In this study, a hybrid silica sol-gel embedded with a photochromic dye has been applied to wool fabric to form a photochromic coating. The treated wool fabrics showed very quick photochromic response. Five different silanes have been used as the silica precursor, and the resultant coating showed slight differences in photochromic performance, fabric washing fastness, and surface hydrophilicity. However, the silica type had a considerable influence on fabric handle property. The silica matrix from the silane containing a long alkyl chain had a very little influence on the fabric handle and better photochromic performance than those from other different silane precursors.