响应曲面法优化紫贻贝酶解液制备海鲜风味基料

以紫贻贝酶解液为原料,采用感官评价和GC-MS分析的方法研究Maillard反应制备海鲜风味基料的最佳工艺条件及产物的挥发性风味成分。结果表明：Maillard反应制备海鲜风味基料的最优模式体系为丙氨酸与脯氨酸的添加质量分数为0.5%、质量比为2:3、葡萄糖与木糖的总添加量为8%、质量比为1:3、反应pH6.2,反应温度为100℃、反应时间为25min;上述条件下制得的海鲜风味基料经GC-MS分析,鉴定出29种挥发性化合物,主要有羧酸类、吡嗪类、酯类、醛类、酮类、醇类、含硫类等化合物,对海鲜风味有贡献的化合物主要有苯并噻唑、3-甲硫基丙醛、吡嗪类等化合物。     

基于人工神经网络法优化河蚌多糖超高压提取工艺

以取珠后的蚌肉为原料,采用超高压方法提取河蚌多糖。利用响应面试验设计获取神经网络所需的训练样本,利用训练成熟的神经网络进行训练和仿真,分析因素(压力强度、料液比和保压时间)以及因素间的交互作用对河蚌多糖得率的影响,并对超高压得河蚌多糖的工艺进行优化。结果表明:人工神经网络法比响应面法的优化准确性高,预测值的可信度较强;超高压提取河蚌多糖最佳工艺条件为:压力强度340 MPa、料液比1:42(g/mL)、保压时间10 min,该条件下的多糖得率预测值为7.18%,实测值为7.12%,相对误差为0.84。该工艺具有短时、高效、环保等优点,为河蚌多糖的开发利用提供技术依据。     

煅烧紫贻贝壳粉对Cd2+和Pb2+的吸附热力学研究

贻贝是我国的重要的海产经济贝类,但由于养殖规模的增大而随之产生的废弃贻贝壳资源成为了关注的热点。研究发现贻贝壳是一种环境友好型的生物吸附剂,本文通过高温煅烧处理,进一步优化了贻贝壳的吸附性能,采用SEM、BET、XRD和IR表征手段对贻贝壳的微结构、孔径及组成进行了分析;同时探讨了贝壳粉吸附剂对Cd2+和Pb2+的吸附热力学性能。结果发现贻贝壳粉经高温煅烧后,其主要成分为CaO,且比表面积显著增大,比表面积达7.8965 m2/g,形成诸多纳米孔径,直径在0.5~1.1 nm,吸附性能提高。贻贝壳吸附剂用量和溶液pH对Cd2+和Pb2+的吸附量影响较大,吸附剂对Cd2+的吸附量明显高于对Pb2+的吸附量,且吸附剂对Cd2+和Pb2+的吸附均符合Freundlich等温吸附模型。由此可知,煅烧后的紫贻贝壳是一种优良廉价的生物吸附剂,可将其开发成一种针对性去除废水中重金属Cd2+的新型吸附剂。     

基于高通量测序的紫贻贝中微生物群落分析

为探究不同状态下紫贻贝制品表面附着的微生物菌群组成情况。本实验以新鲜紫贻贝、冻藏紫贻贝、自制紫贻贝干,贮藏自制紫贻贝干和市售紫贻贝干为研究对象,通过对紫贻贝表面附着微生物提取及高通量测序分析,获得不同紫贻贝样品中微生物组成及变化情况。实验结果表明,各样本中有效序列范围为30066～40563条、Operational taxonomic unit(OTU)范围为28～128,其中市售紫贻贝干OTU数最低,而冻藏紫贻贝OTU数相对较高;新鲜紫贻贝和自制紫贻贝干中主要是嗜冷杆菌属和不动杆菌属,冻藏紫贻贝干中主要为嗜冷杆菌属,贮藏紫贻贝干中主要为假单胞菌属和嗜甲基菌属,而市售紫贻贝干中优势菌群为葡萄球菌属和肠球菌属。不同状态下的紫贻贝样品的菌群组成均存在着较大距离,表明紫贻贝状态、加工过程及贮藏销售环境等,均对贻贝产品菌群组成产生较大的影响。研究结果可为保障紫贻贝制品的质量与安全提供参考。     

沼虾饲料中贻贝液与植物油脚的最适添加量

通过对在罗氐沼虾饲料中，贻贝制品废弃液和植物油脚的不同添加量的投饲试验，以体长增长和个体质量增加以及成活率为指标，经统计分析，结果表明：饲料中最经济且有效的添加量为贻贝液与油脚各添加１％～２％，相应的胆固醇质量分数为２．２×１０（－３）～３．７８×１０（－３）。     

Nonlinear dynamic and pattern bifurcations in a model for spatial patterns in young mussel beds

Young mussel beds on soft sediments can display large-scale regular spatial patterns. This phenomenon can be explained relatively simply by a reaction–diffusion–advection (RDA) model of the interaction between algae and mussel, which includes the diffusive spread of mussel and the advection of algae. We present a detailed analysis of pattern formation in this RDA model. We derived the conditions for differential-flow instability that cause the formation of spatial patterns, and then systematically investigated how these patterns depend on model parameters. We also present a detailed study of the patterned solutions in the full nonlinear model, using numerical bifurcation analysis of the ordinary differential equations, which were obtained from the RDA model. We show that spatial patterns occur for a wide range of algal concentrations, even when algal concentration is much lower than the prediction by linear analysis in the RDA model. That is to say, spatial patterns result from the interaction of nonlinear terms. Moreover, patterns with different wavelength, amplitude and movement speed may coexist. The results obtained are consistent with the previous observation that self-organization allows mussels to persist with algal concentrations that would not permit survival of mussels in a homogeneous bed.     

丹东河蚌抗癌成分结合型多糖的提取

利用丹东地区河蚌(褶纹冠蚌),经匀浆,2450MHz、550W微波处理,80~85℃加热,过滤后,滤渣在pH 2.0~2.5条件下,于40~45℃用胃蛋白酶水解,提取具有抗癌活性的结合型多糖,纯度91.5%,收率1.4%。     

贻贝、牡蛎复合物对肠道菌群紊乱型小鼠便秘的干预作用

本研究探讨了贻贝、牡蛎复合物对抗生素诱导小鼠便秘的干预作用,采用混合抗生素溶液灌胃C57BL/6雌性小鼠,构建肠道菌群紊乱型小鼠便秘模型（ME）,以0.02 mL/g?bw贻贝、牡蛎复合物灌胃ME组小鼠为干预组（IC）。结合16s RNA基因测序技术,7 d后,测定小肠推进率、排便量、饲料消耗量、肠道菌群结构等指标,评估小鼠便秘模型及其贻贝、牡蛎复合物的干预作用。对比空白组,ME组小肠推进率下降22.89%（p<0.05）,排便量降低41.00%（p<0.05）,日平均饲料消耗量显著下降2.68 g/d（p<0.05）,粪便含水率显著下降19.40%（p<0.05）,同时,ME组肠道菌群有益菌多样性减少,表现为Prevotella-9、Lachnospiraceae、Enterobacter、Verrucomicrobia等有益菌菌群丰度降低;经贻贝、牡蛎复合物干预后,对比ME组,IC组小鼠小肠推进率提升70.00%（p<0.05）,排便量提升52.00%（p<0.05）,粪便含水率显著增加18.10%（p<0.05）,IC组肠道菌群多样性增加,表现为Proteobacteria、Fusobacteria、Akkermansia、Bacteroidetes、Verrucomicrobia丰度增加,同时IC组肠道菌群结构恢复至与空白组小鼠相似。综上,贻贝、牡蛎复合物可显著改善由抗生素导致的便秘小鼠的小肠推进率等小肠蠕动功能,增加小鼠排便,并提高粪便含水率,同时调节便秘小鼠的肠道菌群结构及组成,增加Akkermansia等肠道有益菌。     

Bioadhesive Hyaluronic Acid/Dopamine Hydrogels for Vascular Applications Prepared by Initiator-Free Crosslinking

Intimal hyperplasia, a vascular pathology characterized by vessel wall thickening, is implicated in vein graft failures. For efficient prevention, a biodegradable drug delivery system should be applied externally to the graft for an extended time. Finding a gel suitable for such a system is challenging. We have synthesized HA-Dopamine conjugates (HA-Dop) with several degrees of substitution (DS) and used two crosslinking methods: initiator-free crosslinking by basic pH shift or commonly used crosslinking by a strong oxidizer, sodium periodate. The rheological properties, bioadhesion to vascular tissue, cytocompatibility with fibroblasts have been compared for both methods. Our results suggest that initiator-free crosslinking provides HA-Dop gels with more adequate properties with regards to vascular application than crosslinking by strong oxidizer. We have also established the cytocompatibility of the initiator-free crosslinked HA-Dop gels and the cytotoxicity of dopamine-sodium periodate combinations. Furthermore, we have incorporated a drug with anti-restenotic effect in perivascular application, atorvastatin, into the gel, which showed adequate release profile for intimal hyperplasia prevention. The oxidizer-free formulation with improved bioadhesion holds promise as an efficient and safe drug delivery system for vascular applications.     

生物质材料木材胶粘剂的研究进展

大豆蛋白作为一种廉价、易得、资源丰富、环境友好的生物质材料受到了广泛的关注,为了解决豆蛋白胶自身易水解、易受微生物侵蚀的缺陷,化学改性豆蛋白被广泛采用,以贻贝胶为模板对豆蛋白、木素等生物质材料进行化学改性用于制备木材胶粘剂也是研究的热点,本文对这2方面的研究进展做了简要的回顾。