壳寡糖制备方法研究进展

水产品加工行业副产的大量虾蟹壳不能得到充分高值利用,造成资源浪费、环境污染。壳寡糖作为虾蟹壳的高值衍生物,具有高的生理活性,广阔的应用空间。壳聚糖降解是由虾蟹壳制备壳寡糖的关键环节。开发环保的、经济的、易于工业化的壳聚糖降解技术是突破壳寡糖制备瓶颈的主要方向。壳聚糖降解的基础研究是开发壳寡糖新生产方法的根本。     

基于Web服务的分布式销售智能系统的研究

构建基于Web服务的分布式销售智能系统(DSIS)是提升现代企业竞争力的有效手段.通过分析DSIS的两个关键技术:Web服务和数据挖掘技术,设计了以Web服务代理作为注册中心、以销售智能模块作为服务提供者的DSIS的框架结构,并对销售智能模块及Web服务代理的功能进行了分析.     

序信息系统的知识粗糙熵与粗集粗糙熵

在序信息系统中引入了知识粗糙熵和粗集粗糙熵的概念,得到了它们的有关性质,并证明了二者都随着知识确定程度的增强而单调下降的结论,从而给出了序信息系统的信息解释。进一步通过讨论它们之间的联系说明了粗集的粗糙熵可以更精确地度量粗集地粗糙程度。这些结论为序信息系统的知识发现奠定了一定的理论基础。     

Structure and characteristics of acid and pepsin-solubilized collagens from the skin of cobia (Rachycentron canadum)

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin of cobia (Rachycentron canadum). The yields of ASC and PSC were 35.5% and 12.3%, respectively. Based on the protein patterns and carboxymethyl-cellulose chromatography, ASC and PSC were composed of α1α2α3 heterotrimers and were characterised as type I collagen with no disulfide bond. Their amounts of imino acids were 203 and 191 residues per 1000 residues, respectively. LC-MS/MS analysis demonstrated the high sequences similarities of ASC and PSC. Fourier transform infrared spectroscopy spectra showed that the amide I, II and III peaks of PSC were obtained at a lower wave number compared with ASC. The thermal denaturation temperatures of ASC and PSC, as measured by viscometry, were 34.62 and 33.97°C, respectively. The transition temperatures (T(max)) were 38.17 and 36.03°C, respectively, as determined by differential scanning calorimetry (DSC). Both collagens were soluble at acidic pH and below 2% (w/v) NaCl concentration.     

壳聚糖对腌制鱿鱼防腐作用的研究

用不同浓度的壳聚糖对腌制鱿鱼进行涂膜处理,以感官评定、细菌总数、TVB-N值、TBA值及pH作为鲜度指标,探讨壳聚糖涂膜保鲜对延长腌制鱿鱼货架期的可行性及其效果。实验结果表明:经过壳聚糖涂膜处理的腌制鱿鱼比未经壳聚糖涂膜处理的有一定的防腐抗菌作用;不同浓度的壳聚糖涂膜处理中,2%壳聚糖是最佳的涂膜浓度。2%壳聚糖浓度(在室温光照条件下14d后)与空白组相比:感官评分高出4分,细菌总数低29%,TVB-N值低11%,TBA值低39%,pH低6.9%。     

Construction of a water-in-oil-in-water (W/O/W) double emulsion system based on oyster peptides and characterisation of freeze-dried products

In order to broaden the range of applications for oyster peptides in the food field, the amino acid composition of oyster peptide was analysed, after which the peptide sequence was identified using liquid-mass spectrometry technology. A W₁/O/W₂ double emulsion was prepared by the two-step shear emulsification method. The W₁/O/W₂ double emulsion was further freeze-dried after addition of alginate to obtain the final product, and the characteristics of the related product were analysed. The results show that oyster peptides are mainly composed of short peptides with molecular weights between 459.3 Da and 2716.3 Da. Polyglycerol polyrinoleate (PGPR) was selected as the emulsifier and added at 5% of the mass of the oil phase. The mass ratio of the oil phase to the water phase was O:W = 6:4, and optimal stability of the W₁/O emulsion was obtained by shearing and emulsifying for 2 min at 12 000 rpm. A superior W₁/O/W₂ double emulsion can be obtained by secondary emulsification in which the hydrophilic emulsifier Tween 80 was added at 0.8% (w/w) of the mass of the external water phase (W₂). The mass ratio of the emulsion to the external water phase was 5:5. The lyophilised product has good re-solubility, with the reconstituted emulsion maintaining the double-emulsion structure. Electronic nose results showed that the peculiar smell of the reconstituted emulsion was significantly lower than that of the oyster peptide solution. The results of this research provide a reference for the development and application of oyster peptides in the field of functional health foods.     

罗非鱼下脚料分离蛋白的制备及其性质研究

采用酸碱法(pH-shifting)提取罗非鱼下脚料蛋白,主要探讨提取的pH对提取蛋白的得率、分离蛋白的基本成分、溶解性、乳化性和分子量分布的影响。结果表明:在料液比1∶9(g/g)、pH 2.0、pH 3.0以及pH 12.0、pH 13.0条件下溶解,pH 5.5条件下沉淀,提取蛋白得率达52%以上。冷冻干燥制备罗非鱼下脚料分离蛋白粉,其蛋白含量高于85%(干基)。功能特性的研究显示,在pH12.0条件下提取的分离蛋白功能特性最好,其溶解度和乳化活性指数分别为60.80%和42.07 m2/g。SDS-PAGE电泳分析显示,不同pH条件下提取的罗非鱼下脚料蛋白的分子量分布差别不大,主要显示分子量为200 ku和44.3 ku的蛋白条带,分别是肌原纤维蛋白组分中的肌球蛋白和肌动蛋白,另有部分蛋白条带在14.30 ku,属于小分子的肌浆蛋白。     

湛江硇洲岛全缘马尾藻共附生抗菌活性菌的筛选与多样性分析

本文采用倾注平板法从湛江硇洲岛全缘马尾藻(Sargassum integerrimum)分离共附生细菌,分别以大肠埃希菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)和白色念珠菌(Candida albicans)作为指示菌,利用牛津杯法测定抗菌活性,并对分离到的抗菌活性菌进行形态观察、生理生化试验及分子生物学水平的鉴定与多样性分析。共分离到36株细菌,经形态观察与生化试验去重,筛选到具有抗菌活性的细菌11株。经过16S rRNA分析发现,11株抗菌活性细菌分属于细菌域的厚壁菌门(Firmicutes)和放线杆菌门(Actinobacteria)的5个科(Bacillaceae,Staphylococcaceae,Micrococcaceae,Microbacteriaceae,Dermabacteraceae)、5个属(Bacillus,Staphylococcu,Kocuria,Microbacterium,Brachybacterium),其中7株菌为Firmicutes门,占活性菌株的63.6%,并成为优势类群,同时发现4株潜在新种(菌株X21、X24、X31、X34)。研究表明,该岛全缘马尾藻中存在较为丰富的抗菌物质产生菌,并蕴藏着较多的微生物新类群。     

基于GC-MS鉴别活体太平洋牡蛎不同流通阶段气味特征变化

为揭示活体牡蛎在商业流通各环节风味品质变化规律,优化活品运输管理,提升牡蛎存活质量,本研究模拟太平洋牡蛎产业流通实际,采用固相微萃取-气相色谱-质谱联用技术对活体太平洋牡蛎暂养净化、诱导休眠、无水保活流通中挥发性风味物质种类及含量变化进行分析。结果显示：活体太平洋牡蛎组织中共鉴定出49种挥发性风味物质,主要由醛类、酮类、酯类、烃类、醇类、含氮含硫杂环类化合物构成;采捕后应激胁迫对其风味品质有较大影响,通过24 h暂养净化,牡蛎愉悦性风味化合物明显提升,刺激性气味化合物明显降低,脂质氧化得到明显的缓解;诱导休眠至保活流通阶段,牡蛎脂质氧化随保活流通时间的延长进一步加剧,挥发性风味物质总量呈缓慢积聚特征。气味活性值分析表明,己醛、庚醛、十一醛、(E)-2-壬烯醛、4-乙基苯甲醛、壬醛、(E)-2-癸烯醛、(E,E)-2,4-壬二烯醛、癸醛、(E)-2-辛烯醛、2-戊基呋喃、3-辛酮、2-壬酮是活体太平洋牡蛎流通中的关键风味物质,可以作为反映活体牡蛎生理状态的参考。主成分分析显示,前3个主成分累计贡献率为85.6%,可对不同流通阶段进行明显区分。研究表明,太平洋牡蛎采捕后通过暂养净化24 h...     

江蓠即食风味食品碱法脱腥工艺条件研究

以新鲜江蓠为原料,对即食风味食品制备过程中的碱法去腥技术进行了研究,探索碱处理温度、碱处理浓度、碱处理时间对去腥效果的影响。正交实验结果表明:最佳去腥工艺条件为:碱处理浓度为10%,处理时间为90min,处理温度为25℃,所制备的江蓠食品腥味较淡,颜色鲜绿自然,光泽度较好,弹性适中,爽脆感较好。