不同收割期坛紫菜挥发性成分分析

通过电子鼻和SPME-GC-MS 方法对不同收割期的坛紫菜的挥发性成分进行分析,电子鼻实验表明不同收割期的坛紫菜挥发性成分差异明显;SPME 萃取坛紫菜的挥发性成分,通过GC-MS 分别从一水、二水、三水和四水坛紫菜中分离鉴定出35、38、51 和55 种化合物,其中以醛酮类和烷烃类为主,8- 十七烯、壬醛和己醛是坛紫菜中主要的挥发性物质;实验结果还表明一水和二水坛紫菜挥发性成分变化较小,质量较稳定,三水和四水坛紫菜挥发性变化较大,因此一水和二水坛紫菜适宜开发作为食品。     

日韩两国紫菜产业分析及启示

简要叙述日韩两国紫菜产业发展历史,阐述日韩两国在紫菜产业发展中采取的政府扶持、计划生产、限制进口等现行产业政策,介绍了日、韩两国紫菜贸易流通体制和行业管理现状。进而分析世界紫菜业的产业前景,对中国紫菜产品出口日本应注重的问题进行探索,并对中国紫菜产业的可持续发展提出4点建议:(1)加强紫菜栽培卫生质量控制及预警体系建设;(2)加强紫菜交易市场规范化体系建设;(3)加强紫菜计划生产调控体系建设;(4)加强行业指导网络体系建设。     

Effects of Water Activity on the Lipid Oxidation and Antioxidants of Dried Laver (Porphyra) During Storage in the Dark

Lipid oxidation and antioxidant degradation in dried laver (Porphyra) were determined during storage at water activities (A_w) of 0.11, 0.30, 0.51, 0.75, or 0.89 in the dark at 40 °C for 15 d. Lipid oxidation was evaluated by measuring peroxide value (POV) and conjugated dienoic acid (CDA) contents, and fatty acid composition was analyzed by gas chromatography. Contents of polyphenols, tocopherols, and porphyran were determined by spectrophotometry, HPLC, and gravimetry, respectively. The POV and CDA contents of the dried laver lipids increased during storage as A_w increased from 0.11 to 0.30, 0.51, 0.75, and 0.89, whereas the relative content of eicosapentaenoic acid was decreased; however, the contents of polyphenols, α‐tocopherol, and porphyran in dried laver showed the reverse phenomena. Lipid oxidation and antioxidant degradation in dried laver sharply increased at an A_w of 0.51. Polyphenols, α‐tocopherol, and porphyran contributed to reduction of lipid oxidation in dried laver. The degree of lipid oxidation of dried laver was more dependent on the concentration of α‐tocopherol than that of either polyphenols or porphyran during storage in the dark. The results strongly suggest that the quality of dried laver can be improved by preserving tocopherols as much as possible while decreasing A_w during storage.     

用偏光显微镜解析界面层分子有序度

阐述了用偏光显微镜测量液晶盒中分子有序度分布的方法。采用楔形液盒获得了仅有十几个ｎｍ的界面层信息,并提出具有创意性的偏光解析方法。通过这一工作得出以下结论：在高分子膜表面通过摩擦过程获得的液晶取向排列,其界面子有序度为体内部序度的６０％以下,有序度远低于体内部;由于固体界面对液晶排列的影响,产生一个有序度连续变化的界面层,其厚度大约于体内部;由于固体界面对液晶排列的影响,产生一个有序度连续变化的界     

Characteristics of moisture-absorbing film impregnated with synthesized attapulgite with acrylamide and its effect on the quality of seasoned laver during storage

Moisture-absorbing film impregnated with synthesized attapulgite with acrylamide (ATPGAA) was developed. The effects of ATPGAA concentrations of 0.5%, 1%, 2%, and 4% (w/w) in a linear low-density polyethylene polymer (LLDPE) matrix on the film properties were determined by measuring the physical properties, the oxygen and water vapor barriers, and moisture absorbency. The 4% ATPGAA film had high moisture absorbing efficiency. A packaging system fabricated from ATPGAA-impregnated films was applied to a dried-seasoned laver to evaluate its change in quality during storage. Seasoned laver packaged with ATPGAA-impregnated films had significantly greater crispness in texture and a lower peroxide value during storage than that packed with LLDPE film. The surface color of the seasoned laver packaged by ATPGAA-impregnated films was more stable than the control film. This study shows that moisture-absorbing films could serve as a packaging system to improve the storage quality of moisture-sensitive products.     

养殖紫菜的退色现象与其色素及金属元素含量关系的研究

测定了正常生长和退色紫菜中的光合色素叶绿素、类胡萝卜素及藻胆色素蛋白，包括藻缸蛋白、藻蓝蛋白和变藻蓝蛋白的含量；同时对不同紫菜样品中的Fe、P等微量及常量元素进行了分析。计算了叶绿素a、藻胆色素蛋白与Fe、Zn、Mn、P等元素的相关系数，发现它们之间呈明显的正比例关系，其中Fe与以上色素的相关性最好。因为Fe是生物体内合成上述4类吡咯类色素所不可缺少的微量元素，所以在实验室内对退色紫菜进行了外源性添加Fe^3＋实验，发现该紫菜中的色素含量有明显提高。本文提出：与陆地植物的黄化病一样，缺少Fe等微量元素可能是造成紫菜退色现象的直接原因之一。     

铝型材挤压模具电加工后的低温处理

分析了电加工对铝型材挤压模具工作带表面组织、应力状态的影响．提出了在电加工后进行低温处理的工艺，以延长挤压模具的使用寿命．     

紫菜超细粉体加工技术及其在食品加工中的应用

本文介绍了紫菜超细粉体加工工艺及其在食品加工中的应用,比较了热风干燥、喷雾干燥和冷冻干燥对紫菜超细粉体色泽的影响.     

坛紫菜干品色差测定条件的优化研究

坛紫菜具有很高的营养价值,其品质与色泽密切相关,坛紫菜干品的色差研究有利于其优质化和标准化加工。以坛紫菜干品为研究对象,采用单因素和L₉(3⁴)正交试验确定色差最佳测定条件,以L^*、a^*、b^*值及变异系数为指标,研究光照强度、温度、湿度、背景色和坛紫菜干品片数对色差测定结果的影响。结果显示,坛紫菜干品色差测定的最佳条件为,光照强度为黑暗、温度为15℃、低湿度(40%以下)、白色背景及坛紫菜片数为4张,在该条件下坛紫菜干品的L^*、a^*、b^*值变异系数分别为0.41%、2.08%、2.07%。适宜测定条件有利于提高坛紫菜干品色差测定的稳定性,可为坛紫菜干品色差测定提供技术上的支持。