Metal hydride materials for solid hydrogen storage: A review

Hydrogen is an ideal energy carrier which is considered for future transport, such as automotive applications. In this context storage of hydrogen is one of the key challenges in developing hydrogen economy. The relatively advanced storage methods such as high-pressure gas or liquid cannot fulfill future storage goals. Chemical or physically combined storage of hydrogen in other materials has potential advantages over other storage methods. Intensive research has been done on metal hydrides recently for improvement of hydrogenation properties. The present review reports recent developments of metal hydrides on properties including hydrogen-storage capacity, kinetics, cyclic behavior, toxicity, pressure and thermal response. A group of Mg-based hydrides stand as promising candidate for competitive hydrogen storage with reversible hydrogen capacity up to 7.6 wt% for on-board applications. Efforts have been devoted to these materials to decrease their desorption temperature, enhance the kinetics and cycle life. The kinetics has been improved by adding an appropriate catalyst into the system and as well as by ball-milling that introduces defects with improved surface properties. The studies reported promising results, such as improved kinetics and lower decomposition temperatures, however, the state-of-the-art materials are still far from meeting the aimed target for their transport applications. Therefore, further research work is needed to achieve the goal by improving development on hydrogenation, thermal and cyclic behavior of metal hydrides.     

脉冲强光处理对菜籽油品质的影响

为探索脉冲强光(IPL)处理对富含油脂食品的影响,采用能量为500 J的IPL对菜籽油进行照射,研究IPL处理对储藏过程中菜籽油氧化稳定性及相关成分的影响。结果表明,IPL处理可诱导菜籽油的氧化,增加总酚含量,降低α-生育酚含量,但其主要不饱和脂肪酸含量变化不明显(P0. 05)。IPL处理组和对照组菜籽油储藏过程中的氧化程度均随时间的延长而增加,但处理组菜籽油过氧化值(POV)和p-茴香胺值(p-AV)的变化比对照组缓慢。储藏32 d后,处理组菜籽油POV值、p-AV值和主要不饱和脂肪酸含量均显著低于对照组(P0.05),而总酚含量仍显著高于对照组,α-生育酚含量则与对照组相比无显著差异。IPL处理能延缓储藏期内菜籽油的氧化及酚类物质含量的下降。本研究为IPL技术用于富脂食品的加工提供参考。     

蒸发油气污染的生物控制技术探讨

生物降解气态有机污染物的研究是近年来发展起来的大气污染控制新领域。通过介绍生物降解气态有机污染物的基本原理，探讨石油储运过程中的蒸发油气污染运用生物控制技术的可行性，提出需要解决的问题和研究的重点。     

基于PLSR分析樱桃酒呈味物质与感官属性之间的相关性

以6种不同厂家生产的樱桃酒为研究对象,进行感官评价并利用高效液相色谱法鉴定出樱桃酒样品的33种特征呈味物质,并进行了主成分分析和聚类分析。结果显示,相同产地的樱桃酒聚集在一起成一类,不同产地的樱桃酒明显区分开来。通过偏最小二乘法对不同产地樱桃酒中特征呈味物质与感官属性之间的相关性进行研究,结果发现甜味与葡萄糖、蔗糖、果糖呈现出显著正相关;涩味与丝氨酸、苯丙氨酸呈显著正相关;苦味与咖啡酸、谷氨、丝氨酸、甘氨酸、苏氨酸、丙氨酸、缬氨酸、蛋氨酸、苯丙氨酸、异亮氨酸、亮氨酸、赖氨酸呈现显著正相关。     

柠檬果肉真空冻结过程中挥发性风味成分变化

目的：探索柠檬果肉真空冻结过程中挥发性风味成分的变化规律。方法：利用电子鼻（E-nose）和气质联用（GC-MS）技术分别对新鲜、真空冻结10,20,30 min的柠檬果肉样品的挥发性风味物质进行分析。结果：E-nose可从整体上分析柠檬果肉中不同类别的挥发性风味成分,主成分分析和线性判别分析可区分新鲜和不同冻结时间的样品;GC-MS分析发现真空冻结过程中柠檬果肉挥发性风味物质的种类和含量均显著下降（P<0.05）;柠檬果肉中的主要挥发性风味物质主要是烯烃类、醇类、醛类化合物,其在真空冻结过程中的损失均呈先快后慢的趋势,通过热图和聚类分析可将真空冻结过程中所出现的挥发性风味成分划分为四大类;真空冻结10 min后,D-柠檬烯损失率最高;真空冻结20 min后,烯烃类、醇类和醛类化合物含量下降较为显著,酮类化合物含量变化不明显;真空冻结30 min后,出现了2,4-二甲基苯甲醛和2,4-二叔丁基苯酚新生挥发性风味成分。结论：柠檬果肉中绝大多数挥发性风味成分在真空冻结过程中呈明显下降趋势,并有部分新物质生成。     

微波预处理对芝麻油风味、营养和安全品质的影响

本实验系统研究微波预处理对芝麻油风味、感官、营养和安全品质的影响,旨在为微波产香技术在芝麻油中的应用提供理论参考。芝麻籽经不同功率（0、180、360、540、720 W和900 W）微波预处理6 min,再经液压压榨制得芝麻油。利用溶剂辅助风味蒸发、顶空固相微萃取结合气相色谱-质谱-嗅闻技术在芝麻油中鉴定出91 种香气活性物质。芝麻油的杂环类气味物质（吡嗪、吡咯、吡啶、噻唑、噻吩和呋喃）总含量与微波功率呈正相关,羰基类气味物质（醛、酮和酯类）总含量随着微波功率的增大先升高后降低。随着微波功率的增大,芝麻油的烤芝麻味、坚果味、焦糊味、烟熏味和苦味感官强度逐渐增强,土腥味、木质味和生青味强度持续减弱。微波预处理芝麻籽的出油率（30.02%～31.93%）与功率呈正相关,显著高于生芝麻籽（24.89%）。微波预处理提高了芝麻粕的氮溶解指数（nitrogen solubility index,NSI）（由11.7%升至18.07%）和芝麻油中生育酚含量（由392.18 mg/kg增至462.92 mg/kg）,且最高NSI和生育酚含量分别出现在540 W和700 W微波预处理后。芝麻油中芝麻酚（13.01～15.78 mg/100 g）、杂环胺（33.19～143.88 ng/g）和多环芳烃（0.40～9.03 ng/g）的含量与微波功率呈正相关,其中多环芳烃和杂环胺的含量均未超过国家标准限量。综上所述,适度的微波预处理可以赋予芝麻油浓郁的香气,提高芝麻油的营养成分含量和氧化稳定性,同时提高芝麻粕蛋白的利用价值。因此,微波作为一种新型产香技术在芝麻油加工和芝麻粕蛋白的高值化利用中具有明显的优势和良好的应用前景。     

猪脂控制氧化及其香气成分GC-MS分析

文中以过氧化值(POV)、酸值(AV)、茴香胺值(P-AV)表征猪脂氧化状态,并确定生产优质猪肉味香精的脂肪控制氧化条件为:温度130℃,时间4h,此时油脂的过氧化值为341 meq/kg、酸值为1.4 mgKOH/g、茴香胺值为580。通过固相微萃取法(SPME)萃取油脂挥发性成分,气-质联用(GC-MS)分析猪脂控制氧化前后的产物,试验共检测出85种呈味物质,其中醛类物质20种,含量占香气成分总量的53.34%,(E,E)-2,4-癸二烯醛含量最高达到27.03%。此外还检测到酮类、醇类、烃类、呋喃、吡喃、吡啶类、δ-戊丁基内酯、γ-十二内酯等多种呈味物质。     

Antibiofilm effects of pomegranate peel extracts against B. cereus,B. subtilis,and E. faecalis

In this study, the antibacterial and antibiofilm properties of pomegranate (Punica granatum L.) extracts (PPLs) prepared by 10 g of pomegranate peels (PPL10) and 100 mL of different solvents (ethanol, methanol, and their acid combinations, and water) were investigated as sources of bioactive compounds against food-related bacteria. The antimicrobial activities of the extracts were measured by using agar well diffusion assay. The acid-treated extracts exhibited the highest antimicrobial activities (31–34 mm). The biofilm formations were assessed by using a microplate reader (570 nm) after crystal violet staining. The prevention and removal of bacterial biofilms were also evaluated by using extracts prepared by 5 g of initial pomegranate peel (PPL5) with the different solvents or 200 ppm chlorine solution. All PPL5 and PPL10 extracts diluted at different ratios inhibited and removed biofilms, and the highest antibiofilm effects were up to 80% by acid-treated extracts. In addition, PPL5s and PPL10s were as effective as or more effective than chlorine for the prevention of biofilms. Therefore, from an economical perspective the PPL5s could represent promising candidates as natural antibiofilm agents for food industry.     

Composition, quality control and antimicrobial activity of the essential oil of cumin (Cuminum cyminum L.) seeds from Bulgaria that had been stored for up to 36 years

The essential oil of seeds of cumin (Cuminum cyminum L.) from Bulgaria stored for more than 35 years was analyzed by physicochemical methods, GC, GC‐MS and olfactometry and its antimicrobial activity tested using different strains of microorganisms. More than sixty constituents of this cumin oil could be identified as essential volatiles, responsible for the pleasant fresh, clean, spicy (typical cumin‐like) odour of a high quality product. Cumin aldehyde (36%), β‐pinene (19.3%), p‐cymene (18.4%) and γ‐terpinene (15.3%) were the principal compounds found. Antimicrobial testing showed high activity of the essential C. cyminum oil against the mold Aspergillus niger, the Gram (+) bacteria Bacillus subtilis and Staphylococcus epidermidis as well as the yeast Saccharomyces cerevisiae and Candida albicans.