Antioxidative and synergistic effects of bene kernel and hull oils during oxidation of virgin olive oil

Total amounts of conjugated diene hydroperoxides and carbonyl compounds of a virgin olive oil (VOO) and its purified form as affected by 0.1–6% w/w bene kernel (BKO) and hull (BHO) oils were monitored during 16 h heating at 180°C. The VOO was more prone to the production of off‐flavour carbonyl compounds than to the formation of conjugated diene hydroperoxides. The VOOs oxidative stability decreased significantly due to the removal of the indigenous antioxidative compounds. Oxidative stability, especially regarding the secondary oxidation, significantly improved with increasing concentrations of the BKO than with those of the BHO.     

The Role of Metal Hydroxide Complexes in Late Transition Metal‐Mediated Transmetalation Reaction: The Case of Gold

In gold chemistry, the hydroxide function on the metal center was observed to act as a potent transmetalation group facilitator when reacted with boronic acids leading to the exceedingly rapid formation of gold‐aryl bonds.     

Protein-binding approaches for improving bioaccessibility and bioavailability of anthocyanins

Color is an important characteristic of food. Over the last 15 years, more attention has been paid to natural colorants because of the rising demand for clean-label food products. Anthocyanins, which are a group of phytochemicals responsible for the purple, blue or red hues of many plants, offer a market advantage. In addition, anthocyanin-rich foods are associated with protection against cardiovascular disease, thrombosis, diabetes, cancer, microbial-based disorders, neurological disorders, and vision ailments. However, the real health value of anthocyanins, whether as a natural colorant or a functional ingredient, is dependent on the ultimate bioaccessibility and bioavailability in the human body. Many animal and human clinical studies revealed that, after intake of anthocyanin-rich foods or anthocyanin extracts, only trace amounts (< 1% of ingested content) of anthocyanins or their predicted metabolites were detected in plasma after a standard blood draw, which was indicative of low bioavailability of anthocyanins. Protein binding to anthocyanins is a strategy that has recently been reported to enhance the ultimate bioactivity, bioaccessibility, and bioavailability of anthocyanins as compared to anthocyanins delivered without a protein carrier. Therefore, in this review, we address anthocyanin properties in food processing and digestion, anthocyanin-protein complexes used in food matrices, and changes in the bioaccessibility and bioavailability of anthocyanins when bound into anthocyanin-protein complexes in foods. Finally, we summarize the challenges and prospects of this delivery system for anthocyanin pigments.     

离子阱质谱分析仪在研究气态配位化合物形成及配位平衡方面的应用

本研究利用离子阱质谱仪的碰撞诱导解离技术（collision-induced dissociation）和气态离子-分子反应（ion-molecule reaction）技术研究气态配位化合物的配位键形成,解离以及再平衡过程。实验发现,气相中配位化合物在被外来能量打断配位键后,可以捕获其它分子形成新的配位化合物,从而达到新的络合稳定平衡,并提出化学气相系统中配位新平衡的建立是基于金属配合物的热力学稳定性。实验结果表明,可以通过改变离子阱质谱仪的碰撞诱导解离过程中激发时间,研究配位化合物的热力学稳定性。     

Influence of non-ionic surfactant on electrostatic complexation of protein-coated oil droplets and ionic biopolymers (alginate and chitosan)

The purpose of this study was to examine the influence of a non-ionic cosurfactant (Tween 20) on the formation and properties of electrostatic complexes consisting of charged oil droplets and charged biopolymers. The mean droplet diameters in oil-in-water emulsions prepared using a membrane homogenizer were considerably larger when β-lactoglobulin (BLG) was used alone (≈8 μm), than when it was used in combination with Tween 20 (≈2 μm). The cationic oil droplets formed by membrane homogenization (4.0 μm pore size) were mixed with either alginate (anionic) solution (1% oil: 0–0.5% alginate: pH 3.5) or with alginate (anionic) and then chitosan (cationic) solutions (0.4% oil: 0.1% alginate; 0–0.2% chitosan: pH 4.5). The electrical characteristics, microstructure, and physical stability of the electrostatic complexes formed were determined. Under certain conditions multilayer emulsions consisting of oil droplets coated by alginate or alginate/chitosan layers were formed, whereas under other conditions microclusters consisting of aggregated oil droplets embedded within alginate or alginate/chitosan complexes were formed. The presence of the cosurfactant had a major impact on the electrical charge and dimensions of the electrostatic complexes formed. This study shows that various kinds of electrostatic complexes can be formed from charged oil droplets and charged biopolymers, and that their functional characteristics can be controlled using non-ionic cosurfactants.     

二苯并-18-冠-6及其配合物结构的理论研究

在捕获和输送碱金属离子时,冠醚的分子构型起着重要作用。利用密度泛函理论B3LYP方法,在6-31G(d)水平上对二苯并-18-冠-6及其配合物进行构型优化、频率、相互作用能等计算,得出了最稳定结构。研究表明,直径的匹配,配体的构象变化以及溶剂化效应都影响着二苯并-18-冠-6对离子的选择。     

分光光度法测定苦参碱配合物的组成

采用分光光度法测定了锌(Ⅱ)和苦参碱配合物的组成。以水为参比在341 nm处测定苦参碱-锌(Ⅱ)配合物的组成比。测得锌(Ⅱ)和苦参碱配合物的组成比为1∶1,与文献报道的一致。该方法简便,可靠,可作为测定苦参碱配合物组成的一种方法。     

钌及其配合物应用研究进展

钌及其配合物具有较好的催化活性及抗肿瘤活性,在化工及医学领域的应用较广泛。查阅大量相关资料,对其在催化方面及抗肿瘤等领域的研究现状进行综述。     

Theoretical Estimation of Acid Strength of Boron-Fluoride-Alcohol Complexes during Cationic Polymerization of Olefins

Abstract

The quantum-chemical investigations of ROH BRnF₃-n-complexes were carried out and their acidic strength determine as function of alcohols and ligand characteristics and the environment of the heteroatom B.