Methoxy poly(ethylene glycol)-grafted-chitosan based microcapsules: Synthesis, characterization and properties as a potential hydrophilic wall material for stabilization and controlled release of algal oil

Methoxy poly(ethylene glycol)-grafted-chitosan (mPEG-g-CS) was synthesized in an attempt to increase the water solubility of CS, and it was applied as wall material to microcapsulate algal oil (AO). Both Fourier transformed-infrared (FT-IR) spectra and solubility test confirmed that mPEG had been successfully grafted onto CS. The larger particles showed smooth surfaces, whereas smaller ones presented surface folds. The amount of free and total oil were 2.73 and 47.87 g/100 g, respectively, with high encapsulation efficiency of 94.30%. Fourteen fatty acids were detected in free algal oil (FAO) and microcapsulated algal oil (MAO), and the important fatty acids were preserved after microcapsulation. AO contained within microcapsules was protected from UV-light and heat compared with FAO. Release rate of AO was initially rapid and then followed by controlled release with the erosion mechanism playing a dominant role. The mPEG-g-CS proved to be a promising wall material with excellent solubility and film forming ability, and therefore supplied great potential applications in food industry.     

茁霉多糖在果蔬保鲜应用的研究

茁霉多糖是出芽短梗霉产生的细胞外多糖,一般都一蓝黑色素伴随着茁霉多糖一起产生,因此,出芽短梗霉俗称黑酵母。茁霉多糖一种无色无味的中性多糖,极易溶于水。具有安全性,无毒性,耐热性,耐酸碱性,耐盐性,粘性,可塑性,成膜性质等特性,具有广泛的应用前景。本实验将茁霉多糖制成茁霉多糖膜溶液,进行果蔬保鲜的研究。     

Optimization of Total Flavonoid Compound Extraction from Gynura medica Leaf Using Response Surface Methodology and Chemical Composition Analysis

Optimization of total flavonoid compound (TFC) extraction from Gynura medica leaf was investigated using response surface methodology (RSM) in this paper. The conditions investigated were 30-60% (v/v) ethanol concentration (X(1)), 85-95 °C extraction temperature (X(2)) and 30-50 (v/w) liquid-to-solid ratio (X(3)). Statistical analysis of the experiments indicated that temperature and liquid-to-solid ratio significantly affected TFC extraction (p < 0.01). The Box-Behnken experiment design showed that polynomial regression models were in good agreement with the experimental results, with the coefficients of determination of 0.9325 for TFC yield. The optimal conditions for maximum TFC yield were 55% ethanol, 92 °C and 50 (v/w) liquid-to-solid ratio with a 30 min extraction time. Extracts from these conditions showed a moderate antioxidant value of 54.78 μmol quercetin/g dry material (DM), 137.3 μmol trolox/g DM for 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 108.21 μmol quercetin/g DM, 242.31 μmol trolox/g DM for 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS(+)), respectively. HPLC-DAD-MS analysis showed that kaempferol-3-O-glucoside was the principal flavonoid compound in Gynura medica leaf.     

A novel carrier of radionuclide based on surface modified poly(lactide-co-glycolide) nanofibrous membrane

Electrospun nanofibrous membrane is an approved drug carrier. However, the radionuclide carrier used an electrospun membrane is rare. In this study, Poly(lactide-co-glycolide)(PLGA) nanofibrous nonwovens were prepared through electrospinning technology, and then surface modification of the nonwoven was performed to stably conjugate the radioisotope with the fibrous membrane. A novel PLGA nanofibrous nonwoven conjugated with radioactive yttrium ⁹⁰Y for tumor internal radiotherapy was prepared for the first time. Evaluation of the stability of the radioisotope indicated that the leakage of ⁹⁰Y from the PLGA membranes can be neglected after 24 h incubation in saline. The retention of ⁹⁰Y on the PLGA membrane was 75% when five half lives of ⁹⁰Y expired and the vast majority of radioactive decay had occurred. This labeled nanofibrous membrane function as a novel radio-medical appliance with excellent surface hydrophilic and mechanical properties that can be directly implanted into the lesions not only to locally kill the cancerous cells but also to play the anti-adhesion role at where surgical procedures have been made to remove the tumor tissue.     

功能低聚糖对植物乳杆菌ZDY2013发酵乳发酵特性及冷藏效果的影响

为探究功能低聚糖对植物乳杆菌ZDY2013发酵乳的发酵特点和冷藏期功能的影响,选取具有益生元特性的低聚木糖、低聚异麦芽糖及其组合物为发酵乳中碳水化合物,评价发酵乳中植物乳杆菌发酵特性和pH值变化,同时对发酵乳的持水性及冷藏期抗氧化活性进行解析。结果表明：植物乳杆菌能利用不同浓度功能低聚糖进行代谢;相比葡萄糖,发酵乳中添加低聚糖更有利于植物乳杆菌的生长,尤其是其组合物浓度为3.0%时,能显著提高发酵乳中活菌数及降低发酵乳pH值;冷藏期（21 d）内,各组发酵乳活菌数呈下降趋势,但均高于108 cfu/g,pH值在7 d后比较稳定,而持水性不断增强;发酵乳DPPH自由基清除能力在第7 d最强,而ABTS+和羟自由基的清除能力呈下降趋势,且添加同浓度的组合物优于葡萄糖。该研究结果将为功能低聚糖及植物乳杆菌ZDY2013在乳品开发中的应用提供理论依据。     

Thermal stability of N-polar n-type Ohmic contact for GaN-based light emitting diode on Si substrate

Thermal stability of N-polar n-type Ohmic contact for GaN light emitting diode (LED) on Si substrate was investigated. Al/Ti/Au were deposited as the contacts on the N-polar n-type GaN with and without AlN buffer layer on the surface, respectively, and both contacts exhibited Ohmic behaviors. The samples with AlN showed excellent Ohmic contact thermal stability when annealed below 700 °C, while the samples without AlN experienced serious degradation on electrical properties after being annealed in the temperature range of 250-600 °C. After the process of aging at 30 mA (155 A/cm²) and room temperature for 1000 h, operating voltage increase less than 0.05 V for LEDs with AlN but more than 0.45 V for LEDs without AlN. Therefore, we conclude that the existence of AlN buffer layer is a key of forming high stable Ohmic contact for GaN-based vertical structure LED on Si substrate.     

尼辛的特性及在啤酒酿造中的应用

对天然食品防腐剂———尼辛（Ｎｉｓｉｎ）的特性作了简要的论述。在啤酒酿造中添加尼辛的作用及使用方法也作了较详细的介绍     

产品创新设计的分析与构想

从我国产品设计现状出发,运用经济学和消费心理学的基本原理,分析了产品设计创新的必要性,并得出产品设计创新可以使产品更富有人性化,利于消费欲望的满足和增大产品附加值等功能的结论.在此基础上提出了今后产品创新设计的几点构想,即增强产品设计的创新意识,避免产品同质化,注重产品的生态设计,培养高素质的创新人才.