不同植物材料对烟草甲的引诱效果分析

为了减少烟草加工、贮存、流通等环节中烟草甲虫的为害,以10种具有不同特征气味的植物样品(辣椒、花椒、陈皮、香叶、白豆蔻、甘草、当归、白芷、罗汉果和绿茶)为材料,采用昆虫四臂嗅觉仪进行植物材料粉末及其提取物(甲醇、乙醇、正己烷单一溶剂提取物及甲醇正己烷、乙醇正己烷组合溶剂提取物)对烟草甲成虫引诱活性的试验。结果表明:辣椒、罗汉果、白芷、绿茶粉末对烟草甲成虫的引诱活性较高,引诱指数均达45%以上。在这4种植物材料单一溶剂提取物中,辣椒正己烷提取物、绿茶乙醇提取物的作用效果较好,引诱指数在40%以上。在植物组合溶剂提取物中,辣椒两种组合溶剂提取物均表现显著引诱效果,引诱指数分别为56.42%和67.46%,明显高于单一溶剂提取物;绿茶和罗汉果乙醇正己烷提取物的引诱活性优于甲醇正己烷提取物,也优于其单一溶剂提取物。     

Cultivation and downstream processing of microalgae and cyanobacteria to generate protein-based technofunctional food ingredients

Abstract

Microalgae are unicellular microorganisms that can be rich in proteins and are therefore a valuable ingredient in different foods. So far microalgae are mainly utilized in foods in low concentrations as a whole-cell ingredient even though it is known that proteins extracted from microalgae can possibly posess various technofunctional properties, such as high protein solubility, emulsification, foaming, and gelation properties. The widespread usage of protein-rich ingredients obtained from microalgae is for the most part prevented by the high price of the biomass, the lack of efficient downstream processes, and the adverse taste. The aim of this review is to give insights into the fundamental properties of the growth and processing of microalgae, highlight the advantages of microalgae ingredients and show potential applications based on the technofunctional, nutritional and sensory properties that were reported. Moreover, the existing challenges and knowledge gaps that hinder the application of microalgal proteins in foods are discussed.     

An active steganalysis approach for echo hiding based on Sliding Windowed Cepstrum

This paper presents an active steganalysis technique for echo hiding (EH). This approach can differentiate stego audios (with hidden message) from nature ones (without hidden message), and then extract sequential EH messages in stego audios without prior knowledge about the EH technique. The procedure of this algorithm can be simplified as follows: (i) Sliding Windowed Cepstrum (SWC) is obtained by employing a Sliding Window (SW) to move over the audio signal sample by sample. (ii) The echo detector is designed based on statistical analysis of the Cepstrum Peak Location Aggregation Degree (CPLAD). (iii) For stego signals, both echo delay and the range of segment length are estimated by exploring the changing rule of the SWC. (iv) The accurate estimation of segment length and synchronism position is acquired by the grid search algorithm. (v) Finally, the binary secret message can be extracted using the estimated parameters in the previous steps. The proposed method has been implemented and tested to extract the message which is embedded into audio clips by using EH techniques with different kernels. The experimental results show that the accuracy of extraction is no less than 90% when attenuation is greater than 0.45.     

Enhancing exterior durability of jack pine by photo-stabilization of acrylic polyurethane coating using bark extract. Part 1: Effect of UV on color change and ATR–FT-IR analysis

Heat-treated wood is a value-added product but its exposure to various environmental factors leads to discoloration of wood surface due to the photochemical reactions. Discoloration has become an important economic problem for wood industries since product specifications are now more demanding. In addition, stricter environmental legislations necessitate the development of environmentally friendly transparent coatings with minimal use of chemicals which balances aesthetic and protection. In this study, the acrylic polyurethane coating was improved with the addition of natural antioxidant (bark extract) and lignin stabilizer alone or in combination to enhance the resistance of this coating to different weathering factors. An accelerated aging test was conducted with the aim of comparing the acrylic polyurethane coatings containing different additives with the commercially available pigmented solvent borne coating used by industry and organic UV absorbers. The modifications in chemical structure of coatings were characterized by ATR–FT-IR analysis. The color change data showed that the coating containing bark extract was the most effective and performed better than the industrial coating. However, the visual assessment showed that the coating containing bark extract and lignin stabilizer had the best performance. FT-IR analyses suggested that the chain scission reaction took place throughout the weathering but its effect was not significant for any of the coatings.     

Macromolecular structure of water-extractable arabinoxylans in endosperm and wholemeal rye breads as factor controlling their extract viscosities

Viscosity is one of the most important attributes of rye-based products related to some health benefits. To identify the factors affecting arabinoxylan-dependent extract viscosity (AX-EV) of rye bread, the structural features of water-extractable arabinoxylans (WE-AXs) and their ammonium sulphate precipitated subfractions were investigated in breads with varied viscosities. Also, an endoxylanase activity in the starting flours was examined. The HPSEC-RI profiles revealed the higher extent of AX depolymerisation in whole-meal bread (WMB) when compared to that in endosperm bread (EB), resulting in its lower AX-EV. This was mostly related to lower molecular weight of the parent WE-AX fraction with distinctly lower proportion of 2-Xylp in the chain. The AX-EV of rye bread decreased with decreasing proportion of AX-I, the major subfraction with 3-Xylp as only branching site. The endoxylanase activity was at least two times lower in endosperm flour than that in WM and negatively correlated with the AX-EV of WMB. The importance of densely substituted AX subfractions with exclusively 2-Xylp and 2,3-Xylp branches, protecting the AX-I from enzymic degradation during bread-making, has been evidenced.     

基于非平稳噪声估计的改进谱减语音增强算法

传统的谱减法无法有效地抑制实际语音通信中的非平稳噪声,为了进一步提高谱减法的去噪性能,提出了一种改进的噪声估计算法,首先将带噪语音的功率谱按照Bark频率进行子带划分,然后分别在每个子带内利用改进的最小统计量控制递归平均方法跟踪噪声的变化,从而在准确估计非平稳噪声的功率谱的同时减少计算量。将该算法应用到谱减法中,并与传统的增强型谱减法进行对比实验,实验结果表明：改进的谱减法能够更好地去除各种非平稳噪声,而且能够有效抑制“音乐噪声”,使得增强后的语音具有更好的音质。     

基于风洞模拟的车身气密性特性分析

针对中级乘用车车身气密性和车内空气流动性能进行试验和分析。这些试验是基于全尺寸风洞完成的,包括模拟静态及动态外部气流;测试涵盖了车身漏气当量孔、车身气密性及校正曲线、空调鼓风机风量测定等。     

广玉兰花精油的化学成分、抗氧化及抑菌活性分析

用乙醚为溶剂索氏提取广玉兰花精油。气相色谱-质谱联用仪(GC-MS)分离并分析鉴定广玉兰花精油成分及相对含量;鉴定出43个化合物,占精油总量的95.49%。DPPH自由基清除法测定精油的抗氧化活性;广玉兰精油有很强的清除DPPH自由基的能力,当质量浓度达到20μg/m L时,去除率与抗坏血酸相当。抑菌圈法和平板菌落生长法测定精油的抑菌抗菌活性;广玉兰花精油对细菌、真菌均有抑制作用,特别是对红酵母有强的抑制作用,当培养基中精油质量浓度为5.00 mg/m L时能完全抑制培养基中的红酵母生长。广玉兰花精油用于食品工业不仅可作香料还具有食品防腐保鲜效果,具有一定的开发和利用价值。     

面罩语音质量评价算法适用性研究

针对语音编码的音质评价算法性能已十分明确,但对于面罩语音不一定适用。讨论了语音质量评价算法对空气语音与面罩语音在不同噪声环境下的适用性。采用主观意见得分和三种客观评价测度对多种信噪比的带噪语音和增强语音进行评价,包括分段信噪比、改进的巴克谱失真（MBSD）和语音感知质量评价（PESQ）,根据与主观评价的一致性判断客观评价方法的适用性。增强算法采用维纳滤波法和对数谱最小均方误差法（LSA-MMSE）,噪声采用粉红噪声、海浪噪声。仿真结果表明,语音质量评价算法的适用性与语音类型、信噪比、背景噪声、增强算法种类有关。粉红噪声环境下,PESQ不适合评价经维纳滤波增强的空气语音;MBSD算法只适用于评价经LSA-MMSE增强的面罩语音。海浪噪声环境下,PESQ适用于评价面罩语音,MBSD不适合评价面罩语音。     

紫皮甘蔗色素的提取及理化性质的研究

从甘蔗中提取食用色素,并对甘蔗色素的提取方法和基本性质进行研究。该色素的理化性质表明色素的最大吸收波长为535nm,在PH3—11都能稳定存在,有较好的耐热性,但不耐光照,Mg2 、Ca2 、S2 等离子对该色素无不良影响,且耐氧化能力一般。但色素有较好的耐还原能力。Vc等食品添加剂溶液的加入会使色素增色。