利用木质纤维素原料生产高附加值产品的技术前景

在过去的10年间,对生物质废料资源化利用的研究逐渐成为了热点。为实现生物质经济的可持续发展,必须对抽提、回收及合成工业应用的生物质产品进行研究。生物质废料的有效利用,尤其是木质纤维素原料（主要由纤维素、半纤维素以及木质素组成）的大规模应用必须通过创新性研究来实现。文中通过一种生物质精炼工艺路线介绍了木质纤维素生物质加工的最新进展,并进行了深入分析,同时,还在生物质精炼工厂范围内讨论和检验了现有工业生物质加工工艺。     

有机溶剂法分离木质纤维组分进展

本文简述了利用有机溶剂法分离木质纤维类生物质中纤维素、木质素和半纤维素的原理及应用,概括了有机溶剂法的优缺点,针对几种典型有机溶剂法分离技术进行了概述,并对有机溶剂法分离木质纤维组分进行了总结和展望。     

纤维素、半纤维素与木质素间相互作用研究进展

纤维素、半纤维素和木质素是木质纤维生物质细胞壁中的3种主要组分，其通过复杂的相互作用形成超分子网络结构，使木质纤维生物质具有优异的机械性能及抵抗物理、化学和微生物降解的能力，同时也导致生物质预处理和组分分离困难。本文总结了近年来关于纤维素、半纤维素与木质素间相互作用的研究进展，重点介绍了木质素与半纤维素之间的共价键、范德华力和静电作用等，以期在原子-分子水平上充分认识和了解细胞壁结构，为通过基因工程合成易降解的木质纤维原料，或寻找清洁高效的生物质精炼技术提供一定的理论指导。     

生物质精炼在制浆造纸工业的应用实例

传统的制浆造纸工业与现代的生物质精炼技术相结合,可以完全分离原料中的纤维素、半纤维素、木质素和挥发性抽出物。纤维素除用于生产纸浆以外,通过溶解体系发生均相反应,可以制造人造丝、甲基纤维素、醋酸纤维素等。从废液或预处理液中提取半纤维素和木素等生物质成分,通过转化进一步生产高附加值的产品,如乙醇、碳纤维、聚合物和生物柴油等,使传统的纸浆厂变成一个现代的纸浆生物质精炼联合加工厂,最终实现生物质资源的全组分利用和效益最大化,提高企业的盈利水平。     

木质素对纤维素酶水解抑制作用的研究进展与展望

木质纤维素原料作为新一代生物乙醇发酵的原料备受关注,但在实际生产制备过程中木质纤维素中木质素的存在对纤维素酶水解纤维素这一过程产生了抑制作用,限制了木质纤维素资源在生物乙醇发酵方面工业化规模的推广与应用。本文通过归纳近年来有关减少木质素对纤维素酶水解的抑制、提高酶水解效率的研究进展,明确提出了推动木质纤维生物质炼制实现工业化所需深入探索的策略和方向。     

木质生物质精炼预处理技术研究进展

木质生物质不仅可应用于制浆造纸工业,也可替代有限的石化资源用于生产化学品、合成材料和再生能源等,然而其结构的复杂性限制了其高效转化.预处理技术作为生物质精炼高效转化的关键步骤,已成为世界各国的研究热点.文章对物理法、化学法、物理-化学法和生物法预处理木质生物质技术的国内外研究进展进行了综述,对相应技术的处理效果进行了分析和总结,对预处理技术的发展及其基于制浆造纸工业相结合的前景进行了展望并提出了建议.     

木质纤维素的预处理及应用

木质纤维素主要包括纤维素、半纤维素、木质素3大类,本文对木质纤维素的各种组分结构作了系统综述。概述了纤维素类物质的预处理方法,主要包括物理法、化学法、生物法,并比较了几种方法的优劣点。介绍了木质纤维素实际生产运用的6个实例：木质素制备乙醇、乳酸、二甲醚,半纤维索类物质制备木糖醇,纤维素基重金属离子吸附材料,纳米纤维素晶须在纳米材料中的应用。     

生物质精炼技术与制浆造纸的结合

生物质精炼技术发展与应用是对传统制浆造纸产业转变发展方式的变革与创新,对造纸行业可持续发展具有战略意义。文章主要介绍了部分制浆造纸生物质精炼技术,包括半纤维素的分离纯化及利用、纤维素的高值化利用、黑液中木质素的分离提纯与利用、黑液气化等。     

酶解木质纤维素的预处理技术研究进展

木质纤维素为可再生生物质原料，采用酶解法以木质纤维素为原料制糖发酵生产乙醇，必须对木质纤维进行预处理。目前，对木质纤维素原料的预处理方法主要有物理法、化学法、物理化学法、生物法。本文对以上几种方法的研究进行了综述。（孙悟）     

含木质素的纤维素材料的制备研究进展

纤维素作为储量最丰富的生物质资源,具有良好的生物相容性和优异的力学性能,但其制备过程中需要从生物质中完全脱除木质素,造成了能源消耗,提纯步骤繁琐等问题。此外,木质素作为第二大生物质资源被丢弃,造成极大的资源浪费。含木质素的纤维素（LC）材料不但能够充分发挥两组分间的协同增效优势,还能显著提高生物质的资源利用率。文章综述了LC材料的制备方法,包括酸处理法、碱处理法、有机溶剂法和低共熔溶剂法,展望了LC制备技术的当下定位及发展前景,为生物质高效利用提供了理论依据。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.