添加有机肥和葡萄糖对铜毒害旱地红壤微生物生物量的影响

在预培红壤中加入定量的有机肥和葡萄糖及不同浓度的Cu,25℃培养14d，测定了土壤微生物生物量C（Cmic),N(Nmic)。结果表明，存在有机肥和葡萄糖时，土壤中Cmic和Nmic随着Cu浓度的增加而降低；Cmic/Nmic随着Cu浓度的增加而增大。施加有机肥和葡萄糖的土壤中，在所有Cu处理浓度下，土壤中Cmic和Nmic均比未加有机物质处理高，特别是有机肥处理中土壤Cmic和Nmic均比其它处理高得多，说明有机肥可明显减轻Cu对土壤微生物生物量的毒性，同时也说明有机肥可提供微生物N源。不含Cu时，加入有机肥和葡萄糖导致土壤中Cmic和Nmic增加，其中有机肥明显。     

液相色谱电化学安培检测乳粉中的脂溶性维生素A, E和D3

利用维生素A、D3、E均有电化学活性的特点,采用电化学安培检测,建立了HPLC检测奶粉中的脂溶性维生素A、D3、E的新方法.流动相为甲醇∶水=95∶5(V/V),含0.05 mol/L高氯酸钠.检测器采用玻碳电极,直流安培模式(DC),氧化电位 1.3 V.方法检测限为:VA、VD3、-αVE、-γVE、-δVE分别为0.08、2.3、0.16、0.19、0.28ng.回收率分别为:90.2%~98.2%、91.2%~103%、92.7%~99.5%、92.6%~97.4%、90.7%~98.0%.同紫外检测比较,方法具有灵敏度高、抗干扰强的特点.     

Phosphorus and Energy Recovery from Manure and Digestion Residues

Abstract

Human and animal excrements, in particular manure, stand for a significant and undisputable source of plant nutrients and renewable energy. In Europe, only 36% of P-inputs to soils originate from primary resources (rock phosphate) whereas 63% come from animal and human excretions applied to cropland as manure, digestion residues and sewage sludge. Simultaneously these waste flows represent a potential hazard to human health and aquatic bodies because of pathogens and eutrophication. Management of these waste flows is far from being sustainable, in part due to the lack of efficient processing technologies. A cooperative InnoEnergy—EIT financed KIC Knowledge and Innovation Community—research project pursues development and demonstration of highly efficient technologies to overcome the constraints and to yield renewable phosphate fertilizers and energy from waste flows that may have a combined technical energy potential of 3,600 PJ/year and an annual phosphate recovery potential of 4.5–5.5 million tonnes (as P₂O₅) in Europe.     

Application of accelerated heteronuclear single quantum coherence experiments to the rapid quantification of monosaccharides and disaccharides in dairy products

Monosaccharides and disaccharides are important dietary components, but if insufficiently metabolized by some population subgroups, they are also linked to disease patterns. Thus, the correct analytical identification, quantification, and labeling of these food components are crucial to inform and potentially protect consumers. Enzymatic assays and high-performance anion-exchange chromatography with pulsed amperometric detection are established methods for the quantification of monosaccharides and disaccharides that, however, require long measuring times (60–180 min). Accelerated methods for the identification and quantification of the nutritionally relevant monosaccharides and disaccharides d -glucose, d -galactose, d -fructose, sucrose, lactose, and maltose were therefore developed. To realize this goal, the NMR experiments HSQC (heteronuclear single quantum coherence) and acceleration by sharing adjacent polarization (ASAP)-HSQC were applied. Measurement times were reduced to 27 and 6 min, respectively, by optimizing the interscan delay and applying non-uniform sampling. The optimized methods were used to quantify d -glucose, d -galactose, d -fructose, sucrose, and lactose in various dairy products. Results of the HSQC and ASAP-HSQC methods are equivalent to the results of the reference methods in terms of both precision and accuracy, demonstrating that these methods can be used to correctly analyze nutritionally relevant monosaccharides and disaccharides in short times.     

固相萃取-高效液相色谱法同时检测畜禽粪便中14种兽药抗生素

研究并优化了同时分析畜禽粪便中14种抗生素(四环素、磺胺、氟喹诺酮和大环内酯类)的加速溶剂萃取参数、固相富集净化程序、以及高效液相色谱分离和检测条件。结果表明,以1%乙酸(pH 2.6)作为流动相,在270 nm的检测波长下,14种抗生素能达到基线分离。3倍信噪比下,四环素、磺胺、氟喹诺酮和大环内酯类抗生素的检出限分别为35～90μg/kg,12～28μg/kg,9～17μg/kg及19μg/kg。加标浓度在1和10μg/g时,畜禽粪便样品经过50%甲醇的柠檬酸盐缓冲溶液提取,HLB固相萃取柱富集净化后,四环素、磺胺、氟喹诺酮和大环内酯类抗生素的回收率分别达到了58%～75%和66%～83%,74%～93%和91%～101%,74%～80%和80%～88%,85%和68%,相对标准偏差分别为6.2%～10.7%和7.8%～13.6,2.6%～10.2%和4.4%～13.2%,6.1%～12.5%和8.3%～14.6%,10.6%和12.3%。采用此方法对辽宁省部分规模化养殖场的猪粪、牛粪和鸡粪样品进行了检测。4类抗生素都有检出,浓度范围分别为0.75～22.34 mg/kg,0.10～1.71 mg/kg,0.38～4.46 mg/kg和0.23～0.35 mg/kg。     

Natural Polyphenols for the Preservation of Meat and Dairy Products

Food spoilage makes foods undesirable and unacceptable for human use. The preservation of food is essential for human survival, and different techniques were initially used to limit the growth of spoiling microbes, e.g., drying, heating, salting, or fermentation. Water activity, temperature, redox potential, preservatives, and competitive microorganisms are the most important approaches used in the preservation of food products. Preservative agents are generally classified into antimicrobial, antioxidant, and anti-browning agents. On the other hand, artificial preservatives (sorbate, sulfite, or nitrite) may cause serious health hazards such as hypersensitivity, asthma, neurological damage, hyperactivity, and cancer. Thus, consumers prefer natural food preservatives to synthetic ones, as they are considered safer. Polyphenols have potential uses as biopreservatives in the food industry, because their antimicrobial and antioxidant activities can increase the storage life of food products. The antioxidant capacity of polyphenols is mainly due to the inhibition of free radical formation. Moreover, the antimicrobial activity of plants and herbs is mainly attributed to the presence of phenolic compounds. Thus, incorporation of botanical extracts rich in polyphenols in perishable foods can be considered since no pure polyphenolic compounds are authorized as food preservatives. However, individual polyphenols can be screened in this regard. In conclusion, this review highlights the use of phenolic compounds or botanical extracts rich in polyphenols as preservative agents with special reference to meat and dairy products.     

高效液相色谱法比较3种固相萃取柱净化对乳品中8种抗生素残留检测的影响

对比了3种固相萃取柱(HLB柱、C18柱和PEP柱)对复杂乳品基质中目标物检测的影响,并建立了同时测定乳品中四环素类、β-内酰胺类及氯霉素等8种抗生素残留的固相萃取/高效液相色谱法。结果表明:HLB固相萃取柱的洗脱及净化效果较好,适用于复杂乳品基质的洗脱净化。在优化条件下,8种抗生素在5.0~100.0μg/L浓度范围内的线性关系良好(r20.999),检出限为0.09~0.84μg/kg,定量下限为0.32~2.23μg/kg。8种抗生素在不同加标浓度下(5,10,30μg/kg)的回收率为73.2%~93.3%,相对标准偏差(n=5)为1.4%~3.6%。研究结果表明,该方法适用于复杂乳品基质中8种不同种类抗生素的同时检测。     

Effect of Co-flowing Vapor during Vertical Falling-film Evaporation

A large number of industrial processes use falling-film evaporation to concentrate liquid products. This technology allows for small temperature differences during operation and is often significantly more energy efficient than other techniques. When processing dairy products, a reduction in the solvent fraction results in an increased product viscosity and may thus result in non-Newtonian features. The interaction between a co-flowing vapor that is produced during the evaporation process and the falling film is an important feature of the process. Few studies have accurately studied the effect of co-flow on evaporative falling films at high solid contents. In this work, an experimental study of the influence of co-flowing vapor on the heat transfer coefficient for a dairy product is presented as a function of both the solid content (from 10 to 50%) and the mass flow rate of the feed. The experimental set-up, consisting of a unique industrial pilot-scale evaporator, provides the possibility of obtaining results useful for realistic industrial conditions. An analytical approach that enables the simultaneous evaluation of heat transfer in every experimental condition, e.g., for Newtonian or non-Newtonian fluids and with or without co-flowing vapors, is presented.     

Water vapor adsorption onto activated carbons prepared from cattle manure compost (CMC)

Activated carbons were prepared from cattle manure compost (CMC) using zinc chloride activation. The structural and surface chemical characteristics of CMC-based activated carbons were determined by N₂ adsorption-desorption and Boehm titration, respectively. The water vapor adsorption properties of the prepared activated carbons with various pore structure and surface nature were examined, and the mechanism of water adsorbed onto activated carbon was also discussed. The results show that the adsorption of water vapor on carbons begins at specific active sites at low relative humidity (RH), followed by micropore filling at medium RH through the formation of pentamer cluster of water molecules in the narrow micropores. The water vapor adsorption capacity of activated carbon is predominantly dependent on its pore volume and surface area. Although capillary condensation is not the mechanism for water adsorption onto activated carbon, water can adsorb on narrow mesopore to some extent.     

Cocoa Shell as a Step Forward to Functional Chocolates—Bioactive Components in Chocolates with Different Composition

Chocolate is considered as both caloric and functional food. Its nutritional properties may be improved by addition of fiber; however, this may reduce polyphenols content. The aim of this research was to determine the influence of cocoa shell addition (as a source of fiber) and its combination with different ingredients (cocoa butter equivalents (CBE), emulsifiers, dairy ingredients) on polyphenols of dark and milk chocolates. Total polyphenol (TPC) and total flavonoid (TFC) contents were determined spectrophotometrically, identification and quantification of individual compounds by high pressure liquid chromatography and antioxidant capacity by ferric reducing antioxidant power (FRAP) assay. Results showed that even though addition of cocoa shell to chocolate results in reduced contents of TPC, TFC, and individual compounds, it is not significant compared to ones reported by other authors for commercial chocolates. Other ingredients influence determined values for all investigated parameters; however, additional research is needed to reveal exact mechanisms and implications.