Foam fractionation for effective recovery of leaf protein from alfalfa (Medicago sativa L.)

ABSTRACT

Foam fractionation for recovering leaf protein from alfalfa (Medicago sativa L.) has been investigated. The extraction yield of alfalfa leaf protein (ALP) from the dried alfalfa leaves reached 71.90% under the extraction conditions of pH 8.0, temperature 70°C, and extracting time 40 min. For strengthening foam drainage at room temperature, a novel foam fractionation column with a cross-internal component covered superhydrophobic coating was developed. By using the extraction liquor as the feeding solution, a two-stage foam fractionation had been performed. Under the suitable operation conditions, the enrichment ratio and the recovery percentage of ALP were 4.33 and 89.0%, respectively.     

HPLC同时测定胡黄连中香草酸、阿魏酸和肉桂酸

建立了一种采用Shim-pack C18-ODS柱,以乙腈-0.05%磷酸溶液(13∶87)为流动相,检测波长为290 nm,同时测定胡黄连中三种苷元有机酸的反相高效液相色谱方法.香草酸、阿魏酸和肉桂酸的线性范围分别为14.0～210.0 ng(R=0.9996)、52.0～520.0 ng(R=0.9995)和6.0～90.0 ng(R=0.9993),平均回收率分别为96.6%、98.9%和97.4%.     

胺类化合物合成与应用研究进展

主要依照烃基的不同,分类介绍胺类化合物的合成研究现状,详述了脂肪胺、芳香胺的合成。阐述了胺类化合物在矿物浮选、湿法冶金及废水处理等工业应用的进展,并由此提出胺类化合物未来研究的发展趋势。     

Effects of ferulic acid,an allelopathic compound,on leaf expansion of cucumber seedlings grown in nutrient culture

Cucumber seeds and seedlings at various ages (7–19 days old) were treated with a single treatment or multiple treatments (at 2-day intervals) of ferulic acid in nutrient culture. Ferulic acid treatments of cucumber seeds during stages of germination and radicle growth did not significantly reduce subsequent seedling growth. Ferulic acid treatments to seedlings reduced leaf area, leaf expansion, and dry weight of cucumber seedlings. Pretreatment of seeds and seedlings with 0.1 or 0.2 mM ferulic acid did not modify the effects of a single 1 mM ferulic acid treatment on leaf expansion when a single treatment was given at various times to seedlings ranging from 7 to 19 days of age. Treatments of 1mM or greater induced rapid wilting of leaves, but visible recovery occurred within 24–48 hr and subsequent treatments did not cause wilting. Once seedlings were removed from ferulic acid treatments, leaf expansion resumed. The magnitude of recovery depended on the concentration of ferulic acid, frequency of ferulic acid application and age of the seedling. Mean relative rates of leaf expansion recovered rapidly even in the presence of ferulic acid. Recovery of leaf expansion after ferulic acid treatments was faster for seedlings grown in an adequate nutrient environment than for seedlings grown in a limited nutrient environment. Ferulic acid disappeared from nutrient solutions with time, and two microbial metabolic products of ferulic acid (i.e., vanillic and protocatechuic acid) were identified in nutrient solutions.Paper No. 9256 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the Agricultural Research Service and does not imply its approval to the exclusion of other products that may be suitable.     

邻氨基苯甲酸与氯化稀土配合物的固相合成及性质研究

应用固相反应法合成了稀土氯化物与邻氨基苯甲酸的配合物。对配合物进行了组成分析及热谱分析,确定了配合物组成为[RE(LH)2(L)C12]·6H2O(RE:Nd,Eu,Tb;LH:C6H4(NH2)COOH;L:C6H4(NH2)COO-)。通过IR光谱、紫外光谱及摩尔电导的测定推测了配位情况。溶解性实验表明配合物可溶于乙醇,但不溶于水。荧光光谱实验表明,固相反应合成的Tb3+配合物有较好的荧光性能。粒径测量表明:固相合成的配合物[Nd(LH)2(L)Cl2]·6H2O达到纳米级水平。     

Optimization of microwave-assisted extraction of bioactive compounds from pistachio (Pistacia vera L.) hull

ABSTRACT

Phenolic compounds were extracted from pistachio hull using microwave-assisted solvent extraction (MASE). The effects of four parameters, microwave power, extraction time, solvent to sample ratio, and ethanol concentration were evaluated. The extraction conditions were optimized by response surface methodology to enhance the total phenolic content (TPC). Optimal conditions were found as 140 W microwave power, 4.5 min extraction time, 19:1 (v/w) solvent to sample ratio, and 56% ethanol concentration to get maximum TPC (62.24 mg GAE/g dry hull). Also, MASE was compared with conventional solvent extraction (CSE) and MASE gave higher TPC, yield, and antioxidant activity.     

Phenolic acids affect photosynthesis and protein synthesis by isolated leaf cells of velvet-leaf

The effects ofp-coumaric, ferulic, chlorogenic, and vanillic acids on photosynthesis and protein synthesis by isolated leaf cells of velvetleaf (Abutilon theophrasti Medik) were investigated. Photosynthesis and protein synthesis were measured in cell suspensions by the incorporation of¹⁴CO₂ and [¹⁴C]leucine, respectively. None of the tested phenolic acids except vanillic reduced photosynthesis by more than 50% at the highest concentration and 30 min of incubation. At 100M concentrations and 60-min incubation periods,p-coumaric, ferulic, chlorogenic, and vanillic acids inhibited photosynthesis by 33, 37, 57, and 65%, respectively. Ferulic acid was the most inhibitory to protein synthesis and reduced the incorporation of [¹⁴C]leucine by 50% at about 1.0M after 60 min of incubation. At the highest concentrations tested in this study, vanillic and ferulic acids were inhibitory to photosynthesis and protein synthesis, respectively, whereas chlorogenic andp-coumaric acids did not inhibit either physiological process. The maximum inhibition of protein synthesis by chlorogenic acid was 19% and by vanillic acid was 28% at 100M concentrations. Chlorogenic, vanillic, andp-cou-maric acids at 0.1M caused increased protein synthesis over the untreated control. Overall, photosynthesis was more sensitive than protein synthesis to the four phenolic acids tested.Florida Agricultural Experiment Station Journal Series No. 9228.     

Inhibition of cucumber leaf expansion by ferulic acid in split-root experiments

Experiments were conducted to determine how the proportion of a root system in contact with an allelopathic compound may affect seedling responses. Cucumber seedlings grown in a split-root nutrient culture system were given either single (1 mM) or multiple applications (0.5 mM) of ferulic acid. Seedlings receiving single applications were left in the treatment solutions for two days and then harvested, while seedlings receiving multiple applications had their solutions changed every other day for a total of three changes. Leaf areas were determined daily starting with the initial ferulic acid treatment. Mean absolute and mean relative rates of leaf expansion were inversely related to the proportion of the root system in ferulic acid solution. Leaf expansion was inhibited primarily during the first 24 hr after each treatment. A partial recovery of growth occurred during the second 24-hr period following each treatment. Root length was reduced by ferulic acid. These results suggest that information on root and allelochemical distribution in soils is important when assessing the potential of allelopathic interactions between plants.Paper No. 11940 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina 27695-7643. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service of products named, nor criticism of similar ones not mentioned.     

Inhibition of copper corrosion in aerated hydrochloric acid solution by amino-acid compounds

The effect of two amino-acid compounds, dl-alanine and dl-cysteine, on copper corrosion in an aerated 0.5 mol l⁻¹ HCl solution was studied by weight-loss measurements, potentiodynamic polarisation curves, and electrochemical impedance spectroscopy. A conventional benzotriazole (BTA) inhibitor was also tested for comparison. dl-cysteine was shown to be the most effective inhibitor among those tested inhibitors. Potentiodynamic polarisation results revealed that both the dl-alanine and dl-cysteine acted as an anodic inhibitor; however, dl-cysteine, in particular, was more effective, as it strongly suppressed anodic current densities. The improved inhibition efficiency of dl-cysteine in the 0.5 mol l⁻¹ HCl solution was due to its adsorption on the copper surface via the mercapto group in its molecular structure.     

直接缩聚合成聚乳酸研究进展

聚乳酸是一种性能优良的完全生物降解塑料,产品价格高是其进入市场的重要障碍,通过直接缩聚法有望能合成低 成本的聚乳酸。综述了溶液缩聚及直接熔融缩聚、熔融缩聚-扩链、熔融缩聚-固相聚合合成聚乳酸的研究进展。展望了直接 缩聚法合成聚乳酸的前景。     

Production of mustard protein isolates from oriental mustard seed (Brassica juncea L.)

A membrane-based process to produce protein isolates from seeds of oriental mustard (Brassica juncea) was developed by modifying a method originally developed for rapeseed. The optimized process consisted of extraction at pH 11, ultrafiltration with concentration factor 4, diafiltration with diavolume 3, and precipitation at pH 5. The process, based on defatted oriental mustard seed containing 45–50% protein, recovered 81% of the protein in useful products: 47.3% in precipitated protein isolate (PPI), 3.8% in soluble protein isolate (SPI), and 13% in meal residue. Mass yields were 21.9% in PPI, 2.8% in SPI, and 38.4% in meal residue. The losses in the system included ∼10% loss of nonprotein nitrogen, and <9% into permeate and transfer losses. The PPI compared favorably with soy protein isolate in typical meat products in terms of color, texture, and flavor. The work confirms that oriental mustard is a potentially useful source of edible protein.     

Volatile compounds from the interdigital gland of reindeer (Rangifer t. tarandus L.)

The isolation, identification, and synthesis of volatile compounds from the interdigital gland of reindeer (Rangifer t. tarandus L.) are reported. Two of the major constituents have been identified as 1-hydroxy-7-methyl-3-octanone and 7-methyl-1-octen-3-one.     

Interactions oftrans-cinnamic acid,its related phenolic allelochemicals,and abscisic acid in seedling growth and seed germination of lettuce

Phenolic compounds have been identified as the most common allelochemicals produced by higher plants. Inhibitions of cinnamic acid, its related phenolic derivatives, and abscisic acid (ABA) on seedling growth and seed germination of lettuce were studied.trans-Cinnamic acid, ando-,m-, andp-coumaric acids inhibited the growth of etiolated seedlings of lettuce at concentrations higher than 10^–4 M and seed germination above 10^–3 M. Coumarin inhibited seedling growth and seed germination at 10^–5 M or above. Chlorogenic acid inhibited seedling growth above 10^–4 M, but did not inhibit seed germination at 10^–5–5×10^–3 M. Low concentrations (below 10^–3 M) of caffeic and ferulic acids promoted the elongation of hypocotyls, but higher concentrations (over 10^–3 M) inhibited seedling growth and seed germination. These phenolic compounds and abscisic acid had additive inhibitory effects both on seedling growth and seed germination. The inhibition on lettuce was reversed by caffeic and ferulic acids at concentrations lower than 10^–3 M except for the inhibition of germination by coumarin. These results suggest that in naturetrans-cinnamic acid,o-, m-, p-coumaric acids, coumarin, and chlorogenic acid inhibit plant growth regardless of their concentration. However, caffeic and ferulic acids can either promote or inhibit plant growth according to their concentration.     

纳米H_3PW_(12)O_(40)/SiO_2复合杂多酸催化合成乙酸正己酯

以纳米二氧化硅为载体,采用溶胶-凝胶法负载磷钨酸,以冰乙酸、正己醇为原料,纳米H3PW12O40/SiO2复合杂多酸为催化剂,考察原料配比、催化剂用量、反应时间、反应温度等因素对酯化反应的影响,同时也考察了催化剂循环使用的情况。实验表明,纳米H3PW12O40/SiO2复合杂多酸催化剂是合成乙酸正己酯的良好催化剂,其最优合成条件为:纳米H3PW12O40/SiO2复合杂多酸催化剂用量约为反应酸醇配料总质量的2.5%,酸醇配比为1∶1.4,反应时间1 h,反应温度130℃,产率达89.72%。     

Characterization of High-Value Bioactives in Some Selected Varieties of Pakistani Rice (Oryza sativa L.)

The present study reports the composition and variation of fatty acids, sterols, tocopherols and γ-oryzanol among selected varieties namely Basmati Super, Basmati 515, Basmati 198, Basmati 385, Basmati 2000, Basmati 370, Basmati Pak, KSK-139, KS-282 and Irri-6 of Pakistani rice (Oryza sativa L). Oil content extracted with n-hexane from different varieties of brown rice seed (unpolished rice) ranged from 1.92% to 2.72%. Total fatty acid contents among rice varieties tested varied between 18240 and 25840 mg/kg brown rice seed. The rice tested mainly contained oleic (6841-10952 mg/kg) linoleic (5453-7874 mg/kg) and palmitic acid (3613-5489 mg/kg). The amounts of total phytosterols (GC and GC-MS analysis), with main contribution from β-sitosterol (445-656 mg/kg), campesterol (116-242 mg/kg), Δ(5)-avenasterol (89-178 mg/kg) and stigmasterol (75-180 mg/kg) were established to be 739.4 to 1330.4 mg/kg rice seed. The content of α-, γ- and δ-tocopherols as analyzed by HPLC varied from 39.0-76.1, 21.6-28.1 and 6.5-16.5 mg/kg rice seed, respectively. The amounts of different γ-oryzanol components (HPLC data), identified as cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate and β-sitosteryl ferulate, were in the range of 65.5-103.6, 140.2-183.1, 29.8-45.5 and 8.6-10.4 mg/kg rice seed, respectively. Overall, the concentration of these bioactives was higher in the Basmati rice cultivars showing their functional food superiority. In conclusion, the tested varieties of Pakistani rice, especially the Basmati cultivars, can provide best ingredients for functional foods.     

Effect of row space and irrigation on seed composition of Turkish sesame (Sesamum indicum L.)

The effect of row space (RS) and irrigation (IR) on total protein, total oil, and fatty acid composition of Harran-grown sesame seed was studied. Total oil content of sesame varied from 46.4 to 51.5%. The oil and protein contents were significantly different among treatments (P<0.01) in 1998 and 1999. IR affected oil content significantly (P<0.01) in both years, and RS had no significant effect. The protein content was significantly influenced by RS and IR at P<0.05 and P<0.01, respectively. RS 70 cm had the highest protein content followed by RS 60, 50, and 40 cm, respectively. IR every 24th day resulted in the highest level of protein, followed by 18th-, 12th-, and 6th-day irrigation, respectively. Correlation coefficients between protein and oil content were −0.34 in 1998 and −0.59 in 1999. RS (P<0.05) and IR (P<0.01) influenced oleic and linoleic acid contents significantly. Interactions of RS and IR were also found to be significant (P<0.05) over the oleic and linoleic acid levels.     

Effects of ferulic acid,an allelopathic compound,on net P,K, and water uptake by cucumber seedlings in a split-root system

Since distribution of allelopathic compounds in soils is highly variable, injurious effects by such compounds should be related to the frequency of contact with roots. Experiments were conducted to determine how P, K, and water uptake of cucumber seedlings were affected as the fraction of roots in contact with ferulic acid (FA) was increased. Seedlings were grown in Hoagland's nutrient solution for 14 days and then transferred to 0.5 mM CaSO₄ solution for 24 hr before being placed into a split-root culture system. The containers in the system were filled with 0.5 mM concentrations of KH₂PO₄ and CaSO₄ or 0.5 mM concentrations of KH₂PO₄, CaSO₄, and ferulic acid (FA). Net uptake of P by seedlings (milligrams per seedling) decreased in a curvilinear (concave) manner as the fraction of the roots in contact with FA increased. Net uptake of K (milligrams per seedling) and water (milliliters per seedling) by seedlings decreased linearly as the fraction of the roots in contact with FA increased. Net uptake of P, K, and water by seedlings was reduced 57, 75, and 29%, respectively, when the whole root system was exposed to FA. Net P and K uptake of roots (milligrams per gram root fresh weight) not in contact with FA decreased in a linear and curvilinear (convex) manner, respectively, as the fraction of roots in contact with FA increased. Net P and K uptake of roots in contact with ferulic acid increased in a linear and curvilinear (convex) manner, respectively. Net water uptake of roots (milliliters per gram root fresh weight) not in contact with FA increased in a curvilinear (concave) manner as the frequency of the roots in contact with FA increased. Net water uptake of roots in contact with FA did not show a trend. Transpiration (milliliters per square centimeter) was reduced in a linear manner as the fraction of roots in contact with FA increased. A very slight compensation by roots not in contact with FA for roots in contact with FA was observed for net water uptake rates. No compensation for P and K uptake rates was observed.Paper Mo. 12421 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina 27695-7643. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service of the products named, nor criticism of similar ones not mentioned.     

Nitrogen requirements of corn (Zea mays L.) as affected by monocropping and intercropping with Alfalfa (Medicago sativa)

Intercropping perennials with corn has the potential to improve utilization of the growing season over monocropping corn in regions where a substantial portion of the growing season is too cool for corn growth. The biomass potential and fertilizer N requirements of monocropped corn (Zea mays) grown using conventional tillage were compared with those of corn intercropped with alfalfa (Medicago sativa) in 1987 and 1988. The intercropped alfalfa was harvested once prior to planting the corn each spring. Rotation effects on and N fertilizer requirements for monocropped corn following these treatments and also following monocropped alfalfa, were evaluated in 1989 and 1990. During the two years of intercropping for which data is presented, the critical intercropped corn biomass (13.05 Mg ha^–1) estimated using a quadratic-plus plateau model, was close to the monocropped corn biomass (13.01 Mg ha^–1), but an estimated 83 kg ha^–1 more N was required for intercropped corn to reach the critical biomass. Total biomass (intercropped corn and alfalfa) was 25% greater than that of the monocropped corn, and the total N uptake was 55% greater than that by monocropped corn over the two- year period. After rotation to monocropped corn using conventional tillage in 1989, corn biomass averaged over N rates following intercropping or monocropped corn was lower (P=0.01) than following monocropped alfalfa. Critical corn biomass estimated was highest following alfalfa and lowest following monocropped corn, and more N fertilizer was required to attain the critical biomass under continuous monocropped corn in 1989. Corn yields and N uptake values in 1990 were not significantly different among the cropping systems. The N fertilizer replacement values due to intercropping decreased from above 90 kg N ha^–1 in the first year of rotation to less than 40 kg N ha^–1 in the second year of rotation. Considering the higher potential for total biomass production and rotation benefit, intercropping is a viable alternative to conventional corn monoculture for forage production.     

Aggregation of larvae ofBlattella germanica (L.) by lactic acid present in excreta

Lactic acid has been identified in extracts of filter paper conditioned by the German cockroach,Blattella germanica (L.). One-to two-week old larvae aggregated on filter paper wetted with solutions of lactic acid.     

一锅环合偶联法合成N-叔丁氧羰基-3-苯甲基-2,3-二氢吲哚

以邻溴苯胺为原料,经过氨基酰化反应和烯丙基反应得到中间体N-烯丙基-N-叔丁氧羰基邻溴苯胺,中间体在醋酸钯和三苯基膦催化下,与苯硼酸发生环合偶联反应,得到目标产物N-叔丁氧羰基-3-苯甲基-2,3-二氢吲哚,总收率为37%。采用IR,1H NMR,13C NMR和MS对产品进行表征。