Microspectrophotometry of bermudagrass (Cynodon dactylon) cell walls in relation to lignification and wall biodegradability

The walls of the major plant cell types, sclerenchyma and parenchyma, of the second (upper) and fifth (lower) internodes from the apex of bermudagrass (Cynodon dactylon L) stem have been examined by ultraviolet absorption microspectrophotometry and the results related to wall digestibility (measured in vitro with rumen liquor) and to histochemical reactions for ‘lignin’ and phenolics. Sclerenchyma walls from the lower internode gave high values of absorbance in the ultraviolet region of the spectrum equivalent to 109 mg trans-ferulic acid g^?1 dry walls; similar walls from the upper internode also gave high values but these were lower than values from the lower internode. Histochemical examination showed that the sclerenchyma walls, which were indigestible to rumen microorganisms, gave positive tests with acid phloroglucinol reagent for lignin. Parenchyma walls, which were either digested or partially digested, gave much lower absorbance values in the ultraviolet region and negative tests with acid phloroglucinol but positive tests with diazotised sulphanilic acid (upper and lower internodes) and chlorine-sulphite (lower internode) reagents. Ultraviolet absorption microspectrophotometry is a useful technique for examining phenolics within individual cell walls that vary in biodegradability.     

Phenolic acids released from bermudagrass (Cynodon dactylon) by sequential sodium hydroxide treatment in relation to biodegradation of cell types

Sections of solvent-extracted bermudagrass (Cynodon dactylon L Pers) leaf blades were treated sequentially with increasing concentrations of sodium hydroxide. The amounts of saponifiable phenolic acid monomers and cyclobutane dimers released and the digestibility of the treated blades (ie % dry weight loss) were determined. Leaf sections were examined by scanning electron microscopy for biodegradation of cell types and histochemically (light microscopy) for lignin after treatment with sodium hydroxide. Treatment with 0.1 m sodium hydroxide for 1 h resulted in only minor changes from untreated sections. However, this treatment for 24 h released 86% of the ferulic acid, 65% of the dimers, and c 50% of the p-coumaric acid. Digestibility was increased from 6.5% in the untreated control to 56.6%. Substantial loss of the slowly biodegradable tissues (ie epidermis and parenchyma bundle sheath) and partial biodegradation and disruption of the refractory tissues (ie sclerenchyma, xylem and mestome sheath) occurred; histochemical reactions for lignin were less intense after NaOH treatment. Treatment with 1 m sodium hydroxide for 24 h released 50% of the p-coumaric acid and the remainder of the alkali-extractable ferulic acid and dimers, increased digestibility to 72%, and increased biodegradation of mesophyll and phloem. Mestome sheath cell walls only gave a histochemical reaction for phenolics and the reaction was weak after 1 m NaOH treatment. Alkali treatment increased the biodegradation of all cell types, with lignified tissues reduced to single-cell fibres after 1 and 2 m treatments.     

植物甾醇对蛋鸡产蛋后期生产性能、鸡蛋胆固醇含量及血清生殖激素水平的影响

选用1 500羽520日龄伊莎褐商品蛋鸡,随机分成5组,每组6个重复,第1组为对照组,试验组日粮中分别添加5、10、20和40 mg/kg植物甾醇,研究植物甾醇对蛋鸡产蛋后期生产性能、鸡蛋胆固醇含量及血清生殖激素水平的影响.结果表明,与对照组相比,添加植物甾醇对蛋鸡产蛋后期的平均蛋重及产蛋率均无显著影响,但能降低死淘率,20 mg/kg的植物甾醇添加量效果较好;降低了蛋黄的胆固醇含量;试验前期,试验组血清的生殖激素水平无显著变化,试验后期,第2和5组的雌二醇(E2)有显著提高,第2和4组的促黄体素(LH)明显降低,试验组的促卵泡素(FSH)及促乳素(PRL)均无显著影响.     

Carry-over of Acrylamide from Feed (Heated Potato Product) to Eggs and Body Tissues of Laying Hens

A total of 16 hens were allocated to two groups. Hens were kept individually in a cage battery. During a four-week experiment 120 g feed were given per hen and day of consumption. The diet consisted of commercial potato meal (50%) as well as soy meal, barley and premix. The potato meal for the experimental group was heated for 2 h at 150°C. While the determined acrylamide content in the experimental diet was 671 ± 32 μg per kg, it was 125 ± 40 μg/kg in the diet of the control group. Acrylamide was determined by gas chromatography – mass spectrometry in the diet as well as in body tissue and eggs. During the experiment the acrylamide concentration in the eggs increased in both, the experimental and the control group. After three weeks, the acrylamide concentration in the eggs remained constant (max. 17.2 μg/kg egg). The carry-over rates for acrylamide from the diet to the egg were 0.022 in experimental and 0.010 in control hens. All hens were slaughtered at the end of the trial. The highest content of acrylamide was found in the kidneys of the experimental hens (27.7 μg/kg). It may be concluded that even for the highest acrylamide concentration considered the contribution of poultry products to the total acrylamide intake by humans is low.

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Zusammenfassung. 16 Legehybriden (LSL) wurden in 2 Gruppen aufgeteilt und in Einzelhaltung untergebracht. Die Hennen erhielten über vier Wochen t?glich 120 g Futter. Die Futtermischung setzte sich aus 50% eines küchenfertigen, handelsüblichen Kartoffelpulvers sowie Sojaextraktionsschrot, Gerste und einem Pr?mix zusammen. Das Kartoffelmehl der Versuchsgruppe wurde bei 150°C 2 h lang ger?stet. Die fertige Futtermischung der Versuchsgruppe enthielt 671 ± 32 μg Acrylamid/kg Futter und die Mischung der Kontrollgruppe 125 ± 40 μg/kg. Der Gehalt an freiem, unkonjugiertem Acrylamid in den Proben und im Futter wurde mittels GC-MS untersucht. Im Versuchsverlauf stieg in den Eiern der Hennen beider Gruppen die Acrylamidkonzentration an. Nach einer dreiw?chigen Versuchsdauer ?nderten sich die Konzentrationen an Acrylamid im Ei nicht mehr (max. Konzentration: 17,2 μg/kg Eimasse). Die Carry-over – Faktoren für Acrylamid vom Futter ins Ei betrugen bei den Kontroll- bzw. Versuchstieren 0,022 bzw. 0,011. Die h?chste Acrylamid-Konzentration wurde in den Nieren der Tiere der Versuchsgruppe ermittelt (27,7 μg/kg). Selbst unter Berücksichtigung der h?chsten Acrylamidkonzentrationen ist der Beitrag der Geflügelprodukte an der gesamten Acrylamidaufnahme des Menschen gering.

     

Plasma Cholesterol Oxidation Products (Oxysterols) in Human Subjects Fed a Meal Rich in Oxysterols

There is no evidence whether humans absorb cholesterol oxidation products (COPS) from food sources. Therefore, (after-meal) absorption of COPS in humans was studied following consumption of a powdered egg meal containing 30–90 ppm each of four different COPS. Both total plasma and plasma chylomicron COPS concentrations increased. By contrast, subjects consuming fresh eggs containing very low levels of the same four COPS (0–2 ppm) demonstrated no significant rise in plasma COPS. We concluded that the human subjects studied had the capacity to absorb COPS from food sources. The brief residence time of COPS observed in both chylomicrons and plasma suggested rapid transfer of COPS among lipoprotein fractions and/or clearance from plasma.     

Deposition of Carotenoids in Eggs from Hens Fed Diets Containing Saponified and Unsaponified Oleoresin Paprika

Deposition of carotenoids in saponified paprika (SP) and unsaponified oleoresin paprika (OP) in egg yolks as well as the dietary level for desired pigmentation were evaluated. Sixty-four hens on a carotenoid-depletion diet were divided into two replicated groups of each of eight dietary treatments containing from 0 to 16 mg paprika carotenoids per kg feed. Colour and the carotenoid content of egg yolk increased linearly ( P< 0·01) with the amounts of paprika carotenoids in the diets. The colours of egg yolks from hens fed similar concentra-tions of OP or SP were not significantly different ( P< 0·01). A low dose (4 mg kg⁻¹) of OP or SP provided yolk colour equivalent to the colour of eggs in supermarkets. High-performance liquid chromatographic analyses showed that carotenoids deposited in the yolk are in the free alcohol form, regardless of the form of carotenoids in the diet. Capsanthin, the predominant carotenoid in paprika, was deposited in egg yolk less efficiently than zeaxanthin and lutein.     

菜籽饼粕多糖对小鼠免疫功能的影响

本实验以小白鼠为试验动物,研究菜籽饼粕多糖(PRMs)的免疫促进性质。研究结果表明:与对照组相比,PRMs促进小鼠胸腺、脾脏和吞噬指数的增加,显著性促进脾淋巴细胞和腹腔巨噬细胞的增殖,迟发型过敏反应和溶血空斑和溶血素抗体的形成。因此,菜籽饼粕多糖有免疫促进作用。     

甘蓝型黄籽油菜饼粕浓缩蛋白的制备

以甘蓝型黄籽油菜冷榨浸出粕为材料,测定了蛋白质、粗纤维、木质素、可溶性糖和多酚含量,并对黄籽油菜制备浓缩蛋白条件进行了初步探索。结果表明,未脱壳的黄籽油菜饼粕具有蛋白质含量高、抗营养物质含量低的特点,采用乙醇脱糖即可制备浓缩蛋白。黄籽浸提粕的蛋白质含量达50．31％,可溶性糖含量为5．90％,粗纤维和木质素分别为4．40％和1．05％;黑籽粕蛋白质含量为38．38％,可溶性糖含量为5．43％,粗纤维和木质素分别为10％和6．10％。采用多因素正交试验对乙醇浸提工艺奈件进行优化,方差分析表明乙醇浓度和浸提温度对蛋白质含量的影响分别达显著和极显著水平。在乙醇浓度95％、浸提温度70℃、料液比1：7、浸提5次、每次20min的条件下,获得的甘蓝型黄籽浓缩蛋白产品蛋白含量达60．07％,赖氨酸等必需氨基酸含量显著提高,氨基酸总量达49．51％,各氨基酸比例均匀,硫甙脱除率达74％,并且浓缩蛋白的溶解度、氮溶解性、吸水性、吸油性、乳化性、起泡性与泡沫稳定性等功能特性良好。     

Chromatographic Separation of Anthocyanins in Cowberry (Lingonberry) Vaccinium vites-idaea L

The analysis of anthocyanins by a combination of droplet counter-current chromatography, thin-layer chromatography and on-line high-performance liquid chromatography was applied to the acidified ethanol extract of cowberry (lingonberry), Vaccinium vitesidaea L, In addition to 3-galactoside (88.0%), 3-arabinoside (10.6%), and 3-glucoside (1.4%) of cyanidin, delphinidin-3-glucoside (less than 0.1%) was identified. The total anthocyanin content was determined to be 174 mg/100g fresh fruit.     

On Sodium Chloride Action in the Gelation Process of Low Density Lipoprotein (LDL) from Hen Egg Yolk

Gelation of 40% LDL solution with 1~10% NaCl was inhibited during frozen storage at ?20°C and ?25°C. Frozen storage of LDL solutions with more than 4% NaCl at ?30°C, ?40°C and ?60°C induced the gelation, whereas gelation was inhibited by addition of 1 and 2% NaCl at temperatures lower than ?30°C. Differential scanning calorimetry analyses revealed that when NaCl acts as an inhibitor of gelation, it increased the unfrozen water in the LDL solutions through formation of LDL-water-NaCl complex where the water is hardly frozen; and when it acts as an accelerator of gelation, it promoted removal of water from the complex.     

Inhibition of Modori (Gel Weakening) in Surimi by Plasma Hydrolysate and Egg White

The effects of beef plasma hydrolysate and egg white solids were evaluated in surimi gels using measurements of torsional shear stress and strain, bound water, cook loss and SDS-PAGE. Treatments included level of protein addition, surimi type (by species and grade) and cooking schedule. Addition of proteins, regardless of type or level of addition, significantly increased torsional shear stress and strain for all gels precooked at 60°C (90°C final cook). For gels made from low quality surimi, all levels of treatment proteins improved stress and strain for all cooking schedules and improved water holding for gels precooked at 60°C. Electrophoretic results showed a decrease in the density of the myosin heavy chain only in those gels without added proteins precooked at 60°C.     

取食CMV烟株的烟蚜谷胱甘肽S-转移酶和羧酸酯酶活性变化

以取食健康烟苗的烟蚜为对照,测定了取食黄瓜花叶病毒(CMV)烟草病苗的烟蚜谷胱甘肽S-转移酶(GSTs)和羧酸酯酶(CarE)的活性。结果表明:①取食健康和发病烟苗的烟蚜GSTs比活力差异达显著水平;②分别以1-氯-2,4-二硝基苯(CDNB)和还原型谷胱甘肽(GSH)为底物时,发病烟草上饲养的烟蚜与健康烟草上饲养的烟蚜比较米氏常数(Km)值有显著提高,表明发病烟苗上烟蚜的GSTs对CDNB和GSH的亲和力均明显下降;③发病烟苗上饲养的烟蚜CarE比活力显著高于健康烟苗上饲养的烟蚜,分别为0.3618和0.1858μmol/mg.min,且烟蚜CarE比活力的个体间分布也存在显著差异。     

Egg concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans in double-crested (Phalacrocorax auritus) and pelagic (P. pelagicus) cormorants from the Strait of Georgia,Canada, 1973-1998

Eggs of double-crested and pelagic cormorants were collected between 1973 and 1998 from colonies in the Strait of Georgia, BC, Canada, and assayed for concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and non-ortho- and mono-ortho-biphenyls (PCBs). Double-crested cormorant eggs contained (on average) up to 433 ng kg(-1) wet weight 1,2,3,6,7,8-HxCDD, 151 ng kg(-1) 1,2,3,7,8-PnCDD, and 74 ng kg(-1) 2,3,7,8-TCDD, whereas pelagic cormorant eggs contained up to 300, 99, and 28 ng kg(-1) wet weight of these respective congeners. The dominant non-ortho-PCB was CB-126, which ranged as high as 2263 ng kg(-1) in double-crested cormorant eggs. Concentrations of PCDDs and PCDFs fell dramatically in the early 1990s, following both severe restrictions on the use of chlorophenolic wood preservatives and antisapstains and a switch from molecular chlorine bleaching to alternative bleaching technologies at pulp mills in the region. Concentrations of PCBs did not show similar marked declines over time. On the basis of total TEQs > or = 148 ng kg(-1) and previously published documentation of effects in siblings of the cormorant eggs analyzed here, double-crested cormorant young may have exhibited significantly elevated EROD activity and/or brain asymmetries at all colonies from 1973 to 1989 and even at some colonies during the 1990s. Pelagic cormorant eggs collected from a few colonies in 1988-1989 also contained total TEQs greater than the threshold value estimated for double-crested cormorants.     

Solubility of Proteins from Quail (Coturnix coturnix japonica) Egg White as Affected by Agitation Time,pH, and Salt Concentration

The solubility of proteins from quail egg white subjected to different agitation times, pH, and NaCl at 25°C was evaluated in this study. The greatest solubility achieved was obtained in the 0.05 mol/L of NaCl, pH 10.0, and under agitation for 1 h. The lowest solubility was found in the NaCl 1.0 mol/L, pH 3.0, and agitated for 2 h. Under the test conditions, aqueous solutions of NaCl 1.0 mol/L, pH 3.0, and agitated for 2 h may provide the greatest extraction index of proteins from quail egg white because these conditions promoted the protein precipitation in a large extension.     

Heat Gelling Properties of Hen's Egg Yolk Low Density Lipoprotein (LDL) in the Presence of Other Protein

Ovalbumin (OV), bovine serum albumin (BSA) and lysozyme (Lys) were added to egg yolk low density lipoprotein (LDL) and the heat-induced gel formation of LDL-protein mixture was studied. The gel formation of LDL-protein mixture was different between the acidic and alkaline pH region; fine stable gels were formed in the alkaline pH region, but weak paste-like gels were formed in the acidic pH region. The effect of added BSA or OV on the gel strength of LDL was much larger than that of Lys. Scanning electron micrographic observation showed that the microstructures of both LDL-BSA and LDL-OV gels were more uniform than that of LDL-Lys gel.     

Color Evaluation in Raw, Baked and Smoked Flesh of Rainbow Trout (Onchorhynchus mykiss) Fed Astaxanthin or Canthaxanthin

Color of rainbow trout (Onchorynchus mykiss) was investigated using sensory and instrumental analysis. When judged in pairs with equal carotenoid concentration, astaxanthin caused less whiteness, higher chromaticity and more red hue of trout flesh than canthaxanthin. Sensory assessed whiteness, chromaticity and red hue significantly correlated with instrumental values for lightness, chromaticity and hue [CIE (1976) L*a*b* and H(°)_ab]. Multivariate regression analysis improved the predictability for all sensory variables compared with univariate analysis. Prediction of carotenoid concentration from instrumental values was better for astaxanthin than for canthaxanthin.     

夯实基础 稳定发展——茧丝绸行业2009年运行分析与2010年展望(1)

2009年中国茧丝绸行业出现了极其矛盾而复杂的运行特点,通过对全国蚕桑生产、丝绸工业、出口情况、茧丝价格,以及行业综合竞争力的比较分析,可以看到,中国茧丝绸行业虽然遭受了国际金融危机的影响,但在国家出台的一系列促进消费拉动内需的重大措施支持下,行业运行仍然保持基本稳定。当前全球经济不稳定、不确定的因素还很多,国际市场消费需求尤其是包括真丝绸产品在内的奢侈品消费需求经历大幅度下滑后依然低迷,世界经济复苏依然缓慢,2010年中国茧丝绸行业发展面临的机遇与挑战并存。     

夯实基础 稳定发展——茧丝绸行业2009年运行分析与2010年展望(2)

<正>(续上期)1.5综合竞争力得到进一步提升2009年以来,全行业紧紧围绕强化标准、推进品牌建设,不断提高标准化水平,提升产业核心技术竞争力,促进产业结构调整和技术进步,综合竞争力得到进一步提升。