一种检测乳过氧化物酶方法的建立

【目的】建立一种简便、快速、精确的乳过氧化物酶（LP）检测方法。【方法】以ABTS为底物，利用动力学方法，建立了检测LP含量的ABTS法，并以优化后的体系检验ABTS法的精确度。【结果】以ABTS法检测LP含量的最佳反应条件为：吸收波长416nm，作用时间100s，pH5．5，ABTS浓度2mmol／L，H2O2浓度5mmol／L，工作温度25℃（室温）。经检验，该法的批内变异系数为2．39％，批间变异系数为3．42％，相关系数（R2）为0．9953，准确误差均未超过5．00％。【结论】以ABTS法检测LP精密度和准确度均较好，且操作步骤比较简便、快速，实现了对LP的简便、快速、精确检测。     

塞内加尔达喀尔地区沙丘土壤中有机添加物的荧光表征及去向

The application of organic amendments on soils poor in organic matter (OM) can improve long-term soil fertility, but may also enhance the mineralization of native soil organic matter. Three organic amendments, compost, sewage sludge and horse manure used by urban market gardeners in Dakar, Senegal were analyzed for their OM maturity. Their fate was evaluated in a 45-d agronomic trial in a sandy Arenosol with lettuce. In each case, water-extractable organic matter (WEOM) and humic-like substances (HLS) were isolated from raw amendments and amended soils, and characterized using ultraviolet-visible (UV/Vis) spectroscopy. Results highlighted the general more aromatic character of HLS and WEOM fractions extracted from compost compared to the other two amendments. When applied to soils, however, these differences were not clearly observed. The aromaticity and humification degree of the labile fraction (WEOM) increased with depth in the first 30 cm for all amendments. This indicated the high lixiviation rates that fresh OM underwent in the studied sandy soil. Finally, a statistical analysis of the results was able to discriminate between surface and deeper horizons and between amended- and non-amended soil samples. Spectroscopic indices showed indeed strong increase/decrease with depth linked with the mineralization/humification processes that the fresh OM from amendments underwent during the 45 d of the agronomic trial. This study highlights the potential of spectroscopic techniques to study agricultural amendment organic matter fractions and their fate in soils.     

Effect of sodium nitrite and sodium chloride on growth of lactic acid bacteria.

The effect of NaNO2 and NaCl on the growth of 24 lactic acid bacteria strains isolated from vacuum-packed cooked ring sausages were examined by analyzing different growth parameters with Bioscreen. NaNO2 had a very limited effect on the growth of lactic acid bacteria at 50 and 100 mg/l but at 400 mg/l a more pronounced inhibitory effect was found. Bacterial growth was enhanced by 1-2% (w/v) of added NaCl, while NaCl concentrations above 3% (w/v) had a clear inhibitory effect. Leuconostoc isolates seemed to be more sensitive to sodium nitrite and sodium chloride than homofermentative lactobacilli strains. Among homofermentative lactobacilli, the strains resembling Lactobacillus curvatus were more sensitive to NaCl than those resembling Lactobacillus sake.     

电超滤浸提土壤养分的研究 Ⅱ.表征旱地土壤有效氮的电超滤—吸光量

论述了新的表征旱地土壤有效氮的电超滤-吸光量(EUF-Q)概念、原理和计算法;提出了十分简便、快速、灵敏的测定方法;检定了土壤 EUF-Q 值的精密度和准确性。通过4年62份华北旱地土壤的 EUF-Q 值与盆栽冬小麦对氮肥反应的相关研究,表明土壤 EUF-Q 可以很好地表征旱地土壤有效氮的供应水平,远比通常所用的土壤全氮、碱解氮或有机质等化学法指数优越得多。此外还探讨了土壤 EUF-N 中 NO_3-N 和有机 N 的分配以及 EUF-N 的浸提动态。     

紫外吸收法、电导率法检验大白菜种子活力的研究

通过人工老化种子和不同年代种子具有的活力不同,以发芽指数为活力参考标准来探索种子浸泡液电导率测定法和紫外吸收测定法是否适合大白菜种子活力的快速检测.结果表明:大白菜种子紫外区随着波长的缩短吸收值增大,但经玻璃比色杯滤过后会在286 nm下显示吸收峰,随着种子活力的降低286 nm下的OD值呈上升趋势,对发芽率高于85％的种子适用,而对于活力过低的种子检验不可靠;随着种子活力的降低电导率呈上升趋势,但对活力差异较小的种子间检验不可靠.因此,对发芽率合格范围内的种子可以根据286 nm(玻璃比色皿)紫外吸收值评价大白菜种子活力的高低,其他的种子可参考电导率值比较种子活力.     

正交法优化‘胭脂萝卜’红色素超声提取工艺

为了优化‘胭脂萝卜’红色素的提取工艺,以‘胭脂红2号’萝卜为原料,采用超声辅助提取法提取萝卜红色素,分析了提取液种类及配比、料液比、提取温度和提取时间等因素对‘胭脂萝卜’红色素提取液吸光值的影响。结果表明：（1）在试验条件下,盐酸丙酮提取的红色素溶液的吸光值最高。（2）提取液配比对吸光值影响达显著水平,料液比、提取温度对吸光值影响达极显著水平。对吸光值的影响从大到小依次为提取温度、料液比和提取液配比。（3）用优化后的提取条件测试不同萝卜品种的红色素含量,发现‘胭脂红1号’和‘胭脂红2号’红色素提取液的吸光值最高。综上,在提取料液比取1:8,提取温度取50℃,提取液选用盐酸丙酮提取液,其配比为10.8%的盐酸:30%的丙酮=1:1,提取时间选20 min的条件下,红色素提取液吸光值最高。     

几种化学药剂处理对蔬菜劣变种子生活力的影响

用ＧＡ３（赤霉素）,硫脲,ＮＫＯ３,Ｈ２Ｏ２不同浓度或不同时间浸泡处理菠菜、茼 、芫荽劣变种子,结果表明,ＧＡ３对３种种子的萌发没有明显促进作用,且过高的浓度会抑制种子萌发;０．２％有硫脲对菠菜、芫荽种子萌发效果较好,发芽率分别比对照提高２３％和３０％,茼蒿以０．５％的浓度为适宜,发芽率比对照提高３１％;ＫＮＯ３处理３种种子均以０．２％效果最好,菠菜、茼蒿、芫荽的发芽率分别比对照提高２４％,１２％,１４％;Ｈ２Ｏ２处理只对菠菜种子有效,浸泡５,１０ｍｉｎ,发芽率分别提高１８％,２０％。发芽势也有所提高。测定浸出液电导率、紫外吸收表明,各有效处理相对电导率及紫外吸收均比处理低,表明化学药剂处理种子均导致无机离子和核酸、蛋白质等有机和的渗出减少。说明药剂处理种子对细胞膜系统具有一定的保护和修复作用。     

醇提水沉与水提醇沉对桉叶多酚提取物抗氧化活性的影响

本文以氧化自由基吸收能力(ORAC)、DPPH自由基清除能力以及多酚含量为指标,探讨醇提水沉法、水提醇沉法对桉多酚提取物抗氧化性的影响.结果表明,醇提水沉法上清液组分ORAC值高于其沉淀组分,也高于水提醇沉法的沉淀组分和其上清液组分.醇提水沉上清液组分多酚含量以及清除DPPH自由基活性均强于其他组分.因此可得醇提水沉法优于水提醇沉法,这对桉多酚后期的分离纯化起到指导作用.     

基于稳态空间分辨光谱的猪肉肌红蛋白检测方法

The objective of this work was to determine the concentration of myoglobin in fresh pork meat and establish a fast non-invasive method using steady spatially-resolved spectroscopy (SRS). The concentration of myoglobin was calculated based on absorbance coefficients at 640, 760, 800, 850 nm. The results showed that the value of myoglobin using SRS was significantly correlated (r2=0.955) to traditional methods with the accuracy of 3.6%F.S. The results showed that the concentration of myoglobin can be measured by using near infrared steady spatially-resolved spectroscopy.