玉米浆为有机氮源的L-乳酸发酵的研究

利用细菌厌氧发酵生产L-乳酸,以降低L-乳酸生产成本为主要目的,实验以玉米浆为有机氮源,以硫酸铵为主要无机氮源,研究了不同接种量对发酵过程的影响;并就以玉米浆替代酵母粉、豆粕水解液、生物素为有机氮源的L-乳酸发酵进行了对比研究实验,实验证明了玉米浆做为有机氮源用于L-乳酸发酵的可行性。在保证生产能力的同时,使用玉米浆为有机氮源对进一步降低L-乳酸生产成本,减少玉米浆对环境的污染进行了探索。     

玉米淀粉胶粘剂的改性研究

以玉米淀粉为主要原料 ,通过预糊化、氧化、加碱糊化进行化学改性 ,并加入稳定剂可制备固含量高、贮存稳定性好 ,具有一定初粘力和透明性的改性淀粉胶粘剂。本论文主要研究了改性玉米淀粉胶粘剂的主要成分配比及工艺条件对产品性能的影响。结果表明 :淀粉氧化前是否进行预糊化处理、氧化剂的用量、体系pH值、加碱糊化时碱液用量、稳定剂的种类和用量等对改性玉米淀粉胶粘剂性能影响较大。     

玉米芯木聚糖硫酸酯化条件的研究

用碱提法从玉米芯中提取木聚糖,采用氯磺酸吡啶法进行硫酸酯化,通过正交试验确定最佳工艺条件为:吡啶与氯磺酸摩尔比1∶1,温度65℃,时间6h;木聚糖硫酸酯wisX-S通过DEAESepharoseFF层析柱分离得到一个相对分子量为1.3×104的组分,硫酸基取代度为2.24。对此木聚糖硫酸酯进行红外光谱分析,结果显示在波数1259、1228和813cm-1处分别有S=O和C-O-S键的特征吸收峰。     

A phosphorus budget of a poultry farm and a dairy farm in the southeastern U.S., and the potential impacts of diet alterations

Current and potential environmental problems associated with P transport from lands receiving high application rates of animal waste are a major concern. Phosphorus management strategies are needed to reduce P loading on land. This study was conducted to compare on-farm P budgets for a modern broiler farm and a dairy farm under traditional diets and management practices. Phosphorus inputs, recycling and outputs were assessed for both farms. A typical broiler and a dairy farmer from North Carolina were interviewed and pertinent information for the study was obtained, in cooperation with extension agents, and other professionals associated with the farms. The annual on-farm P surplus for the broiler farm was 6,380 kg, while that for the dairy farm was 1,141 kg. This corresponds to an annual application of 65 kg P ha^–1 for the broiler farm and 20 kg P ha^–1 for the dairy farm in excess of removal. The potential for reducing P surpluses by the addition of phytase enzymes and/or the use of low phytic acid corn (Zea mays L.) feed in the broiler farm diet was also assessed. Estimates by animal nutritionists indicate that feed supplementation with phytase enzyme can reduce the broiler farm's P surplus by 33%. The use of low phytic acid corn can reduce the surplus by 49% and a combination of the two can reduce the surplus by 58%. In this study, the incorporation of soybean (Glycine max (L.) Merr.) and alfalfa (Medicago sativa) land into the waste utilization plan of the dairy farm decreases the annual P surplus from 20 to 9 kg P ha^–1. The use of new feed technology and expanding waste application to a larger land base can significantly alter the P budgets of broiler and dairy farms and reduce P surpluses, minimizing the risk of environmental problems.     

Structure-activity relationship observations for European corn borer moth pheromone and fluoro analogs via computer molecular modeling

Structure-activity relationship (SAR) observations were made for theZ-type European corn borer moth pheromone, (Z)-11-tetradecen-1-ol acetate, and a series of analogs with fluorination in the alcohol portion of the molecule. The attractiveness of these analogs and the pheromone was compared to the electrostatic potential map of the molecular mechanics (MM) minimized lowest energy conformation for each compound. A critical range of electrostatic potential on the protons of the double-bond appears to be essential for optimal acceptor fit and attractiveness.     

Antioxidant activity of red wine phenolic extracts towards oxidation of corn oil

The antioxidant activity of Xinomavro red wine phenolic extracts in corn oil stripped of tocopherols was evaluated. One wine extract, at 100 mg/L total phenolics, rich in phenolic acids and flavonols, inhibited the oxidation of corn oil stripped of tocopherols to a greater extent than butylated hydroxyanisole, at 200 mg/L. Moreover, another extract, at 100 mg/L total phenolics, rich in flavanols, flavonols and tyrosol, also exhibited high inhibitory action. The present results indicate that some red wine phenolics – such as phenolic acids, flavonols or flavanols – may be strong antioxidants in corn oil.     

农作物秸秆增强氟石膏复合材料的微观结构研究

将玉米秸秆加入改性后的氟石膏中，研究改性剂、玉米秸秆对氟石膏复合材料结构性能的影响；并用苯丙乳液对玉米秸秆纤维进行表面处理，用以改善基体材料和增强材料的界面结合状况，由此显著提高制品性能。     

秸秆黄腐酸包膜尿素在水稻上的应用效果

在石灰性土壤上进行田间小区试验，结果表明，秸秆黄腐酸包膜尿素能满足水稻生长最大效率期对营养的要求，有利于有效穗的分化，提高结实率。等氮量试验平均增产9．6％，等重量试验平均增产7．4％。     

Effect of randomization on the oxidative stability of corn oil

Randomized corn oil TAG oxidized much faster than natural oil, but after purification with alumina, they oxidized at the same rate. We showed that this effect could not be attributed to a difference, in total tocopherols in the randomized and natural oils. Polar material recovered from the alumina treatment was fractionated by TLC, and a pro-oxidant effect was found in the fractions containing MAG and DAG. However, MAG and DAG, although mild pro-oxidant could not account for the pro-oxidant effect generated by randomization. No other compounds could be detected in the MAG fraction by MS. The pro-oxidant effect of randomized oil disappeared when EDTA or citric acid was added in sufficient amounts. The pro-oxidant effect of randomized corn oil was increased by the incorporation of additional copper or iron at a concentration that did not catalyze oxidation of the purified oil. Treatment of corn oil with ascorbic acid, ascorbyl-6-palmitate, ethyl acetoacetate, ethyl diacetoacetate, and acetylacetone did not reproduce the effect of the unknown pro-oxidant. Although the identity of the pro-oxidant is still unknown, we have confirmed that it is produced during randomization; it does not have pro-oxidant activity alone, but it facilitates the catalytic activity of the transition metal ions.     

Male european corn borer,Ostrinia nubilalis (Hübner), antennal responses to analogs of its sex pheromone

Experiments were conducted to (1) determine whether the electroantennogram (EAG) can detect differences among the responses of antennae from males derived from the three strains ofOstrinia nubilalis (Hübner), and (2) characterize the EAG responses of each strain to isomeric forms of the natural pheromone, (E)- and (Z)-11-tetradecen-1-ol acetate (TDA), and analogs possessing differences in the terminal alkyl group, cyclopropyl (CPA), ortert-butyl (TBA).EAG responses differed among the strains in two ways: (1) Antennae fromZZ males always produced an EAG to (Z)-TDA with an extended duration of response. This signature EAG response was found to be unique to the antennal response ofZZ males to (Z)-TDA, thus providing a relatively easy method of distinguishing liveZZ males fromEE orZE males. Correlated with this longer EAG response was a longer disadaptation time, i.e., the EAG response ofZZ antennae disadapted more slowly (ca. 10 min) than the response ofEE antennae. (2) Strain differences in the relative EAG amplitudes to isomers and analogs were observed at the stimulus amounts eliciting the peak EAG amplitude as follows: TDA CPA > TBA forZZ males and both isomers; TDA > CPA TBA and CPA TDA > TBA forEE males and theE andZ isomers, respectively; CPA > TBA TDA forZE males and both isomers. Dose—response relationships were seen for all compounds if amplitude (peak height) of the EAG was used as a measure of response. However, if width of the EAG at half the peak height (peak width) was used, then only theZZ antennal response to (Z)-TDA resulted in a meaningful dose-response relationship. For all strains, the EAG amplitudes elicited by theZ isomers of any of the tested compounds were greater than those elicited by the correspondingE isomers. Therefore, correlations between the relative EAG and upwind flight responses were observed in theZZ (r = 0.86) andZE (r = 0.80) strains but were not correlated in theEE strain (r = 0.18). Temporal studies showed that adaptation, not postexcision deterioration, was responsible for the observed decreases in the EAG amplitude after repetitive stimulation or after stimulation with amounts in a descending order. Disa-daptation required at least 20 min for a moderate dose (10 g for 1 sec). Developmental studies showed that antennae from 2-day-old adults had the greatest EAG response.