Inactivation of aflatoxins in peanut and cottonseed meals by ammoniation

Aflatoxins in peanut and cottonseed meal can be inactivated by treatment with gaseous ammonia. In pilot plant runs, contaminated peanut meal was ammoniated at two levels each of moisture content, reaction time, temperature and ammonia pressure. Thin layer chromatography indicated that ammoniation inactivated the aflatoxins (121 ppb) in the meal to a nondetectable level. With a similar treatment, total aflatoxins (350 ppb) in cottonseed meal were reduced to 4 ppb. A series of runs was made with large scale equipment using cottonseed meal containing an average of 519 ppb total aflatoxins. Under optimum processing conditions, aflatoxin content of this meal was reduced to below 5 ppb and non-detectable levels. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Inactivation of aflatoxins in cottonseed meal by ammoniation: I. Reaction studies

Cottonseed meal containing an average of 340 ppb total aflatoxins was treated with anhydrous liquid ammonia under varying conditions of time, temperature, and ammonia concentration. Meal moisture was held constant at 10%. A unique sampling device was constructed and used to withdraw meal at time intervals as frequent as 5 min during the reaction period, without interrupting the ammoniation process. The rate of aflatoxin inactivation occurring under a given set of treatment conditions was thus monitored. The data obtained in this study indicate that the inactivation of aflatoxins in cottonseed meal, as determined by chemical assay, may be successfully achieved by use of less stringent conditions of time, temperature, pressure, and moisture content than previous studies have indicated.     

磷酸氨化的宏观动力学研究

在自制双磁力驱动搅拌反应器中研究磷酸一铵生产条件下的磷酸氨化过程。结果表明,磷酸与气氨的反应属气膜传质控制的快速气液反应,气膜传质系数与其影响因素的准数关联式为：Ｓｈ＝２．０１×１０－４Ｒｅ２．４９。凡能增强气液湍动、增加气液相界面积的措施均能强化反应过程,提高设备生产能力。     

两步氨化造粒技术在氨化转鼓硫基复合肥装置中的应用

介绍氨化转鼓硫基复合肥生产工艺流程及存在问题,以及应用两步氨化造粒技术改造实例及改造效果。通过采用两步氨化造粒技术改造后,装置产能提升50%以上,生产中的水、电、蒸汽、燃煤消耗量大幅度降低,产品pH值提高,水分含量降低,产品配方灵活可调。     

白云石氨化法制取氢氧化镁新工艺研究

介绍了白云石氨化法制取超细含镁碳酸钙和氢氧化镁系列产品的反应机理 ,分析了其生产工艺过程特点 ,并对氢氧化镁阻燃剂进行了应用试验。     

The effect of ammoniation upon ricinine in castor meal

When castor meal is detoxified by treatment with ammonia to destroy ricin and various allergens the amount of ricinine, a toxic pyridone normally present in castor, is also reduced by about 25%. It was shown that the majority of ricine loss can be accounted for by the production of 4-amino-3-cyano-N-methyl-2-pyridone, a product formed by displacement of the original methoxyl group of ricinine with ammonia. In vitro enzymatic studies have demonstrated that neither this compound nor ricinine significantly affects lactate dehydrogenase. Another possible derivative of ricinine formed from ammoniation, 4-amino-3-carboxamido-N-methyl-2-pyridone, which was not found in ammoniated castor meal,did inhibit lactate dehydrogenase. W. Market. Nutr. Res. Div., ARS, USD     

Dietary fat composition influences fatty acid composition of milk fat globule membrane in lactating cows

Milk fat globule membranes are derived directly from the apical plasma membrane of mammary epithelial cells. To evaluate the effect of dietary fat on mammary membranes, we determined the fatty acid composition of the milk fat globule membrane in lactating dairy cows fed diets supplemented with fats of different fatty acid composition, or infused intravenously with soy oil emulsion. A preliminary survey, using an abbreviated preparation procedure (membranes isolated at 48,000 x g-max for 15 min), yielded about 45% of the total membrane fatty acids that could be recovered by centrifuging at the same speed for 120 min, and showed that changes in fatty acid composition of membranes reflected dietary fatty acids to some extent. Dietary palmitic acid increased the content of 16:0 in the membranes. A high corn diet increased ruminal formation of t18:1, and its level increased to 12% of membrane fatty acids. Infusion of soy oil emulsion increased 18:2 membrane content, and decreased the levels of 18:1 and 20:4. All treatments decreased the ratio of unsaturated/saturated fatty acids as compared to controls, whereas the ratio of polyunsaturated/saturated fatty acids was increased by feeding a high corn diet or by infusing soy oil. The ratio of 18:2/c18:1 increased from 0.31 to 1.0 after infusing soy oil for 4 days. The fatty acids of membranes isolated upon 120-min centrifugation were slightly more saturated. The differences were not sufficiently large, however, to affect overall results significantly.     

氨化对PAN原丝结构性能的影响

在聚丙烯腈(PAN)原丝湿法纺丝生产过程中,以二甲基亚砜/水(DMSO/H_2O)为凝固体系,在DMSO质量分数为72%,温度为52℃的凝固浴中通过流量计定量加入氨,以凝固浴溶液的pH值衡量氨化量的大小,研究了不同pH值对PAN原丝结构、性能及可纺性的影响。结果表明:在凝固浴溶液的pH值为8.6~10.0时,PAN原丝径向形态由腰形变成腰圆形,最后变成圆形;随着凝固浴溶液pH值的升高,PAN原丝的结晶度先升高后下降,膨润度则先降低后升高,直径不均率下降,强力不均率先下降后升高;凝固浴溶液pH值为9.5时,PAN原丝的结晶度最高,膨润度最小,直径不均率和强力不均率最低,可纺性最好,最终PAN基碳纤维的强度最高为3.83 GPa。     

外环流氨化反应技术在磷酸二铵生产中的应用

原外环流氨化反应器应用于生产磷酸一铵 ,介绍安徽六国化工股份有限公司应用外环流氨化反应技术生产磷酸二铵所采取的若干技术 ,使外环流氨化反应装置实现了长周期稳定运行生产 DAP,生产强度比原中和槽提高 10倍 ,达 4 .5 t/ (m3· h) ,无需搅拌 ,每年节约大修及维修费 2 8万元 ,向大气排放氨每年减少 18.9t     

对大陆氨酸法工艺的几点浅见

将大陆氨酸法工艺制复肥的主要设备之设计及操作与TVA改良工艺制复肥做比较,期望大陆使用氨酸法生产之复肥企业能从两者之差异间,找出解决成品温度居高不下及干燥机等设备严重结疤的方法。     

氨酸法工艺在复合肥料生产中的应用

介绍氨酸法工艺用于复合肥料生产的发展进程及其特点,比较了氨酸法管式反应器工艺与氨酸法料床直接反应工艺的优缺点,进行了初步的技术经济比较。氨酸法工艺用于传统团粒法生产装置的改造切实可行。     

CLA isomers in milk fat from cows fed diets with high levels of unsaturated fatty acids

The concentrations of CLA isomers were determined by Ag⁺-HPLC in the milk fat of cows fed a control diet consisting of hay ad libitum and 15 kg of fodder beets or this diet supplemented with oilseeds containing either high levels of oleic acid (rapeseed), linoleic acid (sunflower seed), or α-linolenic acid (linseed). Highly significant (P≤0.001) correlations were found between the daily intakes of oleic acid and the concentration of the CLA isomer trans-7,cis-9 in milk fat; of linoleic acid and the CLA isomers trans-10,trans-12, trans-9,trans-11, trans-8,trans-10, trans-7,trans-9, trans-10,cis-12, cis-9,trans-11, trans-8,cis-10, and trans-7,cis-9; and of α-linolenic acid and the CLA isomers trans-12,trans-14, trans-11,trans-13, cis,trans/trans,cis-12,14, trans-11,cis-13, and cis-11,trans-13. CLA concentrations were also determined in the milk fat of cows grazing in the lowlands (600–650 m), the mountains (900–1210 m), and the highlands (1275–2120 m). The concentrations of many isomers were highest in milk fat from the highlands, but only three CLA isomers (cis-9,trans-11, trans-11,cis-13, and trans-8,cis-10) showed a nearly linear increase with elevation. Therefore, these three CLA isomers, and particularly the CLA isomer trans-11,cis-13, the second-most important CLA in milk fat from cows grazing at the three altitudes, could be useful indicators of milk products of Alpine origin.     

硫酸脲氨化法生产尿基复合肥工业化生产的研究

介绍硫酸脲氨化法生产尿基复合肥的工艺过程,阐述硫酸脲氨化造粒的机理.在此基础上对硫酸脲氧化法生产尿基复合肥生产过程中出现的主要问题和影响造粒的主要因素进行了分析,提出解决办法,实现了连续正常生产,为蒸汽团粒法、尿液喷浆法、氨酸法造粒装置技术升级和改造提供了可借鉴的思路.     

凝固浴氨化对PAN湿法纺丝凝固行为的影响

在二甲基亚砜/水(DMSO/H_2O)凝固体系中加入氨水,以pH值控制凝固浴氨化程度,研究了凝固浴氨化对聚丙烯腈(PAN)湿法纺丝凝固行为的影响;采用扫描电子显微镜表征PAN初生纤维的皮层结构,采用卡尔费休水分仪和气相色谱仪研究了氨化对水和DMSO扩散系数的影响。结果表明:当凝固浴pH值为8.0时,PAN初生纤维的皮层最薄;随着凝固浴pH值的增大,水的扩散系数逐渐减小,DMSO的扩散系数(D_(DMSO))先减小后增大,当pH值为8.0时,D_(DMSO)出现最小值;氨化的作用机理是通过氨与水和DMSO分子间的氢键作用来实现的。     

Efficacy and stability of ammoniation process as aflatoxin B1 decontamination technology in rice

Rice, a cereal widely used in Venezuela for human and animal nutrition, is susceptible to aflatoxin contamination in the field and during storage. Therefore, the goal of this research was the evaluation of the efficacy and permanence of the ammoniation process through high pressure/high temperature (HP/HT) and atmospheric pressure/moderate temperature (AP/MT) conditions applied to rice samples artificially contaminated with aflatoxin B1. For this purpose a 2k design was drawn up considering the temperature, the rice moisture and the process time as variables. Under both sets of conditions, aflatoxin B1 concentration was reduced in a range of 90% to 100%. After in vitro stomach digestion simulation, toxin reversion ranged from 0% to 19%. In conclusion, the process efficacy and permanence were achieved through the use of high temperature and long process time for both sets of conditions (HP/HT and AP/MT), respectively.     

Survey of aflatoxins in California tree nuts

Surveys of the California walnut and almond crops to determine incidence of aflatoxins are reported. Average proportions of contaminated nuts from the field were one in 28,250 for walnuts and one in 26,500 for almonds. It was shown that there is a high correlation of contamination with damaged nuts which are removed by standard sorting procedures. Statistical treatment of data from the surveys indicates some of the problems in sampling tree nuts for analysis.     

The determination of aflatoxins in cottonseed products

A rapid and simplified procedure is proposed for the determination of aflatoxins B₁, B₂, G₁, and G₂ in cottonseed products. The method involves extraction of aflatoxins essentially free of lipid contamination by equilibrium extraction with 70% acetone. Interfering gossypol pigments are removed from the aqueous acetone extract by precipitation as insoluble lead salts. Aflatoxins in the centrifugate are quantitatively separated from excess lead salts, residual pigments and carbohydrates by extraction into chloroform to yield final extracts for thin-layer chromatographic (TLC) analysis on silica gel which are low in total solids and pigmentation. The procedure is sensitive to about 1 ppb in cottonseed meats and 4 ppb in cottonseed meal. Honorable mention, Bond Award competition. Presented at the American Oil Chemists’ Society, Chicago, October 11–14, 1964. A laboratory of the So. Utiliz. Res. and Dev. Div., ARS, USDA.     

Preparation of14C-labeled aflatoxins and incorporation of unlabeled aflatoxins in a blocked versicolorin-A-accumulating mutant ofaspergillus parasiticus

We have compared 2 methods for preparing radiolabeled aflatoxins from [¹⁴C] acetate for use in biosynthetic studies at the end of the aflatoxin pathway. The Salhab-Edwards method (SE) used a 3-day-old mycelium and a defined medium containing MnCl₂ with incubation at 28 C. The Lee-Bennett method (LB) used a 2-day-old mycelium and a defined medium containing low levels of Mn with incubation at 30 C. Generally, the LB method produced lower quantities of aflatoxin but the product had higher specific activities (sp act). The SE method produced 0.157μmol of aflatoxin B₁ and 0.028μmol of G₁ compared to the LB method with 0.058μmol of aflatoxin B₁ and 0.001μmol of G₁. The sp act (inμCi/μmol) for aflatoxin produced by the LB method were: B₁ = 1.379; B₂ = 0.130; G₁ = 5.0 and G₂ - 0.063. The sp act of aflatoxin produced by the SE method were: B₁ = 0.267; B₂ = 0.014; G₁ = 0.178; and G₂ =0.133. Unlabeled aflatoxins were presented to resting cell cultures of the versicolorin-A-accumulating mutant ofAspergillus parasiticus. No conversion of aflatoxin B, was noted. However, when aflatoxins B₂ or G₁ were presented low levels of aflatoxins B₁ and G₂ were recovered. Aflatoxins B₂ and G₁ were recovered when aflatoxin G₂ was presented. Similar low levels of recovery were obtained in experiments using autoclaved mycelia. Thus we conclude that these minor quantities of aflatoxins recovered were not produced enzymatically.     

造粒机氨化粒化差的原因分析及技改措施

青海云天化国际化工股份有限公司240kt／a磷酸二铵装置采用预中和加管式反应器转鼓氨化造粒工艺．造粒机运行状况一直不理想。通过对造粒机内部结构进行改造,降低了胶板使用量,二次氨利用率提高到70％以上,造粒机的运行率和产品质量也得到较大提高。