豆浆豆腐中胰蛋白酶抑制因子活性的研究

豆制品中含有丰富的营养物质,但其中的抗营养因子阻碍人体对营养物质的吸收。分别采用6种不同制浆工艺将5种原料豆进行豆浆、豆腐的制备,测定大豆和豆浆中蛋白含量以及豆浆、豆腐的产量,通过分析不同大豆品种及制浆工艺与豆制品产量及蛋白含量之间的关系,以产量为指标,研究不同大豆品种及其加工工艺对豆制品产量及蛋白含量的影响,选取高产量、高蛋白的豆制品。并采用紫外分光光度计法分别对原料豆、豆浆、豆腐等进行大豆胰蛋白酶抑制因子活性的检测,得出低大豆胰蛋白酶抑制因子活性的品种及加工豆制品的制浆工艺。结果表明,豆制品产量与蛋白含量成正比,不同大豆品种采用不同制浆工艺所制得的豆浆、豆腐中胰蛋白酶抑制因子活性具有显著性差异,为不同大豆品种适用性加工及工业化生产提供理论依据。     

加工对大豆中微量元素锂含量的影响

采用Z-8000型原子吸收分光光度计对大豆及豆制品中锂进行了测定研究,结果表明:大豆中的锂含量丰富,对人体有益;因加工条件不同而存在豆制品中锂含量明显区别。     

大豆及豆制品中硼含量测定及其迁移行为研究

本文基于GB/T 21918-2008,采用ICP-AES测定了大豆及豆制品中硼的含量,并对硼元素在大豆及豆制品中的分布迁移行为进行了初步探讨。通过研究发现,大豆是一种含硼较高植物,硼含量均大于30mg/kg。豆制品中,豆腐皮和豆豉硼含量最高,高于25mg/kg,而豆浆、豆腐乳最低,均不高于1mg/kg。最后,本文探讨了四川地区大豆和新鲜大豆中硼含量本底值。此研究结果可为相关标准的制定提供理论依据。     

豆制品废水综合利用现状

该文对豆制品废水中所含成分、前处理方法以及综合利用方法进行了阐述。豆制品废水通过多级冷冻浓缩进行预处理,可提高绝大部分功能性成分的保留效率。采用膜分离和絮凝等技术可以从豆制品废水中分离大豆乳清蛋白、大豆低聚糖和大豆异黄酮等产物。向豆制品废水中加入微生物所需的营养物质再灭菌后可制成微生物培养液,用于培养微生物以获得菌体或副产物。对以豆制品废水为原料进行食品生产进行了展望。     

大豆及豆制品可抑制乳腺癌、前列腺癌、大肠癌

近年来研究表明，大豆及豆制品还可以抗癌，特别对乳腺癌、前列腺癌、大肠癌的防抑效果尤为明显。英国伦敦皇家学院营养学家海伦怀斯曼博士在一次现代营养学研讨会上提出：大量食用豆制品的人，其乳腺癌的发病率较低，经常吃豆腐可使大肠癌危险性降低一半。为什么大豆及豆制品可抗癌呢？原因有多方面。一是大豆含丰富的异黄酸质．这是一种弱雌激素作用的植物激素，可调整乳腺对雌激素反应，使雌激素不易引起乳腺组织发生异常改变。日本妇女尿中异黄体酮浓度为美国、芬兰妇女的10o－1000倍，这与日本人多食大豆及豆制品有关，也是造成与欧美…     

在豆制品生产中控制AI危害的 HACCP体系的建立

采用原子吸收光度法对大豆及豆制品中的铝进行了测定,并且调查发现,由于原料及生产工艺问题导致豆制品中的铝存在安全隐患;对豆制品生产过程中影响食品安全性的Al危害因素,运用HACCP原理进行了分析,研究确定了铝的关键控制点、临界值;并采取相应的控制措施,将Al的危害因素降低至最低限度,从而在豆制品生产中对铝进行了有效的安全控制。     

大豆制品生产废水综合开发研究进展

豆制品生产中产生大量的有机废水,这些废水中含有多种多样的营养物质,直接排放不仅污染环境而且浪费资源。文章阐述了从大豆制品生产废水中提取功能性物质如大豆低聚糖、大豆乳清蛋白、大豆异黄酮、大豆皂苷、大豆多糖等的研究进展,为豆制品废水的综合利用提供理论依据和实践基础。     

大豆在加工豆制品过程中蛋白质的变化

豆制品生产在我国已有悠久的历史,近年来随着人们生活水平的不断提高,广大群众对豆制品的需求也与日俱增,豆制品厂如何提高豆制品的出品率,提高经济效益。就要求我们对大豆的营养成份及其在做豆制品过程中蛋白质的变化给以进一步的认识。大豆中含蛋白质40—42%,油脂16一18%,还含有几种有机酸和维生素。而在大豆蛋白体中占绝对优势的是贮存蛋白,贮存     

豆制品废水资源化利用研究进展

豆制品生产过程中会产生大量的有机废水。由于豆制品废水中含有丰富的营养物质,所以它具有可以资源化利用获得经济效益和保护环境的潜在价值。豆制品废水资源化利用不仅可以大幅度降低化学需氧量,而且可以获得高附加值物质,例如:大豆异黄酮、大豆皂甙、大豆低聚糖、大豆乳清蛋白等。而且,通过微生物发酵的方法可以获得单细胞蛋白、生物能源的原料等有用物质。本文综述了从豆制品废水中回收利用的多种生物活性物质,以及利用微生物发酵的方式得到有用物质的研究进展。这些物质都是豆制品废水的资源化利用的有益去向。     

水质与豆制品生产的关系

我国是世界上最早利用大豆生产豆制品的国家.从古书记载:“豆腐之法,始于前汉淮南王刘安”,距今已有二千多年的历史.众所周知,豆制品是用大豆为原料制作的,但俗话却说:“豆腐水做”,可见水在豆制品生产中是非常重要的,因此对水,尤其是研究水质与豆制品生产的关系,很有必要. 一、水在豆制品内部结构的地位水是组成豆制品的一个不可缺少的成份,在豆制品结构中占有很大的比例。如在我们日常食用的嫩豆腐中,蛋白质含量仅占6%左右,而水却含有     

Ion-specific isotopic fractionation of molybdenum during diffusion in aqueous solutions

Experiments modeling diffusion of Mo in aqueous solutions have been performed and, using multicollector ICP-MS, the ratios of the diffusivities of Mo isotopes, D97Mo/ D95Mo, in aqueous solutions have been determined. Diffusion of MoO42- ions in solution was concomitant with Mo isotopic fractionation with D97Md/D95Mo = 0.99988+/-0.00004 (2sigma for n = 3). In contrast, during diffusion of Mo polyanions, such as Mo70246- and Mo8O264-, no measurable isotope fractionation has been found with D97Mo/D95MO = 1.00000 +/- 0.00002 (2sigma for n = 3). These results indicate the need for due consideration to Mo speciation when attempting to interpret the role of diffusive fluxes in the formation of Mo isotopic signatures in nature. They also raise the possibility that the various chemical forms of other transition metals may be characterized by species-specific isotopic fractionation effects during physicochemical reactions.     

Molybdenum speciation in uranium mine tailings using X-ray absorption spectroscopy

Uranium (U) mill tailings in northern Saskatchewan, Canada, contain elevated concentrations of molybdenum (Mo). The potential for long-term (>10,000 years) mobilization of Mo from the tailings management facilities to regional groundwater systems is an environmental concern. To assist in characterizing long-term stability, X-ray absorption spectroscopy was used to define the chemical (redox and molecular) speciation of Mo in tailings samples from the Deilmann Tailings Management Facility (DTMF) at the Key Lake operations of Cameco Corporation. Comparison of Mo K near-edge X-ray absorption spectra of tailings samples and reference compounds of known oxidation states indicates Mo exists mainly as molybdate (+6 oxidation state). Principal component analysis of tailings samples spectra followed by linear combination fitting using spectra of reference compounds indicates that various proportions of NiMoO(4) and CaMoO(4) complexes, as well as molybdate adsorbed onto ferrihydrite, are the Mo species present in the U mine tailings. Tailings samples with low Fe/Mo (<708) and high Ni/Mo (>113) molar ratios are dominated by NiMoO(4), whereas those with high Fe/Mo (>708) and low Ni/Mo (<113) molar ratios are dominated by molybdate adsorbed onto ferrihydrite. This suggests that the speciation of Mo in the tailings is dependent in part on the chemistry of the original ore.     

烤烟土壤有效钼临界值的初步研究

为有效合理施用钼肥,通过盆栽和田间试验研究了钼素营养对烤烟不同性状指标的影响和土壤有效钼的临界值.结果表明,施钼能提高烟叶产量,改善和提高烟叶品质.在盆栽试验条件下,对于烟叶产量性状的土壤有效钼临界值约为0.30 mg/kg,对于烟叶油分性状的土壤有效钼临界值约为0.10 mg/kg.在大田试验条件下,对于烟叶产量性状的土壤有效钼临界值为0.15 mg/kg,对于上等烟和杂色烟性状的土壤有效钼临界值均约为0.20 mg/kg.     

X-ray absorption spectroscopic investigation of molybdenum multinuclear sorption mechanism at the Goethite-water interface

Understanding in situ metalloid surface speciation on mineral surfaces is critical to predicting the bioavailability in surface and subsurface environments. In this study, Mo K-edge X-ray absorption spectroscopy (XAS) was used to elucidate Mo(VI) surface speciation at the goethite-water interface. Effects of pH and loading levels were investigated. X-ray absorption near edge structure (XANES) analysis indicated that the Mo(VI) coordination environment changes from tetrahedral to octahedral with decreasing pH. At near neutral pH, Mo(VI) predominantly remains as tetrahedral molecules, forming inner-sphere surface species via corner- and edge-sharing attachment with iron octahedral structures (interatomic distance of Mo-Fe (R(Mo-Fe)) at ～2.8 and ～3.4 ?, respectively). In contrast, a mixture of surface species comprising tetrahedrally and octahedrally coordinated Mo(VI) exists at pH ～3-4. While the same Mo(VI) tetrahedral surface species are present at acidic pH, there was an additional MoO(6) polymer attachment on iron octahedral structures, resulting in a R(Mo-Fe) at 3.53 ?. The coordination number (CN) of a Mo-Mo backscatterer gradually increased with increasing loading level, suggesting the formation of surface polymerization. Overall, there seems to be a transition from Mo(VI) tetrahedral to octahedral coordination environment with decreasing pH. The XAS findings further support a Mo(VI) inner-sphere adsorption mechanism that was previously suggested in the pressure-jump relaxation study by Zhang and Sparks (Soil Sci. Soc. Am. J. 1989, 53 (4), 1028-1034). pH-Dependent multinuclear Mo(VI) surface speciation may be important in predicting Mo(VI) transport process in the soil-water environment.     

Seed reserves of chickpea in relation to molybdenum supply

Chickpea (Cicer arietinum L), cv K75 plants were grown till maturity at 0.00001, 0.0001, 0.001 (deficient), 0.02 (adequate), 0.2 (supranormal) and 2.0 (excess) mg dm^?3 Mo in refined sand. The pod and seed yield of chickpea were at a maximum at 0.2 mg dm^?3 Mo, which is ten times higher than the usual Mo requirement. The seed weight of chickpea was decreased more by low (<0.02 mg dm^?3) than excess (2 mg dm^?3) Mo. In chickpea seeds, the concentrations of starch, reducing, non‐reducing and total sugars were highest at 0.02 mg dm^?3 Mo and decreased by Mo stress (<>0.02–0.2 mg dm^?3). In comparison, the content of methionine, lysine, legumin, vicilin, total proteins, protein and non‐protein nitrogen in seeds of chickpea decreased variably both at low (<0.02 mg dm^?3) and high (>0.2 mg dm^?3) Mo. Both deficiency and excess of Mo deteriorated the quality of seeds by increasing the content of phenols, cysteine and albumin and decreasing that of methionine, lysine, legumin and vicilin protein fractions, apart from reducing the seed weight. The quality of seeds deteriorated more by deficiency than excess of Mo in chickpea. Copyright © 2004 Society of Chemical Industry     

硼钼对烟叶膜脂过氧化及体内保护系统和钾吸收的影响

通过盆栽试验,研究了硼、钼的不同水平对烟草叶片膜脂过氧化及体内保护系统的变化和对钾吸收的影响。结果表明:在低硼、低钼胁迫下,烟草叶片的质膜透性(MP)、丙二醛(MDA)的含量、多酚氧化酶(PPO)和抗坏血酸氧化酶(AO)的活性增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(AP)、过氧化氢酶(CAT)的活性下降,烟叶含钾量低;施钼或施硼都有利于烟草抗膜脂过氧化胁迫,提高烟叶含钾量。烟草体内保护系统中的酶类(SOD、POD、CAT和AP)协同抗氧化,在抵御膜脂过氧化的程度上,钼和硼的作用存在一定的差异,同时表明在缺硼和钼的土壤上施硼肥和钼肥有利于提高烟叶对钾的吸收。      

酸性黄棕壤中钼磷配施对甘蓝型油菜苗期碳氮代谢的影响

利用酸性黄棕壤进行盆栽试验,研究了钼磷配施对甘蓝型油菜苗期碳氮代谢的影响。结果表明,施钼和施磷均显著增加叶片叶绿素含量、光合速率、可溶性总糖含量以及地上部干物质重和可溶性蛋白质含量,显著降低油菜苗期叶片硝态氮含量;且钼肥和磷肥配施对促进油菜苗期碳氮代谢存在协同效应。钼肥和磷肥提高油菜光合速率的机制有所不同,钼肥主要提高叶肉细胞光合活性,而磷肥则增加气孔导度。     

Added dietary sulfur and molybdenum has a greater influence on hepatic copper concentration,intake, and performance in Holstein-Friesian dairy cows offered a grass silage- rather than corn silage-based diet

To test the hypothesis that the metabolism of Cu in dairy cows is affected by basal forage and added S and Mo, 56 dairy cows that were 35 (standard error ± 2.2) days postcalving and yielding 38.9 kg of milk/d (standard error ± 0.91) were offered 1 of 4 diets in a 2 × 2 factorial design for a 14-wk period. The 4 diets contained approximately 20 mg of Cu/kg of dry matter (DM), and had a corn silage-to-grass silage ratio of 0.75:0.25 (C) or 0.25:0.75 (G) and were either unsupplemented (?) or supplemented (+) with an additional 2 g of S/kg of DM and 6.5 mg of Mo/kg of DM. We found an interaction between forage source and added S and Mo on DM intake, with cows offered G+ having a 2.1 kg of DM lower intake than those offered G?, but no effect on the corn silage-based diets. Mean milk yield was 38.9 kg/d and we observed an interaction between basal forage and added S and Mo, with yield being decreased in cows offered G+ but increased on C+. No effect of dietary treatment on milk composition or live weight was noted, but body condition was lower in cows fed added S and Mo irrespective of forage source. We found an interaction between forage source and added S and Mo on milk somatic cell count, which was higher in cows offered G+ compared with G?, but not in cows fed the corn silage-based diets, although all values were low (mean values of 1.72, 1.50, 1.39, and 1.67 log₁₀/mL for C?, C+, G?, and G+, respectively). Mean plasma Cu, Fe, and Mn concentrations were 13.8, 41.3, and 0.25 µmol/L, respectively, and were not affected by dietary treatment, whereas plasma Mo was 0.2 µmol/L higher in cows receiving added S and Mo. The addition of dietary S and Mo decreased liver Cu balance over the study period in cows fed either basal forage, but the decrease was considerably greater in cows receiving the grass silage-based diet. Similarly, hepatic Fe decreased more in cows receiving G than C when S and Mo were included in the diet. We concluded that added S and Mo reduces hepatic Cu reserves irrespective of basal forage source, but this decrease is considerably more pronounced in cows receiving grass silage- than corn silage-based rations and is associated with a decrease in intake and milk performance and an increase in milk somatic cell count.     

Antioxidant activities of polyphenols from sage (Salvia officinalis)

The antioxidant activities of the sage polyphenols, consisting of flavone glycosides and a range of rosmarinic acid derivatives, were evaluated for their capacity to scavenge DPPH and superoxide anion radicals and also to reduce Mo(VI) to Mo(V). The rosmarinic acid derivatives all showed potent antioxidant activity in three test systems and their capacity to reduce Mo(VI) to Mo(V) and their superoxide radical scavenging activities, with values ranging from 220 to 300 SOD units/mg, in particular, were 4–6 and 15–20 times greater than trolox, respectively. The high SOD activity of rosmarinic acids could be attributed to the radical-scavenging catechols and the xanthine oxidase-inhibiting caffeic acid moieties contained in them. The antioxidant activity of the flavonoids was variable and those with a catechol B-ring (luteolin glycosides) were more active than those without (apigenin glycosides).     

Molybdenum scavenging by iron monosulfide

Molybdenum profiles in dated sediment cores provide useful historical information about anoxia in anthropogenically impacted natural waters but would be of greater service if Mo fixation mechanisms were better understood. Here, we explore Mo scavenging by precipitated FeS in a model system consisting of an FeIII-bearing kaolinite (KGa-1B) dispersed in NaHS solutions. Test solutions contain 18 microM thiomolybdates (mainly MoOS3(2-)). Optically measuring dissolved polysulfides monitors the rate of FeS production from FeIII minerals. Even though the exposed clay surface area is large (450 m2/L), the clay itself sorbs little Mo at pH 8.6. As FeS forms, Mo is taken up in initial Mo/Fe mole ratios of 0.04-0.06, irrespective of HS- concentration (4-40 mM range). After about a day, Mo expulsion from the solids begins, accompanied by net polysulfide consumption. These changes reflect recrystallization of amorphous FeS to more ordered products such as greigite. FeS captures some MoO4(2-) but captures thiomolybdates more effectively. Kaolinite accelerates conversion of MoOS3(2-) to MoS4(2-), as predicted previously, and thiomolybdates facilitate reduction of FeIII minerals in the clay compared to Mo-free solutions. FeS is a potentially effective, transient scavenging agent for Mo in sulfidic environments, although FeS2 and organic matter appear to be the ultimate sedimentary hosts.