共查询到19条相似文献,搜索用时 234 毫秒
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以合浦珠母贝开珠后的贝壳为原料,研究制备碳酸钙、丙酸钙的工艺技术.通过分析贝壳粉颗粒大小和酸的品种、浓度及用量对酸溶率的影响,结果表明:100目的贝壳粉与4mol/L的盐酸,按固液比为1:20,在40℃酸溶处理2h,酸溶率可达到99%,该酸溶液与Na2CO3溶液的体积比为9:5时,碳酸钙得率最高;利用L6(34)正交实验优化丙酸钙工艺,结果表明,最佳工艺条件为碳酸钙与水的比例1:40(W/V),碳酸钙与丙酸比例1:3(W/V),反应温度60℃,反应时间0.5h,丙酸钙产率为86%,产品纯度为83.4%. 相似文献
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研究了盐酸浓度(A)、盐酸用量(B)、提取温度(C)、提取时间(D)对鳗鱼骨钙的溶出率的影响.在此基础上进行了正交试验,确定了鳗鱼骨钙提取的最优组合是A2B3C2D3,即盐酸浓度为3mol/L、盐酸用量4mL、提取温度50℃、提取时间150 min.在最优组合条件下,鳗鱼骨钙的溶出率为81.31%.影响鳗鱼骨钙的溶出率的因素主次顺序为:盐酸浓度>盐酸用量>提取温度>提取时间. 相似文献
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醇变性大豆蛋白在物理改性条件下的溶出行为和机理 总被引:5,自引:0,他引:5
研究了超声波、高速剪切以及加热对醇变性大豆蛋白的溶出速率和溶出蛋白质分子质量分布的影响。常温下的溶出速率随时间延长而降低 ,超声波或高速剪切作用使溶出速率增加 ,其溶出物中的蛋白质主要以分子形式存在。加热至 90℃可以将溶出初速率明显提高 ,但随后很快降低 ;溶出物主要是分子质量较大的蛋白质聚集体。研究表明 ,超声波和高速剪切的增溶机理是增加醇变性大豆蛋白中可溶性蛋白质的扩散速率 ;加热增溶的机理是破坏分子间非共价键从而使不溶性蛋白转化为可溶性蛋白。 相似文献
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鸡骨明胶生产中浸酸工艺的控制 总被引:5,自引:1,他引:5
鸡骨浸酸过程中,采用EDTA螯合滴定法检测浸酸溶液中钙含量,可以准确定量浸酸过程所需的盐酸消耗量,盐酸消耗量与浸酸溶液中可检测的钙离子浓度之间具有良好的相关性。搅拌可以加速钙的溶出,当溶液中钙摩尔量达到盐酸添加量的68%时,及时更换新酸,以此方式控制鸡骨的浸酸过程,整个浸酸过程耗时为12h,浸酸骨素的灰分仅占干物质含量的0.90%,如采用静态浸酸,则需9d的时间。 相似文献
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建立微波萃取结合高效液相色谱-电感耦合等离子体串联质谱同步分离和测定水中砷、硒和铬的9?种元素形态。0.5?mmol/L?EDTA(pH?7.5)缓冲液在100?℃微波萃取2?min,通过Hamilton?PRP-X100阴离子交换色谱进行分离。流动相用氨水调节pH?7.5,以4?mmol/L?NH4HCO3和0.3?mol/L?NH4HCO3分别为流动相A和B进行梯度淋洗,成功地分离了砷甜菜碱、亚砷酸根、二甲基砷酸根、一甲基砷酸根、砷酸根、亚硒酸根、硒酸根、三价铬和六价铬9?种元素形态。电感耦合等离子体串联质谱具有2?个独立质量筛选功能的过滤器,能够很好地消除质谱干扰,同时在不使用甲醇等有机物的情况下使用氧气与目标离子反应生成新的目标待测离子,降低了背景等效浓度,提高了灵敏度。9?种元素形态检出限分别为0.023、0.056、0.032、0.064、0.061、0.091、0.089、0.21?μg/L和0.18?μg/L,均远低于标准限量。精密度(0.23%~11.9%)和回收率(72%~119%)良好,均满足要求。本方法的建立为食品中砷、硒和铬的元素形态分析和前处理方法提供基础研究。 相似文献
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Effect of EDTA, HCl, and Citric Acid on Ca Salt Removal from Asian (Silver) Carp Scales Prior to Gelatin Extraction 总被引:1,自引:0,他引:1
ABSTRACT: Pretreatments with different chemicals at different concentrations to remove Ca compounds were studied to determine their effects on gelatin extraction from silver carp ( Hypophthalmichthys molitrix ) scales. During Ca removal with HCl, citric acid, and EDTA, all 3 chemicals were able to decalcify (>90%) scales; however, protein losses with EDTA were lower than with HCl and citric acid ( P < 0.05), and protein losses with citric acid were lower than with HCl ( P < 0.05). Ca removal with HCl yielded a solution where 4% to 5% of the protein was Hyp, with estimated gelatin losses from 0.9% to 2.5%. After 0.20 mol/L HCl was used for Ca removal, the extracted gelatin solution was 15.4% of the initial scales weight and gave a gel strength of 128 g. After using 1.2 g/L citric acid for Ca removal, the extracted gelatin solution was only 9% of the scales and the gel strength was 97 g. Using 0.20 mol/L EDTA for Ca removal gave a yield of 22% and a gel strength of 152 g. These data suggest that EDTA at 0.20 mol/L provides the best Ca removal with minimal collagen/gelatin removal (estimated gelatin loss was less than 0.013%) during the Ca removal step, and subsequently gave a high gelatin yield and gel strength. Fish gelatin has generally been extracted from fish skins and occasionally fish bones. This article focuses on removing the Ca compounds in fish scales and then producing fish gelatin with a good gel strength and yield. With further studies, this study may help the fish industry to have a new source of fish gelatin for food and pharmaceutical applications. 相似文献
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表面展示南极假丝酵母脂肪酶B的毕赤酵母FM22发酵培养基响应面优化 总被引:1,自引:0,他引:1
FM22培养基以中富的氮源、较强的适应性等优势,适用于毕赤酵母发酵。为进一步对毕赤酵母发酵表达南极假丝酵母脂肪酶B进行优化,选取培养基中对其影响较大的CaSO4、KH2PO4、(NH4)2SO4、PTM4为自变量,酶活力为响应值。通过单因素试验得自变量最佳值及高低水平,再采用Box—Behnken组合设计方法,模拟二次多项式同州方程的预测模型,研究各自变鼍及其交瓦作用埘酶活力的影响。最终得到自变最最佳值:KH2P0445.02g/L、(NH4)2s045.63g/L、CaS040.46g/L、PTM41.63mL/L,酶活力为3214.7U/gDCW,较优化前提高约40%。 相似文献
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Waste materials, stored in inappropriate places, are one of the most significant environmental issues concerning mining activities. In Brazil, one closed uranium mine has faced such a problem. The waste, produced during the neutralization of acid drainage and containing several metals including uranium, has been disposed into the mine opening as a temporary alternative for over 20 years. The present work aimed at the recovery of the uranium present in the aforementioned waste. The effect of the following parameters on the leaching procedure was investigated: solid/liquid ratio, time, temperature, extracting agents, concentration of reagents, and the use of oxidants. The chemical characterization showed that the main constituents of the sample are Ca, S, Mn, and Al. Uranium is around 0.25%. The crystallized phases are ettringite (Ca(6)Al(2)(SO(4))(3)·(OH)(12)·26H(2)O) as the major phase followed by gypsum (CaSO(4)·2H(2)O), calcite (CaCO(3)), and bassanite (CaSO(4)·0.5H(2)O). Carbonate and bicarbonate were observed to be effective extractants for the uranium. However, a combination of both reagents proved to be a better option than their individual use, and extractions around 100% were achieved. The optimum experimental condition for attaining the maximum dissolution is 0.11 solid/liquid ratio, 0.50 mol L(-1) Na(2)CO(3), 1.00 mol L(-1) NaHCO(3), 20 h, and room temperature. 相似文献
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大豆植酸分离方法对测定结果的影响 总被引:5,自引:0,他引:5
探讨了大豆植酸的浸提、离心和离子交换条件对其测定结果的影响。大豆经磨粉、过筛后 ,用 0 3 5mol/LHCl 0 7mol/LNa2 SO4溶液能充分提取出大豆的植酸 ;沸水浴后40 0 0r/min离心 10min可除去蛋白质 ;阴离子交换时 ,依次用 15mL蒸馏水、15mL 0 0 5mol/LNaCl淋洗 ,而后用 2 0mL 0 7mol/LNaCl以 1 0mL/min的速度洗脱 ,洗脱液的植酸加标回收率达到 98%以上 ;4个大豆样品中植酸测定结果的相对标准偏差分别为 1 2 3 %、4 0 5 %、1 5 3 %和 1 83 %。 相似文献
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研究紫色红曲霉(Monascus purpureus)Y20液态发酵过程中不同铵盐对目的产物红曲色素及有害物质桔霉素的合成代谢的影响。在发酵培养基中添加不同铵盐,检测M. purpureus Y20发酵液中红曲红色素、红曲黄色素及桔霉素含量,分析其变化及原因。结果表明:M. purpureus Y20发酵过程中发酵液pH值相对较稳定,未添加铵盐的对照组发酵液基本维持在pH 4.8;添加CH3COONH4、NH4H2PO4、C6H5O7(NH4)3的发酵液pH>6;添加NH4NO3、(NH4)2SO4、NH4Cl的发酵液初始pH<5.5,发酵过程中持续降低至pH 2.5左右;含有0.3 mol/L NH4+的(NH4)2SO4的发酵液中桔霉素含量降为0.05 mg/L,较对照组降低88.6%;含有0.1~0.3 mol/L NH4+的NH4Cl发酵液中桔霉素含量降为0.05 mg/L;含有0.3 mol/L NH4+的NH4NO3发酵液未检出桔霉素,红曲黄色素含量较对照组升高31.0%、红曲红色素含量降低11.6%;添加CH3COONH4、NH4H2PO4、C6H5O7(NH4)3的发酵液无桔霉素检出,但菌体干质量较小,色价较低。因此,添加铵盐可影响发酵液pH值,影响M. purpureus Y20对营养物质吸收和代谢,改变红曲色素的组成比例和抑制桔霉素的生成;添加适量(NH4)2SO4、NH4Cl、NH4NO3有利于促进红曲黄色素的生物合成,阻碍桔霉素的生成。 相似文献
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采用还原法与金属盐法结合,利用Na2S2O3/LiBr/SDS溶剂体系溶解废旧羊毛提取角蛋白,通过设计正交试验和单因素对比试验,以羊毛溶解率和大分子量角蛋白回收率为考察对象确定最佳工艺条件,结果表明:Na2S2O3浓度1.5 mol/L,LiBr浓度0.2 mol/L,SDS浓度0.03 mol/L,pH值12,反应温度80℃,反应时间3 h,羊毛溶解率达91.8%,角蛋白回收率44%,相比单纯还原C法均有提高。 相似文献