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以银耳多糖为原料,采用乙酸酐法制备乙酰化银耳多糖,以乙酰化取代度为指标,探讨反应的时间、温度和乙酸酐用量对取代度的影响,在单因素的基础上,采用响应面法对银耳多糖乙酰化工艺进行优化,并研究乙酰化修饰前后银耳多糖的抗氧化活性。结果表明:银耳多糖乙酰化修饰最佳工艺条件为反应时间2.37h,反应温度61.04℃,乙酸酐用量为2.89mL,在该最佳修饰工艺条件下,乙酰化银耳多糖取代度为0.39。抗氧化研究表明:与未修饰银耳多糖相比,乙酰化银耳多糖对DPPH自由基的清除能力有所增强,对·OH和O2-·的清除能力减弱。 相似文献
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以银耳为原料,在单因素试验基础上,采用响应面法优化银耳多糖提取工艺条件。结果表明,提取银耳多糖最佳工艺参数为液料比79∶1(mL/g)、提取温度91℃、提取时间5 h,此工艺条件下,测得多糖提取率为(20.29±0.15)%;银耳多糖对DPPH自由基、羟基自由基、ABTS+自由基清除能力呈剂量依赖性,在浓度为5 mg/mL时,3种自由基的清除率接近峰值,分别为47.31%、47.43%、52.14%,银耳多糖的抗氧化性是抗坏血酸的50%左右;在相对湿度43%、81%的环境下48 h,银耳多糖的吸湿率分别为25.15%、44.75%,远低于甘油的吸湿率(83.03%、122.65%),接近透明质酸钠(33.50%、53.50%);在干燥硅胶环境下48 h,银耳多糖的保湿率为42.15%,略低于透明质酸钠(49.50%)。 相似文献
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《中国食品添加剂》2017,(1)
以银耳子实体为原料,研究湿法打浆快速提取银耳多糖的工艺条件。以银耳多糖提取率为评价指标,考察料液比、打浆时间、加水温度3个影响因素对银耳多糖提取率的影响,并通过正交试验,确定出最佳提取条件。使用凝胶渗透色谱法(GPC)测定银耳多糖的分子量。结果表明:最佳优化条件为料液比1∶50(g∶m L),打浆时间7min,加水温度为80℃,在此最佳条件下银耳粗多糖的提取率可达40.57%,是传统热水浸提法多糖提取率的2.2倍,提取时间仅为传统热水浸提的1/60。湿法打浆快速提取法和热水浸提法所制备的银耳多糖的平均分子量分别为5.89×10~4KDa和5.86×10~4KDa。 相似文献
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优化微波辅助提取银耳多糖工艺,并研究银耳多糖的流变特性及凝胶特性。利用单因素试验和正交试验确定最佳提取条件为液料比50∶1(mL/g)、粒度120 目、微波功率400 W、微波时间2.0 h,此条件下银耳多糖的提取率达到(33.25±0.14)%。傅里叶变换红外光谱和流变性质测定结果表明,银耳多糖是一种独特的酸性杂多糖,多糖溶液表现出假塑性流体的性质,随着角频率的增加,动态模量增加,银耳多糖溶液在高频区域可形成弱凝胶结构。通过质构测定表明银耳多糖质量浓度显著影响银耳多糖凝胶的硬度及弹性。流变学测试和质构分析表明,银耳多糖具有良好的流变特性和凝胶特性,可替代部分胶体在食品中的使用。 相似文献
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高浓度IgG初乳粉的工业制备技术研究 总被引:1,自引:0,他引:1
本实验探讨了工业化生产高浓度IgG含量初乳粉的工艺条件.通过单因素实验研究了中空纤维超滤膜的超滤条件,确定最佳操作条件为:温度25℃、压力0.10MPa.为了能大规模生产更高浓度IgG含量的初乳粉,对超滤浓缩乳清进一步盐析,比较了两种方法,得出辛酸.硫酸铵法所得的冷冻干燥乳粉其IgG含量最高,达到85%左右,但饱和硫酸铵法更适宜大规模生产. 相似文献
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Ultrafiltration has been successfully used in the manufacture of chhana, an Indian milk product used as a base material for making sweets. The ultrafiltration behaviour of pasteurized whole milk versus severely heated whole milk, as regards the flux, energy requirement for concentration and retention coefficients, was studied. Chhana was manufactured from ultrafiltrated retentates obtained by ultrafiltration of pasteurized whole milk and that of severely heated whole milk and the process standardized with respect to the heat treatment, concentration of coagulant and temperature and pH of coagulation. An increase of 31.4% in the yield of chhana on product basis and of 16.4% on dry matter basis was achieved. Only 4.35 kg of milk was used to produce 1 kg chhana by the ultrafiltration method against 5.7 kg of milk by the conventional method. The process offers access to easy automation and control ensuring uniformity of production on a large scale. 相似文献
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采用不同截留相对分子质量的超滤膜进行超滤分离大豆分离蛋白酶解液,研究超滤过程中操作压力、料液质量浓度、超滤时间对超滤膜通量的影响,确定最佳超滤条件,并测定各超滤级分清除·OH与DPPH·的能力。结果表明:在操作压力0.2 MPa、料液质量浓度50 g/L、通过相对分子质量为10、3、1 k D超滤膜的操作时间80 min、通过相对分子质量为5 k D的超滤膜的操作时间100min的超滤条件下分离大豆肽,超滤效果较好;相对分子质量小于3 k D的小分子大豆肽具有较高的自由基清除率,且对于·OH与DPPH·的清除率具有较高的一致性。 相似文献
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The feasibility of producing protein hydrolyzates using an ultrafiltration (UF) reactor system was evaluated. Soy protein isolate is reacted with a soluble protease in a reaction vessel coupled in a semi-closed loop configuration to a hollow fiber UF unit. Reaction products are pumped past the membrane where hydrolyzate of molecular size small enough to pass through the membrane is removed as permeate. Enzyme and unreacted protein are recycled back to the reaction vessel. The effect of operational parameters such as flow rate (flux), reaction volume, substrate, and enzyme concentration on reactor product output and conversion were studied. The product is typically 91% hydrolyzed protein (N × 6.25) and 9% ash, dry basis, and contains at least four fractions of molecular weight 2500 or less. 相似文献
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Ultrafiltration in Food Processing Industry: Review on Application,Membrane Fouling,and Fouling Control 总被引:1,自引:0,他引:1
Abdul Wahab Mohammad Ching Yin Ng Ying Pei Lim Gen Hong Ng 《Food and Bioprocess Technology》2012,5(4):1143-1156
Ultrafiltration process has been applied widely in food processing industry for the last 20 years due to its advantages over
conventional separation processes such as gentle product treatment, high selectivity, and lower energy consumption. Ultrafiltration
becomes an essential part in food technology as a tool for separation and concentration. However, membrane fouling compromises
the benefits of ultrafiltration as fouling significantly reduces the performance and hence increases the cost of ultrafiltration.
Recent advances in this area show the various intensive studies carried out to improve ultrafiltration, focusing on membrane
fouling control and cleaning of fouled membranes. Thus, this paper reviews recent developments in ultrafiltration process,
focusing on fouling mechanisms of ultrafiltration membranes as well as the latest techniques used to counter membrane fouling. 相似文献
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研究了采用多种膜分离技术生产霉酚酸的工艺。通过陶瓷膜、超滤膜、纳滤膜的组合试验,对膜组件进行了筛选,得到了优化的试验方案。通过工艺优化,霉酚酸收率提高至65%~70%,有机溶剂用量减少70%,溶剂损耗减少80%以上,大幅度降低了生产成本,简化了生产工艺,提高了产品的收率和质量,使工艺过程更安全,环保。 相似文献