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Naringinase Immobilization in Packaging Films for Reducing Naringin Concentration in Grapefruit Juice 总被引:4,自引:0,他引:4
Naringin, a bitter compound in citrus, may be converted to a nonbitter form by enzymic hydrolysis. Our objective was to determine the feasibility of immobilizing naringinase in a food contact approved packaging film. Naringinase from Penicillium sp. was immobilized in cellulose acetate films with up to 23% efficiency at 7°C. Kinetic studies showed that the free enzyme had an optimum pH=3.5 and the immobilized enzyme pH=4.0. Activation energy decreased upon immobilization (from 14.2 to 11.0 Kcal/mol), thus providing an increased catalytic efficiency for immobilized naringinase. The Michaelis constant for immobilized naringinase (Km =2.1 mM) was lower than for free enzyme (Km m=3.6 mM). Keeping films under dry storage for 1 mo at room temperature did not cause decreased enzyme activity. A film area/volume ratio (cm2 /mL of 10° Brix grapefruit juice) of 7.2 hydrolyzed 60% of the naringin in 15 days at 7°C. 相似文献
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黑曲霉产柚苷酶的发酵条件优化 总被引:1,自引:0,他引:1
利用高效液相色谱法,检测发酵液中α-鼠李糖苷酶和柚苷酶的活力,考察碳源、pH值、搅拌转速、发酵温度对柚苷酶产量的影响,对黑曲霉DB056产柚苷酶的7L罐发酵工艺进行优化.研究结果表明,以20g/L柚皮苷为唯一碳源,发酵黑曲霉DB056产柚苷酶的效果最佳.发酵过程的pH值、搅拌转速和发酵温度的最优控制值分别为6.0、700 r/min和32℃,此时产酶效果最理想,发酵过程α--鼠李糖苷酶和柚苷酶最大酶活力分别达到1 133.00和788.42U/mL.将优化的发酵工艺放大到200 L发酵罐进行试验,α-鼠李糖苷酶和柚苷酶的最大酶活力分别为1 069.30 U/mL和727.44 U/mL.中试放大效果良好. 相似文献
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研究了超声波及热处理对柚皮苷酶的活性及热稳定性的影响,通过圆二色谱分析超声波及热处理对柚皮苷酶二级结构的影响。结果表明,随着温度的升高,酶失活速率加快,在80℃下保温150min,柚皮苷酶残留酶活仅为原酶的15.69%。超声功率为40~120W时,短时间的超声处理对柚皮苷酶活性有促进作用,而功率大于160W时超声波处理对柚皮苷酶活性有钝化作用。80W处理对柚皮苷酶的热稳定性有促进作用,处理5min后60℃保温150min,酶活性比未经处理的柚皮苷酶活性增加了64.34%;而280W处理对柚皮苷酶的热稳定有钝化作用,处理40min后60℃保温150min,酶活性比未经处理的柚皮苷酶活性降低了42.61%。圆二色谱分析结果表明,未经处理的柚皮苷酶中α-螺旋含量较少,主要结构为β-折叠和无规则卷曲;热处理及超声波处理对α-螺旋结构几乎没有影响,β-折叠、β-转角及无规则卷曲含量的变化分别在0.4%~1.1%、0.1%~0.4%及0~0.9%之间。 相似文献
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分析柚苷酶产生菌青霉(Penicillium sp.)1523在5 L自控发酵罐中的分批发酵动力学。探讨了青霉1523在5 L罐分批发酵过程中菌体生长、柚苷酶合成及基质消耗的变化规律,结果表明:菌体生长呈典型S型曲线,酶的合成与菌体生长趋势呈现部分相关性,属于部分偶联型。基于这些过程曲线的变化规律,结合Logistic方程和Luedeking-Piret方程,建立了柚苷酶产生菌青霉1523分批发酵过程的动力学模型,并通过数学推导和非线性拟合获得了模型中各参数的最佳取值,最终确定了能够较好表征青霉1523分批发酵过程中菌体生长、产物柚苷酶合成以及基质消耗的动力学方程。 相似文献
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微生物来源柚苷酶的研究进展及应用 总被引:2,自引:0,他引:2
柚皮苷是影响柚子汁品味的最主要因素,柚苷酶具有将柚皮苷分解为普鲁宁、鼠李糖、葡萄糖和柚皮素等物质的功能,并且这些物质已广泛用于制药和饮料行业。本文介绍了近年来国内外微生物来源的柚苷酶的研究、酶学特性、酶活测定、结构与功能等,表明细菌来源的柚苷酶最适温度为37~70℃,最始pH值为4.5~8.0;真菌来源的柚苷酶最适温度为30~75℃,最始pH值为4.0~11.0。介绍了柚苷酶及其相关产物在食品、饮料和制药工业中的应用进展,发现柚苷酶不仅具有脱苦的作用,还对人类的身体健康具有重要作用。展望了今后的研究方向,应该从柚苷酶高产菌株的选育、发酵产酶的工艺优化和酶的应用等方面开展工作,大幅度提高柚苷酶的产酶水平。 相似文献
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本文在磁性Fe3O4外包覆一层SiO2,再在其外包裹壳聚糖制备出磁性硅基壳聚糖微球(MSC),对MSC进行环氧基修饰后用于柚苷酶的固定化研究,并对磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷的pH、温度、操作和储藏稳定性进行了考察。通过单因素实验,确定了环氧基修饰的磁性硅基壳聚糖微球(MSCE)固定化柚苷酶的最佳工艺条件为:pH 3.0,温度30 ℃,时间4 h、给酶量57.48 U/mL。在此条件下,MSCE固定化柚苷酶的载酶率、酶活回收率和酶比活力分别为31.29%、88.92%和409.33 U/g。与游离柚苷酶相比,MSCE固定化柚苷酶用于水解柚皮苷具有良好的pH稳定性和温度稳定性,重复使用8次后仍具有53.36%的相对酶活力,4 ℃条件储存一个月后仍具有80.97%的相对酶活力。 相似文献
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Munish Puri Harsimran Kaur John F Kennedy 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(10):1160-1165
Naringinase (EC 3.2.1.40) from Penicillium sp was immobilized by covalent binding to woodchips to improve its catalytic activity. The immobilization of naringinase on glutaraldehyde‐coated woodchips (600 mg woodchips, 10 U naringinase, 45 °C, pH 4.0 and 12h) through 1% glutaraldehyde cross‐linking was optimized. The pH–activity curve of the immobilized enzyme shifted toward a lower pH compared with that of the soluble enzyme. The immobilization caused a marked increase in thermal stability of the enzyme. The immobilized naringinase was stable during storage at 4 °C. No loss of activity was observed when the immobilized enzyme was used for seven consecutive cycles of operations. The efficiency of immobilization was 120%, while soluble naringinase afforded 82% efficacy for the hydrolysis of standard naringin under optimal conditions. Its applicability for debittering kinnow mandarin juice afforded 76% debittering efficiency. Copyright © 2005 Society of Chemical Industry 相似文献