一种新的提高法夫酵母中虾青素稳定性的方法

虾青素作为天然的着色剂、饲料添加剂和保健营养品,可广泛应用于食品、医药和化妆品行业,而法夫酵母是可生产天然虾青素的主要微生物之一。为了评价抗氧化剂在法夫酵母虾青素提取中的应用价值,研究其对虾青素稳定性的影响,以提取液中虾青素含量为指标,并在对细胞酸法破壁、酶法破壁以及溶媒萃取色素过程中辅助添加抗氧化剂,测定了虾青素在酸、酶、温度、和溶媒等不同条件下的保留率。试验结果表明,在细胞破壁和溶媒萃取色素过程中,添加适量的抗氧化剂,可以显著提高虾青素的稳定性;在乳酸破壁及丙酮提取过程中分别添加抗坏血酸和生育酚,使得虾青素的提取率较传统方法提高了28.01%。抗坏血酸和生育酚属于天然抗氧化剂,不会引起残留毒性,具有较好的工业应用前景。     

Studies of astaxanthin biosynthesis in Xanthophyllomyces dendrorhous (Phaffia rhodozyma). Effect of inhibitors and low temperature

The effect of nicotine and diphenylamine on astaxanthin biosynthesis in Xanthophyllomyces dendrorhous was studied. The effects were analysed under standard and low temperature conditions. It was found that 10 mm-nicotine inhibits the cyclization of lycopene and de novo protein synthesis was not needed to reverse the inhibition. The oxidation of β-carotene was irreversibly inhibited by 10 μM -diphenylamine while the dehydrogenation of phytoene was reversibly inhibited by 60 μM -diphenylamine. The simultaneous exposure to low temperature (4°C) overcomes the inhibition of β-carotene oxidation at low diphenylamine concentration. © 1998 John Wiley & Sons, Ltd.     

法夫酵母中虾青素的稳定性研究

采用贮藏试验对碱法破壁酵母类胡萝卜素的稳定性进行了研究。结果表明，不同贮藏条件下，酵母色素连续以两个速度常数不同的一级方程进行降解（k1〉k2）。第一个一级反应主要反映受损脂肪粒中类胡萝卜紊的变化，第二个反应主要反映未受损脂肪粒中类胡萝卜素的变化。比较不同贮藏条件下的试验结果及各个动力学方程的速度常数，表明采用低温、避光、隔氧及添加抗氧化剂有利于提高酵母色素的存留率，而酵母水分（〈12％）及矿物盐对之影响不大。     

Purification and biochemical characterization of an alpha-glucosidase from Xanthophyllomyces dendrorhous

Xanthophyllomyces dendrorhous grown in different media shows amylolytic activity, consisting in an extracellular exo-acting enzyme able to hydrolysed alpha,1-4 glycosidic bonds from soluble starch, which also cleaves maltose and malto-oligosaccharides. The enzyme was purified, using basically a couple of chromatography process on DEAE-Sephacel. It is a glycoprotein with a molecular weight estimated to be 60.2 kDa based on its mobility in SDS-PAGE and 115 kDa based on gel filtration. N-linked carbohydrate accounts for 12% of the total mass. It exhibited optimum activity at pH 5.5 and 45 degrees C. Thermostability analysis indicated that it was stable to thermal treatment up to 50 degrees C; 50% of the activity was maintained after 3 h. The rate parameters measured for the hydrolysis of starch and various chain length malto-oligosaccharides shows high catalytic efficiency, calculated by the relationship V(cat)/K(m), for malto-oligosaccharides, such as maltotriose (873 mM(-1) min(-1)), or maltoheptose (698 mM(-1) min(-1)). The new enzyme hydrolysed soluble starch with nearly 3.5- and 1.4-fold lower efficiency than that for maltotriose and maltose, respectively. No activity was found on heterogeneous substrates, such as sucrose and aryl alpha-glucoside, or on isomalto-oligosaccharides. In accordance to substrate specificity profile, the new enzyme was classified as an alpha-glucosidase.     

响应面法优化雨生红球藻中虾青素的提取条件

以雨生红球藻粉为原料,选取乙酸乙酯:乙醇(1:1,v/v)为提取溶剂,以虾青素提取率为评价指标,在单因素实验的基础上,利用响应面法对雨生红球藻中虾青素的提取条件进行了优化。结果表明,影响虾青素提取条件的强弱分别为温度>液固比>时间,通过计算回归方程优化得到的最佳提取条件为:温度50℃,时间100 min,液固比1.5:1。通过与荆州公司提供的提取方法和碱提法对比,应用此方法虾青素提取率分别提高了44.31%和86.80%。     

响应面法优化雨生红球藻虾青素的超声提取工艺

以雨生红球藻为原料,选取乙酸乙酯∶乙醇(v/v,1∶1)为提取溶剂,采用超声法提取虾青素,固定液料比为100∶1,以超声功率、超声时间和超声温度为因子,虾青素提取率为评价指标,在单因素实验的基础上,利用响应面法对提取条件进行优化。三因素对虾青素提取率的影响顺序为:时间>温度>功率。优化得到的最佳提取条件为:超声功率200W、时间30min、超声提取温度25℃,在此条件下提取率可达1.045%,与预测值1.05%相近,表明模型可用。      

红酵母虾青素提取工艺的优化

对一株红酵母菌胞内虾青素提取工艺进行研究。首先分别从二甲亚砜(DMSO)浓度、破壁温度、破壁时间方面进行红酵母破壁实验;其次从浸提溶剂、浸提温度、浸提时间及浸提溶剂pH方面进行虾青素提取实验;再通过正交实验优化虾青素提取工艺。结果表明:二甲基亚砜浓度100%,温度40℃,时间30min为最适破壁条件;提取溶剂二甲基亚砜:无水乙醇为3:2(v:v),温度40℃,时间60min,pH6为虾青素提取最适条件。结论:二甲亚砜联合乙醇提取红酵母虾青素,提取方法简便,效果良好。     

虾壳中虾青素的乙醇解吸-稀碱提取工艺优化

采用乙醇解吸—稀碱液提取的内部沸腾法对虾壳中虾青素进行提取。考察解吸时间、乙醇的用量、稀碱的浓度、稀碱的量、提取的温度、提取的时间等因素对提取效果的影响。结果表明,在室温下,虾壳粉在12 L的95%乙醇中解吸30 min,然后用30 mL浓度为1.0 mol/L的氢氧化钠溶液提取4 min,可获得虾青素浓度为171.2μg/g的溶液体系,虾青素提取得率达19.5%。该工艺采用的有机溶剂无毒且用量少,提取液色泽透亮,用时短,提取效果较好。      

不同来源虾青素提取、纯化及定量检测方法的研究进展

虾青素是一种较强的天然抗氧化剂,能有效淬灭单线态氧和清除自由基,减少氧化对组织细胞和DNA损伤的能力,能有效防治相关的疾病,还可用作鱼类和家禽饲料的添加剂,改善皮肤和肌肉颜色、提高繁殖能力、增加营养及商品价值,在饲料、食品、医药及化妆品等领域具有广泛的应用。天然虾青素存在于虾蟹外壳、牡蛎、鲑鱼及藻类和真菌中,其存在形态和结构存在差异。由于虾青素有3种光学异构体、多种几何异构体,且极易与脂肪酸结合形成虾青素单酯、虾青素双酯,导致虾青素的结构复杂多样,对虾青素的分析存在许多困难和挑战。本文从虾青素的结构、应用、破壁方法、提取纯化及定量检测方法等方面,对不同来源的虾青素进行了概述,以期为虾青素资源的深入研究和开发利用提供参考。     

低毒高效提取雨生红球藻中虾青素的工艺优化

随着虾青素的应用范围不断扩大,提取剂的安全性问题也日益突出。以雨生红球藻为原料,研究了多种提取剂的得率,以选出低毒高效的提取溶剂。同时,还研究了料液比、温度及提取时间对雨生红球藻中活性成分虾青素得率的影响,并通过正交实验优化提取参数,获得最佳提取工艺。结果显示,各因素对得率的影响大小依次为:料液比>提取时间>温度>提取溶剂。提取溶剂、料液比、温度和提取时间的最佳条件分别是:乙酸乙酯∶乙醇(1∶1)、1∶100、40℃、20 min,最佳得率为49.96%。      

高压蒸汽提取啤酒废酵母还原型谷胱甘肽的工艺优化

为了得到高压蒸汽提取废酵母中还原型谷胱甘肽的最佳工艺条件,利用Box-Behnken的中心组合设计及响应面法（RSM）探讨了表压、提取时间、液料比和提取次数四因素的优化组合。通过建立二次回归模型,确定其最佳提取工艺条件为:表压1.1MPa,提取时间15min,液料比10∶1,提取次数1次,在此条件下得率最大为4.63mg/g。结果表明高压蒸汽提取技术是提高啤酒废酵母还原型谷胱甘肽得率的有效途径之一。      

A new environmentally friendly method for astaxanthin extraction from <Emphasis Type="Italic">Xanthophyllomyces dendrorhous</Emphasis>

Few environmentally friendly solvents are available to extract food-grade astaxanthin. In this paper, some environmentally friendly solvents, such as lactic acid, ethyl lactate, and ethanol, were employed in cell disruption and astaxanthin extraction from Xanthophyllomyces dendrorhous. The extraction procedure was optimized, validated and compared with other conventional extraction techniques. This method gave the best result due to the highest extraction efficiency within short extraction time. The optimum extraction conditions were as follows: the yeast cell wall was disrupted by lactic acid at 65° C for 1 h and then extracted with ethyl lactate:ethanol (1:1, v/v) for 0.5 h. It was proved that the extraction efficiency was enhanced by the addition of the natural antioxidant α-tocopherol. This new method showed low chemical toxicity and gave high extraction efficiency, which had good prospects for mass production at the industrial scale.     

天然虾青素生产方法研究进展

为进一步提高湖泊红球藻（Haematococcus lacustris）的工业利用价值,本研究使用常压室温等离子体（atmospheric and room temperature plasma,ARTP）诱变仪对湖泊红球藻进行等离子诱变。以藻细胞致死率为指标确定等离子诱变的适宜输入功率和诱变时间。诱变之后通过固体平板培养初筛和液体培养复筛获得高产虾青素的突变藻株。再以藻细胞密度为指标采用单因素实验及正交试验对高产藻株的营养生长阶段的培养条件进行优化,并筛选虾青素诱导阶段适宜虾青素积累的高光照条件。在优化的培养条件下多次继代后观察高产突变藻株的遗传稳定性。结果表明,湖泊红球藻等离子诱变的适宜条件是功率240 W、诱变时间150 s或功率400 W、诱变时间120 s。通过初筛和复筛获得生长快、虾青素产量高的突变藻株有11株,其中编号为HP3的突变藻株生长最快、虾青素产量最高,培养后藻细胞密度和虾青素产量较出发株分别提高了25.5%和61.6%。经过两阶段培养条件的优化,HP3的藻细胞密度和虾青素产量较优化前分别提高了14.3%和19.3%,达7.2×10⁵ cell/mL和31.264 mg/L。湖泊红球藻高产突变藻株HP3多次继代后藻细胞生长良好,遗传稳定,培养后藻细胞密度和虾青素产量均与初代培养相近。研究结果对湖泊红球藻产虾青素工业藻株的选育具有实际意义。

     

仙草多糖提取工艺的优化

目的对仙草多糖碱液提取工艺条件进行优化。方法研究碱提法提取仙草多糖的条件,考察碱浓度、提取温度、提取时间及液料比等因素对仙草多糖得率的影响。在单因素实验的基础上,选取碱浓度、提取时间及液料比3因素应用响应面中Box-Benhnken设计原理进行试验设计,以仙草多糖提取率为响应值,建立多糖提取率的二次回归方程,得到碱液提取多糖的最佳条件。结果仙草多糖提取的最佳浸提条件:Na HCO_3 1.25%,提取时间3h,液料比35:1(V:m),在此条件下仙草多糖提取率为8.10%。结论碱液提取法能够提高仙草多糖的提取率。     

Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: Non-conventional methods for the recovery of high-added value compounds

BackgroundA large amount of wastes and by-products are generated during olive oil production process. Traditionally, these products have been considered as a problem. However, they constitute a great source of high-added value compounds, which have the potential to be used as food additives and/or nutraceuticals. Therefore, valorization of wastes and by-products from food industry kills two birds with one stone and addresses both the use of waste and by-products and societal health, thus greatly contributing for a sustainable food chain from an environmental and economical point of view.Scope and approachIn the present review, current and new insights in the recovery of high-added value compounds from wastes and by-products generated during olive oil production process will be discussed. Several conventional (solvent, heat, grinding) and non-conventional methodologies (ultrasounds, microwaves, sub- and supercritical fluid extractions, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges) have been investigated for the recovery of high-added value compounds (polyphenols, fatty acids, coloring pigments (chlorophylls and carotenoids), tocopherols, phytosterols, squalene, volatile and aromatic compounds) from wastes and by-products generated during olive oil production process.Key findings and conclusionsNon-conventional technologies can constitute a promising tool to recover high-added value compounds from olive oil wastes and by-products. However, the content of these valuable compounds can vary greatly depending on the matrix and the efficiency in the recovery of these compounds is highly dependent of the technology used for extraction.     

鳕鱼卵中磷脂提取工艺的优化

为了充分利用鳕鱼资源,提高海产品附加值,采用溶剂提取法,以乙醇液为提取溶剂,以磷脂得率及纯度为考察指标,通过单因素实验及正交实验,探讨乙醇浓度、料液比、提取次数和提取时间等四个因素对磷脂提取的影响,并制定出最优鳕鱼卵中磷脂的提取工艺。结果表明,鳕鱼卵中磷脂的最佳提取工艺条件为:以1:10 (g/mL)的料液比比例,采用乙醇浓度为90%的乙醇溶剂搅拌提取鳕鱼卵3 次,每次提取6 h。该工艺成本低、方法简单、污染少、易于实现工业化。     

酶解-溶剂法提取罗汉果中黄酮类物质的研究

研究酶法与溶剂提取相结合提取罗汉果中黄酮类化合物的工艺条件,通过正交试验找出纤维素酶法及溶剂提取的最佳工艺条件。纤维素酶法的最佳提取工艺条件为纤维素酶浓度50U/mL、酶解液pH5.2、酶解温度65℃、酶解时间80min;溶剂提取的最佳工艺条件为乙醇∶粗提液(体积比)=1∶8,石油醚∶粗提液(体积比)=3∶1,乙酸乙酯∶粗提液(体积比)=2∶1,结果表明酶解-溶剂法提取罗汉果黄酮具有较高的提取率,是一种安全可靠的提取方法。     

纤维素酶辅助提取茶树菇多糖的研究

通过单因素及正交试验研究纤维素酶酶解辅助提取茶树菇子实体多糖的最佳工艺。研究结果表明:水浴提取茶树菇子实体多糖料液比为1∶60,提取时间120m in,温度为60℃时提取效果最佳;纤维素酶酶解辅助提取茶树菇子实体多糖,料液比为1∶80,酶浓度1.5%,浸提液pH 6.0,提取温度50℃。对2种提取法进行了比较,水浴法提取茶树菇多糖的平均提取率为1.40%;纤维素酶酶解辅助提取茶树菇多糖的平均提取率2.38%,比水浴法提高了70.47%。纤维素酶酶解辅助提取茶树菇多糖明显优与水浴法。     

羊栖菜多酚提取工艺优化

目的对羊栖菜多酚提取工艺进行优化研究。方法通过乙醇溶剂提取羊栖菜中多酚,探讨乙醇浓度、提取时间、料液比以及提取温度等因素对羊栖菜多酚提取的影响,在单因素的基础上,选取乙醇浓度、提取时间和液料比为影响因子,应用Box-Benhnken中心组和设计原理进行3因素3水平实验设计,以羊栖菜多酚的提取量为响应值,运用响应面(response surface methodology,RSM)法对羊栖菜多酚提取工艺进行优化。结果回归模型具有高度显著性,方程对试验拟合较好,可以对羊栖菜多酚提取量进行很好的分析和预测;各因子对提取量的影响大小依次是乙醇浓度料液比提取时间,羊栖菜多酚最佳提取条件为乙醇浓度25%、提取时间3 h、液料比30:1(V:m)、提取温度40℃。结论在此条件下羊栖菜多酚的提取率达7.91 mg/g,与预测值8.02 mg/g基本一致。