果胶酶在果蔬加工中的应用

果胶酶是指分解果胶类物质的多种酶的总称。通常包括原果胶酶、果胶甲酯水解酶、果胶酸酶。果胶酶普遍存在于细菌、真菌和植物中,在果蔬加工、饲料、纺织和造纸业中应用非常广泛。本文对果胶酶的来源、分类、作用机制及其在果蔬加工中的应用等方面进行综述。     

棉织物染整中不同果胶酶精练效果的比较研究

通过试验得出果胶酶应用的较佳工艺条件:酸性果胶酶A pH值3～5,温度30～60℃;碱性果胶酶B pH值7～9,温度40～60℃.在此工艺条件下比较2种酶的精练效果,并测定2种果胶酶酶活、SDS-PAGE电泳等,分析研究了它们的精练特点.结果表明:碱性果胶酶B分子质量小,酶的专一性更强,对棉纤维果胶物质去除具有较好的效果[碱性果胶酶B 0.025%(owf),JFC 0.2 g/L,果胶去除率70%].     

果胶酶在果蔬汁加工中的应用

果胶作为细胞结构的一部分,是一种高分子的多糖化合物,存在于植物及微生物细胞中。果胶酶是分解果胶物质的酶的总称,广布分布在自然界当中。如今,通过对果胶酶应用的相关研究,果胶酶已充分应用到食品加工领域,尤其是在果蔬汁加工中起着重要的作用。本文就果胶酶在果蔬汁加工过程中的应用加以概述及研究,希望对食品加工领域有一定的借鉴作用。     

果胶酶及其在果蔬汁加工中的应用

果胶酶普遍存在于细菌、真菌和植物中，是分解果胶类物质的多种酶的总称，在果蔬加工、饲料、纺织和造纸工业中应用非常广泛。介绍了果胶的组成和结构，论述了果胶酶的分类、作用机制及酶活测定方法，并对果胶酶在果蔬汁加工中的应用等方面进行综述。     

苎麻果胶的提取及在果胶酶活测定中的应用

研究了苎麻中纤维果胶的提取,优化的提取工艺为:温度90℃,草酸铵质量浓度5g/L,液料比为30:1,反应时间90min。以纤维果胶和苹果果胶为底物,采用DNS法测定了棉精练用碱性果胶酶的酶活力。结果表明,以纤维果胶为底物测定的棉织物精练用碱性果胶酶酶活力为151.6U/mL,远高于苹果果胶的5.3U/mL,更适合用来表征棉织物精练用果胶酶的酶活力。     

微生物果胶酶的应用研究

针对微生物果胶酶的不同用途,介绍了其分为原果胶酶、多聚半乳糖醛酸酶、裂解酶和果胶酯酶,并着重介绍了利用果胶酶分解植物细胞的细胞壁、分解细胞间质中的果胶物质和生产果胶低聚糖上的应用.     

果胶酶在亚麻纱前处理中的应用

采用碱性果胶酶代替碱对亚麻纱进行精练,通过正交试验,确定了碱性果胶酶精练的最佳工艺条件,分析了影响碱性果胶酶对亚麻纱精练的因素.实验证明在较低的温度下采用碱性果胶酶进行精练,与常规的高温碱精练工艺相比,果胶去除程度高,润湿性好,白度相当,可节约能源,减少环境污染.     

果蔬贮藏保鲜过程中果胶酶变化的研究进展

果胶是植物细胞壁胞间层的主要成分,果胶酶存在于天然植物组织中,可以催化果胶分解,进而破坏细胞壁的完整性,使得果蔬硬度下降。在贮藏过程中影响果蔬软化的因素主要有乙烯、Ca2+及温度等。常见的果蔬保鲜技术包括有物理、化学及生物保鲜技术,不同的保鲜技术对果蔬软化的机制不同。本介绍了果胶的结构及果胶酶的分类,同时总结了影响果胶酶活性的主要因素及其常见贮藏保鲜技术对果胶酶的影响,为果蔬贮藏保鲜过程中抑制软化的研究奠定理论基础。     

果胶酸类物质的酶解及其对DCS稳定性的影响

选用两种商品果胶酶制剂,首先优化其酶解果胶类物质的反应条件,结果发现,两种果胶酶在pH值9.0,温度为60～70℃的较优条件下可以有效地酶解果胶类物质和马尾松化学机械浆DCS,降低其阳离子需求量(CD值).在探求两种果胶酶酶解果胶类物质的机理时,得出在对PGA类物质(酸性果胶物质)进行果胶酸(盐)裂解酶(PGL)处理以降低CD值时,没有必要将其完全酶解成单体,而只需将其聚合度降为6左右即可.碱性果胶酶(PL)处理果胶时也有类似的结果.同时发现,在漂白浆DCS中的果胶类物质主要是以果胶酸的形式存在,在选用果胶酶时应选用PGL.马尾松化学机械浆DCS经PGL酶处理以后虽然对提高DCS的稳定性作用不大,但可以减缓其沉淀的速度.     

生物酶在纺织工业中的应用(十一)

9 其它水解酶及在纺织行业中的应用 9.1 果胶酶 9.1.1 果胶物质及特性 果胶的主要聚合单体如下: 果胶物质主要是由D-半乳糖醛酸及D-半乳糖醛酸甲酯通过α-1,4-糖苷键连接形成的直线状高聚物,在植物中呈胶态分布<'[1]>.果胶在自然界中分布很广,是植物合成纤维素和半纤维素的营养物质,也是植物细胞间质和初生胞壁的重要组成部分,在植物细胞组织中起粘合作用.     

Combined Bioscouring and Bleaching of Cotton Fibres

SUMMARY

Cotton fibres were scoured with acid and alkaline pectinases and bleached with peracetic acid. Because of similar treatment conditions of both processes, they were combined in one bath as one-step and two-step processes. At the beginning of the treatments, pH 5 was set for acid pectinases and pH 8 for alkaline pectinases. To activate the peracetic acid, pH was also adjusted during the process. Tetrasodium pyrophosphate was added to improve the effects of bleaching and scouring. The highest CIE whiteness values and water absorbencies were obtained in a one-step process with alkaline pectinases and peracetic acid.     

高产果胶酶菌株的选育及其发酵生产的研究进展

文章论述果胶酶的分类、作用机制及近年来微生物果胶酶产生菌的研究情况,综述微生物果胶酶产生菌的选育方法和发酵方法的研究进展,展望果胶酶研究、开发和应用的广阔前景。     

酶在植物多糖研究中的应用进展

植物多糖是植物生命活动所必需的生物大分子,其研究主要集中在提取分离、结构修饰、结构解析及生物活性等方面。酶作为常见的生物催化剂,因其高效、专一的特性,在植物多糖研究中的应用也越来越广泛。该文概述植物中淀粉、纤维素、果胶、半纤维素等多糖的结构信息,并介绍淀粉酶、纤维素酶、果胶酶、半纤维素酶等的分类和作用方式;总结酶在植物多糖提取、结构修饰及在结构分析中的应用研究进展,以期深化对酶、植物多糖的理解以及开发多糖在食品、生物医药和其他领域的应用。     

果胶酶生产及其在苹果汁澄清中的应用

对黑曲霉(Aspergillus niger)LLW-1菌株固态发酵生产酸性果胶酶的发酵培养基组成和发酵条件以及利用果胶酶澄清苹果汁的工艺条件进行了研究。固态发酵产酶条件为:250 mL三角瓶装10 g基料(豆饼∶麸皮=2.0 g∶8.0 g),(NH4)2SO420 g/kg,Tween-80 1.5 g/kg,玉米浆50 mL/kg,KH2PO43.0 g/kg,CaCl21.0 g/kg,MgSO4.7H2O 1.0 g/kg(均相对于基料),料水比1∶1.2,自然pH;31℃静置培养72 h,期间在为24 h翻曲1次,果胶酶活力达2 418 IU/g(干曲)。酸性果胶酶澄清苹果汁的工艺条件为:果汁自然pH值,果胶酶用量500IU/L(果汁),明胶添加量0.05 g/L(果汁),酶解温度和时间分别为45℃和1 h。     

响应面法优化酥李果汁的酶法提取工艺

目的:研究酶解提取酥李果汁的最佳工艺条件,为李深加工利用提供理论参考。方法:以酥李出汁率为指标,在单因素实验基础上采用响应面试验优化,对单一果胶酶、单一纤维素酶、复合酶（果胶酶和纤维素酶）提取酥李果汁的工艺条件分别进行优化。结果:不同加酶方式中对酥李出汁率的影响因素顺序均为酶解温度>加酶量>酶解pH>酶解时间;果胶酶酶解提取酥李果汁的最佳工艺条件为:加酶量0.45 g/L、酶解温度38 ℃、酶解pH3.8、酶解时间72 min,出汁率提高27.13%;维素酶酶解提取酥李果汁的最佳工艺条件为:加酶量0.55 g/L、酶解温度41 ℃、酶解pH4.2、酶解时间105 min,出汁率提高20.18%;复合酶酶解提取酥李果汁的最佳工艺条件为:果胶酶添加量0.45 g/L、纤维素酶添加量0.55 g/L、酶解温度41 ℃、酶解pH4.0、酶解时间87 min,出汁率提高31.79%。三种加酶方式中,回归模型均能较好地反应相应酶制备酥李果浆的出汁率,所得工艺合理可靠。结论:在酶法提取酥李果汁过程中,果胶酶和纤维素酶的不同添加方式均能有效提高酥李出汁率,其中采用复合酶提取酥李果汁效果最佳。本研究成果为贵州李产品开发提供了一定的技术参考。     

The pectin substance used to detect the activity of pectinase suitable for bioscouring

Structural characteristics of pectins from cotton fabrics, ramie, and apple were investigated by titration method and ATR–FTIR spectra. Pectin from cotton fabrics and ramie showed similar structure characteristics, both these two pectins showed big structural difference with pectin from apple. The activities of five pectinases were determined by using these three pectins as substrates. These five pectinases showed similar hydrolysis action on pectin from ramie and cotton fabrics, they also showed a great difference in the hydrolysis of pectin from apple and cotton fabrics. Moreover, bioscouring effect with these five pectinases was investigated, the pectinases with stronger hydrolysis action on ramie pectin displayed better bioscouring effect and the pectinase suitable for bioscouring was selected out. The bioscouring effect of the pectinase selected out was studied and showed almost perfect bioscouring effect.     

A review on pectinase properties,application in juice clarification,and membranes as immobilization support

Pectic substances cause haziness and high viscosity of fruit juices. Pectinase enzymes are biological compounds that degrade pectic compounds. Nontoxicity and ecofriendly nature make pectinases excellent biocatalysts for juice clarification. However, the poor stability and nonreusability of pectinases trim down the effectiveness of the operation. The immobilization techniques have gained the attention of researchers as it augments the properties of the enzymes. Literature has reported the stability improvement of enzymes like lipase, laccase, hydrogen peroxidase, and cellulase upon immobilization on the membrane. However, only a few research articles divulge pectinase immobilization using a membrane. The catalysis-separation synergy of membrane-reactor has put indelible imprints in industrial applications. Immobilization of pectinase on the membrane can enhance its performance in juice processing. This review delineates the importance of physicochemical and kinematic properties of pectinases relating to the juice processing parameters. It also includes the influence of metal-ion cofactors on enzymes’ activity. Considering the support and catalytic-separation facets of the membrane, the prediction of the membrane as support for pectinase immobilization has also been carried out.     

Influence of Enzymatic Pretreatment on the Colours of Bleached and Dyed Flax Fibres

SUMMARY

In this paper the effect of enzymatic bioscouring on the bleaching and dyeing of flax fibres was studied in comparison with conventional alkaline scouring. Enzymatic bioscouring was performed with a commercial multi-enzyme system consisting of pectinases, hemicellulases and cellulases. The enzyme and alkaline scoured flax fibres were subsequently oxidatively bleached with hydrogen peroxide and dyed with direct dye C.I. Direct Red 80 under the same conditions. The efficiency of both the scouring and bleaching processes was evaluated by weight loss and the whiteness of the bleached samples was determined according to CIE formula. The exhaustion profile of the used dye was followed on-line during the dyeing process using absorbance measurement. The colours of bleached and dyed samples were evaluated using CIELAB colour values. The residual pretreatment and dyeing baths were ecologically analysed with COD, TOC and BOD₅. The obtained results indicate that enzymatic scouring provides a lower weight loss, a higher degree of whiteness, comparable dyeing properties and is more environmentally friendly.     

Pectins in Processed Fruit and Vegetables: Part I—Stability and Catalytic Activity of Pectinases

ABSTRACT: Pectinases catalyze numerous pectin conversion reactions strongly impacting on the quality of fruits, vegetables, and the related intermediate and end products. The effect of processing on the stability and catalytic activity of pectinases is of prime importance to food processors since desirable and/or deleterious reactions can be tailored (accelerated or inhibited) meeting specific quality targets. Of the multiple endogenous enzymes involved in the modification and degradation of pectin, pectinmethylesterase (PME), and polygalacturonase (PG) have been widely investigated in the context of fruit and vegetable processing. This review covers the stability and catalytic activity of endogenous plant PME and PG including the quantitative approaches applied in inactivating and/or boosting the catalytic activity of the enzymes in purified and real food systems. This will be discussed in the context of both traditional and novel food processing technologies.