紫甘蓝色素液澄清工艺研究

以紫甘蓝为原料,采用水剂法提取紫甘蓝色素,利用果胶酶澄清紫甘蓝色素液,分别研究了预处理及酶法澄清工艺对紫甘蓝色素液澄清度的影响,并进行响应面优化实验。结果表明,粉碎预处理以及果胶酶浓度、酶解温度和酶解pH对紫甘蓝色素液的澄清度影响较大,响应面优化酶法澄清最佳工艺参数为:果胶酶浓度0.0013mL/100g、酶解温度55.6℃、pH4.1、酶解时间50min,在此条件下,紫甘蓝色素液透光率达99.2%,且色价提高了33.6%。     

图解法优化荔枝果浆酶解澄清的工艺

为了制备荔枝澄清果汁,探讨不同的果胶酶用量(质量分数0.02％～0.06％,m/m),酶解时间(1～3h)和温度(35～55℃)等工艺参数对荔枝果汁的出汁率和澄清度的影响.结果表明果胶酶处理可以提高荔枝果汁的出汁率和澄清度.通过响应面试验设计分析和图解法优化途径,获得果胶酶制备荔枝澄清果汁的较优工艺条件,在酶用量0.045％～0.05％(m/m),温度46～50℃和时间2.0～2.5h时,荔枝果汁的出汁率和透光率的预测值分别为90.40％和91.10％.经实验验证,预测值与实验值相符.     

Optimising clarification of carrot juice by bacterial crude pectinase

This study was undertaken to search for potential use of crude bacterial pectinase enzyme produced from Bacillus subtilis grown on hazelnut shell hydrolysate in clarification of carrot juice and to optimize the enzyme load, pH and time using the Box–Behnken response surface methodology (RSM). The carrot juice was treated with the crude pectinase enzyme (5.60 U mL^?1) at different concentrations (0.1–0.5%), pH (4–7), and time (2–6 h). The obtained enzyme was also compared with commercial fungal pectinase at identical conditions. RSM provided optimal clarification conditions of 0.5% (w/v) enzyme load, 7.0 pH, and 6 h of time estimating 100% clarity, whose experimental counterpart was 94.47 ± 0.01%. High values of coefficient of determination (R² = 0.9631), predicted R² (0.8989) and insignificant lack‐of‐fit (0.12) also showed that the model was successful in predicting % clarity for various combinations. This study also indicated that crude bacterial pectinase providing about 95% clarity is superior to commercial fungal pectinase, which gave 78% clarity under tested conditions, in terms of clarification ability for carrot juice.     

Loss of rutin and antioxidant activity of asparagus juice caused by a pectolytic enzyme preparation from Aspergillus niger

We found that a commercial pectolytic enzyme preparation from Aspergillus niger (pectinase AN) contained laccase activity that decreased rutin content and antioxidant activity of asparagus juice. This research investigated the effects of pH, temperature, and concentration of pectinase AN on pectinase AN’s laccase activity to decrease rutin content and antioxidant activity of asparagus juice. Asparagus juice was incubated with pectinase AN at different pHs (3.2, 4.5 and 5.8), temperatures (25, 37, and 50 °C) and enzyme concentrations (0.1%, 0.5% and 1%). Rutin content and antioxidant activity of samples was determined by HPLC and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) free radical method, respectively. The rate of loss of rutin and antioxidant activity of asparagus juice was smaller at pH 3.2 than at pH 4.5 and pH 5.8, smaller for 0.1% pectinase AN than 0.5% and 1% pectinase AN. The rate of loss of rutin of asparagus juice was greater at 25 °C than at the other two temperatures. Pectinase AN can decrease rutin content and antioxidant activity of asparagus juice at the selected conditions. But rutin content and antioxidant activity of asparagus juice produced using pectinase AN could be less decreased at pH 3.2 and 0.1% of enzyme with less than 2 h of incubation time. This information was helpful for juice industry to produce juices with high antioxidant activity using pectinase AN.     

热杀菌结合冷藏改善绿芦笋汁的贮藏稳定性研究

为研究热杀菌处理对绿芦笋汁贮藏稳定性的影响,通过121℃、3min(F03min)处理绿芦笋汁,并置于(4±1)℃条件下冷藏,定期测定其各指标(菌落总数、色泽、可溶性蛋白、总糖、总酚、总黄酮、VC含量与DPPH自由基清除能力)的变化。结果表明:F03min热杀菌处理可将芦笋汁中的固有微生物完全杀死,且在芦笋汁冷藏的120d均无微生物生长;F03min杀菌处理结合冷藏可有效抑制绿芦笋汁贮藏期间L*和a*值的上升,延缓可溶性蛋白、VC、总酚和DPPH自由基清除能力的下降,维持总糖和总黄酮含量的稳定,保持绿芦笋汁的贮藏稳定性,有效延长绿芦笋汁的贮藏货架期,使其冷藏期延长至120d。      

乳清分离蛋白对鲜榨黄冠梨汁澄清效果的研究

为了探究乳清分离蛋白（whey protein isolate,WPI）对鲜榨黄冠梨汁的澄清效果,在单因素实验的基础上应用响应面法对鲜榨梨汁的澄清条件进行优化,并对比研究WPI、果胶酶、WPI+果胶酶3种处理方法对梨汁澄清度和褐变度的影响。优化的澄清条件为WPI添加量0.69%,处理时间90 min,处理温度60℃,该条件下梨汁透光率为87.9%。3种方法处理后梨汁澄清度的大小顺序为WPI+果胶酶>WPI>果胶酶,褐变度的大小顺序为果胶酶>WPI>WPI+果胶酶。这表明WPI对鲜榨黄冠梨汁具有澄清和抑制褐变的双重作用,效果优于果胶酶,与果胶酶联合处理,效果更佳。      

响应面法优化百香果的酶解工艺

以百香果为原料,响应面法优化果胶酶、纤维素酶酶解百香果全果的最佳酶解工艺。单因素实验研究料液比、p H、酶解时间、酶解温度、酶添加量对百香果出汁率的影响,利用Box-Behnken设计实验响应面法优化三个因素对酶解全果百香果果汁工艺。响应面法优化结果表明,百香果酶解最佳工艺参数为温度38.8℃,果胶酶添加量0.06‰,纤维素酶添加量0.09‰,在此条件下酶解百香果全果果汁60 min,出汁率为94.21%,和理论值94.237%模拟较好。本研究建立百香果酶解工艺二次线性回归模型准确有效,优化百香果酶解工艺参数是可行的,有一定的实用价值,可为百香果果汁、果酒及果醋等进一步研究提供理论依据。      

响应面试验优化胡萝卜浆复合酶解工艺

为优化胡萝卜制汁工艺,以出汁率为指标,通过单因素试验研究纤维素酶-果胶酶配比、酶解时间、酶解温度对胡萝卜出汁率的影响,再通过Box-Behnken试验法与响应面分析法,研究各自变量及其交互作用对胡萝卜出汁率的影响,建立了二次多项式回归预测模型。结果表明：复合酶酶解胡萝卜浆的最佳条件为纤维素酶-果胶酶配比2.2∶10（g/g）、复合酶添加量0.3%、酶解时间1.94 h、酶解温度41.67 ℃。在此酶解条件下,胡萝卜出汁率为（79.36±0.23）%,与响应面预测值79.06%拟合性较好,对实际生产有一定指导意义。     

Pectinase and naringinase help to improve juice production and quality from pummelo (Citrus grandis) fruit

Pectinase and naringinase were investigated for improving the production of pummelo juice by increasing the juice yield and eliminating juice bitterness. Compared to a control, the enzymatic treatment significantly (p<0.05) increased the juice yield, soluble pectin and total soluble solid (TSS) contents, and the clarity, while decreasing the concentrations of the bitter chemicals naringin, limonin, and nomilin. A combined processing treatment of peeling and enzymatic hydrolyses using 5U/g of pectinase and 0.4 U/g of naringinase at 50oC for 60 min resulted in a juice yield of 42.3%, a TSS content of 11.4oBx, a titrable acidity (TA) of 0.96%, a vitamin C concentration of 38.4 mg/100 mL, and concentrations of naringin, limonin, and nomilin of 42.4 μg/mL, 33.5 μg/mL, and 13.3 μg/mL, respectively. The enzymatic method was effective and practical for production of high quantity pummelo juice.     

果胶酶澄清枸杞汁最佳工艺条件研究

选用果胶酶对枸杞汁进行澄清,在最适pH和不调pH条件下、以及最适温度和常温作用下比较了果胶酶对枸杞汁澄清效率及可溶性固形物含量的影响效果。结果表明:果胶酶的澄清效果受温度的影响较大,调节pH值对澄清度的影响则表现不明显。且酶处理不增加枸杞汁的可溶性固形物含量。正交试验证明:最佳澄清工艺条件为:pH4.0,酶解温度55℃,作用时间6h,酶剂量40mg/kg。     

草莓胡萝卜复合果蔬汁澄清工艺研究

澄清是复合果蔬汁加工过程核心技术之一,处理不好直接影响果蔬汁品质。果胶酶作为常用澄清剂,具有简便、快捷、效果好等特点。本文以果胶酶为澄清剂,研究了果胶酶用量、酶解温度、酶解时间和复合果蔬汁pH对草莓胡萝卜复合果蔬汁的澄清效果。单因素试验显示:果胶酶用量为0.65 0.75g/L、酶解温度为40 50℃、酶解时间为3.5 4.5h、复合果蔬汁pH为3.5 4时,草莓胡萝卜复合果蔬汁的出汁率和透光率均较好。通过正交试验获得的最佳工艺条件为:果胶酶用量0.7g/L、酶解温度50℃、酶解时间5h、复合果蔬汁pH值3.75,此条件下澄清后草莓胡萝卜复合果蔬汁透光率为80.34%,出汁率为88.73%,可溶性固形物含量为10.8%。本研究结果表明,在合适的工艺条件下,果胶酶能有效的去除草莓胡萝卜复合果蔬汁中的果胶物质。     

响应面试验优化桑葚汁复合酶解制备工艺及微滤技术对其品质的影响

以新鲜成熟桑葚果实为原料,桑葚出汁率为指标,通过单因素试验及响应面试验,确定果胶酶和纤维素酶酶解制备桑葚汁的最佳工艺参数,并进一步考察非热力杀菌微滤技术对桑葚汁杀菌、澄清、褐变抑制效果以及理化指标的影响。研究结果表明,适于实际生产的最佳酶解工艺为：果胶酶添加量0.42%、纤维素酶添加量1.84%、酶解时间101.26 min、酶解温度50 ℃、酶解pH 3.5～4.0（桑葚汁自然pH值）。在此条件下,桑葚出汁率为86.37%,与理论值88.10%接近。实验表明微滤技术对桑葚汁不仅有很好的抑菌效果,且对桑葚汁的褐变具有一定的抑制作用。     

Evaluation of enzymatic treatment of peach juice using response surface methodology

BACKGROUND: This work aimed to assess peach juice clarification using enzymatic treatment. The enzymatic hydrolysis was performed to reduce the juice viscosity and pulp content, and consequently to increase juice extraction. The hydrolysis conditions were optimized by the response surface methodology, where the influence of temperature, amount and type of enzyme and time of reaction were investigated. RESULTS: Two commercial pectinase preparations (AFP L3 and ULTRA SP WOP from Novozymes) as well as a cellulase (R10 from Onozuka) were tested. The hydrolysis using Pectinex AFP L3 (Novozymes) at 25 °C for 60 min presented the best results of pulp (48%) and viscosity (68%) reduction. CONCLUSION: Physical and chemical analyses showed that the enzymatic treatment is effective for reduction of peach pulp viscosity, pulp content and turbidity and does not influence other juice parameters such as pH, total acidity, vitamin C and soluble solids. Copyright © 2007 Society of Chemical Industry     

果胶酶制剂在澄清苹果汁加工中的应用研究

利用果胶酶制剂处理苹果(品种:国光)、果浆、果汁,结果表明:0.1％的Pectinex Ultra SP果胶酶处理可明显地提高出汁率、可溶性固形物和透光度;降低pH值和相对粘度,处理效果随作用时间增加而增加,对不同贮藏期的苹果处理效果不同。0.1％的TL-enzyme果胶酶与0.1％的纤维素酶结合处理的效果大于0.1％的TL-enzyme果胶酶单独处理的效果。在20～22℃,汁中添加不低于0.1％的黑曲霉(As 3.316)果胶酶或不低于0.001％的Ultrazym100G果胶酶,可分别在8小时和6小时内使果汁澄清;处理温度提高或酶浓度加大,澄清时间缩短。用Ultrazym100G果胶酶澄清的汁,其糖分、滴定酸含量没有明显变化,单宁物质含量降低,矿质元素和沉淀中粗蛋白含量发生变化。     

响应面优化黑果腺肋花楸汁澄清工艺及其抗氧化活性评价

该研究以壳聚糖为澄清剂,采用响应面法优化黑果腺肋花楸汁的澄清条件,筛选出最佳澄清工艺,并对其总黄酮、总酚、花色苷等活性成分进行测定,且通过测定DPPH自由基、羟自由基清除能力,Fe 3+还原能力以及总抗氧化能力评价其体外抗氧化活性。结果表明,黑果腺肋花楸汁最佳澄清条件为壳聚糖添加量0.56 g/100mL,澄清温度49℃,澄清时间67 min,在此条件下其透光率可达到93.89%;黑果腺肋花楸清汁与原汁相比各成分含量发生显著降低(P<0.05),且原汁的抗氧化能力总体上强于清汁。相关性分析表明,黑果腺肋花楸清汁中的总酚和总黄酮含量与清汁DPPH自由基清除率、羟自由基清除率、Fe 3+还原能力和总抗氧化能力呈现较好的相关性。研究结果显示,采用响应面法可优化黑果腺肋花楸汁的澄清工艺,提高汁液透光率,且黑果腺肋花楸汁具有较强的抗氧化活性,该研究为黑果腺肋花楸汁的实际开发利用提供数据支撑和理论基础。     

大蒜清汁加工中脱臭澄清净化技术研究

以大蒜为原料探究大蒜清汁的加工工艺,并对大蒜的脱臭温度、护色VC用量、果胶酶酶解条件及冷冻澄清进行研究,确定了合理的加工工艺和最佳参数.结果表明,大蒜清汁制取最佳工艺参数为：加热脱臭温度70℃,护色vC用量0.03％,酶解pH 4.62,酶解温度50℃,酶解时间45min.在此条件下得到的大蒜清汁澄清度最高.同时冷冻澄清（-18℃）的方法得到的大蒜出汁率最高,澄清稳定性最好.     

复合果蔬汁饮料青椒苹果汁的研制

主要研究青椒苹果汁饮料的制作方法,确定其基本配方为：苹果原汁10%～20%、青椒原汁10%、白砂糖8%～10%、柠檬酸0.3%、柠檬酸钠0.05%。苹果原汁生产中采用抗坏血酸护色与微波灭酶相结合,具有较好的抗褐变效果。青椒原汁生产中采用果胶酶提高青椒出汁率,效果显著。最佳酶解条件为：果胶酶添加量0.01%、加水量40%、酶解温度50℃、酶解时间40min、酶作用pH3.0,此条件下青椒出汁率可提高至57%,比未经酶处理的出汁率23.4%高出33.6%。     

红枣澄清汁加工工艺的研究

为了制备澄清透明且营养丰富的红枣汁,将干红枣经果胶酶解浸提,得到红枣汁。采用果胶酶和壳聚糖分别对红枣汁进行澄清处理,以透光率为指标,比较两种方法的澄清效果。对两种澄清方法进行正交试验的极差分析和方差分析,结果表明,壳聚糖的澄清效果更好。确定了壳聚糖澄清红枣汁的最佳工艺条件为:壳聚糖添加量为0.02%,50℃下澄清1h,所得澄清汁的透光率达到95.6%。清汁与原汁相比,汁液清澈透明、色泽自然。总糖含量提高,总酸含量无明显变化。     

果胶酶澄清柚子汁工艺条件研究

通过单因素试验和正交试验,研究了果胶酶对柚子汁的澄清工艺.单因素试验结果表明,果胶酶用量为0.08～0.10 g/L,pH值为3.0～4.0,温度为25～35℃,酶解时间为1.5～2.5h条件下,果胶酶对柚子汁澄清处理的效果较好,果汁中的可溶性固形物含量基本不变.正交试验得到的果胶酶澄清柚子汁的最佳工艺条件为果胶酶用量0.09 g/L,最适pH值为3.5,酶解温度25℃,酶解时间1.5 h.     

不同预处理方式对柠檬果汁超滤澄清效果和膜污染情况的影响

利用超声辅助果胶酶法和超滤技术相结合对柠檬果汁进行澄清。以柠檬汁的透光率、果胶含量为指标,讨论不同预处理方式对柠檬果汁超滤澄清效果和膜污染情况的影响。结果表明,采用切割分子量为50 kDa的聚丙烯腈(PAN)超滤膜澄清果汁,不同预处理方式对超滤膜的稳定通量大小的影响规律是酶+超声处理>酶处理>未经酶+超声处理,其稳定通量分别为30、33.5和13 L·m^-2·h^-1左右。较优的操作压力可确定为0.1 MPa,此时柠檬汁的果胶含量为0.5%,透光率约99.6%,处理效果较好。超声辅助果胶酶法澄清果汁,有利于提高果汁的透光率,并且在后续膜处理过程中,对于提高超滤膜的通量和缓解膜污染都有显著的效果。