果胶酶产生菌的选育

本试验筛选到一株适于使苹果汁澄清的果胶酶产生黑曲菌No.07,应用物理因素及化学因素对No.07进行处理,从白色突变菌落中获得一高产株CL—8501,对CL—8501的培养基及发酵条件进行了优化,在优化的培养基及较适条件下,CL—8501产酶达631.6单位/毫升,产量此出发株No.07提高约105倍。     

液体发酵果胶酶的防腐保藏技术

对液体果胶酶进行防腐保藏的研究,得到最优防腐剂组分为:山梨酸钾1.0g/l、对羟基苯甲酸丙酯0.1g/l、NaCL0.2g/l。在此条件下,酶液室温保存90天酶活保存率为81.5%,冷藏(5-10)保存90天酶活保存率为89.4%,整个保藏过程中pH值无明显变化。此外,添加定量稳定剂及浓缩酶液能大大提高防腐保藏效果。     

无花果醋的酿造工艺

该文以无花果干为原料，经酒精发酵和醋酸发酵制得无花果醋。添加0．15％的果胶酶进行酶解处理，解决了无花果中含有大量果胶不利于发酵的问题；固定化酵母进行酒精发酵，缩短了澄清时间。产品风味纯正，带有蜜甜味，是一种营养价值很高的保健型果醋。     

Enzyme assisted extraction of luteolin and apigenin from pigeonpea [Cajanuscajan (L.) Millsp.] leaves

Luteolin and apigenin are naturally occurring flavones with a wide spectrum of pharmacological properties. In the present study, enzyme assisted extraction of luteolin and apigenin from pigeonpea leaves using commercial plant cell wall degrading enzyme preparations including cellulase, beta-glucosidase and pectinase were examined. We found that pectinase offered a better performance in enhancement of the extraction yields of luteolin and apigenin than cellulase and beta-glucosidase. The pectinase assisted extraction process was further optimized by varying different parameters such as pectinase concentration, time of incubation, pH of pectinase solution, and incubation temperature. The optimum parameters were obtained as follows: 0.4 mg/ml pectinase, incubation for 18 h at 30–35 °C, pH of pectinase solution 3.5–4. Under the optimum conditions, the extraction yields of luteolin and apigenin achieved 0.268 and 0.132 mg/g in pectinase treated sample, which increased 248% and 239%, respectively, compared with the untreated ones.     

造纸法再造烟叶原料的加酶萃取

为了减少造纸法再造烟叶中的不利成分,研究了在烟梗和烟末萃取过程中加入果胶酶、半纤维素酶和蛋白酶,以及酶添加量、酶解温度和酶解时间对烟末、烟梗中蛋白质、全纤维素和果胶含量及其萃取液中还原糖和氨基酸含量的影响.结果表明:①烟梗和烟末的适宜酶处理萃取条件为:复合酶用量:烟梗,0.5%果胶酶、半纤维素酶和蛋白酶[2∶2∶1(质量比)]、烟末,0.8%果胶酶、半纤维素酶和蛋白酶[1∶2∶2(质量比)];处理温度:50℃;处理时间:2h;②复合酶萃取后,烟梗和烟末的蛋白质、综纤维素和果胶的转化率分别比热水萃取高7.63,4.97,15.87和16.59,5.58,16.13百分点.烟末、烟梗萃取液中还原糖比热水萃取的分别高2.55和3.68百分点,萃取液粘度分别降低0.32和0.149 Pa·s.     

Enhancement of grape seed oil extraction using a cell wall degrading enzyme cocktail

The application of an enzymatic pre-treatment to increase the yield of grape seed oil extraction was studied. Experiments were carried out to measure the effects that reaction time, temperature, pH, particle size and enzyme concentration have upon the enzymatic activity.     

多糖酶在蔗渣中的应用

应用纤维素酶,半纤维素酶和果胶酶水解蔗渣,蔗渣作底物其胞壁多糖被充分水解,当半纤维素酶和果胶并配合纤维素酶可以得到最大水解,为了得到关于花言巧语渣多糖结构的特征的信息,本文使用高效液相色谱法分析产物。     

Effect of macerate enzymes on the yield,quality, volatile compounds and rheological property of prickly pear juice

Pectinase and cellulase enzymes were used to investigate efficacy for improving juice yield, stability and quality from prickly pear fruit. Pectinase improved the yield, stable color, color‐assayed as release of anthocyanins or carotinoids and clarity of the juice. A significant increase in the effectiveness of pectinase was observed as the concentration was increased from 0.05 to 0.50% v/w. However, at concentration >0.25% v/w they tended to impart a bitter flavor in the juice. Among three concentrations of pectinase and cellulase, pectinase at 0.50% v/w produced higher yield, a sediment‐free clear juice and high‐quality juice. The results indicated that depectinated clarified prickly pear juice behaves as a Newtonian fluid. It was found that the activation energy (Ea) for viscous flow was in the range of 5.02×10³–20.06×10³ kJ/mol depending on the concentrations of pectinase and cellulase enzyme treatment of prickly pear juice, in contrast to 22.15×10³ kJ/mol in untreated juice. Volatile compound concentrations of twelve compounds were not affected by pectinase and cellulase treatment. Overall the quality of prickly pear juice was better in pectinase‐treated juice compared with untreated and cellulase‐treated 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.     

Effect of Natural and Pretreated Soybean Hulls on Enzyme Production by Trichoderma reesei

The enzyme induction utility of soybean hulls (SBH), consisting in excess of 50 wt% non-starch polysaccharides (NSP) cellulose, hemicellulose, and pectin, was studied through cultivation of the carbohydrase-producing fungus Trichoderma reesei Rut C-30. Shake flask systems of T. reesei were grown in a medium consisting of defatted soybean flour as a nitrogen source and SBH, some of which were untreated and others pretreated by liquid hot water, alkaline, and supercritical carbon dioxide, as carbon source. Cellulase, xylanase, and polygalacturonase activities were measured for the systems, and the natural hull systems were found to yield optimum enzyme production. Controlled batch fermentation experiments were carried out to compare enzyme production resulting from media with Avicel^® (FMC BioPolymer, Philadelphia, PA, USA) versus natural SBH with and without soybean flour as the nitrogen source. Soybean hull fermentations were also performed at several pH levels to observe the effects on enzyme production. Soybean hulls induced comparable levels of cellulase, and higher levels of xylanase and polygalacturonase, than Avicel^®. With SBH, cellulase and xylanase production were enhanced at higher pH levels (6.0), and polygalacturonase was enhanced at lower pH levels (4.0–4.5). Enzyme production was largely unaffected by the presence of soybean flour as the nitrogen source.