Enzymatic Starch Hydrolysis of Extruded Potato Peels

Potato peels discarded by potato processors are a potential source of dietary fiber and starch. This starch may be hydrolyzed for fermentation to value-added products. Dried steam peels were extruded at 135°C and 22% feed moisture and digested with α-amylase and/or amyloglucosidase. Two barrel temperatures and feed moistures were also studied. Glucose was measured colorimetrically at O,1,2,4,8 and 24h of incubation. All peels treated with either no enzymes or α-amylase alone produced minimal glucose. Nonextruded peels digested with both enzymes produced more glucose than did those treated with amyloglucosidase alone. Complete digestion of starch occurred in extruded peels digested with amyloglucosidase, but not when α-amylase was used.     

Enzymatic Hydrolysis of Wheat Starch into Glucose

In the presented research, glucose hydrolyzates were obtained by acting on wheat starch, which was liquefied with the aid of bacterial α-amylase, with Spezyme GA 300W Y553, an enzymatic preparation composed of glucoamylase and lysophospholipase, as well as with Amyloglucosidase AMG 300L, a glucoamylase preparation. The following physical and chemical properties of the obtained hydrolyzates were tested the glucose equivalent, the filtration power, the colour factor and the transparency factor. In the process of saccharification of wheat starch into glucose, the optimum dose of Spezyme, the enzymatic complex, is a concentration equal to 0.3%/d.m., at which after 72 h of process duration, the maximum 98 DE reducibility was achieved. Using the Spezyme preparation, which, thanks to the fact that apart from glucoamylase, it contains lysophospholipase, results in an improvement of the filtration power of hydrolyzates obtained with the participation of this preparation.     

The Production and Properties of Glucose Syrups I. Production of Glucose Syrups by Enzymatic Hydrolysis of Starch

Certain metal ions are shown to influence the enzymic hydrolysis of maize starch. Amyloglucosidase was not affected by the metal ions but á- and ß-amylase were affected by varying degrees. Calcium ions produced a positive effect with both fungal and bacterial α-amylases but no effect with ß-amylase, whilst zinc, ferric and lead ions produced negative effects or no effect. A simultaneous enzymic hydrolysis (using α- and ß-amylases) and catalytic hydrogenation showed enzyme inhibition by the nickel catalyst. High hydrogen pressure (100 at) had little effect on the enzymes. The hydrolysis and hydrogenation of the starch fraction of milled whole defatted maize was also shown to be feasible.     

淀粉结构对其酶解性能影响的研究进展

淀粉因其来源不同而在结构上表现出较大差异,这些结构上的差异对淀粉的酶解性能产生很大影响。文章从淀粉的分子结构与颗粒结构两方面,阐述了淀粉中直链淀粉、支链淀粉、直链淀粉-脂质复合结构、磷含量、淀粉颗粒大小和形状、颗粒结晶结构以及复合结构对淀粉酶解性能的影响,并提出存存的问题及研究方向。     

复合纤维素酶对杨木SGW浆的游离度和纤维比表面积的影响

研究了杨木SGW浆酶改性过程中,酶解产物、浆的游离度增加值和纤维的比表面积的变化规律。结果表明,在酶解初期,复合纤维素酶很快吸附到SGW浆纤维的表面发生酶解,使还原糖产生速率较高。而液相中酶蛋白浓度下降很快。伴随酶解过程的进行,浆的游离度增加值和纤维的比表面积呈现“波浪形”变化。这可能是复合纤维素酶的酶解作用使纤维表面产生“剥皮效应”所致。     

酶催化水解对玉米淀粉结构的影响研究

颗粒状玉米淀粉经α-淀粉酶催化水解后,应用SEM、X射线衍射和热失重(TG)对产品进行了分析.检测结果表明,α-淀粉酶催化水解玉米淀粉时,其收率与酶的浓度和反应时间成反比;颗粒状玉米淀粉发生酶催化水解时,α-淀粉酶首先使淀粉形成多孔状结构,并进一步使颗粒破裂,断裂的颗粒碎片上显示出淀粉颗粒内部具有层状的生长环结构;酶催化水解不能提高玉米淀粉颗粒的结晶度;酶解时间较长时,产品的热稳定性降低.     

果胶酶酶解红枣浆工艺研究

以市售和田大枣为原料,利用果胶酶处理红枣浆,以提高红枣浆出汁率。通过单因素试验得到在酶解温度30℃~50℃范围内、酶解pH 4.5~5.5、果胶酶添加量0.01%~0.03%、酶解时间60 min~80 min红枣浆出汁率较高,酶解效果较好;通过正交试验得到果胶酶处理红枣浆最佳工艺条件为酶解温度40℃,酶解pH 5.5,果胶酶添加量0.03%,酶解时间60 min,此条件下红枣浆出汁率为87.5%,比未添加果胶酶进行酶解提高了19%。     

酶法红薯多孔淀粉的制备

多孔淀粉是一种新型酶变性淀粉,采用α-淀粉酶和糖化酶复合酶解法制备红薯多孔淀粉,对其工艺条件进行研究,当α-淀粉酶∶糖化酶为1∶7(体积比),反应温度45℃,反应时间28 h,pH5.6,加酶浓度0.5%,淀粉浆浓度65%时,可得到吸油率较高的多孔淀粉。     

紫薯淀粉的提取及酶解制糖工艺研究

紫薯的精深加工越来越受到人们的关注,而其中紫薯淀粉作为一种重要的食品原料,现已成为开发应用的主要方向之一.通过系列单因素和正交试验,探索紫薯中淀粉的浸提和中温α[-淀粉酶酶解紫薯淀粉的最佳工艺条件,从而确定紫薯淀粉分离提取及酶解糖化的最佳工艺参数.结果表明,在淀粉分离提取阶段最适条件是浸提温度35℃,浸提时间90 min,紫薯浸提液pH 1.5;在淀粉酶解糖化阶段,采用中温α-淀粉酶对紫薯淀粉进行酶解,酶解温度55℃、酶解时间150 min、加酶量500.1 nkat/g,pH 6.     

The Effect of Calcium Ions on the Hydrolysis of Starch

The ability of raw and dioxan extracted maize and potato starches to bind calcium is shown to influence the in vitro digestibility of the starches using pancreatic α-amylase. The in vitro digestibility of commercial and fractionated glucose syrups in the presence of calcium is also described. Whilst the extraction process improves the digestibility of both maize and potato starches the addition of calcium lowers the digestibility of raw maize starch. Both raw and extracted potato starch digestibility are increased by the addition of calcium however. When raw and extracted maize and potato starches are converted to glucose syrups by an acid hydrolysis no differences are found in the reducing capacities of the syrup produced.     

Alginate Immobilization of Banana Pulp Enzymes for Starch Hydrolysis and Sucrose Interconversion

A model system has been established that utilizes the entrapment of whole banana pulp homogenates within a calcium alginate matrix in the form of bead that is effective in assaying for enzyme activity in the pulp of the ripe banana fruit. This medium retained enzyme activity for amylase, maltase and invertase and provided indirect evidence of sucrose synthetase activity. A cyclic pathway has been proposed for the biosynthesis and hydrolysis of sucrose in the pulp of ripening banana fruit.     

响应面法优化漂白浆酶水解

采用响应面法中的Box-Behnken实验设计,研究了温度、酶用量和pH值对漂白针叶木浆酶解效率的影响,分别提出了用于预测可溶糖转化率和葡萄糖转化率的数学模型.通过规划求解,优化了3个因素:当温度、酶用肇和pH值分别为52.8℃、10g/L、5.5以及45.9℃、10 g/L、5.3时,可溶糖转化率和葡萄糖转化率分别达到最大81.5%和54.3%.通过实验数据与预测数据的对比,证明模型具有准确的预测性能.     

A Preliminary Note on the Enzymatic Hydrolysis of Starch in Whole-Maize Grits

The role of amylase inhibitors on the liquefaction of starch in maize is discussed. Experiments with a Brabender Amylograph and a Votator continuous cooker for investigating the influence of proteolysis and amylase inhibitors are briefly discussed. Results indicated that excellent yields of sugar could be obtained by pretreating a 30% suspension of maize grits in water in the Votator apparatus at pressures of about 200 lb. p.s.i. before hydrolysing with amylolytic enzymes at this pressure.     

纤维素酶酶解玉米秸秆新型蒸煮浆的工艺研究

本文以玉米秸秆活性氧固体碱蒸煮浆（木素脱除率82.1%）为原料,用国产纤维素酶（酶活为13.94 FPU/100 mL）进行酶解试验,探索酶解最佳工艺条件。结果显示：底物固液比为0.47%（m/V）,酶解pH值为4.70,酶解温度为50℃,酶解时间为72 h时酶解液还原糖含量最大,即糖得率最大,达59.41%。本研究也进行玉米秸秆经不同方法预处理后的酶解实验,结果显示其纤维素酶解效果顺序为：活性氧固体碱蒸煮浆〉硫酸盐浆〉机械粉碎〉未预处理玉米秸秆。     

多孔淀粉制备条件的优化

为探寻α-淀粉酶制备多孔淀粉的最佳工艺条件,采用三因素五水平二次回归正交旋转组合设计。通过计算机模拟寻优,根据回归方程利用统计优选法寻优,确定最优酶解条件:pH值5.3,反应时间7h,反应温度51℃。     

酶脱墨对废纸浆滤水性及其他物理性质的影响

在废纸回用过程中打浆度随着回用次数的增加而增加,而当采用半纤维素酶和纤维素酶脱墨时,发现脱墨后的浆料滤水性有明显改善。当酶用量为1IU/g时,与对照浆相比打浆度分别降低18.2%和20.0%,而化学法脱墨的浆料,其打浆度的下降是有限的。     

纤维素酶酶解苇浆纤维微观结构和结晶结构的变化

采用红外光谱(IR)、X射线衍射分析和扫描电镜对在纤维素酶解进程中苇浆纤维素大分子的结构及纤维形态的变化进行了研究.研究结果表明,纤维素酶酶解进程中,纤维素大分子的晶型没有改变,但结晶度呈现周期性变化,微晶尺寸略有降低.在酶解初期,纤维素酶不仅作用于纤维素无定形区,也开始作用在纤维素结晶区表面;在酶解中、后期,纤维素酶对纤维素结晶区和无定形区的作用呈现周期性变化.纤维素酶解过程中纤维表面呈现周期性"剥皮"现象,并且在纤维表面出现孔洞和沟槽,在孔洞处纤维易断裂,导致纤维长度和粗度的降低.     

核桃粕酶解工艺研究

以核桃粕为原料,用复合蛋白酶与风味蛋白酶水解制备核桃多肽,对酶解工艺中的多种影响因素、工艺参数进行了研究,探索出了酶法水解核桃粕的最佳工艺参数。     

Effect of Starch Sources and Protein Content on Extruded Aquaculture Feed Containing DDGS

A 3 × 3 × 3 completely randomized design was used to investigate extrusion cooking behavior and product characteristics of distillers dried grains with solubles (DDGS), protein levels, and various starch sources in a laboratory scale single screw extruder. Cassava, corn, and potato starches with varying levels of DDGS (20%, 30%, and 40% wet basis (wb)) were extruded with three different proportions of protein levels (28%, 30%, and 32% wb). The extrusion cooking was performed at a constant feed moisture content of 20% wb, barrel temperature of 120 °C, and a preset screw speed of 130 rpm (13.6 rad/s). Extrudate properties such as expansion ratio, unit density, sinking velocity, color, water absorption and solubility indices, and pellet durability index were determined to judge the suitability for various fish species. For all three starch bases, increasing the DDGS levels resulted in a significant increase in sinking velocity, redness (a*), and blueness (b*) and showed a decrease in whiteness (L*). With the increase in DDGS and protein levels, a noticeable increase was observed for unit density and pellet durability indices for cassava and potato starch extrudates. The DDGS-based extrudates produced from cassava starch with lower proportions of DDGS (20%) and protein (28%) levels exhibited better expansion and floatability. Also, the extrudates produced from corn starch with higher levels of DDGS (40%) and protein (32%) levels were more durable and possessed sinking characteristics. Overall, cassava and corn starch with lower and higher levels of DDGS could be more appropriate for the production of floating and sinking aquaculture feeds, respectively.     

水分含量对双螺杆挤压处理山药淀粉理化性质的影响

使用同向双螺杆挤出机研究了水分含量对山药淀粉理化和流变性质的影响.结果 表明:挤压后山药淀粉颗粒受到破坏,出现不规则碎片,其结晶度降低,且随着水分含量的增加而增加.挤压后淀粉的溶解度升高,膨胀度下降,随着水分含量升高,溶解度减小,膨胀度增加.流变学结果表现为弱凝胶性质,山药淀粉的储能模量(G')和损耗模量(G")随水分...