Damaged Starch Determination in Wheat Flours in Relation to Dough Water Absorption

Four methods (three enzymatic and one non-enzymatic) for damaged starch determination have been applied to 51 flours of known moisture and protein contents and known water absorption. The three enzyme methods for damaged starch give results in substantial agreement and in conjunction with the other parameters predict dough water absorption by multiple regression equations more closely than does a colorimetric method.     

Determination of Damaged Starch Content of Flours of Indian Wheats

Results are compared of the four methods used for the determination of damaged starch contents of 63 experimentally milled straight grade flours of a number of Indian wheats. The A. A. C. C. and the Stewart methods gave comparable values, but those of the Williams and Fegol colorimetric method were notably high and of the Farrand method lower.     

The Effect of Pin and Attrition Milling on Starch Damage in Hard Wheat Flours

Starch damage of 10.9 and 15.7%, respectively, in break and reduction flours of commercial hard wheats was increased to 16.0 and 28.6%, respectively, by pin milling. Attrition milling and cryofreezing prior to pin milling resulted in less pronounced starch damage, apparently due to reduced heat evolution and mechanical stresses as evidenced by the intensities of the X-ray diffraction patterns. Pin-milled flours exhibited chipping and splitting of starch granules as compared to surface abrasions and deep pitting on the granules from attrition-milled flours. It appeared that the latter flours would be more suitable for air classification of hard wheat flours into protein concentrates and starch fractions.     

Physicochemical Characteristics of Starch Component of Wheat Flours Obtained from Fourteen Iranian Wheat Cultivars

In this study, the differences in the physicochemical properties of starch component of fourteen Iranian wheat cultivars (Triticum aestivum L.) in terms of thermal, pasting and gel properties were studied. Positive correlations between the apparent amylose content and the gelatinization temperature (r = 0.8) and also the gel strength (r = 0.7) of different samples were established. There was no correlation between the amylose content and pasting properties. Moreover a positive relationship between the peak and final viscosities of different wheat flours (r = 0.8) was found. It was concluded that well selection of wheat cultivars is critical for production of high quality products. For this reason, all factors influencing the quality of wheat or flour should be studied carefully. Commonly yield, weight, protein content and quality have been mentioned as quality factors, however as this study indicated, the physicochemical properties of starch should also be considered as a quality criterion.     

面粉损伤淀粉及其测定

本文叙述了小麦淀粉的结构、影响淀粉损伤的各种因素、损伤淀粉对面粉特性的影响、不同用途面粉的合理损伤淀粉范围、损伤淀粉测定方法:同时介绍了肖邦公司最新研制的SDmatic损伤淀粉测定仪的工作原理、结构、测定方法和优点。     

Damaged Starch and Protein Contents in Relation to Water Absorption of Flours of Indian Wheats

The investigation has shown damaged starch to be a significant factor in the high water absorption by 63 straight-run flours of a number of varieties of Indian wheats. A significantly high positive correlation (r = + 0.81 to + 0.87) was obtained between water absorption and damaged starch contents compared to a value of + 0.50 for water absorption and protein content. The prediction of water absorption from damaged starch and protein contents is discussed.     

影响面粉中破损淀粉含量的因素

不同品种和品质的小麦在加工过程中会产生不同程度的破损淀粉,通过实验,从多方面分析引起面粉产生破损淀粉的主要因素。     

Rheological Properties and Bread Quality of Wheat and Rice Starch Composite Flours

Rice starch was added to wheat flour to form different rice composite flours. The rheological characteristics of different mixtures showed a decrease in the farinograph absorption and an increase in mechanical tolerance index when rice starch was added at 40% level. Dough stability, development time, arrival time and over-all farinograph profile scores were decreased. Extensograph data showed an increase in dough deadness and a drop in dough extensibility. Although dough rheology data indicated that the addition of rice starch weakened the dough, bread of acceptable quality was obtained when rice starch was added at 25% level. This should be of interest for development countries where rice is a native crop.     

不同品种小麦粉黏度特性及破损淀粉含量的差异

以不同专用小麦以及直链淀粉含量极低的糯小麦为试验材料,研究不同品种之间小麦粉黏度特性和破损淀粉含量的差异及其相关性。结果表明,不同专用小麦之间,RVA图谱存在明显差异,糯小麦RVA图谱形状显著不同于非糯小麦。各专用品种小麦粉RVA谱线特征值中,小麦粉峰值黏度、稀懈值大小表现为弱筋小麦>中筋小麦>强筋小麦>糯小麦。破损淀粉含量在不同专用小麦品种之间大小顺序表现为:强筋小麦>中筋小麦>弱筋小麦>糯小麦。相关分析表明,峰值黏度、低谷黏度、最终黏度、反弹值以及峰值时间均与直链淀粉含量、直/支比例以及破损淀粉含量呈极显著正相关。     

Extrusion Cooking in Enzymatic Liquefaction of Wheat Starch

Wheat starch was treated for gelatinization, partial liquefaction, and subsequent further hydrolysis by extrusion cooking together with a thermostable Bacillus licheniformis α-amylase followed by batch incubation of the extrudates at 80°C. The degree of hydrolysis depended on the extrusion feed moisture content, enzyme concentration, mass temperature during extrusion cooking, and the length of the counter screw elements. The degree of hydrolysis was followed both by dextrose equivalent and by molecular weight distribution pattern as determined by high performance gel permeation chromatography. A reaction velocity model was shown to fit well to the kinetic data obtained. The enzyme was only incompletely inactivated by mercuric chloride suggesting the presence of also other than sulfhydryl dependent amylase.     

Progress in the Enzymatic Saccharification of Wheat Starch

Problems were noticed when trying to include wheat starch to the normal liquefaction and saccharification lines because of the formation of precipitations which are difficult to filter. The effects of different side activities of Aspergillus niger glucoamylases on the filterability of wheat syrups are demonstrated. In order to speed up filtration, viscosity has to be decreased by degradation of arabinoxylanes with present pentosanes. A new enzyme has been discovered which is able to split partially the lysophospholipids contained in wheat starch and let the insoluble components flocculate to big particles. This enzyme splits the phospholipids into free fatty acids and glycerophophorylcholines. The properties of this enzyme present in a novel glucoamylase preparation for the wheat starch processing are demonstrated by using an HPLC method, showing the degradation of wheat lipids as well as synthetic lysophopholipids.     

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.     

小麦总淀粉、A-淀粉及B-淀粉的热损伤与其糊化度、糊化特性的关系

为了探索热处理温度和水分对淀粉损伤及损伤后淀粉糊特性的影响,揭示小麦淀粉的热损伤程度与糊化度、糊黏度特性之间的关系,以市售面粉分离的总淀粉、A-淀粉和B-淀粉为原料,经30～90 ℃的温度处理后,测定其在高、低水分下的破损淀粉含量、糊化度及糊化特性的变化。结果表明：低水分下,淀粉损伤、糊化度和淀粉糊性质随热处理温度变化不明显;高水分含量下,随着热处理温度的升高,破损淀粉含量和糊化度呈明显上升趋势,热损伤程度与糊化度之间呈显著正相关（P＜0.05）,糊化温度略有增加,主要的黏度参数显著下降,损伤淀粉与峰值黏度之间呈显著负相关（P＜0.05）。     

小麦破损淀粉含量测定方法的比较研究

用AACC法、液相色谱法及Chopin法分别对相同小麦粉样的破损淀粉含量进行测定,并对其相关性进行比较。研究表明,三种测定方法具有极显著的相关性,复相关系数均达到或超过0.8。     

小麦麸皮淀粉的分离制备与特征分析

利用中性蛋白酶制备小麦麸皮淀粉条件的基础上,进一步分析所制备小麦麸皮淀粉的形态及理化特性。结果表明：中性蛋白酶法制备小麦麸皮淀粉的最佳条件为中性蛋白酶质量浓度3g/L、反应温度45℃、反应时间90min,在此条件下,100g 麸皮的淀粉产量为14.86g、蛋白含量为0.25%;麸皮淀粉中蛋白含量和破损淀粉含量均较低,小淀粉粒体积分数为58.4%;与面粉淀粉相比,麸皮淀粉中直链淀粉含量和糊化值较低,膨胀势较高,淀粉粒的相对结晶度较小。     

The Enzymatic Determination of Starch in Food,Feed and Raw Materials of the Starch Industry

An enzymatic starch determination which can be used for the analysis of starch in a very broad range of different samples is evaluated, ranging from starch in plants, feed and food to industrial applications as starch in starch. The method is based on a complete enzymatic conversion of the starch into glucose, followed by an enzymatic determination of the glucose. A statistical evaluation of the method based on the analysis of 15 different matrices is presented. The performance of the method is compared with other methods for the determination of starch. Especially the sample desintegration and solubilization in this method perform better than in other methods which appear to be applicable in just a limited number of different sample matrices. The protocol described in this paper has been tested in an interlaboratory study, involving seven laboratories and four samples. The determination can be used in routine for the analysis of about 50 samples simultaneously, it has a good repeatability, a high selectivity, and is good applicable to samples from agricultural and industrial origin.     

甘薯淀粉中掺有玉米淀粉的检测方法

采用扫描电镜、激光粒度分析仪、快速黏度分析仪和X-射线衍射仪分析了甘薯淀粉中加入不同比例玉米淀粉后的性质变化。结果表明:甘薯淀粉中玉米淀粉的加入量与平均粒径、峰黏度和5.6°峰面积存在极显著相关。根据所得的回归方程可以快速测定甘薯淀粉中玉米淀粉含量。     

Maltose Values of Flours of Indian Wheats in Relation to α-Amylase Activity and Damaged Starch Contents

Involvement of damaged starch as the principal cause of maltose formation in 63 straight-run flours of a number of Indian wheats in relation to liquefaction numbers derived from the falling number test is indicated. Multiple regression analysis of maltose values on damaged starch and liquefaction numbers was found to be statistically highly significant.     

Effect of Heat Damage on the Baking Quality of Starch Extracted from Wheat

Eight wheat samples of four cultivars, grown in different regions of New Zealand, were heated at 75-110°C in order to heat-damage them. Untreated wheat samples were used as controls. The wheats were then milled to give white flours. Starches were isolated from the treated and untreated flour samples. The baking potentials of the starches were estimated from remix baking tests using a starch gluten system. Heat-damage to wheats had a significant adverse effect on the baking performance of starches isolated from these wheats. This effect was not as large as the effect on gluten quality. Heat-damage caused no apparent alterations in starch physicochemical parameters as measured by scanning electron microscopy, Amylograph pasting, gelatinization ranges, X-ray diffraction, swelling power and solubility, and water hydration capacity.     

Damaged Starch Contents of Wheat Whole Meals in Relation to Maltose Values and Water Absorption

Mean values of damaged starch of 49 samples of wheat whole meals determined by the A.A.C.C., Stewart and the colorimetric method of Williams and Fegol were: 11.4%, 9.96% and 1.44 (O.D.), respectively. Statistically high significant positive correlations between the values of different methods (+ 0.80 to + 0.91), maltose values v. damaged starch (+ 0.89 to + 0.94) and between damaged starch and absorption (+ 0.58 to + 0.74) were obtained. Regression analysis of maltose on damaged starch and of absorption on damaged starch and protein contents of whole meals were statistically highly significant.