Comparative Studies on the in vitro alpha-Amylolysis of Different Wheat Starch Products

The time dependent α-amylolytic degradation of different wheat starch products was investigated in vitro. Starch digests were analysed by gel filtration chromatography and measurement of reducing end groups. The hydrolytic activity of crystalline porcine pancreatic α-amylase was compared to that of human salivary α-amylase in cell-free pooled saliva. With conditions similar to those of the human oral cavity wheat starch solutions, whole wheat bread and wheat starch biscuit were hydrolyzed rapidly to mainly maltose, maltotriose and limit dextrins. The distribution of the main degradation products was different depending on the source of the α-amylase. Independent of the enzyme source the rate of hydrolysis decreased from wheat starch solution to bread and biscuit.     

The Rapid Enzymatic Determination of Starch Damage in Flours from Sound and Rain Damaged Wheat

A starch damage analytical method for use on wheat flours has been developed which is rapid, simple in operation, analytically precise, and is independent of any α-amylase present in flour, as when milled from rain damaged wheat. The new method is based on the use of an analytical grade fungal α-amylase enzyme, which is shown to be free of contaminating amyloglucosidases, and α-glucosidases which produce glucose rather than maltose. The level of analytical α-amylase per starch damage determination was obtained by reference to thin layer chromatography of the hydrolysates so as to obtain maltose as the principal reducing sugar. This ensured that adequate but not excess analytical α-amylase was present, as the undamaged starch granules are some what susceptible to α-amylase.     

Combined Effect of Different Antistaling Agents on the Pasting Properties of Wheat Flour

The combined effect of α-amylase and hydrocolloids addition on the pasting properties of wheat flour was determined. A fungal α-amylase and hydrocolloids of different chemical structure (alginate, κ-carrageenan, xanthan gum, and hydroxypropylmethylcellulose (HPMC) were added to a wheat flour suspension and their pasting properties analysed by using a viscograph. The α-amylase action was highly dependent on the structure of the biopolymer present in the suspension, therefore the observed effects were very specific for each α-amylase-hydrocolloid pair added. The greatest modification of the pasting properties (maximum viscosity, cooking and cooling stabilities, bump area) was promoted with the addition of alginate, κ-carrageenan, and/or xanthan, nevertheless, when α-amylase was also added, a synergistic effect was only observed in the cases of κ-carrageenan and xanthan. The presence of hydrocolloids changed the wheat starch properties, and the α-amylase-starch interactions, modifying in consequence the hydrolytic activity of the enzyme on the starch.     

淀粉酶水解麦麸中淀粉工艺的研究

本文采用α-淀粉酶对麦麸淀粉进行水解,以还原糖含量为评价指标,以酶添加量、料液比、酶解温度和酶解时间为主要影响因素,在单因素试验的基础上进行正交优化试验,确定淀粉酶水解淀粉的最佳工艺参数为:酶添加量0.6%,料液比1∶12,酶解温度55℃,酶解时间60min。此时淀粉的水解效果最好。     

Effects of Germination of Wheat,Oats, and Pearl Millet on Alpha-Amylase Activity and Starch Degradation

Hard red winter wheat, oats, and pearl millet were germinated at 15°C for periods up to 14 days. Endosperm areas in kernels fractured with a razor blade and starches isolated from the malted flours were examined with a scanning electron microscope to determine the morphology of starch granules and the nature of α-amylolytic attack on granules. Free sugars content, damaged starch content, and α-amylase activity of the flours were determined to establish relationships between physical changes in the cereal grains and formation of α-amylase during germination. Starch granules in the three cereals were degraded during germination by α-amylase accompanied by production of free sugars and increases in the damaged starch of flours milled from the germinated grains. The cementing material embedding starch granules in endosperms of wheat and oats decreased and disappeared during germination; these changes were not obvious in germinated millet endosperm. Amorphous-appearing material seemed to cover starch granules in the endosperm of wheat and oats during later stages of germination, but were not observed in the isolated starch granules. Although wheat starch granules had the highest α-amylase activity, this enzymic degradation was less than expected. Enzymic attack was evidenced as channels or pits on the surfaces of wheat and millet starch granules. Compound oat starch granules were relatively resistant to enzymic attack and no evidence of erosion of the granule surface was observed; small granula were released from the compound granules during germination. The most extensive degradation was obtained with millet starch, appearing as discrete holes leading to the interior of the granule. Concentric shells were visible in the interior of wheat and millet starch granules, but were not observed in oat starch granules.     

Control of wheat α-amylase using inhibitors from cereals

A survey of 46 varieties of cereals and related species (including 27 different species from the Poaceae) indicated the presence of a strong inhibitor of wheat α-amylase in all seven Hordeum species tested. Rye contained a lower level of inhibitor activity, but the other species contained insignificant amounts of wheat α-amylase inhibitor activity. The partially purified barley inhibitor was most effective in inhibiting wheat α-amylase activity at high pH. The addition of chromosome 2 of barley to wheat (Chinese Spring addition line 2H) resulted in an apparent increase in the molecular weight of the α-amylase produced during germination. This was probably due to the formation of a complex between the inhibitor encoded by the asi gene on chromosome 2 of barley and wheat α-amylase 2. Breeding of wheat with the barley inhibitor gene may reduce the impact of the high α-amylase levels that result from pre-harvest sprouting in wheat.     

富含低聚木糖的小麦麸皮饮料的研制

以小麦麸皮为原料,经焙烤、酶解、澄清和调配等工艺制成富含低聚木糖的保健功能性饮料。先将小麦麸皮在180℃下焙烤20 min,之后采用木聚糖酶将其中的木聚糖酶解为低聚木糖,采用风味蛋白酶将蛋白质酶解为短肽,中温α-淀粉酶将淀粉酶解为葡萄糖和麦芽糖。优化后的酶解条件为:木聚糖酶153 U/g麸皮、风味蛋白酶138 U/g麸皮、中温α-淀粉酶60 U/g麸皮,料水比1∶8(g∶mL),pH值6.0,反应温度50℃,反应时间4 h。酶解液经稀释后加入0.2 g/L皂土和0.1 g/L壳聚糖澄清,调配时加入10 g/L蜂蜜、60 g/L白砂糖和0.75 g/L柠檬酸,经超高温瞬时杀菌、无菌灌装得到成品。低聚木糖(2.06 mg/mL)和短肽为饮料中主要功能性成分。     

加酶挤压对小麦淀粉结构和理化性质的影响

本文旨在探究加酶挤压对小麦淀粉结构和理化性质的影响。分别设置浓度梯度为0%、0.1%、0.2%、0.5%、1%、2%的α-淀粉酶-小麦淀粉混合物样品,挤压处理后,利用扫描电镜（SEM）、差示扫描量热仪（DSC）、X-射线衍射仪（XRD）、快速粘度仪（RVA）等分析淀粉结构与理化性质的变化。结果表明:各处理组的堆积密度无显著差异（P>0.05）;吸水指数与加酶量呈负相关,水合指数与加酶量呈正相关;挤压后淀粉糊化度均大幅度提高,接近完全糊化;挤压后淀粉的颗粒结构被完全破坏且加酶使得淀粉颗粒粒径更小;加酶挤压处理后相对结晶度降低,从原淀粉的17.52%降至10.29%（酶浓度2%）;挤压处理后小麦淀粉的糊化焓均显著下降（P<0.05）,挤压淀粉样品焓值最低,仅为0.24 J/g,加酶挤压淀粉的焓值高于挤压淀粉,随着加酶量的增加,淀粉的焓值上升至2.5 J/g左右;RVA曲线可明显看出处理组的粘度远低于原淀粉粘度,且加酶挤压样品粘度低于不加酶挤压粘度。本文探明了加酶挤压对淀粉结构和理化性质的作用规律,可为加酶挤压技术在淀粉基食品领域的应用提供理论指导。     

小麦颗粒宏量组分分层定向酶解的研究

采用高温α-淀粉酶、葡萄糖淀粉酶、风味蛋白酶等在保持小麦颗粒完整的条件下,将其宏量组分淀粉和蛋白质逐层定向水解,分别收集各自的水解产物并分析其利用方向。试验结果显示高温α-淀粉酶可将麦粒淀粉完全水解为糊精及少量低分子糖类,进一步糖化得到的糖化液的葡萄糖当量(dextrose equivalent,DE)值为92.48%,残渣蛋白质回收率可达90.06%。剩余残渣使用风味蛋白酶继续水解后,可获得水解度(degree of hydrolysis,DH)为53.58%的蛋白质水解液,其中全氮利用率为80.29%,氨基酸态氮转化率为63.12%。最终酶解后剩余的残渣仍可呈颗粒状态,其中水不溶性膳食纤维含量为80.09%,灰分含量6.85%,脂肪含量6.24%。本研究为小麦的高值化全利用提供了一条新的技术途径。     

Studies on Carbohydrate Metabolising Enzymes. Part XXVIII. Preparation and some Properties of α-Amylase Isoenzymes from Malted Rye

α-Amylase was prepared from an extract of malted rye flour by heat treatment to inactivate β-amylase and other contaminating carbohydrases, followed by continuous electrophoresis. This yielded two isoenzymes which differed considerably in physical properties, although their action patterns appeared to be similar. These findings have been compared with the results of studies on α-amylase isoenzymes from other sources.     

The Influence of Pullulanase and α-Amylase upon the Oligosaccharide Product Spectra of Wheat Starch Hydrolysates

By hydrolyzing wheat starch solutions using different combinations of ä-amylase and pullulanase it has been possible to achieve significantly different oligosaccharide product spectra in hydrolysates with the same dextrose equivalent (D. E.). Where pullulanase was used either as a pretreatment to α-amolysis or in combination with α-amylase starch hydrolysates were produced whose oligosaccharide product spectra differed significantly from the comparable hydrolysate at the same D.E. produced by α-amylase alone. Throughout the range of starch hydrolysate D.E. values the following trends were observed: pullulanase involvement produced less G1, G2 and G5 oligosaccharides and less intermediate molecular weight fraction (D.P. > 12) than when α-amylase alone was used. Where the D.E. values exceeded 20, in addition to these general differences, pullulanase involvement was found to be responsible for the increased production of G6 and G3 oligosaccharides and to significantly reduce the amount of unhydrolyzed polysaccharide both in the intermediate and high molecular weight fractions.     

小麦剥皮麸制取膳食纤维的研究

以小麦剥皮麸为原料,对其进行基本成分测定,并选取40～100目的剥皮麸,利用双酶分步法制备膳食纤维。通过正交实验得出制取膳食纤维的最佳酶反应条件为：α-淀粉酶用量为25 U/g剥皮麸,酶解温度为60℃,酶解时间为45 min;中性蛋白酶的用量为1 200 U/g剥皮麸,温度为50℃,时间为45 min。在此条件下,最终测得不溶性膳食纤维的含量为89.28%。     

配粉对小麦粉成分含量影响作用的研究(英文)

本文对不同小麦品种及不同配粉比例对小麦粉成分影响作用进行了研究。结果表明:不同比例配粉后,小麦粉成分含量将发生一定变化,在优质粉含量较低时(30%～40%),混配粉中酸不溶性麦谷蛋白大聚合体(GMP)含量的变异幅度最大。如果两种粉以合适的比例相搭配,例如稳千一号和006品种以60:40相搭配,GMP含量、可溶性糖含量和α-淀粉酶活性将达到较高值,因而两者的最佳搭配比例为60:40。     

Identification of α-amylase inhibitors in triticale grain

In this study three complete triticales, three substituted (one gene from rye has been replaced by one gene from wheat) triticales, and parental wheat and rye were analysed for α-amylase inhibitory activity to evaluate whether the genetic modification influenced triticale α-amylase inhibitory activity. Gel filtration chromatography and thermostability analyses were performed to partially isolate and characterize α-amylase inhibitors. Results demonstrated that substituted triticales and wheat had higher α-amylase inhibitory activities and higher water-soluble protein contents than complete triticales and rye. Sodium dodecylsulfate-PAGE-electrophoresis showed that all triticales, irrespective of their classification, inherited the water-soluble protein patterns from their parents: wheat and rye. In a substituted triticale (Pony ‘S’), two peaks with α-amylase inhibitory activity were resolved by gel filtration chromatography; they were designated T1 and T2 according to their order of elution. T1 showed a higher inhibitory activity but a lower thermostability at 70 °C than T2; T1 apparently comes from wheat, whereas T2 presumably comes from rye. © 1999 Society of Chemical Industry     

Influence of Monoglycerides on the Gelatinization and Enzymatic Breakdown of Wheat and Cassava Starch

The influence of monoglycerides on the flocculation and gelatinization of suspensions of wheat starch and cassava starch was studied. The sedimentation volumes of native and gelatinized starch with and without added monoglycerides were measured and the quantity of bound monoglycerides was determined. The sediments were examined by scanning electron microscopy and the rate of enzymatic breakdown by α-amylase was determined.     

大豆β-淀粉酶在生产麦芽糖浆上的优势

介绍了β-淀粉酶和α-淀粉酶的酶种来源及其在生产麦芽糖浆中的作用机理,并对大豆β-淀粉酶、大麦β-淀粉酶、小麦β-淀粉酶、真菌α-淀粉酶、普鲁兰酶的适用条件、失活条件进行了比较,得出大豆β-淀粉酶在生产麦芽糖浆上的优势。     

As the number falls,alternatives to the Hagberg–Perten falling number method: A review

This review examines the application, limitations, and potential alternatives to the Hagberg–Perten falling number (FN) method used in the global wheat industry for detecting the risk of poor end-product quality mainly due to starch degradation by the enzyme α-amylase. By viscometry, the FN test indirectly detects the presence of α-amylase, the primary enzyme that digests starch. Elevated α-amylase results in low FN and damages wheat product quality resulting in cakes that fall, and sticky bread and noodles. Low FN can occur from preharvest sprouting (PHS) and late maturity α-amylase (LMA). Moist or rainy conditions before harvest cause PHS on the mother plant. Continuously cool or fluctuating temperatures during the grain filling stage cause LMA. Due to the expression of additional hydrolytic enzymes, PHS has a stronger negative impact than LMA. Wheat grain with low FN/high α-amylase results in serious losses for farmers, traders, millers, and bakers worldwide. Although blending of low FN grain with sound wheat may be used as a means of moving affected grain through the marketplace, care must be taken to avoid grain lots from falling below contract-specified FN. A large amount of sound wheat can be ruined if mixed with a small amount of sprouted wheat. The FN method is widely employed to detect α-amylase after harvest. However, it has several limitations, including sampling variability, high cost, labor intensiveness, the destructive nature of the test, and an inability to differentiate between LMA and PHS. Faster, cheaper, and more accurate alternatives could improve breeding for resistance to PHS and LMA and could preserve the value of wheat grain by avoiding inadvertent mixing of high- and low-FN grain by enabling testing at more stages of the value stream including at harvest, delivery, transport, storage, and milling. Alternatives to the FN method explored here include the Rapid Visco Analyzer, enzyme assays, immunoassays, near-infrared spectroscopy, and hyperspectral imaging.     

不同面筋蛋白组分对小麦淀粉消化特性的影响机理

分别将面筋蛋白、谷蛋白及醇溶蛋白与淀粉按一定质量比（14∶86）混合,运用流变仪、热重分析仪及激光共聚焦显微镜等手段分析不同面筋蛋白组分与淀粉/α-淀粉酶之间的相互作用,以明确面筋蛋白及其不同组分对淀粉消化特性的影响及潜在机理。结果表明：与纯小麦淀粉相比,添加面筋蛋白、谷蛋白及醇溶蛋白使酶解120 min的淀粉消化率分别下降了39.93%、49.48%及26.61%。淀粉与不同面筋蛋白组分之间通过氢键相互作用形成了更稳定的复合物,提高了样品的热稳定性。与面筋蛋白和醇溶蛋白相比,添加谷蛋白在淀粉基质周围形成了更加致密的物理性屏障,更大程度地抑制了酶对淀粉的水解。此外,谷蛋白对α-淀粉酶的抑制率最高（约79%）,激光共聚焦观察到的结果也证实了谷蛋白和α-淀粉酶之间的结合程度更高。研究结果有助于丰富典型蛋白质组分调控食品体系中淀粉消化的机理,为低血糖指数食品的开发提供一定理论指导。     

Potential application of enzymes to improve quality of dry noodles by reducing water absorption of inferior-quality flour

This study has investigated the characteristics of dry noodles made with Korean domestic wheat flours using enzyme treatment for reducing water absorption to improve noodle-making performance. The water solvent retention capacity (SRC) values of flour treated with α-amylase and xylanase significantly decreased with increasing enzyme concentrations up to 0.025% (flour weight basis), which confirmed the enzyme effect on reducing the water absorption capacity of damaged starches and arabinoxylans. Enzyme-treated cooked noodles showed changes in textural characteristics, depended on the enzyme type, water amount, and drying method. Applying α-amylase for reducing the water absorption capacity of flour could mitigate the issue of inferior dry-noodle-making performance. Sensory evaluation showed improved preference attributes of cooked noodles with α-amylase treatment. In conclusion, the α-amylase application could improve the quality of dry-noodle made of Korean domestic wheat flour by diminishing the undesirable effect of damaged starch in flour related to noodle quality.

     

Antistaling Additives, Flour Type and Sourdough Process Effects on Functionality of Wheat Doughs

Antistaling additives—distilled monoglycerides (MGL), diacetyl tartaric ester of monodiglycerides (DATEM), sodium stearoyl lactylate (SSL), carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC) and fungal α-amylase—were studied for effects on rheological and fer- mentative properties of white/whole wheat bread doughs, made following straight/sour dough processes. A fractionated factorial design (L³²) was used to evaluate single additive effects and interactions. Single addition of DATEM, followed by SSL, α-amylase and hydrocolloids improved oven rise and final volume. In presence of DATEM, synergistic (MGL) and antagonistic (SSL) effects of additional emulsifiers were found on gassing power. SSL was the only effective conditioner for enhancement of mixing properties. Dough plasticity was negatively affected by MGL addition and by CMC/HPMC in white/whole flours respectively. Some combinations resulted in detrimental dough handling properties.