Effects of Malting on Phase Transition Behaviour of Starch in Barley Cultivars with Varying Amylose Content

The effect of malting on the phase transition behaviour of starch in barley cultivars with varying amylose content was studied using differential scanning calorimetry (DSC). A slight elevation in the melting transition temperature of amylopectin of malt starch and a pronounced decrease in gelatinisation enthalpy for both malt flour and starch were observed for all samples. Evidence was provided from the calorimetric data and the ¹³C CP/MAS NMR spectra that starch-lipid interactions in the form of complexes are enhanced as a result of malting. There was also a large reduction in the melting transition temperature of the amylose-lipid complexes of malt flours, presumably due to partial degradation of amylose in malt, whereas the transition enthalpies of the complexes increased for both malt flours and starches. The DSC transition characteristics of the three good malting barley cultivars grown in different locations and of their respective malts showed that environmental conditions during starch synthesis have a great influence on starch granule organization, and thereby affect the thermal stability of amylopectin crystallites.     

Effects of Wheat Protein Content on Endosperm Composites and Malt Quality

In this study, the malting performance of six traditional Chinese wheat varieties was evaluated. The effects of protein content on wheat endosperm composition and the malt quality were studied. The β‐glucan in the malt showed a positive correlation (r = 0.806, P<0.1) with the protein content of the wheat. With an increase in protein content, there was a significant linear decrease in extract (r = ?0.923, P<0.01) and Kolbach Index (r = ?0.850, P<0.05), but diastatic power, soluble protein and FAN gave a peak value at 16.0% protein content. Because of the suitable protein and starch content, the malt qualities of wheat W‐3 were satisfactory. Extract was 81.7%, saccharification time was 6.5 min, diastatic power was 484.07WK, FAN was 136.58 mg/100 g, the Kolbach index was 40.0% and viscosity was 1.77 cP.     

Comparison of the starch properties of Japanese wheat varieties with those of popular commercial wheat classes from the USA,Canada and Australia

The starch properties of four Japanese wheat varieties/breeding lines suitable for both bread and noodles were compared with those of popular commercial wheat classes from the USA, Canada and Australia. All starches were analyzed for amylose content, pasting properties measured by a rapid visco analyzer (RVA), swelling power, thermal properties measured by differential scanning calorimetry (DSC), enzyme digestibility, and chain length distribution of amylopectin (DP 6–17). All starch characteristics studied, except the chain length distribution of amylopectin, were significantly different among the tested wheat classes and varieties/breeding lines. Including Japanese wheat varieties/breeding lines, higher amylose contents and lower peak viscosities were found in hard wheats than in soft wheats. Interestingly, enthalpy, in the amylose–lipid complex measured by DSC, showed significant correlations with the pasting temperature from the RVA and swelling power.     

大米淀粉组成与挤压特性之间的相关性研究

分析11种大米的淀粉组成和挤压特性,探讨总淀粉、直链淀粉含量以及淀粉直/支比与膨化度、吸水性、水溶性、容重、硬度等挤压特性之间的相关性。结果表明:直链淀粉含量与吸水性呈显著正相关(r=0.879)、与水溶性呈显著负相关(r=-0.876),与膨化度之间也具有一定的相关性(r=0.530),与容重及硬度无显著相关性;淀粉直/支比与吸水性(r=0.848)呈显著正相关,与水溶性呈显著负显著(r=-0.827),与膨化度具有一定的相关性(r=0.512),但与容重及硬度无显著相关性。大米的直链淀粉含量以及淀粉直/支比与膨化度、吸水性等挤压特性具有相关性,直链淀粉含量和淀粉直/支比可作为大米挤压加工中原料选择和复配的依据。     

The Influence of Environment on Starch Content and Amylose to Amylopectin Ratio in Wheat

There is evidence that starch content plays an active role in determining dough rheological characteristics. The aim of this study was to determine the influence of environment on starch content and amylose: amylopectin ratio, and how this affects breadmaking quality. Ten hard red spring wheat cultivars were planted in three different environments in a randomized complete block design with three replications. Total starch content, amylose: amylopectin ratio, milling, rheological and baking characteristics were measured. Starch content was significantly influenced by the environment. It was significantly negatively correlated with loaf volume, wet gluten content and flour protein content across the three environments. Starch content and protein content were significantly negatively correlated, yet the value was relatively small (r = −0.4) and the relationship was therefore not directly inverse, and other factors influenced this relationship. Some cultivars interacted with specific environments, and they ranked high for starch content and loaf volume. Amylose: amylopectin ratio was very consistent for the three environments but was not significantly correlated with breadmaking quality characteristics across the environments, although there were significant correlations at individual environments. Cultivar choice and environment where cultivars are planted will therefore affect the starch content. High starch content will not necessarily lead to poor baking quality.     

小麦淀粉特性与面包烘烤品质的相关性

利用国内外40个面包小麦品种(系)进行了淀粉性状与面包烘烤品质性状的相关性分析，比较了国内外小麦在加工品质和淀粉性状的差异。结果表明，直链淀粉含量与面包品质性状(Zeleny沉淀值、面团形成时间和稳定时间)呈极显著负相关；淀粉总量与面包品质性状呈负相关，但相关不显著；面粉膨胀势与面包品质性状呈极显著正相关。国内外小麦品种(系)相比，Zeleny沉淀值、面团形成时间和稳定时间等性状差异较大；在淀粉性状和面包品质性状上，国外小麦品种(系)明显优于国内材料。讨论认为，蛋白质和淀粉对小麦的面包烘烤品质都有一定的影响。直链淀粉含量、支链淀粉含量和膨胀势可作为小麦品质育种亲本选配、后代选择的指标。改良我国小麦淀粉的主要目标是降低直链淀粉含量。     

A SIMPLE AND RAPID TEST FOR ASSESSMENT OF ENDOSPERM PROTEIN MODIFICATION DURING MALTING*

A simple test has been developed for the quantitation of endosperm protein modification in malts. Barley meals or ground malts were extracted with a suitable solvent and the clarified hordein extract diluted into an appropriate precipitant. Of a variety of extractants and precipitants investigated, 1M urea-1% (v/v) mercaptoethanol and 1M sodium chloride were respectively found to be most suitable. Under these conditions a turbid suspension forms; the turbidity of extracts decreased progressively during malting. Turbidity was due to selective precipitation of a specific group of “B” hordeins. In an analysis of nine varieties differing in malting qualities, a significant correlation between the reduction in extract turbidity and cell wall modification (Calcofluor staining) was observed at 48 hours' malting. In addition, for each variety examined, protein modification occurred about one day before carbohydrate modification. Analysis of commercial malts and several samples of selected cultivars from regional trials found good correlations between malt turbidities and percent malt extract and Kolbach index. The test is rapid (10–90 mins) and can be used to screen large numbers of samples; since it is simpler than alpha—amino nitrogen or Kolbach index determination, it may be of use in analysis of malts for protein modification.     

THE SUSCEPTIBILITY OF CEREAL STARCHES TO AMYLOLYSIS DURING GERMINATION AND MATURATION

During the maturation of normal and high amylose barley the susceptibility of the raw starches to attack by α-amylase remains constant until the moisture content of the grain falls below about 60%. Thereafter the starch develops a resistance to amylolysis which is directly proportional to the loss of grain moisture. The mean diameter of the starch granules of barleys and malt remains unchanged during digestion but the blue values of the residual starches decrease throughout. During the malting of wheat and barley the bulk of the starch solubilized is the amylopectin fraction although amylose is increasingly utilized when germination is prolonged. When high amylose barley is malted the blue value of the starch declines steadily throughout the growth period, suggesting that the spatial arrangements of the molecules within the granule influence the solubilization of the starch. The susceptibilities of wheats and normal and high amylose barleys to amylolysis were significantly lower than those of the corresponding malted products.     

鲜湿米粉原料加工适应性及配米技术研究

针对我国米粉原料质量不稳定、标准化差、专用品种不明晰等问题,选取我国种植广泛的12种籼稻,研究鲜湿米粉原料加工适应性及配米技术。因子分析及聚类分析结果表明：天优华占、中嘉早1号、中早39号适合加工鲜湿米粉。淀粉含量、直链淀粉含量、支链淀粉含量、直支比、脂肪含量、衰减值、最终黏度值、回生值、白度与米粉综合品质显著相关,核心指标的适宜范围为：总淀粉含量78.5~85.5 g/100g、直链淀粉含量24.3~27.3 g/100g、支链淀粉含量53.5~58.5 g/100g、直支比0.44~0.48、衰减值400~800 cP、最终黏度值3500~3900 cP、回生值1600~1850 cP、白度大于76.4、脂肪含量0.72~1.14 g/100g。配米试验结果表明：把理化性质不同的稻米依据特定的标准进行精准化调配,制作的米线优于市售产品,该方法有利于保证原料的稳定性和产品的质量。     

125th Anniversary Review: The science of the tropical cereals sorghum,maize and rice in relation to lager beer brewing

Mainstream lager beer brewing using the tropical cereals sorghum, maize and rice, either as malt or as raw grain plus commercial enzymes, is becoming widespread. This review examines the differences in composition between these tropical cereals and barley and their impact on brewing processes and beer quality. All of these cereals have a starch gelatinization temperature some 10 °C higher than barley. The sorghum prolamin proteins are particularly resistant to proteolysis owing to disulphide cross‐linking involving γ‐kafirin. Unlike barley, the major endosperm cell wall components in sorghum and maize are arabinoxylans, which persist during malting. The rice cell walls also seem to contain pectic substances. Notably, certain sorghum varieties, the tannin‐type sorghums, contain considerable levels of condensed tannins (proanthocyanidins), which can substantially inhibit amylases, and probably also other brewing enzymes. Tropical cereal malts exhibit a similar complement of enzymic activities to barley malt, with the notable exception of β‐amylase, which is much lower and essentially is absent in their raw grain. Concerning beer flavour, it is probable that condensed tannins, where present in sorghum, could contribute to bitterness and astringency. The compound 2‐acetyl‐1‐pyrroline, responsible for the popcorn aroma of maize and also the major aroma compound in rice, presumably affects beer flavour. However, much more research is needed into tropical cereals and beer flavour. Other future directions should include improving hydrolysis of prolamins into free amino nitrogen, possibly using prolyl carboxypeptidases and investigating tropical cereal lines with useful novel traits such as high amylopectin, high protein digestibility and low phytate. Copyright © 2013 The Institute of Brewing & Distilling     

6种不同种类直支链淀粉相互混合对其回生的影响

目的 研究6种不同种类直支链淀粉相互混合对其回生的影响。方法 将玉米淀粉、甘薯淀粉、木薯淀粉、马铃薯淀粉、糯米淀粉、小麦淀粉等6种不同种类直支链淀粉分离出来, 然后两两混合, 研究不同直支链混合对其回生率的影响。 结果 马铃薯支链淀粉与甘薯支链淀粉以2:8(m:m)混合回生率最低, 为60.0%, 玉米支链淀粉与木薯支链淀粉以8:2(m:m)混合回生率最低为52.6%, 小麦支链淀粉与糯米支链淀粉以8:2(m:m)混合回生率最低为51.2%, 甘薯支链淀粉与小麦支链淀粉以1:1(m:m)混合回生率最低为53.7%。木薯支链淀粉与小麦直链淀粉以1:1(m:m)混合时所得淀粉回生率最大, 达到了92.0%, 混合淀粉回生后X射线晶型为B型。结论 不同种类直支链淀粉混合对其回生率影响很大, 食品加工中尽量不要混合使用木薯支链淀粉与小麦直链淀粉。     

Rice Starch Molecular Size and its Relationship with Amylose Content

The composition and starch molecular structure of eight rice varieties were studied. Waxy and non‐waxy (long‐, medium‐, and short‐grain) rice varieties from California and Texas were used. The amylose contents were measured using the Concanavalin A method and were found to be related to the type of rice: waxy ≈ 1.0%, short and medium grain 8.7–15.4%, and long grain 17.1–19.9%. The weight‐average molar masses (M_w) of the starches varied from 0.52 to 1.96×10⁸ g/mol. As would be expected, a higher M_w of rice starch correlated to lower amylose content. The range of M_w of amylopectin was 0.82 to 2.50 ×10⁸ g/mol, and there was also a negative correlation of amylopectin M_w with amylose content. Amylose M_w ranged from 2.20 to 8.31×10⁵ g/mol. After debranching the amylopectin with isoamylase, the weight‐average degree of polymerization (DP_w) for the long‐chain fraction correlated positively with a higher amylose content. California and Texas varieties were significantly different in their amylose content, starch M_w (short‐ and medium‐grain only), and amylopectin M_w (p < 0.05).     

Wx基因对小麦淀粉生物合成和积累的影响

为研究Wx基因的缺失对小麦淀粉生物合成的影响,本研究以8个Wx小麦近等基因系为材料,在灌浆期的10、20、30和40 d取籽粒测定直链淀粉、支链淀粉、总淀粉的含量及合成速度。结果表明:直链淀粉、支链淀粉和总淀粉含量及积累速率在花后逐渐增加,以花后10~20 d最大,此后逐渐降低。3个Wx基因对直链淀粉的含量及积累速率的影响依次为Wx-B1Wx-A1Wx-D1;小麦Wx基因型对直链淀粉的合成及积累速率影响较大,而对支链淀粉的影响较小,其对总淀粉含量及其积累的影响主要通过直链淀粉进行。     

Properties of Starches from Australian Wheats. Part 2: Some Physico-chemical Properties

Various physico-chemical properties of starches isolated from 21 Australian wheat varieties were assessed. Molecular weights varied between the starches and were lower in those from soft wheats. Proportions of small granules were significantly correlated with starch amylose and protein contents; those of large granules correlated negatively with fat content. Granule crystallinity was correlated with hardness of the parent wheats. Gelatinisation temperatures, measured by differential scanning calorimetry, varied between the starches within the range of 46–79°C. Enthalpies of gelatinisation, 4.6–13.3 J/g of dry starch, were correlated with both amylopectin content and wheat hardness. Minimum moisture for gelatinisation, 0.15–0.56 wa-ter/g of dry starch, was significantly correlated with both amylose and fat contents of the starch.     

优化毛细管电泳法测定山药淀粉中直链/支链淀粉

以市售新鲜怀山药为原料通过石灰水浸泡法制备山药粉,并通过正丁醇反复结晶法分离纯化直链淀粉与支链淀粉。利用碘做显色剂,使用毛细管电泳法测定山药淀粉中直链淀粉与支链淀粉的含量以及比率,本文分别对柠檬酸-磷酸盐缓冲液以及醋酸-醋酸盐缓冲液等不同缓冲液作为流动相进行了对比,实验发现醋酸-醋酸盐缓冲液对于分离测定直链淀粉与支链淀粉的效果较好。随后分析了不同p H条件下的醋酸-醋酸盐缓冲液进行的分离效果进行了比较,并测定其迁移率,当p H 4.8时分离效果最佳且其迁移率达到15.4。利用最佳条件使用纯的马铃薯直链淀粉与支链淀粉标准品,得出支链淀粉的保留时间约为1.8 min,而直链淀粉的保留时间约为2.9 min,对怀山药淀粉进行分析,从而得出怀山药中直链淀粉含量为19.49%。利用重复性试验以及回收率试验该方法的准确性与精确度能达到很好的效果。     

Comparison Between Granular Starch Hydrolyzing Enzyme and Conventional Enzymes for Ethanol Production from Maize Starch with Different Amylose: Amylopectin Ratios

The effect of enzyme treatments (granular starch hydrolyzing and conventional enzymes) and different amylose: amylopectin ratios of maize starch on ethanol production was evaluated. For starch treatments, amylose: amylopectin ratios were prepared by mixing commercially available Hylon VII (70% amylose and 30% amylopectin) and Amioca (˜100% amylopectin) starches. For maize treatments, waxy, high amylose and regular dent hybrids were used to represent varying amylose: amylopectin ratios. All hydrolyses followed by fermentations were conducted at 15% solids content. Differences were observed in ethanol yields among granular starch hydrolyzing and conventional enzymes. Differences also were observed in ethanol yields between different amylose: amylopectin ratios for pure starch and maize samples. For starch samples, final ethanol concentrations varied from 2.2 to 9.1% (v/v) for fermentation with granular starch hydrolyzing enzyme and from 6.7 to 9.3% (v/v) for conventional enzymes. Higher ethanol concentrations were observed for Amioca starch for both enzymes. For maize samples, final ethanol concentrations were highest for waxy maize for both granular starch hydrolyzing (8.2%, v/v) and conventional (8.2%, v/v) enzymes. Lowest ethanol concentrations were observed for high‐amylose maize samples for granular starch hydrolyzing (6.3%, v/v) and conventional (5.2%, v/v) enzymes.     

A RAPID AND SIMPLE METHOD FOR THE DETERMINATION OF STARCH AND β-GLUCAN IN BARLEY AND MALT

A simple and precise method suitable for the routine determination of starch and β-glucan in barley and malt is described. Perchloric acid (50 mM) was used to effect rapid (3 min) and exhaustive extraction of both glucans which were then measured directly from this single extract by specific enzymic hydrolysis of the individual glucans to glucose. The glucose was also measured enzymically. Little or no acid hydrolysis of starch or β-glucan was observed under the extraction conditions used; most or all of the free glucose could be attributed to hydrolysis of sucrose. Complete solubilisation of the gum and hemicellulosic components of β-glucan was achieved. Preincubation of the acid extracts with protease prior to amyloglucosidase digestion resulted in higher measurements (approximately 4% w/w) of starch. The method was used to measure the levels of starch and β-glucan in five varieties of barley with contrasting malting quality, in micro-malts prepared from these samples and in commercial lager and ale malts.     

不同板栗品种(系)抗性淀粉综合评价

对72个板栗品种(系)栗仁中总淀粉、支链淀粉、直链淀粉、抗性淀粉、以及含水量等重要性状分析的测定,为不同板栗品种(系)的利用提供参考。结果表明,不同板栗品种(系)大小、色泽、形状不同;板栗品种(系)中总淀粉的质量分数在51.33%以上,质量分数最高为‘燕秋’,高达71.21%,质量分数最低的是‘波叶-8’,为51.33%;直链淀粉中含量最高的是‘燕秋’,质量分数为18.56%,最低的是‘大兰口’,质量分数为2.43%;支链淀粉含量最高的是‘金丰’,质量分数为58.35%,最低的是‘小官10’,质量分数为35.2%。板栗中含有较高的抗性淀粉。对不同板栗品种(系)中抗性淀粉进行综合评价,抗性淀粉含量最高的品种是‘燕秋’,质量分数为22.2%;最低的是‘徐玉明道’,质量分数为3.44%。通过对不同板栗品种(系)的淀粉进行相关性分析,表明板栗栗仁中直链淀粉与支链淀粉呈极显著负相关,支链淀粉与总淀粉呈极显著正相关,抗性淀粉与直链淀粉呈显著正相关。     

The effect of germination time on malt quality of six sorghum (Sorghum bicolor) varieties grown at Melkassa,Ethiopia

The effect of germination time (48, 96 and 144 h) on malt quality of six sorghum varieties was investigated to determine the potential of grain sorghum cultivars in the local brewery industry. Six sorghum varieties (Gambella 1107, Macia, Meko, Red‐Swazi, Teshale and 76 T1#23) were evaluated in a randomized complete block design with three replications. The results showed that both germination time and variety had a significant effect (p ≤ 0.05) on sorghum malt quality. The hectolitre weight (kg hL^?1 at 12.5% moisture), germination energy (%), crude protein (%) and flour starch amylose content (%) were: 75.8–82.9, 96–99, 7.0 ? 11.9 and 16.0 ? 23.0, respectively. The sorghum malt diastatic power (DP, °L), free amino nitrogen (FAN, mg L^?1), hot water extract (HWE, %) and malting loss (%) were: 18.96 ? 31.39, 185.67 ? 343.29, 41.85 ? 85.08 and 8.68 ? 27.56, respectively. Malting loss, HWE and FAN increased with germination time. The DP increased as the germination duration increased from 48 to 96 h, but the difference between 96 and 144 h was not significant. Considering the excessive malting loss and marginal increase in HWE beyond 96 h, this study suggests that the optimum malting duration would be around 96 h. Among the varieties tested, Teshale and Gambella 1107 produced the better malt quality. Copyright © 2012 The Institute of Brewing & Distilling     

Relationship between Kolbach index and other quality parameters of wheat malt

In order to determine suitable Kolbach indices in wheat malting, the relationships between the Kolbach index and other quality parameters in wheat malt were studied. Eight white wheat malts with different Kolbach indices (31.4, 33.1, 37.0, 37.6, 39.5, 40.7, 42.8 and 45.5%) from the same wheat variety were prepared. The increase ratio of the ALSP (albumins and other soluble proteins) and the decrease ratio of the glutenins were found to have a significant positive correlation with the Kolbach index, and the corresponding r‐values were 0.883 and 0.975 (p < 0.01). The ALSP of the wheat malts had a positive correlation with chromaticity, extract, free amino nitrogen (FAN), viscosity, acidity, xylan glycosidase activity, endo‐β‐1,4‐xylanase activity and malting loss (p < 0.05). When the Kolbach indices were 31.4, 33.1, 37.0, 37.6 and 39.5%, there was a positive correlation between the soluble xylan and the viscosity, and the r‐value was 0.888 (p < 0.05). Comparing the malts, it could be concluded that, for this particular wheat variety, when the Kolbach index was 39.5%, the wheat malts exhibited the best characteristics; the extract was 81.98%, the FAN content was 166.03 mg per 100 mg, the saccharifying power was 496.72 WK, the viscosity was 1.61 cP, and the saccharification time was 6 min. Copyright © 2012 The Institute of Brewing & Distilling