Pilot scale preparation of wheat gluten protein fractions: II. Technological properties of the fractions

Fractions differing in prolamin compositions were obtained on a pilot scale when wheat gluten proteins were separated by differential extraction in dilute acetic acid. The soluble fractions were enriched in gliadins and the insoluble ones were richer in glutenins. The effects of the gluten fractions on the technological properties of wheat flours were investigated using an alveographic test and a comparison was made with gluten-added flours. Gliadin-rich fractions increased the extensibility of the dough and reduced its resistance to deformation. On the other hand, glutenin-rich fractions had an opposite effect and increased the dough resistance more than that of equally-concentrated whole gluten. The magnitude of the effects was strongly related to the gliadin and glutenin contents of the fractions. Prediction of technological effects is thus possible using composition analyses based on protein extractibility or size-exclusion chromatography. Finally, the improving effects of the gliadin-rich and of the glutenin-rich fractions were observed at different stages of the breadmaking process.     

富含小麦面筋蛋白的腐乳白坯工艺条件优化

为研发一种在传统腐乳白坯中添加小麦面筋蛋白的新型腐乳,对腐乳白坯的工艺条件进行优化。此研究以感官评分和保水率为指标,在蹲脑时间、压榨时间、谷朊粉添加量、凝固剂添加量等单因素试验的前提下,进一步进行响应面实验。结果表明,以压榨时间1. 2 h、凝固剂量占总原料质量分数10%、蹲脑时间20 min、谷朊粉量60 g,即占原料总量40%等条件下,所得白坯的保水率为75. 18%,凝胶强度95. 99 g,出品率183. 55%,与传统白坯相比,保水率提高8. 39%,出品率提高38. 36%,硬度、弹性等质构特性均改善,感官评分更高。此研究不仅拓宽了谷朊粉的应用范围,也为今后豆腐和腐乳的品质改善提供了参考。     

Differences in accumulation of storage proteins between wheat cultivars during development

The concentration and composition of storage proteins in the developing kernels of five different wheat cultivars were investigated. The plants were grown in solution culture under strictly controlled conditions in climatic chambers and with long-term limitation of external nitrogen availability. Thus, by growing these cultivars under the same defined treatments, reliable differences in the storage protein development could be determined. The total protein concentration was assayed using an automatic nitrogen analyser. The storage protein composition was examined by acidic polyacrylamide gel electrophoresis and sodium dodecyl sulphate polyacrylamide gel electrophoresis from 6 to 58 days after anthesis. The results showed that, in all stages of plant development, the ranking of the cultivars as to the storage protein concentration was the same as for mature field-grown kernels. The differences in the storage protein concentration between the cultivars could not be explained by differences in protein composition. The start of storage protein formation during plant development did not differ between the tested cultivars, as determined by the electrophoresis pattern. The differences in the storage protein concentration between cultivars most likely depends on the relative balance between starch and nitrogen deposition in the grain, during the whole grain filling period.     

小麦面筋蛋白组成、结构和功能特性

小麦面筋蛋白(俗称谷朊粉)主要由麦醇溶蛋白和麦谷蛋白组成,其蛋白组成和结构是影响小麦面团特性和烘焙品质重要因素。该文对小麦面筋蛋白组成、结构进行综述,以更清楚了解其结构对功能性影响。     

Rheological properties of wheat gluten and their relation to molecular parameters]

In the light of the general results of protein chemistry and of the interrelationships up to now established, it is stated that the factors which determine the mechanical properties are complex in nature. Though the amino-acid composition (cystine content, amino acids with hydrophobic side-chains) and the ratio of the wheat gluten fractions (ratio of high molecular protein components to low-molecular ones) exert some effect on the rheological properties, the linkages and the interactions between the different fractions play the main role in the development of the mechanical properties of the gluten. Among the various linkages and interactions which occur in protein architecture, the disulphide linkages, the hydrogen bonds (amido group, primary amino group) and the hydrophobic interactions (side-chains of proline, leucine, isoleucine, glutamine, etc.) are of great importance. The complex evaluation of data about the content of disulphide linkages, the degree of amidation of the glutamic and aspartic acids and the amount of amino acids with hydrophobic side-chain gives a significant insight which might be of practical value.     

Breadmaking quality of ten greek breadheats. II. Relationships of protein,lipid and starch components to baking quality

Protein, lipid and starch components of ten Greek inter bread heats (four poor quality soft milling varieties, and to soft and four hard milling varieties of good quality) ere examined for possible relationships ith bread loaf volume and volumes in sedimentation tests for flour quality. High molecular eight glutenin subunit quality scores ere loer (4, 4, 6, 6) in the poor quality heats than in the good quality heats (6, 6, 6, 6, 8, 10) and ere only roughly correlated ith the other quality parameters. Gliadin electrophoregram patterns ere distinctive for most heats and might be useful for variety identification, but consistent occurrence of γ-gliadin 40, associated ith eakness, and γ-gliadin 43.5, associated ith strength, as not observed. The ratio non-polar/polar free lipids as highly correlated (P < 0.001) ith loaf volumes using both long fermentation and activated (chemical) dough development processes. Starch granule composition, selling and gelatinisation properties, hich ere very similar to those of other heat starches, did not relate to baking quality. A 15-kDa protein on the surface of starch granules associated ith endosperm softness as found in the soft heats.     

Comparative investigations of gluten proteins from different wheat species I. Qualitative and quantitative composition of gluten protein types

In contrast to the hexaploid common (bread) wheat, little information is available on the qualitative and quantitative compositions of gluten proteins from other cultivated wheat species. Therefore, representatives of hexaploid spelt, tetraploid durum wheat and emmer, and diploid einkorn were compared with three classes of common wheat (winter wheat, spring wheat, wheat rye hybrid). The flours were extracted to yield total endosperm proteins and the gluten protein fractions (gliadins and glutenin subunits). The extracts were characterised using sodium dodecyl sulfate polyacrylamide gel electrophoresis and reversed-phase HPLC; both methods revealed that gluten protein groups and types known from common wheat (ω-, α-, γ-gliadins, HMW and LMW subunits of glutenin) were present in all species. The HPLC platterns of gliadins and glutenin subunits from species with the same genome composition (common wheat/spelt or durum wheat/emmer) were related, and those of einkorn quite different. According to the quantities determined by reversed-phase HPLC, α-gliadins were predominant in most cases, followed by γ-gliadins and LMW subunits; ω-gliadins and HMW subunits were generally minor components. Common wheats were characterised by the highest proportions of total glutenins and HMW subunits, which are known to be important for breadmaking quality. Moreover, the lower ratio of gliadins to glutenins was typical. Emmer had the lowest proportions of total glutenins and of HMW and LMW subunits, together with einkorn the highest proportion of α-gliadins, and, by far, the highest ratio of gliadins to glutenins. The values for spelt and durum wheat were mostly in a medium range between common wheats, emmer, and einkorn, respectively. Amongst common wheats, spring wheat was characterised by more balanced quantities of α- and γ-gliadins, and wheat rye hybrid by the highest proportions of ω-gliadins. Received: 26 November 1999     

Enzymatic preparation and functional properties of wheat gluten hydrolysates

The water-insolublity of wheat gluten is one of the major limitations for its more extensive use in food processing. Wheat gluten was enzymatically hydrolyzed by several commercially available proteases (Pancreatin Trypsin 6.0S, Porcine pepsin, Pancreatin and Alcalase 2.4L) with protein recovery varying from 42.5 ± 0.7% to 81.3 ± 0.1%. The hydrolytic efficiency of these proteases on wheat gluten was also compared. Alcalase served best for the preparation of wheat gluten hydrolysates (WGHs). Thus, Alcalase-assisted hydrolysates of wheat gluten (AWGHs) with different degrees of hydrolysis (DH 5.0, 10.0 and 15.0%) were further assessed for their functionalities. All the AWGHs had excellent solubility (>60%) over a pH range of 2–12. The emulsifying and foaming properties of AWGH with relatively low DH (5.0%) were remarkably higher compared to the original gluten. However, extensive hydrolysis of gluten resulted in remarkable reduction in emulsifying and foaming properties.     

酶解100kg玉米蛋白粉制备玉米功能短肽的中试研究

酶解玉米蛋白对生产高营养且易于吸收、高附加值的具有生物学功能特性的生物产品具有重要意义。本文在多次小试实验的基础上,利用酶工程技术对100kg玉米蛋白粉水解制备玉米短肽进行了中试研究,为推动玉米蛋白资源的深加工和产业化进程提供依据。     

小麦粉面筋蛋白质流变学特性的研究

本试验采用快速黏度仪(RVA)通过面筋蛋白醇溶指数法,研究了不同类型小麦粉的面筋蛋白醇溶指数,探讨了不同小麦粉的粉质特性、拉伸特性及湿面筋、面筋指数及其与醇溶指数、最终黏度的影响.结果表明:不同类型的小麦粉的面筋蛋白RVA曲线存在明显差异,醇溶指数在α=0.05水平上与小麦粉吸水率、延伸性呈负相关,与峰值黏度呈正相关;在α=0.10水平上与小麦粉稳定时间呈负相关,最终黏度在α=0.05水平上与小麦粉面筋指数呈负相关,与峰值黏度呈正相关.因此,麦胶蛋白明显影响小麦粉的吸水率、稳定时间、延伸性及面团的面筋指数,而与拉伸阻力、湿面筋及弱化度无相关性,此与麦胶蛋白的富有延伸性、粘性,但弹性小的性质有关.     

谷朊粉与玉米醇溶蛋白可食性复合膜的研究

研究了谷阮粉和玉米醇溶蛋白可食性复合膜的成膜条件及复合膜的特性。结果表明:复合膜中玉米醇溶蛋白的适宜添加量为25%。在各自最佳成膜条件下,复合膜的水蒸气透过率为5.97g·mm/m2·d·kPa,比对照降低了12.1%;拉伸强度为3.45MPa,比对照提高了22.6%。综合考虑水蒸气透过率与拉伸强度两项指标,确定适宜的成膜条件为:pH12、热处理温度70℃、乙醇浓度55%、甘油浓度10%,此条件下复合膜的水蒸气透过率为6.01g·mm/m2·d·kPa,比对照降低11.5%;拉伸强度为3.39MPa,比对照提高20.7%。该复合膜同时具有良好的热封性。     

湿热-胶体改性对小麦面筋蛋白功能性质的影响

研究了在湿热条件下将羧甲基纤维素钠(CMC)、明胶、海藻酸钠、果胶、瓜尔胶这几种不同胶体作为添加剂添加到小麦面筋蛋白中,测定了其对小麦面筋蛋白功能性质的影响,主要以小麦面筋蛋白的粘稠性、乳化性和乳化稳定性、溶解性、起泡性这几个指标作为参考。实验结果表明,与简单混合相比,羧甲基纤维素钠、明胶、海藻酸钠、果胶在湿热条件下使小麦面筋蛋白的溶解性,乳化性和粘稠性都有一定幅度的提高,但是对小麦起泡性和乳化稳定性的影响不大;瓜尔胶在湿热条件下对小麦蛋白性质的影响与简单混合相比基本持平。     

稀乳酸对小麦粉面筋蛋白质的影响研究

应用快速黏度仪(RVA)通过稀乳酸法主要研究了2#与A2两种类型小麦粉的面筋蛋白特性,探讨了RVA曲线的峰值黏度、3min时黏度、衰减度及最终黏度。另外,应用粉质仪、拉伸仪及湿面筋仪分别对小麦粉粉质特性、拉伸特性及湿面筋进行了研究。结果表明:不同类型的小麦粉的面筋蛋白RVA曲线存在明显差异,对于同一类型的A2粉,衰减值在α=0.10水平上与稳定时间表现为负相关,与弱化度、MTI特性及拉伸阻力表现为正相关,而与面筋指数在α=0.01水平上表现为强正相关。峰值黏度在α=0.01水平上与吸水率、延伸性表现为强正相关性。3min时黏度值在α=0.05水平上与吸水率及延伸性表现为正相关性。另外,最终黏度值在α=0.01水平上与吸水率表现为强正相关性,在α=0.05水平上与延伸性表现为正相关性。     

谷朊粉改性研究进展

谷朊粉是一种营养丰富的植物蛋白资源,其特有功能性质在食品生产中具有广泛用途.通过一定生物化学手段改性,可大大拓宽谷朊粉应用范围.主要综述近年来有关谷朊粉物理、化学、酶法和基因工程改性方面的研究进展.     

大豆分离蛋白与谷朊粉可食性复合膜研究

该文报道影响大豆分离蛋白与谷朊粉复合膜成膜因素,分析各种因素对复合膜性能影响,并对正交试验结果采用极差分析和综合评分法进行评定,得到制备综合性能良好的可食性膜最佳条件为:谷朊粉与大豆分离蛋白比例为1∶5,甘油量为20%,pH为11,预热处理温度和时间分别为80℃和40min;此时,膜的透光率、拉伸强度、撕裂强度、水分含量和水蒸汽透过率依次为60.5%、38.38MPa、198.02N/mm、13.87%和0.507g·mm/kPa·h·m2。     

The influence of 1B/1R chromosome translocation on gluten protein composition and technological properties of bread wheat

The Austrian bread wheat Amadeus without and with 1BL/1RS translocation and three further translocation genotypes with known HMW subunit compositions were grown under the same environmental conditions. Their flours were characterised by the determination of crude protein content and, partly, by the determination of glutathione and cysteine. Furthermore, the qualitative and quantitative composition of gluten protein types was analysed by a combined extraction and reversed phase HPLC procedure. Dough development time, maximum resistance and extensibility of dough and gluten, and bread volume were determined by means of microscale methods. Protein, glutathione and cysteine contents of flours were only slightly influenced by translocation. The HPLC patterns of gliadins and glutenin subunits showed that translocation caused characteristic changes concerning ω‐gliadins, γ‐gliadins and LMW subunits of glutenin. The amount of ω 1,2‐gliadins was significantly increased and that of LMW subunits decreased. The effect of translocation on the rheological properties of dough and gluten was characterised by a strongly reduced dough development time, reduced maximum resistance and increased extensibility. Bread volume was decreased by about 10%. The amount of glutenin subunits was correlated with dough development time, resistance of dough and gluten, and bread volume to a higher extent (r = 0.79–0.91) than the amount of gliadins (r = 0.52–0.80). Correlation coefficients for LMW subunits were higher (r = 0.82–0.88) than those for HMW subunits (r = 0.35–0.61) when all five wheats were included. Instead, when only translocation lines were considered, HMW subunits (r = 0.89–0.98) were more important than LMW subunits (r = 0.64–0.86). Altogether, the results demonstrate that translocation causes important quantitative as well as qualitative changes in gluten protein composition which can be efficiently determined by reversed phase HPLC. © 2000 Society of Chemical Industry     

小麦面筋蛋白酶解特性研究

采用风味蛋白酶对小麦面筋蛋白进行深度水解,通过单因素实验,分析了底物浓度、温度、pH、酶用量、反应时间对水解度和蛋白质提取率的影响,并通过正交实验确定制备酶改性小麦面筋蛋白的最佳工艺参数为:底物浓度5%,T=50℃,pH6.5,酶用量=80LAPU/g,水解时间7h。反应最终可得水解度和蛋白质提取率均很高,且没有苦味的植物蛋白水解液,其中酶解液的水解度可达28.03%,蛋白质提取率可达52%。     

紫苏籽蛋白的提取及纯化研究

本文以紫苏籽为原料,利用石油醚对其进行脱脂。采用微波辅助提取紫苏籽蛋白。在单因素试验的基础上,采用L9(34)正交试验设计,研究pH、微波功率、微波时间和固液比对紫苏籽蛋白提取率的影响。结果表明,在各影响因素中,影响程度依次为:pH>微波功率>微波时间>固液比,微波辅助提取紫苏籽蛋白的最佳工艺条件为:pH10.0、固液比为1∶10、微波时间8min、微波功率200W,在此条件下测得脱脂紫苏粉粗蛋白提取率为25.85%,其蛋白含量为43.01%。经超滤法处理后得到的蛋白提取率为46.90%,其蛋白含量为91.74%。     

Adsorption behaviour of some anthocyanins by wheat gluten and its fractions in acidic conditions

Some anthocyanins, both commercial delphinidin‐3‐O‐β‐d ‐glucoside chloride and cyanidin‐3‐O‐β‐d ‐rutinoside chloride (Dp3glu and Cy3rut) and extracted from plants, were adsorbed by gluten or its fractions to carry out a study that can be considered a premise to estimate the potential effect on bioavailability of anthocyanin adsorption. This process was studied by means of adsorption kinetics and isotherms. Among the parameters determining adsorption, the temperature and the pH value were evaluated. The data show that gluten and its fraction have a great adsorption capacity (about 1.0 mg g^?1 of gluten). The results indicate that the structure of the anthocyanins plays an important role in their adsorption by gluten or its fractions; in fact, the adsorption kinetics show that Dp3glu is more adsorbed than Cy3rut. The isotherms of anthocyanin adsorption by gluten indicate the presence of a strong interaction between the two types of molecules. This could be an important finding to obtain functionalised‐based gluten products.     

Effect of wheat flour protein compositions on the quality of deep-fried gluten balls

Wheat flours milled from five different varieties of wheat and collected at an extraction rate of 60% were used as raw materials in this study. The proximate compositions, dough Farinographic and Extensographic properties, and the quality indices of deep-fried gluten balls prepared from these flours were measured. The proteins of these five different wheat flours were extracted and analyzed using the electrophoretic method, and the effect of protein composition on the quality of deep-fried gluten balls prepared from these flours was investigated. In this study, the proteins in each sample were divided into six groups, and the molecular weights of the proteins in these six groups are as follows: (I) 205.0–97.4 kDa; (II) 97.4–66.2 kDa; (III) 66.2–45.0 kDa; (IV) 45.0–36.0 kDa; (V) 24.0–19.7 kDa; (VI) 14.4–6.5 kDa, respectively. The results show that the protein contents of groups I, II, and V are negatively correlated to peak force and Hunter b value of deep-fried gluten balls, but positively correlated to Hunter L value and sensory evaluation score of appearance. The above results reveal that the high-molecular weight glutenin subunits, ω-gliadins, and albumins/globulins of wheat flour have a profound effect on the quality of deep-fried gluten balls.