Physicochemical and sensory properties of soy bread made with germinated,steamed, and roasted soy flour

For the development of healthful gluten-free soy bread acceptable to consumers, we evaluated the effects of various processing procedures for soy flour on bread quality, in terms of beany flavour and texture. We pretreated soy flour by both non-heating (raw:NS and germinated:GS) and heating (steamed:SS and roasted:RS) methods. In addition, to improve the loaf volume, we added 1% hydroxypropyl-methylcellulose (HPMC) to RS flour. Lipoxygenase activity was retained in the non-heat-treated flours (279 U/g for NS and 255 U/g for GS), but was significantly reduced in the heat-treated flours (106 U/g for SS and 69 U/g for RS). Moreover, heat-treated flour had higher isoflavone and ferric reducing antioxidant power than had non-heat-treated flour. However, RS flour had the lowest moisture content and lowest L^∗ value. The GS bread had the highest specific loaf volume (3.53 cm³/g), followed by NS (2.96 cm³/g), RS (2.25 cm³/g), and SS (1.81 cm³/g) bread. GS bread had the lowest hardness (1.53 N), followed by NS (1.65 N), RS (2.00 N), and SS (3.75 N) bread. The addition of 1% HPMC to RS increased the loaf volume (2.44 cm³/g), but decreased the bread’s hardness (1.80 N). As to the sensory properties, the bread with heat-treated flour was perceived to have a less beany odour and taste than was the bread with non-heat-treated flour. However, the latter had a better appearance than the former. These results indicated that soy flour pretreatment could enhance the loaf volume and reduce the beany flavour of whole soy bread.     

燕麦大豆复合馒头的研究

通过单因素试验和正交试验研究燕麦大豆粉馒头的配方和制作工艺。结果表明,在大豆粉8 g、燕麦8 g、小麦粉84 g、加水量60mL、发酵温度38℃、发酵时间70 min的条件下生产出的燕麦大豆粉馒头品质最佳,风味口感最优。     

不同工艺条件对大豆面包的影响

研究不同工艺条件对大豆面包品质的影响,确定大豆面包制作的最佳工艺。试验结果表明,采用直接发酵法,面团静置20min(26℃、相对湿度75%),醒发60～80min(38～40℃、相对湿度82%～85%),制作的大豆面包品质较佳。     

Some functional properties of fractionated soy protein isolates obtained by microfiltration

Five soy proteins isolate (SPI) fractions were produced using two microfiltration membranes with different pore sizes. Fractionation was carried out on SPI produced by isoelectric precipitation of a crude protein extract. The five fractions were two retentates and two permeates from the two membranes, the fifth fraction was obtained as the retentate on the smaller-pore-sized membrane fed with the permeate from the larger-pore-sized membrane. Solubility, foaming and emulsifying properties of the collected fractionates were investigated. It was observed that in the pH range 3–8 the retentates featured superior solubility compared with permeates. There was no significant difference (p>0.01) in solubility between the retentates and SPI at pH6. Foaming characteristics of the fractions followed the same trend as solubility with regard to foam expansion. There was, however, no particular trend observed with regards to foam stability. Emulsions stabilised by the retentates exhibited higher values (p<0.01) of emulsion stability index (ESI) and emulsifying activity index (EAI) than those stabilised with permeates. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) profiles indicated that the fractions exhibiting high functionality in terms of solubility, foaming and emulsifying properties were also richer in 7S globulin soy protein subunits.Isoelectric focussing (IEF) profiles showed that retentates were richer in species with isoelectric points (pI) between 5.2 and 5.6 while permeates featured more prominently at pIs between 4.5 and 4.8.     

大豆粉对面包粉烘焙品质的影响

将全脂大豆粉和脱脂大豆粉添加到小麦粉中,研究其对精制级面包粉和普通级面包粉烘焙品质的影响.结果表明,在两种面包粉中添加大豆粉后,当全脂大豆粉质量分数不高于2％、脱脂大豆粉质量分数不高于3％时,面包体积和比容有所增加,添加量进一步增大时面包体积和面包比容反而下降;随着添加量的增加,全脂大豆粉和脱脂大豆粉使两种面包粉的面包质量增加;当大豆粉质量分数不超过3％时,两种大豆粉均对两种面包粉的面包综合品质有改良作用,添加量进一步增大反而使面包品质劣变.     

大豆分离蛋白-水溶性大豆多糖可食性复合膜的制备与性质

以大豆分离蛋白(soy protein isolates,SPI)和水溶性大豆多糖(soluble soybean polysaccharides,SSPS)为主要原料进行了可食性复合膜的制备与性质研究。综合考虑SPI与SSPS的比例、甘油、海藻酸钠添加量及钙离子浓度等影响因素,通过单因素与正交实验对成膜配方进行研究,得到了复合膜的最佳配比,并从水溶性、水蒸气透过性、抗拉伸强度、断裂延伸率等方面对膜的性质进行了综合评价。结果显示:在SPI∶SSPS质量比为1∶7,甘油添加量2%,海藻酸钠添加量4%,Ca2+浓度为1.0mol/L的条件下,复合膜的综合性能评分最高,为67.8。     

脱脂大豆粉对面包品质及加工特性的影响

以脱脂大豆粉代替部分小麦粉加工面包,并对面包的营养品质和烘焙品质进行分析。结果表明,添加脱脂大豆粉的面包蛋白质、矿物元素和必须氨基酸的含量明显增加。营养增补效果明显,营养品质得到改善;少量添加时可以改善面包的加工特性,添加量5%为宜,过量添加将对面包的烘焙品质有影响。     

Production of gluten‐free bread using soybean flour

The effect of soybean flour on gluten‐free bread quality was studied. Full‐fat enzyme‐active, semiactive and inactive soybean flours were evaluated. Active soybean flour improved the volume and structure of gluten‐free bread, while semiactive and inactive soybean flours did not have positive effects on bread quality. The particle size and concentration of the soybean flours also affected bread quality. Levels of addition between 125 and 150 g kg^?1 and particle sizes between 90 and 120 µm of active soybean flour yielded the best results. Heating the active soybean flour destroyed its improving effect. The analysis of proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis and size exclusion chromatography showed that heating soybean flour at 60–200°C caused protein aggregation. The overall results indicated that the addition of active soybean flour improved gluten‐free bread quality, and this effect seemed to be due to both the structural proteins and the enzymatic activities of the soybean flour. Copyright © 2004 Society of Chemical Industry     

大豆分离蛋白的乙酰化

本文通过对乙酰化改性大豆分离蛋白(SPI)影响因素的研究,确定了乙酰化大豆分离蛋白(A-SPI)的最佳工艺条件.在这个条件下生产的 SPI 有较好的功能性质,提高了在 pH 值4.5～7范围的溶解性,降低了凝胶强度.同时,乙酰化不会改变大豆蛋白的营养价值和产品质量.研究结果表明,本实验的数据是可靠的,效果是较好的,达到了预定的目的.     

Heat induced gelling properties of soy protein isolates prepared from different defatted soybean flours

Three soy protein isolates were prepared from two commercial defatted soybean flours (SG and ADM) and flour indigenously prepared from soybeans grown in Ontario (ON). Denaturation degree and protein composition of three isolates as measured by DSC and SDS–PAGE were not different significantly, but remarkable differences in ANS surface hydrophobicity and turbidity were noticed. Heat induced gelling properties of these soy protein isolates were examined by small deformation oscillatory rheological test. The critical gelling concentrations of the two isolates from commercial soy flours (SG and ADM) in distilled water were 90 mg/ml, much lower than 110 mg/ml for ON. The effect of type and concentration of salts on the gelling properties of the three protein isolates were also examined. In 1 mol/L NaCl solution, ADM had the higher gel strength than SG. It was found that the increase in gel strength of ON by addition of NaSCN was much greater than that in NaCl solution. N-Ethylmaleimide (NEM) was observed to increased the gel strength for all soy protein isolates examined despite its sulfhydryl groups blocking function. It is suggested that a non-heat aggregation of protein which led to turbidity development was responsible for the inferior gelling property of ON while the different gelling behavior between SG and ADM could be attributed to their difference in ANS surface hydrophobicity.     

Potato flour as a functional ingredient in bread: evaluation of bread quality and starch characteristics

Potatoes have been added to bread for improvement of texture and moisture retention. The functional quality and starch digestibility in bread containing 5%, 10% or 15% potato flour were evaluated. Farinograph absorption of wheat and potato flour blends ranged from 59.0% to 77.7%. Bread with potato flour had significantly (P < 0.05) lower bread firmness during storage. There was a significant (P < 0.05) decrease in starch molecular weight as the level of potato flour increased. Inclusion of potato flour in these breads significantly (P < 0.05) increased the level of resistant starch (RS), while significantly (P < 0.05) decreasing the estimated glycemic index (eGI). Bread with no potato flour had 5.2% RS and an eGI of 95, while the bread with 15% potato flour had 11.3% RS and an eGI of 87. Overall, the addition of potato flour may reduce dough strength and loaf volume, but it reduced staling and increased resistant starch content of the bread.     

大豆蛋白在面包中的应用研究

通过焙烤实验,研究比较了大豆蛋白对面包焙烤质量的影响。结果表明:普通大豆蛋白在4%的用量下,对面包品质就有不良作用;但改性后的面包专用大豆蛋白粉(MSPF)的用量在8%,也表现出良好的作用。     

醇法大豆浓缩蛋白和大豆异黄酮同步提取技术研究

大豆异黄酮是醇溶性物质,在提取醇法大豆浓缩蛋白时,同时将大豆异黄酮提取出来。在保证醇法大豆浓缩蛋白产品质量基础上,考察大豆异黄酮含量的变化情况。通过单因素和正交实验确定的最佳工艺条件为:料液比1∶5,乙醇溶液体积分数65%,萃取温度50℃,萃取时间2.0 h,2.0倍淋洗量。在此条件下可得到蛋白质含量大于70%,得率大于68%的大豆浓缩蛋白产品,此时大豆糖蜜中大豆异黄酮含量为6.4 mg/mL。     

大豆分离蛋白粉对面团流变学特性和馒头品质的影响研究

将大豆分离蛋白粉作为一种食品添加剂添加到小麦粉中,研究其对面团流变学特性和馒头品质的影响。实验结果得出,在小麦粉中添加大豆分离蛋白粉,可以明显地改善面团的稳定时间以及拉伸曲线面积和拉伸阻力。另外还可以提高馒头的品质,当在小麦粉中添加3%的大豆分离蛋白粉时,其对馒头品质有较好的改善作用。     

物理方法对大豆分离蛋白功能性质影响

大豆分离蛋白因其高营养性和独特功能性质在食品工业中有着广泛应用。该文着重介绍一些物理方法,如超高压、超声波技术及加工方法对大豆分离蛋白功能性质改善效果,并对其作用机理进行简单介绍。     

Effects of barley flour and barley protein isolate on chemical, functional, nutritional and biological properties of Pita bread

This study was carried out to investigate the effects of fortification of wheat flour with barley flour (BF) and barley protein isolate (BPI) at three levels; 5, 10 and 15% levels on the chemical composition, nutritional evaluation and biological properties of pita bread. Proteins fractions such as globulin, prolamin, glutelin-1 and glutelin-2 as well as protein isolates were extracted from barley flour and evaluated for protein yield, chemical composition and nutritional quality. Highest yield and essential amino acids contents were obtained in barley protein isolate. SDS-PAGE gels electrophoresis indicated that fortified wheat flour with BPI and BF consists of proteins coming from wheat flour and barley proteins. The contents of essential limiting amino acids in bread were increased from 1.38 to 3.10 g/100 g for lysine and from 0.86 to 1.73 g/100 g for methionine as the ratio of fortification with BF and BPI increased from 0 to 15%. The highest content of total phenolics, antioxidant activity, and inhibitory activity for both angiotensin converting enzyme (ACE) and α-amylase were found in fortified bread with BPI at 15%. Results indicated that bread made from fortification of wheat flour with BF and BPI at 15% showed superior chemical, physico-chemical, nutritional and biological properties.     

Effect of flour blending on functional, baking and organoleptic characteristics of bread

Soybean (full‐fat and defatted) and barley flours were incorporated into wheat flour at 5, 10, 15 and 20% substitution levels. The gluten content, sedimentation value and water absorption capacity of the flour blends and the mixing time of the dough decreased with increase in the level of soybean and barley flour separately and in combinations. Protein and glutelin contents increased significantly on blending of soyflour (full‐fat and defatted) to bread wheat flour. The breads prepared from the blends also varied in their loaf weight, loaf volume and sensory characteristics. The bread volume decreased with increasing amount of non‐wheat flour substitution. The crumb colour changed from creamish white to dull brown and a gradual hardening of crumb texture was observed as the addition of soybean (full‐fat and defatted) and barley flours increased. At the higher levels, the acceptability declined because of the compact texture of the crumb and the strong flavour of the product. The addition of 10% of soyflour (full‐fat and defatted) or 15% of barley flour, full‐fat soy + barley or defatted soy + barley flour to bread flour produced acceptable bread.