Influence of modified starches on properties of gluten-free dough and bread. Part I: Rheological and thermal properties of gluten-free dough

The aim of this study was to analyze the influence of chemically modified starches (HDP and ADA) and high amylose corn starch (HACS) on the rheological and thermal properties of gluten-free dough based on corn and potato starches with pectin and guar gum. The results indicate that the dough with the addition of modified starch behaves as weak gel, the value of storage modulus G′ significantly depends on the frequency and the values of tan δ = G″/G′ range from 0.32 to 0.49. Significant influence of hydroxypropylated distarch phosphate (HDP) on the viscoelastic properties of dough was observed. The share of modified starch in the system caused a decrease of the instantaneous and viscoelastic compliance. It also influenced the retardation time and zero shear viscosity. The application of modified starches (HDP and ADA) for dough preparation did not have much impact on the pasting characteristics. However, significant reduction of the onset and end viscosities were found for high amylose starch (HACS). Thermograms obtained for individual dough systems were characterized by the presence of two peaks, associated with the existence of two different starches in the system. No significant effect of modified starch on the onset temperature (T_O) and only a slight effect of HACS starch on gelatinization enthalpy were observed. However, the level of addition of individual starch affected peak and end (T_E) temperatures, depending on the type of preparation.     

Influence of inulin on physical characteristics and staling rate of gluten-free bread

Inulin preparations with different degree of polymerization (HSI with a DP < 10, GR − DP ? 10 and HPX − DP > 23) were used for the production of gluten-free bread. It was found that an addition of investigated compounds resulted in an increase of loaf volume and reduction of crumb hardness. However, internal structure of the obtained loaves was less uniform and more open than in control bread. Generally, inulin preparations with lower degree of polymerization had stronger effect on all analyzed parameters than that with higher DP. A decrease in staling was observed (measured as the rate of crumb hardening), which was caused by the presence of inulin. The highest content of retrograded amylopectin was found for crumb with HSI, and the lowest for samples with HPX.     

The impact of resistant starch on characteristics of gluten-free dough and bread

The study focused on partial replacement in gluten-free breads of corn starch with tapioca and corn resistant starch preparations. The use of resistant starch resulted in the increase of storage and loss moduli of the dough, and the lowering of loss tangent, which indicates its more elastic character. The incorporation of resistant starch reduced creep and recovery compliance and elevated zero shear viscosity. Modified doughs displayed higher starch gelatinization temperatures and lower viscosities that were proportional to the share of RS. It was found that the loaves baked with the share of resistant starch had less hard crumb than bread without RS addition. The crumb hardness diminished with the increasing amount of applied RS preparation. The addition of resistant starch raised total dietary fibre, by up to 89%, as compared to control (bread without RS addition). The most pronounced change was observed for insoluble dietary fibre (increase 137%), while only slight increase was found for its soluble fraction (18%).     

Substitution of wheat starch with non-wheat starches and cross-linked waxy barley starch affects sensory properties and staling of Arabic bread

Substitution of starch from barley, corn, oat, potato, rice or sorghum for prime wheat starch in the formulation of Arabic bread resulted in breads with significantly (P < 0.05) different textural attributes from regular wheat bread except for barley starch. Substitution of waxy barley starch (957 g kg⁻¹ amylopectin) for wheat starch (279 g kg⁻¹ amylopectin) resulted in bread that was not significantly different from regular wheat bread when assessed in the fresh state. However, upon aging, the waxy barley starch-containing bread staled at a significantly (P < 0.05) faster rate than regular wheat bread. Breads made with waxy barley starch cross-linked with 50, 200 or 500 ppm phosphorus oxychloride showed higher enthalpy of melting (ΔH) upon aging and staled faster than the bread formulated with waxy barley starch. These findings suggest that amylopectin retrogradation is one of the determinants of Arabic bread staling and that cross-linking promotes recrystallisation of amylopectin, possibly by keeping the polymer chains in close proximity. The rate of staling in breads formulated with cross-linked waxy barley starch decreased with increasing levels of cross-linking, possibly owing to restrictions in the degree of starch swelling. © 1999 Society of Chemical Industry     

The effects of maltodextrins on gluten-free dough and quality of bread

The aim of the study was to check if maltodextrins of various dextrose equivalents (DE) could be used to improve stability and quality of gluten-free bakery products, and effectively reduce starch retrogradation. The maltodextrins, which were used for partial replacement of starch in the recipe for gluten-free dough, were characterised by DE 3.6, 15.3, 18.0 and 21.8. Basing on the obtained results it was concluded, that the addition of applied maltodextrins significantly influences starch gelatinisation, by increasing pasting temperature and reducing viscosity of the obtained pastes. Rheological properties of the obtained dough are also modified by maltodextrins, which weaken its structure and increase deformation sensitivity. The addition of maltodextrins with low DE (3.6) diminishes loaf volume and causes deterioration of bread quality. Maltodextrins with higher DE, especially 18.0 and 21.8, positively influence bread volume and have a beneficial influence on crumb hardening during storage. Maltodextrin with the highest DE is also an effective factor reducing recrystallisation enthalpy of amylopectin.     

变性淀粉对面团流变学特性和面包品质的影响

探讨不同添加量的马铃薯变性淀粉和木薯变性淀粉对面团流变学特性和面包品质的影响。结果表明:两种变性淀粉均可改善面团的流变学特性,增大面团的韧性、减小面团的延伸性,改善面团的筋力;与对照相比,马铃薯变性淀粉能有效改善面包的焙烤品质,明显增加面包的比容,有效改善面包的硬度和弹性,木薯变性淀粉对面包品质的影响不明显;马铃薯变性淀粉的最适添加量为0.8%～1.2%面粉。     

Influence of hydrocolloids on dough handling and technological properties of gluten-free breads

BackgroundThe development of gluten-free breads has attracted great attention as a result of better diagnoses of relationship between gluten-free products and health. The market demand for gluten-free products is increasing day by day due to growing number of celiac disease cases. Development of gluten-free bread remains a technological challenge due to the key role of gluten in the breadmaking process and in bread structure, appearance, texture and shelf life.Scope and approachThis review covers recent advances in the application of hydrocolloids in dough handling, technological and nutritional properties of gluten-free breads, which affect its quality and value.Key findings and conclusionsGluten-free breads results from the combination of different ingredients and hydrocolloids required to building up network structures responsible for bread quality. Various gluten-free formulations have applied hydrocolloids to mimic the viscoelastic properties of gluten. In addition, the impact of different hydrocolloids on the characteristics of dough and bread quality is known to be highly dependent on raw materials, the nature and quantity of hydrocolloids. Hydrocolloids improve the texture, increase the moisture content and extend the overall quality of bread. The results of the reviewed studies indicate that some of those products were acceptable and presented similar or better sensory attributes than control formulations and some were even comparable to their wheat-based counterparts. Based on successful applications of hydrocolloids, it is suggested that novel nutritious ingredients, combined with hydrocolloids can be added to gluten-free bread formulations to improve the quality of life.     

Influence of xanthan gum and gluten on in vitro digestibility and textural properties of rice bread

Starch digestibility of gluten-free bread has been expected to be suppressed for the purpose of decreasing glycemic response. The objective of this study was to investigate the effects of adding xanthan gum and gluten on starch and protein digestibility of rice bread prepared using the developed recipe involving pickering stabilization of foams and emulsions. The extent of starch digestion of gluten-free bread was suppressed by adding 2% xanthan gum from 79.8% to 57.3%. This suppressive effect was diminished by using gluten and that of rice bread containing 2% xanthan gum and 20% gluten was 75.5%. The extent of starch digestion of gluten-free bread was similar or less than that of bread containing gluten. The gluten-free bread with 2% xanthan gum had significantly lower loaf volume, porosity, and sticker structure of breadcrumb than the control. The suppressive effects of xanthan gum on starch and protein digestion were mainly dependent on reducing accessibility of the enzyme into the inner structure.     

两种亲水性胶体和两种变性淀粉对青稞-小麦面团流变学特性的影响

将青稞面粉与小麦面粉以7∶3比例混合,制成青稞-小麦基础粉。将黄原胶（XG）、瓜尔豆胶（GG）和马铃薯乙酰化二淀粉磷酸酯（ADP-PS）、木薯乙酰化二淀粉磷酸酯（ADP-CS）按不同比例分别添加到该基础粉中,利用Mixolab混合实验仪研究两种亲水性胶体和两种乙酰化二淀粉磷酸酯对青稞-小麦基础粉面团流变学特性的影响。结果表明:两种水溶性胶体和乙酰化二淀粉磷酸酯均可改善青稞-小麦基础粉面团的流变学特性。对于吸水率而言,GG和ADPCS可以更显著地降低青稞-小麦基础粉面团的吸水率（p<0.05）。就缩短面团的形成时间而言GG和ADP-PS的效果更明显。ADP-PS对增加面团稳定时间方面有略微地改善。在蛋白质的弱化、淀粉的糊化、淀粉糊化胶的热稳定性及淀粉的回生特性方面两种胶体都可以达到减弱的作用,并且ADP-CS在这些方面的减弱作用较ADP-PS更明显。根据这两种亲水性胶体和乙酰化二淀粉磷酸酯在青稞-小麦面团的流变学性质中表现出的特点以及面条用粉的标准可选用GG和ADP-CS作为改良剂更好地用于青稞面条的制作中。      

The role of buckwheat and HPMC on the breadmaking properties of some commercial gluten-free bread mixtures

Although the food industry has risen to the formulation challenges associated with removing gluten from dough, and a number of gluten-free (GF) products are now commercially available, many GF bread formulations are still based on pure starches, resulting in low technological and nutritional quality. The aim of this research was to evaluate the role of buckwheat and HPMC on the breadmaking properties of two commercial GF bread mixtures. A dehulled (DBF) and a puffed (PBF) buckwheat flour were used, and high substitution levels (40%) were tested, with the aim of improving the nutritional value of the final GF breads without decreasing their technological quality. Ten mixtures (2 commercial, 8 experimental) were evaluated. The inclusion of 40% DBF was demonstrated not to reduce but actually improve the baking performances of the commercial GF mixtures. Moreover, the presence of a small amount of PBF, as well as of HPMC, turned out to be useful in limiting both the diffusion and the loss of water from the bread crumb and the interactions between starch and protein macromolecules, resulting in a softer GF bread crumb and reduced staling kinetics during storage.     

水溶性胶体对无麸质面团流变学特性及面包品质的影响

主要研究了黄原胶、羟丙基甲基纤维素(HPMC)、以及海藻酸钠对无麸质面包(糙米与荞麦粉比例为80∶20)流变学特性,比容、气孔,以及感官评分的影响。结果表明,添加胶体后,无麸质面糊的弹性模量和黏模量显著增加,并且无麸质面包的比容增大,感官评定分数也增大。通过各方面综合比较,0.5%黄原胶的添加使无麸质面包感官以及气孔分析各方面指标都有显著改善,无麸质面包无塌陷。经研究发现,与对照组面包相比,当黄原胶添加量为0.5%时,比容增加了9%,image分析中的count值增加了10.9%,硬度降低了13.1%,感官总体可接受度上升了17.4%。     

菊粉添加量对面团流变学特性和面包品质的影响

采用粉质仪、拉伸仪、质构分析仪(TA)研究不同添加量菊粉(2%~10%)对面粉粉质特性、拉伸特性和面包焙烤品质的影响。实验结果表明,随着菊粉的添加,面团的吸水率几乎不变,形成时间和稳定时间延长,弱化度降低,评价值增加;面团延伸度指标呈现一定的增大趋势,但拉伸曲线面积、拉伸阻力、最大拉伸阻力和拉伸比呈现先增加后减少的趋势。面包的硬度、弹性、咀嚼性和回复性因添加菊粉而下降。综合感官评定可知,当菊粉添加量为6%时,面包综合品质达到最佳状态。      

Sourdough on quinoa and buckwheat gluten-free breads: Evaluation of autochthonous starter fermentation on bread nutritional and technological properties

The aim of this work was to evaluate the effect of two autochthonous strains of lactic acid bacteria as sourdough (SD) starters on gluten-free bread technological quality and in vitro starch hydrolysis and antioxidant activity. Two strains of Limosilactobacillus fermentum isolated from buckwheat (BW) and quinoa flours were used. SDs were prepared from wholegrain quinoa or BW flours. Bread technological properties, total polyphenol content and in vitro antioxidant activity and starch hydrolysis and dialysability were assessed. Specific bread volumes were between 2.61 and 2.76 cm³ g⁻¹. Breads with quinoa-based SD had overall higher technological quality than breads made with BW SDs, shown by a softer, well-aerated crumb, with an opener crumb structure and larger air area. Crumb firming during storage was reduced up to 29% when quinoa SD was used, and up to 42% when BW SD was added. Quinoa breads showed higher polyphenols and FRAP values, whereas BW breads had significantly higher ABTS values. Total starch hydrolysis and dialysability were significantly reduced when SD was used. Starch hydrolysis was reduced up to 42% and 25% when quinoa and BW SD were used, respectively. SD application produced breads with higher technological quality and modified in vitro starch hydrolysis and antioxidant capacity. Even though these effects seemed to be influenced by pH, a biological effect was also observed.     

The effect of dairy and rice powder addition on loaf and crumb characteristics,and on shelf life (intermediate and long-term) of gluten-free breads stored in a modified atmosphere

Many commercially available gluten-free breads are inferior in quality to their gluten-containing counterparts. They also have a relatively short shelf life. The current study investigated the effects of 3% milk protein isolate and 3% novel rice starch addition to a gluten-free bread formulation, and on the intermediate (8 days) and long-term (43 days) staling profile of both gluten-free bread formulations, packed in an 80% CO₂\20% N₂ atmosphere. Dairy protein and rice starch addition increased loaf volume and the loaves were preferred to a control sample by an untrained panel. The most notable changes in crumb hardness occurred in the early days of the testing periods for the control gluten-free bread in both the intermediate and long-term studies.     

The effect of chemically‐modified resistant starch,RS type‐4, on body weight and blood lipid profiles of high fat diet‐induced obese mice

This study was conducted to investigate the effects of feeding chemically‐modified resistant starch type‐4 (RS4) of normal (NCS) and high‐amylose corn starch (HACS) on weight gain and plasma and liver lipid profiles of mice fed a high‐fat diet (HFD). The experimental four groups were, respectively, fed following diets: A 40% HFD with NCS, HACS, NCS‐ and HACS‐RS4. A normal diet (ND) group of mice fed the standard diet was also used as control. In order to produce RS4 by chemical modification, corn starches were treated with STMP/STPP. Total RS (TRS) and total dietary fiber (TDF) levels of chemically‐modified NCS were 26.4 and 44.0%, respectively, while TRS and TDF levels in chemically‐modified HACS were 78.1 and 78.5%, respectively. Onset gelatinization temperatures of both modified corn starches clearly shifted to higher temperatures after STMP/STPP treatment. At the end of the diet trial, the mice on the HACS diet decreased body weight gain compared to the NCS‐fed mice. Adding NCS‐ and HACS‐RS4 to the diet significantly reduced the weight gain relative to NCS and HACS groups. Both RS4 diets were effective in improving the lipid profile compared to their respective controls. They significantly reduced the level of total lipid and total cholesterol.     

Effects of freezing and frozen storage conditions on the rheological properties of different formulations of non-yeasted wheat and gluten-free bread dough

Empirical and fundamental rheological measurements were made on fresh and frozen dough to study the effects of freezing and frozen storage conditions. Frozen dough was stored at two different temperatures, −18 °C and −30 °C, and for 1, 7 and 28 days. Four dough formulations were tested: a standard wheat dough, a fibre-enriched wheat dough, a standard gluten-free dough and a gluten-free dough containing amaranth flour. No yeast was used in any formulation. The wheat dough is more affected by freezing and by the first days of storage whereas the gluten-free dough is more affected by a longer storage time. A storage temperature of −30 °C alters dough rheological properties more than a storage temperature of −18 °C. The addition of dietary fibres to the wheat dough increases its resistance to freezing and frozen storage. The addition of amaranth flour to gluten-free dough also increases its resistance to freezing but decreases its resistance to storage conditions.     

Influence of guar gum on the baking quality of gluten-free cheese bread made using frozen and chilled dough

The aim of the study was to assess the effect of guar gum on the quality and textural properties of gluten-free (GF) cheese bread made using chilled and frozen GF cheese dough. The guar gum addition was at 3.5% (G3.5), 4% (G4) and 4.5% (G4.5) levels, based on the weight of the cheese in the product. Samples of frozen dough with 3.5% guar gum and of chilled dough with 4.5% guar gum were chosen for sensory analysis as they had the closest hardness and specific volume to samples of fresh dough and dough without guar gum (Control). The overall consumer acceptance of samples that had been processed using freezing treatment presented the lowest liking score due to the light salty taste.     

苦荞粉添加量对面团性质及馒头品质的影响

通过添加不同量的苦荞粉配成苦荞-小麦混粉,研究混粉揉混特性、面团微观结构的变化以及苦荞馒头的感官品质。结果表明,当添加量在5%~15%时,揉混结果中的和面时间和峰值面积变化不大,微观结构中蛋白质面筋网络结构略微减弱,但当添加量达到20%后,和面时间和峰值面积都有大幅度降低,微观面筋网络结构也出现明显的下降。同时,苦荞粉添加量为15%时馒头感官品质较好。综合分析可知,添加量为15%时苦荞馒头仍具有较好的品质。