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%).     

抗性淀粉对馒头的感官评价及物性的影响

抗性淀粉的特性与膳食纤维基本相似,但它又不同于膳食纤维。抗性淀粉添加到食品中后,它不会像膳食纤维那样影响食品的感官和质构。但当较高含量的抗性淀粉添加于小麦粉中,在一定程度上恶化了小麦粉的加工性能。实验证明：将中筋粉中添加5%左右的抗性淀粉制作馒头,既可保证馒头的保健品质又不失其食用品质及感官品质。     

Characterization of Resistant Starch from Autoclaved Wheat Starch

The nature of a particular type of in vitro undigestible starch, i.e. resistant starch (RS), was studied. This type of undigestible starch is found in products processed at relatively high moisture contents, such as baking and autoclaving. The RS was concentrated by enzymic digestion of available starch and protein and recovered by centrifugation. RS from autoclaved wheat starch was evaluated by various methods. The crystallinity was studied by X-ray diffraction and DSC. The degree of polymerization (DP) was evaluated with gel permeation chromatography and iodine binding and the starch content and linearity by enzymic methods. The results indicate that RS consist of crystallized, linear α-glucans of relatively low molecular weight (DP approx. 65). The recovery of RS after various drying procedures, and the introduction of a thermostable amylase (Termamyl®) in the RS assay was also studied. Oven-drying of the fibre residues used in the analysis had no significant effect on RS recovery, whereas freeze-drying was accompanied by a slight increase in RS content. The use of Termamyl®, in the assay of RS in the fibre residues, decreased the yield of RS by 10–15%.     

甘薯抗性淀粉研究进展

甘薯是重要的淀粉作物,其块根中抗性淀粉（resistant starch,RS）含量较高,具备良好的产品开发潜力。要进一步促进甘薯RS的应用和推广,不仅需要筛选或培育出RS含量更高的甘薯品种,还需要加大开发甘薯深加工淀粉产品。除调控淀粉合成相关基因的表达外,生产实际中还可通过调整栽培措施等方式提高甘薯RS的含量。通过化学修饰法、物理法和酶解法等方法可制备甘薯RS产品,也能提高产品中RS的含量。本文系统综述了近年来甘薯淀粉的保健效果、RS含量的测定方法、影响甘薯淀粉中RS含量的因素、RS的制备方法及其特性等方面的进展,为未来甘薯中RS的制备、产量提高、产品开发和推广提供理论依据和技术指导。     

酯化淀粉制备方法的研究

本文研究了多种制备酯化淀粉的方法,包括淀粉柠檬酸酯制备方法、淀粉苹果酸酯制备方法和二淀粉磷酸二酯制备方法,对制备条件进行了探索和改进。用傅立叶变换红外光谱仪进行了鉴定和分析,证明了酯基的存在。但是二淀粉磷酸二酯在1300～1250cm-1波数范围内没有发现有明显不同于原淀粉的吸收峰,表明可能仅存在很少量的无法检测到的酯基。用扫描电镜观察到,淀粉粒呈球形或多面体形,表面光滑而且没有发现明显的孔隙或裂缝。用DSC观察到,吸热峰的峰值在105.8℃,在100℃之前,没有任何吸热峰,表明没有糊化。这可能是由于在淀粉粒表面上的淀粉分子通过磷酸根形成交联,将淀粉粒束缚,使淀粉难以糊化。对二淀粉磷酸二酯、淀粉柠檬酸酯和淀粉苹果酸酯的制备条件进行了探索和改进,进一步提高了抗性淀粉产率,探讨了它们的抗淀粉酶消化的机理。与国外的研究相比,本试验使抗性淀粉含量有了很大幅度的提高,最高值为93%左右。     

高抗性淀粉大米对方便米饭品质及GI值的影响研究

以高RS大米和市场普通大米为原料,研究不同添加量的高RS大米对方便米饭质构特性、感官评分、GI值的影响。通过质构特征分析和差示扫描量热仪测定在不同贮存时下,不同添加量的高RS大米对方便米饭淀粉抗回生效果的影响。结果显示,高RS大米添加量的增加,提高了方便米饭硬度、粘性和咀嚼性,增加了方便米饭的直链淀粉和抗性淀粉含量,同时降低了方便米饭的感官评分和GI值。此外,随着贮存时间的增加,高RS大米的添加量越高,方便米饭的硬度、相对结晶度、回生焓也越高。为方便米饭产品开发与大米精深加工提供依据。     

Development of gluten free bread containing carob flour and resistant starch

Gluten free bread from rice flour substituted with carob flour and resistant starch (RS) was investigated. RS and protein amount added were optimized in model gluten free breads (MGFB's) containing rice flour using Response Surface Methodology (RSM). RS addition did not influence MGFB's crumb firmness, but it acted as an elastifying agent. A MGFB with soft and elastic crumb was produced with 10 g protein/100 g flour and 15 g RS/100 g flour. MGFB recipe was further improved by adding carob flour. Its addition raises the water content needed for the breadmaking procedure, but did not significantly affect any of the textural and structural parameters measured. Water amount increase diminished crumb firmness and contributed to the development of an open crumb cell structure. The design allowed the determination of the optimum formulation for obtaining gluten-free bread with low crumb firmness and improved porosity values by combining 15 g carob flour/100 g flour, 15 g RS/ 100 g flour, 10 g protein/ 100 g flour and 140 g water/ 100 g flour. The use of carob flour and RS constitutes a promising approach in producing fibre-rich formulations of high quality characteristics in order to fulfil population deficiency of dietary fibre intake.     

食物中抗性淀粉的研究进展

在查阅的近十几年对淀粉在人肠道内消化吸收的文献基础上,综述了食物中抗性淀粉的研究进展,抗性淀粉是指不能在健康正常人小肠中消化吸收的淀粉及其降解物食中物存在抗性淀粉可分为３类,物理包埋淀粉（ＲＳＩ）抗性淀粉颗粒（ＲＳ２）和老化淀粉（ＲＳ３）其检测一般采用体外肠道模拟酶解法,影响食物中抗性淀粉形成的因素主要有淀粉自身的理化性质,食物中的其它成分,处理方式和工艺以及食物形态等,抗性淀粉属于人体无法消化吸     

Effect of dietary fibre enrichment on selected properties of gluten-free bread

The enrichment of gluten-free baked products with dietary fibre seems to be necessary since it has been reported that coeliac patients have generally a low intake of fibre due to their gluten-free diet. In the present study different cereal fibres (wheat, maize, oat and barley) were added at 3, 6 and 9 g/100 g level into a gluten-free bread formulation based on corn starch, rice flour and hydroxypropyl methyl cellulose (HPMC). Doughs were evaluated based on consistency, viscosity and thermal properties. Results showed that maize and oat fibre can be added to gluten-free bread with positive impact on bread nutritional and sensory properties. All breads with 9 g/100 g fibre increased the fibre content of control by 218%, but they were rated lower than those with 3 and 6 g/100 g fibre due to their powdery taste. The formulation containing barley fibre produced loaves that had more intense color and volume comparable to the control. During storage of breads a reduction in crumb moisture content and an increase in firmness were observed. The micrographs of the crumb showed the continuous matrix between starch and maize and/or oat fibre obtaining a more aerated structure.     

籽粒苋保健面包的研制(II)——籽粒苋对赖氨酸和膳食纤维的营养强化作用

以 5%、10 %、15%、2 0 %、2 5%籽粒苋粉代替小麦粉 ,制成籽粒苋保健面包。对这类面包中赖氨酸、膳食纤维含量进行分析 ,结果表明籽粒苋粉能明显提高赖氨酸和膳食纤维的含量 ,特别是能改善可溶性膳食纤维与不溶性膳食纤维的配比。与全麦粉面包相比 ,籽粒苋面包中蛋白质的提高率为 0 .58%～ 6 .91% ,赖氨酸含量提高率为 13.50 %～ 56 .57% ,总膳食纤维提高 8.2 6 %～ 39.4 5% ,不溶性膳食纤维提高 7.91%～33.33% ,可溶性膳食纤维提高 9.76 %～ 6 5.85% ;而脂肪的含量则随籽粒苋粉的增加而减少。由于籽粒苋对赖氨酸和膳食纤维具有强化作用 ,使籽粒苋保健面包可以作为高脂血症、糖尿病和肥胖人群的理想食品     

高链玉米淀粉改善面包的品质及消化性能

本文研究添加高链玉米淀粉对面包品质特性和消化性能的影响,以期为高链玉米淀粉等抗性淀粉在慢消化食品中的应用提供理论依据。结果表明,添加高链玉米淀粉能显著性提高面包的持水性和表面亮度,有利于提高消费者的接受度。但面包比容随高链玉米淀粉添加量的增加而逐渐显著降低。弹性、粘附性和恢复性未受高链玉米淀粉的影响,但硬度明显增加,添加10%和20%高链玉米淀粉的面包硬度升高为未添加时的1.2和1.8倍。面包的胶黏性和咀嚼性在高链玉米淀粉添加量小于10%时没有明显变化,而添加量进一步增加时,其胶黏性和咀嚼性逐渐显著提高。高链玉米淀粉能显著降低面包的消化速率,添加量为20%时面包的消化速率降低了54%。说明添加高链玉米淀粉会对面包的品质产生一定的影响,但合理控制其添加量可在面包的品质没有大幅降低的同时显著降低淀粉的消化速率。     

Sensory and physical quality characteristics of bread fortified with apple pomace using fuzzy mathematical model

Apple pomace, after different processing procedures, was added into wheat flour in bread production to improve the dietary fibre content of breads. A fuzzy mathematical model was used in the sensory assessment of bread to improve the reliability of final conclusion. The addition of both apple pomace (AP) and skimmed apple pomace (SAP) reduced the extensibility and improved the resistance of wheat dough compared to the control sample. Wheat dough fortified with apple pomace of differing particle sizes did not have significant effects on either farinograph properties or extensograph properties. Sensory assessment of bread based on fuzzy mathematical model indicated that optimum concentration of apple pomace, both AP and SAP, added into wheat dough was 3%. Such results may be of importance when considering the use of apple pomace in bread production so as to enhance the dietary fibre intake, and also improve the sensory properties of bread.     

抗性淀粉对糖、脂以及肠道代谢影响的研究进展

综述了近年来国内外对抗性淀粉及其生理功能的研究动态;介绍了抗性淀粉的定义、分类及其生理功能;阐明了抗性淀粉对血糖、血脂及肠道代谢的影响和作用机理。抗性淀粉是一种新型的膳食纤维,在小肠中不被消化吸收, 但在大肠中能被肠道菌群发酵分解。它作为一种低热量、高纤维含量的功能性食品成分,越来越被人们所认识和重视。     

Production of Resistant Starch by Extrusion Cooking of Acid-Modified Normal-Maize Starch

ABSTRACT:  The objective of this study was to utilize extrusion cooking and hydrothermal treatment to produce resistant starch (RS) as an economical alternative to a batch-cooking process. A hydrothermal treatment (110 °C, 3 d) of batch-cooked and extruded starch samples facilitated propagation of heat-stable starch crystallites and increased the RS contents from 2.1% to 7.7% up to 17.4% determined using AOAC Method 991.43 for total dietary fiber. When starch samples were batch cooked and hydrothermally treated at a moisture content below 70%, acid-modified normal-maize starch (AMMS) produced a greater RS content than did native normal-maize starch (NMS). This was attributed to the partially hydrolyzed, smaller molecules in the AMMS, which had greater mobility and freedom than the larger molecules in the NMS. The RS contents of the batch-cooked and extruded AMMS products after the hydrothermal treatment were similar. A freezing treatment of the AMMS samples at −20 °C prior to the hydrothermal treatment did not increase the RS content. The DSC thermograms and the X-ray diffractograms showed that retrograded amylose and crystalline starch–lipid complex, which had melting temperatures above 100 °C, accounted for the RS contents.     

Soybean protein isolate-rice starch interactions during the simulated gluten-free rice bread making process

Gluten-free bread (GFB) is usually of poor quality due to lack of gluten. Addition of exogenous protein is one of the important ways to improve the quality of GFB products. In this study, different levels of soybean protein isolate (SPI) mixed with rice starch (RS) system were prepared to simulate different processing stages during bread making. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), rapid viscosity analysis (RVA), confocal laser scanning microscopy (CLSM), texture analyser and rheometer were used to analyse the effects of SPI on the structural, microstructure and functional properties of RS. The results showed that: hydrogen bonds could be formed between SPI and RS, thus improving the stability of RS; compared with RS, the ∆H and setback values of the blend were reduced by 43.79% and 34.53%, respectively, when SPI was added at 12%; and the storage modulus (G') and loss modulus (G") reached the minimum value at 9% SPI content. CLSM and texture analysis show that the addition of protein inhibits the leaching of starch, reduces the hardness, chewiness and gumminess of the system, which is conducive to the quality of GFB.     

Resistant Starch Made from Banana Starch by Autoclaving and Debranching

Resistant starches (RS) were prepared from banana starch by debranching with pullulanase for different times and after autoclaving treatment. The different treatments produced seven RS products, which were tested with respect to available starch (AS), RS and in vitro hydrolysis rate. The control sample (without debranching) had the highest AS (80.5%) and the lowest RS content (9.1%). The samples debranched for 5 h and longer did not show significant differences (α = 0.05) in AS (approximately 72%) and RS (approximately 18%). The RS values obtained in the samples prepared were twice as high as that of the control sample. However, the sample debranched for the longest time had the highest hydrolysis rate, demonstrating that this product has a high digestion rate. Banana starch is a good source for RS preparation by autoclaving due to its high RS content and can be an alternative source in developing countries for obtaining a nutraceutic ingredient for functional food preparation.     

Emulsifiers: Effects on Quality of Fibre-Enriched Wheat Bread

Resistant starch (RS) is a nutritional ingredient commonly used in bread products as dietary fibre (DF). This ingredient presents similar physiological functions than those imparted by DF, promoting beneficial effects such as the reduction of cholesterol and/or glucose levels on blood. Quality improvement of bread containing RS, with an optimized combination of emulsifiers, will be useful in the development of new and healthy bakery products. The objective of this research was to analyse the effects of different emulsifiers on several quality parameters of dough and bread prepared with wheat flour partially substituted with resistant starch as a dietary fibre. A blend of wheat flour/maize-resistant starch (MRS; 87.5:12.5) with sodium chloride, ascorbic acid, α-amylase, compressed yeast and water was utilized. Emulsifiers were incorporated to formulations in different levels according to a simplex centroid design. The viscoelastic, textural and extensional properties of dough were analysed. Bread quality was evaluated throughout the gelatinization and retrogradation of starch, specific volume of loaves, and texture and firmness of bread crumb. The incorporation of 12.5% (w/w) of MRS to wheat flour caused an increase of 5% in water absorption. Stability decreases markedly (from 9.9 to 2.2 min) and the mixing tolerance index increased (from 79 to 35 UF). The sodium stearoyl lactylate (SSL)–diacetyl tartaric acid esters of monoglycerides (DATEM) mixture increased hardness and resistance to extension on dough, whilst dough containing Polysorbate 80 (PS80) was softer; nevertheless, both types of dough retained less CO₂. An optimized concentration of the three emulsifiers (0.24% SSL, 0.18% PS80, 0.08% DATEM, w/w) was obtained by surface response methodology. The bread prepared with this combination of emulsifiers presented a considerable specific volume with a very soft crumb.     

Improving gel formation of rice starch added with cross‐linked resistant starch prepared from rice starch

The gel formation properties of non‐waxy rice starch with cross‐linked resistant starch with phosphate (RS4, 10, 20, and 30% based on rice starch) prepared from three rice varieties with different amylose (AM) content were investigated to increase dietary fiber content, improve gel structure, and reduce the glycemic index of rice products. The AM contents of rice starches were 1.71% in Hanganchal1, 22.47% in Nampyeong, and 33.39% in Goamy. All RS4 showed A‐type crystallinity and their RS levels were 46.91, 54.54, and 66.01%, respectively. The initial pasting temperatures of RS4 added rice starches increased as RS4 contents increased, but peak and breakdown viscosities and enthalpy change (△H) reduced. The RS4 addition improved gel shape and texture properties including hardness, cohesiveness, and gumminess, except the 30% Goamy RS4 added gel. The 20% RS4 addition was appropriate to form rice starch gels. The network structure of RS4 added gel formed more regular and firmer than that of control, because RS4 granules were entrapped within the gel matrix like observed by light microscope and scanning electron microscopy. It is suggested that RS4 not only assist in forming a rigid network structure but also increasing a dietary fiber content.

     

Evaluation of methods of analysis for dietary fibre using real foods and model foods

Rationale and objectives

There are several rational and empirical methods for the measurement of dietary fibre and its components. A selection of these methods were evaluated by investigation of a range of real foods and model foods with added resistant starch (RS), non-starch polysaccharides (NSP) and resistant oligosaccharide (RO) ingredients.

Methods

A range of rational methods were applied in determining specific carbohydrate constituents: RS, NSP and RO, including fructans. For comparison, empirical methods AOAC 991.43 (2001.03) and AOAC 2009.01 were applied, based on determination of gravimetric residues for high molecular weight and size-exclusion HPLC analysis of the ethanol filtrate for low molecular weight components.

Results

In general there was agreement between different rational methods for the analysis of RS and fructans, though there were notable exceptions for some product types. Comparison of methods for total RS and those that only measure the RS3 fraction, from retrograded starch, indicated that RS3 was the only type present for most processed products. This also explains the similar results obtained by AOAC 991.43 (2001.03) and AOAC 2009.01, though the latter is intended to recover other RS types as well. For many products there was agreement between results obtained by rational and empirical methods, though there were exceptions and the reasons for these are discussed.

Conclusion

Rational and empirical methods can both be used to determine dietary fibre in most situations. The information provided by rational methods is useful in identifying the specific carbohydrate constituents present in foods and can assist in determining whether added extracted and synthesised ingredients are ones that conform to the Codex and EU dietary fibre definition.     

Evaluation of performance of dough and bread incorporating chia (Salvia hispanica L.)

As a result of the opinion given by the European Food Safety Authority about the safety of chia seed (Salvia hispanica L) and whole ground chia seed as food ingredients, they may be placed on the market in the European Community as novel food ingredients to be used in bread products. The objective of the present investigation was to develop new cereal-based products with increased nutritional quality by using chia and ground chia seeds (whole chia flour, semi-defatted chia flour and low-fat chia flour) in order to evaluate its potential as a bread-making ingredient. The samples with chia addition significantly increased the levels of proteins, lipids, ash and dietary fibre in the final product compared to the control sample. Breads with seeds or ground seeds showed similar technological quality to the control bread, except for the increase in specific bread volume, decrease in crumb firmness and change in crumb colour. Sensory analysis showed that the inclusion of chia increased overall acceptability by consumers. The thermal properties of the starch did not alter substantially with the inclusion of chia. However, the incorporation of chia inhibited the kinetics of amylopectin retrogradation during storage, which would be directly related to the delay in bread staling.