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1.
The effect of hydrocolloids addition (0, 25, or 1.5 g/100 g of flour) on water absorption of flour and their influence on dough rheology were analyzed. The influence of guar gum (GG), xanthan gum (XG), high‐methoxyl pectin (P), locust bean gum (LBG), and a 1:1 mixture of locust bean gum and xanthan gum (LBG+XG) on water absorption was tested by different techniques including farinograph water absorption, water imbibing capacity, SDS sedimentation test, and sucrose solvent retention capacity. The rheological behavior was analyzed through the farinograph parameters and texture profile analysis (TPA). Principal component analysis (PCA) was applied to evaluate the behavior of the different mixtures. Absorption values obtained by different methods were increased by XG and LBG+XG addition, particularly at the highest levels (1–1.5%). Flour‐P mixtures showed the lowest absorption. GG‐added mixtures led to the more stable doughs and P to the less stable ones. Addition of NaCl increased stability in all cases. According to TPA, softer and less cohesive doughs than control were obtained when hydrocolloids were added, both in conditions of water availability and water restriction (except for XG and GG at the highest levels). However, when enough water was added, more variation in textural attributes among doughs could be observed by PCA. No remarkable differences compared with the control were observed in the gluten network, as evaluated by scanning electron microscopy. Hydrocolloid incorporation led to rheological changes in dough; the trend and degree of this effect was affected by the amount of water added and the structure and concentration of the hydrocolloid.  相似文献   

2.
The impact of freezing on dough rheology, fermentation performance, and final steamed bread quality was investigated in this study. Also, the incorporation of sodium alginate and xanthan gum into the frozen dough formulation, in comparison with 0.1% salt, was studied to test their suitability as frozen dough improvers. Incorporating these hydrocolloids into steamed bread revealed their totally different characteristics from those in baked bread. Freezing of dough led to diminished specific volumes of proofed dough and steamed bread, and it also caused higher crumb firmness for steamed bread. The incorporation of sodium alginate and xanthan gum did not improve the quality of the steamed bread but led to further reduction in specific volume and increase in crumb firmness at the higher levels of 0.3, 0.5, and 1.0% and 0.07 and 0.1%, respectively. Xanthan gum and sodium alginate showed dough strengthening effects by increasing resistance to uniaxial deformation, bubble burst stress, and declining dough weakening coefficients at these levels, but decreased dough extensibility and bubble burst strain were revealed at these concentrations tested.  相似文献   

3.
为确定合适的亲水胶体种类及其添加量,以带鱼鱼糜为原料,通过测定凝胶强度、质构(硬度、粘聚性、弹性和咀嚼性)、白度、持水性和凝胶溶解度等指标,分析瓜尔胶、魔芋胶和沙蒿胶3种亲水胶体对带鱼鱼糜凝胶品质的影响。结果表明,瓜尔胶、魔芋胶和沙蒿胶均能提高带鱼鱼糜凝胶强度,但相同添加量下魔芋胶的改善效果最好,而瓜尔胶对鱼糜凝胶强度的影响不显著。魔芋胶能显著改进带鱼鱼糜凝胶的质构特性;瓜尔胶添加量为2.0%时鱼糜凝胶硬度、弹性、咀嚼性、粘聚性比对照组低;沙蒿胶对鱼糜凝胶的粘聚性影响显著,当添加量为1.5%或2.0%时,带鱼鱼糜凝胶的咀嚼性、硬度增加,弹性下降。瓜尔胶、魔芋胶和沙蒿胶均能提高带鱼鱼糜持水性,降低鱼糜凝胶白度和溶解度,但对鱼糜凝胶色泽的影响不显著。扫描电镜结果显示,1.5%魔芋胶处理组形成的鱼糜凝胶表面规则有序、网络结构致密均一。综合比较,添加1.5%魔芋胶能有效改善带鱼鱼糜的凝胶品质。本研究结果为提高带鱼鱼糜制品品质及生产研发提供了一定的理论依据。  相似文献   

4.
Carboxymethyl cellulose (CMC) is added to tortillas to maintain a pliable texture during storage. A need exists to optimize or replace CMC in masa and tortilla manufacturing with cheaper yet adequate alternatives. Change in water distribution upon gum addition may be key to understanding stability of cooked masa. Therefore, the objective of this study was to characterize the state and distribution of water in masa systems containing two types of CMC and guar gum. Masa was mixed with 10% (1% in viscosity measurements) of different gums (either one of two CMCs varying in viscosity or guar) then hydrated to 50% moisture content. Viscosity, water holding capacity (WHC), total moisture content (TGA) as well as “freezable” (FW) and “unfreezable” (UFW) water (DSC) of all samples were obtained and compared. Viscosity measurements indicated guar gum may provide a good substitution for high viscosity CMC. The two water measurements, WHC and UFW, differed as to the effect of viscosity on water entrapment. WHC represented the short‐term imbibing of gums, while UFW indicated how the hydrocolloids responded in masa given full hydration time. UFW in guar gum was lower than in medium viscosity CMC. These initial results indicate that guar gum may prove a good substitute for CMC in masa applications.  相似文献   

5.
The objective of this study was to examine the effects of added xanthan gum, guar gum, or kappa-carrageenan on the formation and properties of emulsions (4 wt % corn oil) formed with an extensively hydrolyzed commercial whey protein (WPH) product under a range of conditions. The rate of coalescence was calculated on the basis of the changes in the droplet size of emulsions during storage of the emulsions at 20 degrees C. Compared with the emulsion made without the addition of polysaccharides, the rate of creaming and coalescence in emulsions containing xanthan gum, guar gum, or kappa-carrageenan was markedly enhanced with increasing concentration of polysaccharides during storage for up to 7 days. At a given concentration, the rate of coalescence was highest in the emulsions containing guar gum, whereas it was lowest in the emulsions containing kappa-carrageenan. All emulsions containing xanthan gum, guar gum, or kappa-carrageenan showed flocculation of oil droplets by a depletion mechanism. This flocculation was considered to enhance the coalescence of oil droplets. The different rates of coalescence could be explained on the basis of the strength of the depletion potential, which was dependent on the molecular weight and the radius of gyration of the polysaccharides.  相似文献   

6.
The effects of transglutaminase (TG) on the properties of semolina dough and pasta cooking properties in durum‐only and fiber‐enriched pasta were investigated. TG was blended at levels 0, 0.05, 0.1, 0.25, 0.5, and 1% of semolina weight with semolina and semolina‐pollard (60% w/w) and semolina‐guar gum (15%) mixtures. The addition of TG increased dough maximal resistance, making the dough inextensible at >1%. Optimum effects on dough strength were obtained at 0.5% TG; this dough gave the firmest and least sticky pasta. A more extensive and thicker protein matrix was observed in the TG pasta by confocal scanning laser microscopy, indicating more cross‐links were formed, a finding supported by measuring percentage of unextracted polymeric protein. TG was unable to overcome the negative effect of 60% pollard on cooking loss or 15% guar gum on stickiness. Gluten was generally more effective than TG in restoring the properties of pastas with added fiber.  相似文献   

7.
Guar gum, a nonionic galactomannan, is used as an economical thickener and stabilizer in the food industry and is often combined with xanthan, locust bean gum (LBG), or carboxymethylcellulose (CMC) to promote synergistic changes in viscosity or gelling behavior via intermolecular interactions; however, the adulteration of LBG with guar gum is a well-known industrial problem. The ability to identify the purity of gums and concentrations of individual gums in mixtures would be advantageous for quality control in the food industry. Fourier transform infrared spectroscopy (FTIR) methods are rapid and require minimum sample preparation. The objectives of this study were to evaluate the ability of FTIR techniques to (1) differentiate LBG with a variety of mannose/galactose (M/G) ratios, (2) differentiate guar, LBG, tara, and fenugreek gums, (3) differentiate pure guar gum from guar gum mixed with LBG, xanthan gum, or CMC, (4) quantify LBG, xanthan gum, and CMC in guar gum, and (5) quantify guar gum in LBG. Two FTIR methods were used: diffuse reflectance (DRIFT) on powdered gum samples added to KBr at 5%, w/w, and attenuated total reflectance (ATR) on 1%, w/w, gum solutions. Spectra were collected and then analyzed by multivariate statistical procedures (chemometrics). The DRIFT method provided better discrimination and quantitative results than the ATR method. Canonical variate analysis (CVA) of DRIFT spectra (1200-700 cm(-1)) was able to classify LBG with various M/G ratios, pure galactomannans, and pure versus mixtures of gums with 100% accuracy. Quantification of an individual gum in gum mixtures (0.5-15%, w/w) was possible using partial least-squares (PLS) analysis of DRIFT spectra with R2 > 0.93 and using this approach for quantifying guar gum added to LBG resulted in an R2 > 0.99, RMSEC = 0.29, and RMSEP = 3.31. Therefore, the DRIFT FTIR method could be a useful analytical tool for quality control of select gums and gum mixtures used in the food industry.  相似文献   

8.
玉米淀粉与黄原胶复配体系流变和凝胶特性分析   总被引:1,自引:0,他引:1  
为考察胶体对淀粉流变及凝胶特性的影响,该文以玉米淀粉为原料,加入不同比例黄原胶,研究两者复配后流变及凝胶特性的变化,对其相互作用机理进行了初步探讨。结果表明,玉米淀粉及两者复配体系属于屈服-假塑性流体,随着黄原胶比例的提高,复配体系的稠度系数显著增加,流体指数降低,假塑性增强,但黄原胶比例大于10%时,增加不再显著。动态流变学试验显示,复配体系具有更为优越的黏弹性,黄原胶可与淀粉分子间相互作用形成氢键,使得分子链段间的缠结点增加,同时,可延缓及阻止部分直链淀粉分子间的重新排列,从而抑制淀粉凝胶体系的回生,复配体系形成了质地更为柔软的凝胶。综合考虑,在实际应用中选择玉米淀粉与黄原胶质量比为9.0∶1.0 (g/g)较为适宜。研究结果可为更好的在食品工业中应用玉米淀粉/黄原胶复配体系及品质控制提供理论依据。  相似文献   

9.
玉米淀粉与黄原胶复配体系流变和凝胶特性分析   总被引:12,自引:3,他引:9  
为考察胶体对淀粉流变及凝胶特性的影响,该文以玉米淀粉为原料,加入不同比例黄原胶,研究两者复配后流变及凝胶特性的变化,对其相互作用机理进行了初步探讨。结果表明,玉米淀粉及两者复配体系属于屈服-假塑性流体,随着黄原胶比例的提高,复配体系的稠度系数显著增加,流体指数降低,假塑性增强,但黄原胶比例大于10%时,增加不再显著。动态流变学试验显示,复配体系具有更为优越的黏弹性,黄原胶可与淀粉分子间相互作用形成氢键,使得分子链段间的缠结点增加,同时,可延缓及阻止部分直链淀粉分子间的重新排列,从而抑制淀粉凝胶体系的回生,复配体系形成了质地更为柔软的凝胶。综合考虑,在实际应用中选择玉米淀粉与黄原胶质量比为9.0∶1.0 g/g较为适宜。研究结果可为更好的在食品工业中应用玉米淀粉/黄原胶复配体系及品质控制提供参考。  相似文献   

10.
Disadvantages of frozen doughs are their variable performance and loss of stability over long‐term frozen storage. Changes in rheological properties of frozen doughs have been reported to be due to the physical damage of the gluten network caused by ice crystallization and recrystallization. The objective of this study was to determine the effect of hydrophilic gums on ice crystallization and recrystallization for improvement of the shelf‐life stability of frozen dough. The present research involved use of the Hard Red Spring wheat cultivar Grandin and hydrophilic gums such as carboxymethyl cellulose (CMC), gum arabic, kappa carrageenan (κ‐carrageenan), and locust bean gum at three different levels each on doughs stored frozen for up to 16 weeks. The dough characteristics were analyzed after day 0, day 1, and after 4, 8, 12, and 16 weeks of frozen storage using data from differential scanning calorimetry (DSC), water activity, extensigraph, and proof time. The ΔH value of freezable water endothermic transitions obtained using DSC increased with storage time for all treatments. However, addition of different levels of the four gums lowered the ΔH value, indicating a decrease in freezable water. Doughs with locust bean gum gave a higher peak force, measured using the Kieffer dough extensibility rig of the texture analyzer, and lower proof time, indicating better retention of baking quality. Maximum resistance to extension increased upon addition of 1 and 3%; CMC; 1 and 3%; κ‐carrageenan; and 1, 2, and 3% locust bean gum as compared with the control. The various periods of storage or gum treatments did not affect the water activity of the thawed frozen doughs. Doughs with locust bean gum gave significantly lower proof time compared with the other treatments and the control. CMC gave the second lowest values, followed by gum arabic treatment. Addition of κ‐carrageenan increased the proof time compared with the control. In summary, locust bean gum, gum arabic, and CMC improved the dough characteristics to varying degrees. κ‐Carrageenan was the only gum that showed a detrimental effect on frozen dough.  相似文献   

11.
Nixtamalized corn flour for tortilla preparation had added xanthan gum at different concentrations. Rollability, puncture, and extensibility tests using a texture analyzer machine measured the effect of xanthan gum on the staling of corn tortillas. Rollability, puncture, and extensibility tests were simple, fast, and repeatable. The rollability parameters showed that the addition of gum produced more flexible tortillas with decreased staling. The addition of hydrocolloid decreased the force required to penetrate the tortilla, but this parameter was slightly increased when storage time increased. The parameters determined in the extensibility test showed textural differences because the fresh tortillas had a higher distance of extensibility and this parameter decreased when storage time increased. Untreated stored tortillas presented a higher modulus of deformation, work, and rupture force values. However, the addition of xanthan gum decreased these values. The addition of hydrocolloid to tortilla decreased the hardness and increased the flexibility and rubbery characteristics of tortillas.  相似文献   

12.
基于低场核磁和差示量热扫描的面条面团水分状态研究   总被引:3,自引:8,他引:3  
为了解低水分面条面团中水分的存在状态,明确真空度及和面时间对水分状态的影响,该研究以3个小麦品种(济麦20、宁春4号、济麦22)磨制的面粉为材料,采用真空和面制作低水分面条面团(含水率35%),采用低场核磁共振技术(LF-NMR,low-field nuclear magnetic resonance)和差示量热扫描(DSC,differential scanning calorimetry)2种技术,测定不同真空度(0、0.06、0.09 MPa)和搅拌时间(4、8、12 min)下面团中水分的形态和分布,并进一步分析2种技术测定水分形态结果的相关性。结果表明,在低水分面条面团中,水分主要以弱结合水形态存在。不同品种的小麦粉面团的水分形态及分布存在差异,强筋小麦粉(济麦20)制作面团的水分自由度较低。真空和面(0.06 MPa)可以促进水分与面筋蛋白的相互作用,降低面团中水分子流动性,促进水分结构化;而非真空或过高真空度均会导致面团中水分自由度增加。济麦20、济麦22小麦粉和面时间为8 min时,面团水分流动性较低;而宁春4号小麦粉面团在4 min时,水分自由度较低;继续搅拌,深层结合水减少、弱结合水增多。LF-NMR和DSC测得面团水分状态的结果具有一致性。LF-NMR测得的弱结合水峰面积百分比与DSC测得的可冻结水百分比具有相同的变化趋势(r=0.695),且深层结合水峰面积百分比与非冻结水百分比具有相同的变化趋势(r=0.564)。研究结果为认识制面过程中水分的作用,优化和面工艺和调整产品特性提供参考。  相似文献   

13.
The possible relationships between the main emulsion components (namely, Arabic gum, xanthan gum, and orange oil) and the physicochemical properties of orange beverage emulsion were evaluated by using response surface methodology. The physicochemical emulsion property variables considered as response variables were emulsion stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility. The independent variables had the most and least significant ( p < 0.05) effect on viscosity and zeta-potential, respectively. The quadratic effect of orange oil and Arabic gum, the interaction effect of Arabic gum and xanthan gum, and the main effect of Arabic gum were the most significant ( p < 0.05) effects on turbidity loss rate, viscosity, viscosity ratio, and mobility, respectively. The main effect of Arabic gum was found to be significant ( p < 0.05) in all response variables except for turbidity loss rate. The nonlinear regression equations were significantly ( p < 0.05) fitted for all response variables with high R (2) values (>0.86), which had no indication of lack of fit. The results indicated that a combined level of 10.78% (w/w) Arabic gum, 0.56% (w/w) xanthan gum, and 15.27% (w/w) orange oil was predicted to provide the overall optimum region in terms of physicochemical properties studied. No significant ( p > 0.05) difference between the experimental and the predicted values confirmed the adequacy of response surface equations.  相似文献   

14.
Gelation of whey protein concentrate-cassava starch in acidic conditions.   总被引:2,自引:0,他引:2  
Whey protein concentrate (WPC)-cassava starch (CS) gels were prepared by heating WPC-CS dispersions (0-12.5% protein-0-4.2% starch, w/w; pH 3.75 and 4.2). Gels were characterized by measures of water-holding capacity (WHC), estimation of the relative size and/or density distribution of the gel particles, and light microscopy. Differential scanning calorimetry (DSC) of WPC-CS dispersions was also performed. Results show that CS increased the WHC of gels. Mixed gels presented separate zones of gelatinized starch and aggregated protein and a higher proportion of large/high-density particles. DSC assays showed that starch gelatinization preceded protein denaturation during heating. Starch gelatinization shifted to higher temperatures in dispersions containing WPC, due to the presence of whey proteins, lactose, and calcium.  相似文献   

15.
Starch physicochemical parameters and phase transitions were determined in flours of 10 advanced lines and cultivars of triticale (Cananea, Currency, Eronga, LA 24 Bve, LA 20 FCA, LA 83 FCA, Tatú, Tehuelche, Quiñé, and Yagan). Starch behavior was also analyzed during the baking of cookies prepared with triticale flours. Starch granule size, crystal type patterns, and size distribution were determined by light microscopy, X-ray diffraction, and gel-permeation chromatography, respectively. Two types and sizes of starch granules with characteristic A-form crystals were obtained in all samples tested. The Quiñé cultivar showed the lowest extent of starch crystallinity. Only a monophasic endotherm was found by differential scanning calorimetry for water content >50–60%. Gelatinization temperature and enthalpy values varied significantly among samples. A biphasic endotherm was detected for water contents between 35 and 60%, and no endothermic transitions were observed for water levels <35%. Only one endotherm corresponding to starch gelatinization was detected in baked cookies prepared with five triticale flours. In all samples, the highest enthalpy of gelatinization of starch was detected for the cookie surface, whereas the highest gelatinization temperature was observed for the center. These differences may be attributed to the presence and content of the solutes in cookie dough and also to the degree of starch gelatinization during the cooking process.  相似文献   

16.
Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.  相似文献   

17.
亚麻籽胶对面团流变性质的影响及其在面条加工中的应用   总被引:10,自引:4,他引:10  
该文重点研究了添加亚麻籽胶对面粉的粉质特性、面团的流变性质以及面条品质的影响。粉质特性的结果表明,添加亚麻籽胶使面团的吸水率增加,面团的形成时间和稳定时间延长,弱化度降低,使面团的稳定性更好。动态流变性质和超微结构的显微观察表明,添加亚麻籽胶后,亚麻籽胶的网络结构加固了面筋蛋白的网络结构,因而面团的稳定时间和粘弹性均能提高。质构分析的结果表明,添加亚麻籽胶使面条烹煮后的硬度和咀嚼度提高,并具有较好的弹性和拉伸性能,面条的烹煮损失和面汤浊度降低,因而亚麻籽胶可用于面制品中以改善其食用品质。  相似文献   

18.
《Cereal Chemistry》2017,94(5):840-846
Currently, production of pasta that is either gluten‐free or having lower content of gluten, using low‐cost nonwheat cereals and legumes, is becoming increasingly popular worldwide. This is mainly done to increase the nutritional value and reduce the allergenicity of the product. The quality attributes of pasta prepared from micronized maize flour with additives such as guar gum (MPG) and a combination of guar and xanthan gum (MPGX) were compared with pasta prepared from unmicronized flour with guar gum (UMPG). The optimum cooking time for pasta in all three cases (UMPG, MPG, and MPGX) was 3 min. The cooked weight of pasta MPG and MPGX was less compared with UMPG, indicating limited water penetration during cooking. The solid loss of pasta ranged between 8 and 9.5% and was within acceptable levels (<12%). Micronization increased the firmness in MPG (3.7 N) and MPGX (4.5 N) compared with UMPG pasta (2.7 N). MPGX pasta exhibited improved texture, color, and overall acceptability compared with UMPG, and these quality attributes were also comparable to commercial wheat pasta. The study indicated that micronized maize flour with gums can be used in the preparation of maize pasta with good quality attributes.  相似文献   

19.
莲子热风干燥过程对其淀粉热特性及凝胶化的影响   总被引:1,自引:1,他引:0  
为解决莲子干燥过程中淀粉形态结构变化造成莲子结壳、硬化,不利于干燥以及复水难、易返生问题,该文利用差示扫描量热技术(differential scanning calorimetry,DSC)对新鲜莲子以及不同热风干燥(70、80、90℃)莲子的淀粉热特性与凝胶化过程进行了研究.研究发现,莲子淀粉在低水分环境(42.2%,以质量比计)时存在2个明显的吸热峰,高水分环境(71.1%,以质量比计)时存在1个明显的吸热峰;莲子在干燥过程中不断失水,并伴随着淀粉凝胶化.方差分析(analysis of variance,ANOVA)表明,高温干燥显著影响莲子淀粉的热特性,其淀粉凝胶化温度(峰起温度To、峰顶温度Tp以及峰止温度Te)部分显著升高.相同干燥条件下,莲子淀粉糊化焓ΔH受水分显著影响,但干燥温度、升温速率对其影响不显著(P>0.01).采用Kissinger、Crane方程获得了淀粉凝胶化动力学参数(活化能Ea、指前因子Z以及反应级数n).莲子淀粉的非等温凝胶化反应可近似为一级反应,高温干燥后其Ea值出现增加,并随着水分增加呈现降低趋势.研究结果可为确定莲子高品质干燥工艺以及干莲子、莲子淀粉后续加工过程提供技术支持.  相似文献   

20.
The relationship between flour quality or processing conditions and pretzel quality has not been extensively investigated. The objective of this study was to elucidate the role of water in pretzel dough development and the consequent impact on pretzel integrity. Control pretzel and pretzels made with lower or higher levels of added water in the dough were produced under standard processing conditions at Reading Bakery Systems' pilot plant in Robesonia, PA. Dough samples were evaluated for their appearance, moisture content, and extensibility and were viewed under a microscope to evaluate the gluten network. Pretzels before and after the kiln were evaluated for moisture content, pasting properties, and hardness and were viewed under a microscope to evaluate the extent of starch gelatinization. The structural and functional attributes of dough and pretzels were significantly different for the three treatments. The degrees of gluten development during mixing and starch gelatinization during baking were influenced by the levels of water added and consequently influenced pretzel quality. Pretzels made using low‐water treatment were brittle due to a lack of gluten development in the dough and inadequate starch gelatinization during baking, while pretzels made using high water treatment were unacceptable due to extensive gelatinization and retrogradation of starch. Pretzel quality therefore appeared to be a function of appropriate gluten development and starch gelatinization in the product.  相似文献   

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