Influence of Gluten-free Flours and their Mixtures on Batter Properties and Bread Quality

Gluten is a major component of some cereals and is responsible for flour technological characteristics to make bakery products. However, gluten must be eliminated from the diet of celiac patients because its ingestion causes serious intestinal damage. The objectives of this study were to assess the effect of different flours and their mixtures on thermal and pasting properties of batters, and to study the quality parameters and staling rate of gluten-free breads. Starch gelatinization temperatures and enthalpies depended on batter composition. Soy flour addition had a higher effect on rice than on corn starch, indicating some differential interaction between starch and proteins. Inactive soy flour incorporation improved all bread quality parameters in both corn- and rice-based breads. Higher batter firmness of formulations with soy addition (extrusion force was doubled in rice/soy and rice/corn/soy batters with regard to rice and rice/corn batters) partially explained higher specific volume (rice breads: 1.98 cm³/g; rice/soy 90:10 2.51 cm³/g, corn/soy 90:10: 2.05 cm³/g, whereas corn/soy 80:20: 2.12 cm³/g), as these batters retained more air during proofing. The staling rate was decreased by soy flour incorporation on rice (staling rate of rice breads with 10% soy diminished 52%, and with 20% of soy addition, 77%, both regarding to 100% rice breads) and corn formulation (the staling rate of corn/soy 80:20 breads was 5.9% lower than corn/soy 90:10) because of the high water-holding capacity of soy proteins and the interactions established with amylopectin that could retard the retrogradation process. Breads made with rice, corn, and soy flours showed the best quality attributes: high volume, good crumb appearance, soft texture, and low staling rate.     

Influence of Cephalaria Syriaca Addition on Physical and Sensorial Properties of Wheat Bran Bread

The effect of different Cephalaria syriaca products (CSP) (whole Cephalaria syriaca flour (WCSF) and defatted Cephalaria syriaca flour (DCSF)) on the final quality of bran breads was investigated. Five levels of Cephalaria syriaca products (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) were used in this study. Results of this study showed that addition of CSP (WCSF and DCSF) to wheat bran bread had significant positive impact on bread specific volumes, crumb firmness and bread sensory characteristics, although addition levels (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) were very low. In general, specific volume, yield of volume, and some sensory characteristics of the bran bread increased when the addition levels of WCSF and DCSF increased, except for the level of 1.51 g/100 g bread CSP addition, in which a slight decrease was observed. Bran breads containing WCSF had significantly higher loaf specific volume, softness of breadcrumb and sensory characteristics than those of breads containing DCSF at all addition levels. Especially, the addition of 1.17 g WCSF significantly improved the quality of bran breads. This study indicates that these two CSP can be used as additives in bran bread production in order to improve the quality of bread.     

Effect of Near-infrared Radiation and Jet Impingement Heat Transfer on Crust Formation of Bread

Rapid heat transfer methods can be used to speed up the baking process and create new product properties. This study investigates the effect of air jet impingement and infrared radiation (alone or in combination) on crust formation of par‐baked baguettes during post‐baking. The parameters investigated are crust color, crust thickness, total water loss, and heating time. The results show that infrared radiation and jet impingement, as compared with heating in a conventional household oven, increased the rate of color development of the crust and shortened the heating time. The fastest color development was obtained by combining infrared and impingement heating. The water loss rate was increased due to the high heat transfer rate, but the total water loss was reduced because of the shorter heating time. Crust thickness was most dependent on heating time and crust temperature. In general, the crust was thinner for infrared‐heated baguettes.     

Effect of Yeast Extracts Containing Propionic Acid on Bread Dough Fermentation and Bread Properties

ABSTRACT: Three commercial yeast extracts (Oxoid, Champlain, Lallemand) fermented with immobilized cells of Propionibacterium freudenreichii were added in broths and bread formulations, and their effect on growth and gas production by bakers yeast was determined. Appearance and preservation of the breads were examined. There was significantly more gas produced by the yeast when fermented yeast extracts were added to the dough. In broths, the initial growth rate was slower with media containing fermented yeast extract when compared to their unfermented equivalents. Loaves formulated with propionic acid of the fermented yeast extract contained less ethanol. Paired t-tests showed that breads formulated with fermented yeast extract were protected for a longer period against mold than those that contained non-fermented yeast extract.     

Functional Properties of Hydrolyzed Whey Permeate Syrups in Bread Formulations

Hydrolyzed whey permeate syrups (HWPS) prepared by various treatments were incorporated at 6% flour basis as a substitute for sucrose in a typical white pan bread formulation. Results indicated that there were little significant differences in the yeast fermentation rate, proof time, and bread quality among doughs formulated with sucrose (control) and HWPS. Demineralized 75% HWPS produced good functional qualities of dough and yielded bread equal to or better than the control. The 50% and 95% HWPS had some adverse effects on the handling characteristics of the doughs. Breads made with demineralized 50% and 95% HWPS were firmer than the control. The 50% HWPS breads showed darker crust colors, whether HWPS was or was not demineralized.     

添加剂对面包老化的影响

综述了添加淀粉酶、乳化剂、起酥油、可溶性蛋白、戊聚糖和水解胶体等品质改良剂对面包老化的影响,根据不同面粉的要求正确、合理选用一种或几种添加剂,能达到延缓面包老化的目的。     

Amyloglucosidase and maltase activities in soy sauce fermentations

Evidence for the participation of amyloglucosidase and maltase in the koji (mould growth) stage of experimental soy sauce fermentations is presented. Despite the problems associated with distinguishing between these two enzyme activities in a complex mixture, it seems clear that both are present and that maltase increases in concentration throughout the fermentation whereas amyloglucosidase concentrations declined in fermentations conducted for more than 64 hr. TLC showed that maltose quickly disappears from the koji leaving glucose as the only major sugar. Submerged liquid fermentations and incubation of starch solution with crude enzyme extracts from koji both supported the conclusions obtained from experiments with koji.     

Measurement of Starch Properties During Staling of Arabic Bread

The DSC and X-ray diffraction data showed that the starch crystallinity increased in Arabic bread (khaboos) samples during the storage period. The appearance of crystalline regions during ageing as shown by X-ray diffraction data could serve as an indication of the extent of staling that was observed in these khaboos samples. The information obtained from scanning electron microscopy could not be used for assessing the extent of staling of Arabic bread, but showed interesting differences in the gelatinization behaviour of starch granules in the crumb and crust areas. The crust areas, when viewed under the scanning electron microscope, show intact small as well as large starch granules. The limited amount of water available in the crust area of khaboos may be responsible for the incomplete gelatinization of starch granules.     

面粉黏度对面包粉的影响

在面包生产中,当面粉自身的淀粉酶含量很低时,淀粉的凝胶化就会很低,导致成品面包心发硬、发黑,面包体积小,松软度差等不良品质出现。为了使淀粉充分糊化,产生足够的糊精和麦芽糖,需添加一定的真菌淀粉酶,添加量通过黏度仪测定,并通过实验室制作成品面包,综合评价。结果表明,通过添加一定量的真菌淀粉酶,增加了酶活性,使得面包体积加大,包心增白且松软,提高了整体评分。     

馒头的微波烹制工艺与特性研究

采用正交试验研究加水量、醒发时间、微波剂量和烹制时间对微波烹制馒头感官品质的影响,确定最佳工艺参数,并对比分析微波和蒸汽2种不同烹制方式下馒头的微观形貌、质构特性和消化特性。试验表明,微波烹制馒头的适宜工艺参数为:加水量为50 g/100 g小麦粉,醒发时间为35 min,采用2.76 W/g的微波剂量,烹制时间为2.5 min。在此工艺条件下所制作的馒头感官品质与蒸汽烹制馒头较为接近。与蒸汽烹制馒头相比,微波烹制馒头的口感稍劣;内部微观结构较为粗糙,孔洞均匀性稍差,孔壁较厚,局部区域略呈聚集状,部分网络结构有轻微程度的断裂;硬度、黏聚性和咀嚼度较大,弹性较小;淀粉消化率较高,蛋白质消化特性与之相近。     

Influence of Media Composition on the Production of alpha-Amylase and Amyloglucosidase by a Strain of Aspergillus niger

The nature of thermophilic amylolytic enzymes produced by a strain of Aspergillus niger Van Tieghem was influenced by media composition. While glucose, maltose, dextrin and soluble starch induced the production of amyloglucosidase, pectin and sodium polypectate almost exclusively induced the formation of α-amylase. Alkali ions suppressed the formation of amyloglucosidase. NH₄NO₃, (NH₄)₂HPO₄ and (NH₄)₂C₄H₄O₆ served as good inorganic nitrogen sources, while casein, groundnut protein and corn steep liquor served to a similar capacity as nitrogen sources from organic material. Deletion of the growth factors pyridoxine-hydrochloride and inositol suppressed enzyme production, while the absence of riboflavin had the opposite effect.     

面包改良剂功能与特性的研究（I）

生产高品质的面包离不开优质的面包原料,诸如面粉、酵母、改良剂的使用等。本论述了面包改良剂的主要种类及其对面包的品质改良作用,并就国内外研究概况进行了分析和探讨。     

Texture and other Physicochemical Properties of Whole Rice Bread

ABSTRACT: Samples of experimental rice breads baked in a home bread machine were evaluated by physicochemical methods and compared with a local commercial whole-wheat bread. The results showed that rice breads had less specific volume, harder texture, and were more prone to retrogradation during storage than whole wheat bread. All stored breads showed a peak at about 52 °C by differential scanning calorimetry (DSC) analysis, which is characteristic of retrograded starch. However, the δH for rice bread was about 3 times the value of whole-wheat bread, suggesting its strong tendency to retrograde. X-ray diffraction (XRD) evaluation also indicated the appearance of a strong 20 peak between 16.7 °C to 17.0 °C in rice bread than in whole-wheat bread, which is consistent with starch retrogradation.     

木糖添加量对面团流变学特性与面包品质的影响

添加木糖代替面包配方中的蔗糖,采用直接发酵法制作木糖面包。采用粉质仪法、拉伸仪法测定添加木糖前后面团的流变学特性,研究木糖添加量对面团流变学特性和面包品质的影响。结果表明:木糖添加量越高,面团的粉质指数越低,稳定和断裂时间越短,软化度和公差指数越高;添加木糖可使面团的吸水量减少,对形成时间无影响。随木糖添加量的增加,面团的拉伸能量、拉伸阻力和拉伸比降低,而延伸度增加;但是随醒发时间的增加,木糖添加量与拉伸特性各指标间相关系数降低,木糖对面团拉伸特性的影响效果减弱。配方中添加1.5%的蔗糖即可满足面包酵母生长需求。添加木糖对面包的规则度影响较小,但可使面包的体积和比容变小,感官品质变差;木糖添加量3.0%时面包硬度最小,超过3.0%时面包体积、比容和感官得分明显降低。添加木糖可提高面包的水分保持能力和抗氧化能力,对酸度和酸价无影响。     

面包皮中水溶性晚期糖基化终产物对人肾小管上皮细胞的氧化损伤

晚期糖基化终产物（advanced glycation end products,AGEs）是食品在热加工和贮藏过程中形成的一类化 合物,与心血管疾病、糖尿病、肾病等多种慢性病的发生有重要联系。本实验研究了含有AGEs的面包皮水提取物 （bread crust extract,BCE）对人肾小管上皮细胞（human kidney tubular epithelial cells,HKCs）内氧化应激的影响 及细胞损伤。采用不同质量浓度的BCE处理HKCs,并经噻唑蓝法确定后续BCE处理质量浓度;通过检测细胞内活 性氧（reactive oxygen species,ROS）、总超氧化物歧化酶（superoxide dismutase,SOD）、脂质过氧化产物丙二醛 （malondialdehyde,MDA）及培养上清液中乳酸脱氢酶（lactic dehydrogenase,LDH）水平,评价BCE对HKCs胞内 氧化应激平衡及细胞损伤程度的影响。结果表明：不同质量浓度的BCE处理24 h后,HKCs胞内ROS水平随着BCE 质量浓度的增大不断升高,且在8 mg/mL和12 mg/mL时胞内ROS水平达到最大值;与对照组相比,胞内MDA含量 在BCE质量浓度为4 mg/mL和8 mg/mL时极显著增加（P＜0.01）,但BCE质量浓度达12 mg/mL时,MDA含量却显 著降低（P＜0.05）。相反,胞内总SOD活力却随着BCE质量浓度的增大而降低,在8 mg/mL和12 mg/mL时,胞内 总SOD活力发生极显著降低（P＜0.01）。胞外分泌型LDH水平随着BCE处理质量浓度的增大而升高,在BCE质量 浓度为8 mg/mL和12 mg/mL时,LDH活力发生极显著增加（P＜0.01）。因此,BCE可以通过提高HKCs胞内活性氧 水平,引起胞内总SOD活力降低,进而促进细胞发生脂质过氧化反应,改变细胞膜通透性,使胞外LDH活力升高, 导致细胞严重受损。     

冷却过程馒头硬度变化研究

研究了馒头冷却过程中其硬度的变化趋势。测定馒头冷却过程中的质构,研究其硬度的变化趋势,通过改变馒头冷却过程中的冷却条件,包括冷却风速、冷却温度及冷却湿度,对蒸制好的馒头进行冷却,测定硬度值。结果显示:冷却过程中,馒头的硬度随冷却时间的延长逐渐增大,冷却60 min后硬度值基本保持不变;馒头的硬度值随冷却风速、冷却湿度的增大呈上升趋势,而随冷却温度的上升呈先下降、后上升的趋势。     

板栗粉对面包面团流变学性能影响的研究

用布拉班德粉质仪和拉伸仪研究分析了板栗粉对面团流变学性质的影响。结果表明:板栗粉对面团流变学性质的影响随着其添加量及栗粉处理条件不同而不同,随着栗粉量添加比例的增加,混粉面团的形成时间、稳定时间有所减小,吸水率增加,弱化度增大,熟栗粉的影响要小于生栗粉。在 5%~6%左右添加量时混粉面团具有较好的综合粉质性能。     

葡萄糖氧化酶和木聚糖酶对面包特性的影响

研究葡萄糖氧化酶(GOD)和木聚糖酶(XY)对面团的发酵特性[最大发酵高度(Hm)、持气率(R)和气体逸出时间(Tx)],面包的焙烤品质(面包比容、高径比)和面包质构(硬度、弹性)的影响.结果表明,添加30U/100 gGOD的面团Hm、R和Tx分别为空白样品的1.26、1.05和1.15倍,同时面包比容增加9%,高径比提高10.6%.添加适量XY亦对面团的各项参数有改善作用,其中对面包弹性的效果最为明显.XY和GOD的复合使用具有协同性,对面包各项参数的改善效果都优于单独使用.