Bread staling assessment of enzyme-supplemented pan breads by dynamic and static deformation measurements

Dynamic mechanical analysis and thermal mechanical analysis techniques were used in order to evaluate the effect of amylolytic-, non-amylolytic- and gluten-cross-linking enzymes on the viscoelastic properties of fresh and stored pan breads. The relationships between dynamic and static compression measurements in bread staling characterization and the correlations between sensory firmness and thermomechanical properties were also investigated. Rheological changes in bread associated with recipe and storage time were successfully detected via dynamic thermomechanical analysis (DTMA) in the compression mode. Relationships between the dynamic (DTMA) and static (texture analysis) methods were found. All the bread quality indicators measured by static methods were negatively correlated with the viscoelastic dynamic parameters.     

Effect of gluten addition and storage time on white pan bread quality: instrumental evaluation

 Continuing an investigation into the different factors affecting the quality of white pan bread and the changes taking place during storage, on the basis of instrumental determinations of firmness using compression and bending tests, this second instalment addresses the influence of adding gluten to the dough. Three types of bread were prepared using three different water contents and three proportions of added gluten each. Firmness was evaluated at 24, 48 and 72 h. Addition of gluten significantly increased flexibility and significantly decreased firmness in the bread at the higher water content levels. It also improved the keeping properties of the bread by slowing the increase in firmness with time; this effect was also higher at the higher water content levels. Received: 4 May 1998     

Effect of water content and storage time on white pan bread quality: instrumental evaluation

 The firmness of white pan bread was measured using compression and bending tests to determine the influence of the water content of the dough on bread quality and on the changes taking place with storage time. Three sample breads were prepared using different flours and three different water contents, and firmness was tested at 24, 48 and 72 h. For gluten-enriched flours, higher water contents tended to bring about a decrease in compression force and bending values, improving shelf-life by reducing the increase in firmness over time. Received: 24 March 1997     

Effect of water content and storage time on white pan bread quality: instrumental evaluation

 The firmness of white pan bread was measured using compression and bending tests to determine the influence of the water content of the dough on bread quality and on the changes taking place with storage time. Three sample breads were prepared using different flours and three different water contents, and firmness was tested at 24, 48 and 72 h. For gluten-enriched flours, higher water contents tended to bring about a decrease in compression force and bending values, improving shelf-life by reducing the increase in firmness over time. Received: 24 March 1997     

面包老化研究中新技术及研究进展

面包在中国市场上所占比重越来越大同时,面包老化问题也越来越引起人们关注。该文综述近红外、核磁共振、差示热量扫描几种新技术在面包老化研究中应用进展,旨在对面包老化研究工作起到一定指导意义。     

Effect of amino acids on Maillard reaction product formation and total antioxidant capacity in white pan bread

Maillard reaction products (MRPs) can be an important dietary antioxidant source. Bread is the most popular bakery product; however, limited information is available on the antioxidant activities of MRPs generated during bread-baking. This paper reports the effect of different amino acids on bread properties, melanoidin formation and antioxidant activities. Totally six amino acids at four different levels were evaluated. Increasing the amount of amino acid led to darker bread crust, higher melanoidin content and stronger antioxidant activity. Among the six amino acids, bread with glycine had the highest melanoidin content and ABTS radical scavenging activity up to 1079.77 ± 8.43 μmol TE mg⁻¹. Bread with lysine had the highest DPPH radical scavenging activity up to 281.97 ± 10.52 μmol TE mg⁻¹. Bread with alanine had the highest crust metal chelating activity compared with others. Adding certain dietary amino acids is a potential approach to enhance the antioxidant capacity of bread products.     

Physical, textural and sensory characteristics of 7-day frozen part-baked French bread

Bread partially baked for 7 min at 250 °C, after cooling, was frozen until core temperature reached −18 °C and stored at this same temperature up to 7 days. Samples were removed daily from the freezer, thawed and baked at 250 °C for 6 min. Analyses were performed 1 h after final baking, and were also conducted on fresh French bread daily produced (control). Weight and specific volume of frozen part-baked bread presented significant difference (P<0.05) compared with fresh one. Sensory analysis was carried out by a trained panel using the Difference from Control test to evaluate the difference and the degree of difference between frozen part-baked French bread (FPBFB) and fresh bread regarding appearance, tactile by direct touch and mouthfeel. All scores obtained indicated that the panelists, during the studied period, considered FPBFB to be slightly different compared with fresh one. Consumer Acceptance test was applied to compare appearance (gloss, roughness and cut on bread surface), oral texture (crust crispness and crumb firmness) and overall flavor between frozen part-baked bread and a commercial brand. All sensory scores obtained from Consumer test indicated that the 4-day frozen part-baked presented a superior acceptance to the commercial brand.     

Bread crumb quality assessment: a plural physical approach

The aim of this study was the assessment of pan bread crumb quality attributes of commercial samples using a plural physical approach to better match consumer awareness. Static (texture profile analysis, firmness AACC and relaxation test) and dynamic (innovative oscillatory test) deformation techniques, image analysis, sensory analysis and colour measurements (colorimeter and Photoshop system) were used for white/whole commercial pan bread quality evaluation over 10 days of storage. Static (k ₁, k ₂, cohesiveness, springiness, hardness, chewiness and resilience) and dynamic (stress) bread crumb rheological properties were correlated illustrating that both techniques can be useful in evaluating crumb physical characteristics. In addition, sensory perceiveness with regard to softness and overall acceptability exhibited dependence with either dynamic stress or static firmness. Despite the fact that empirical measurements are closely linked to macroscopic features whilst dynamic tests are strongly linked to molecular characteristics, the obtained results support that both techniques are complementary since derived instrumental parameters are related to some sensory attributes. As data achieved using the proposed novel approaches might be better linked to the consumer awareness than those obtained from classical analyses, the obtained results are promising for a proper bread crumb quality assessment.     

Fibre-rich additives--the effect on staling and their function in free-standing and pan-baked bread

BACKGROUND: The use of dietary fibre in bread products is increasing because of consumer demand for healthier products. However, an increase in dietary fibre level changes the rheological properties of the dough and also the quality properties of the final bread product. In this study, effects on dough and bread staling were followed after replacing 3% of wheat flour by fibre‐rich additives (fine durum, oat bran, rye bran and wheat bran). Free‐standing and pan‐baked loaves were baked to compare the influence of baking method and loaf shape. RESULTS: All additives increased dough stability, with oat bran giving the greatest stability and longest development time. Parameters measured during storage were distribution, migration and loss of water, cutability, crumbliness, firmness and springiness. Furthermore, amylopectin retrogradation and amylase‐lipid complex formation were assessed. Oat bran provided similar or better results than the control for all staling parameters, while other additives gave no general improvements. Cutability reached a plateau when crumb firmness was ≥ 4 N. CONCLUSION: Small amounts of fibre‐rich additives had a significant influence on staling. However, the baking method (free‐standing or pan‐baked bread) had a greater impact on staling than the additives, thus displaying the importance of the baking method. Cutability was found to be related to firmness. Copyright © 2011 Society of Chemical Industry     

Effect of baking conditions and storage with crust on the moisture profile,local textural properties and staling kinetics of pan bread

To investigate the impact of baking conditions on staling kinetics and mechanical properties, pan breads were baked at 180 °C/34 min and 220 °C/28.6 min using a ventilated oven and metallic moulds. After baking, bread slices were stored with and without crust at 15 °C in hermetic boxes for 9 days. This investigation provides a textural and physical analysis by examining the Young's modulus, crumb density and crust/crumb ratio during storage. In order to understand the relationship between firmness and moisture content, a moisture profile and a Young's modulus profile were determined during the storage of bread. To fit the staling, a first order model was used. It was found that the kinetics were faster for samples baked with a fast heating rate than for those baked with a slow heating rate. Moreover, the staling rate of bread stored with crust was faster than for bread without crust and the outer crust area staled more rapidly than the centre of the bread slice. These results suggest that the firming of the crumb is related to moisture distribution between the crumb and crust and to the impact of local baking conditions on local firmness.     

溶血磷脂在面包中应用研究

磷脂酶A1催化酶解大豆磷脂获得溶血磷脂,采用单因素试验研究溶血磷脂在面包中应用,发现在面包中添加0．65％～0．9％范围内溶血磷脂能有效增大面包体积。利用质构仪对添加溶血磷脂面包和浓缩磷脂面包储存期物性参数进行测定,硬度值变化表明,溶血磷脂能有效缓解面包老化。     

溶血磷脂在面包中应用的探讨

磷脂酶A1催化酶解大豆磷脂获得溶血磷脂。采用单因素试验研究溶血磷脂在面包中的应用,发现溶血磷脂在面包中添加量在0.65%～0.9%范围内能有效增大面包的体积。利用质构仪对添加溶血磷脂面包和浓缩大豆磷脂面包储存期间的物性参数进行了测定,硬度值变化表明,溶血磷脂能有效延缓面包的老化。     

Influence of modified starches on properties of gluten-free dough and bread. Part II: Quality and staling of gluten-free bread

The aim of the study was to check the quality of gluten-free bread produced basing on the recipes, in which part of native starch was replaced with high amylose corn starch (HACS), acetylated distarch adipate (ADA), and hydroxypropyl distarch phosphate (HDP). The application 10 or 15% of chemically modified starches (HDP, ADA) caused the increase in volume of the obtained gluten-free loaves. The changes were accompanied by a decrease of average cell size, and an increase in their number. Due to the addition of modified starch crumb structure became more elastic, which was revealed in the results of stress relaxation. A slight decrease in hardness and chewiness of the crumb was also observed on the day of baking, and its extent depended on the level of modified starch, and was a little more pronounced in case of starch adipate. In comparison to the chemically modified starches, HACS deteriorated structural and mechanical properties of the crumb, which is probably related to their resistance to pasting and divergence in retrogradation pattern, where amylose component is more important than amylopectin.     

复合改良剂在面包中的应用

面包改良剂通常包含面粉强筋剂、活性面筋、乳化剂、酶活性大豆粉及α-淀粉酶,但单一改良剂的效果往往不足,复合使用可满足面包的整体要求,会带来更好的效果.综述各种复合改良剂对面包的改良效果.     

大豆膳食纤维在面包生产中应用的研究

以大豆深加工副产物大豆皮为原料,经过适当处理制得高品质膳食纤维,并利用其生产大豆纤维面包。通过正交试验对影响大豆膳食纤维面包品质的主要因素进行分析,确定了大豆膳食纤维面包的最佳配方。结果表明,糖的用量对产品感官品质影响最大,其次是油脂用量、大豆膳食纤维用量,添加剂用量影响最小。且当大豆纤维用量为20%,糖用量为8%时,油脂用量为4%,添加剂用量为1%时,产品品质最好。     

金耳粗多糖在面包生产中的应用

本文采用金耳子实体,经过热水提取,乙醇沉淀后得到含多糖为51．4%的金耳粗多糖。作为功能食品添加剂应用于面包生产中,结果表明面粉中添加了1%~3%粗多糖,改善了面团的胶体性能,增加了面团的吸水性,减缓了淀粉的老化,增加了面包体积和持水性,使面包口感柔软,内部组织细腻均匀,并具有保健功能。     

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。     

Digital bread crumb: Creation and application

Bread is a foam and the softness of breads is an important quality attribute. For many non-food foams, digital environments have been implemented which can be used to characterize the structure to optimize products for specific functionalities. For breads, structure based models that incorporate pore structure, which is comprised of the pore distribution and overall porosity, with solid matrix properties are lacking. For the first time, such structure based models have been stochastically, or randomly, generated for a range of breads using previously published X-ray microtomography data (Wang et al., 2011). The Weibull probability distribution has been used to characterize closed pore distributions, stochastic probability theory has been used to obtain representative porosities, and digital bread crumb models which incorporate pore structure have been created. Digital bread crumbs have been compared against real world samples via visual texture and small strain compression experiments. Digital bread crumbs exhibited similarities to real products in terms of cell wall thicknesses as seen from surface appearance. Results from digital compression experiments using finite element analysis showed differences in Young’s moduli between breads can be attributed to both differences in pore distribution as well as porosity.