发酵面团气室结构稳定性调控理论研究进展

均一且细腻的气室结构是衡量发酵面制品品质优劣的关键因素。过去常认为发酵面制品的质构特性,尤其是产品内部气室结构主要与面筋蛋白网络的流变学性质相关。但近年来的研究成果表明发酵面团气体分散相与面筋蛋白网络半固态连续相基质之间存在粘弹性薄层液膜结构,它对面团调质时气体的渗透、发酵和醒发期间气泡的膨胀、以及面团焙烤过程中气泡粘弹性具有不同程度的影响。本文综述了影响发酵面团气室稳定性的两种理论机制,即面筋蛋白网络稳定理论和薄层液膜稳定理论,同时详述了影响面团气室稳定性的关键因素和调控手段,以期为发酵面制品品质改良提供新思路,并为多相食品体系功能特性改善提供理论支撑。     

The effects of bread‐making process factors on Australian sweet lupin‐wheat bread quality characteristics

Factorial experimental design was used to investigate the effects of: sponge proofing time (min), sponge and dough mixing time (min), final proofing time (min), final proofing temperature (°C) and baking time (min) on Australian sweet lupin‐wheat bread physical attributes. Factorial models show that bread specific volume was positively associated with sponge and dough mixing time (P = 0.01) and baking time (P = 0.02). Crumb area was positively associated (P = 0.01) with sponge and dough mixing time. Final proofing time positively influenced cell wall thickness (P < 0.01) and cell diameter (P < 0.01) but negatively affected number of cells (P < 0.01). Cell diameter was positively associated with baking time (P = 0.04), whilst number of cells was negatively influenced by sponge and dough mixing time (P = 0.01). Instrumental springiness was positively associated with sponge and dough mixing time (P = 0.02). Sponge and dough mixing and baking times were the two most significant process parameters affecting the bread physical quality and hence should be optimised.     

Performance of mechanically developed dough in pita bread production

The feasibility of adapting a mechanical dough development process, using a high speed mixer (Tweedy-35), to pita bread production was studied 'on line' at a commercial, traditional pita bakery.
A satisfactory pita bread was produced from a mechanically developed dough under the following conditions: work input 5.5 Whr/kg dough (mixing time 2 min), 3% yeast, 55% water absorption, dough temperature 30°C, no oxidizing agents and intermediate proofing (between mixing and dividing) of 10 min. The advantages of the mechanical over the conventional process were: increase in water absorption by 10%, which brought about a proportional gain in product yield per unit weight of flour; and reduction in holding floor time from 40–60 min to 12 min.
The baking performance of the pita bread under different controlled conditions gave insight into the mechanisms involved in the baking process, especially the relationship between dough mechanical properties and heat transfer during baking.     

Monitoring the dynamic density of dough during fermentation using digital imaging method

A simple and new method was developed for monitoring the dynamic density of dough during fermentation process. In this method digital imaging was applied to determine volume of dough sample in actual proofing conditions, i.e., temperature and relative humidity of the fermentation oven. The method resulted that the volume increasing profile affected by temperature and relative humidity conditions of the fermentation oven. As when temperature and relative humidity was increased, volume expansion rate was higher. The data also demonstrated that dough density decrease with the investigated proofing temperatures of 25, 30 and 35 °C more significantly (p < 0.01) than proofing relative humidity of 65%, 75% and 85% (p < 0.05). The new imaging method have the advantage of being low cost and measuring dough density in actual proofing conditions as used in bread making.     

Functionality of different emulsifiers on the performance of breadmaking and wheat bread quality

Emulsifiers are widely used in bakeries as dough strengtheners and crumb softeners, but there is a great diversity of compounds with emulsifier action. The objective of this study was to analyze the influence of emulsifiers with different functionalities on the rheological characteristics of wheat dough, as well as their effect in the final bread parameters, including behavior during aging. All the emulsifiers tested increased dough stability, although the extent of this effect was concentration-dependent. The presence of emulsifier retarded dough proofing; in consequence, longer proofing times would be required when emulsifiers are used. In fact, the positive effects of emulsifiers on bread volume were only observed with long proofing times, and that also became evident when crumb hardness was analyzed. Sodium stearoyl lactylate, sucrose ester, lecithin and enriched lecithin were the emulsifiers with the greatst crumb softening effects at extended proofing times. However, when the objective is a hardening delay during storage, the emulsifiers of choice are monoglyceride and lecithin enriched in lysophospholipids. This study reveals the importance of the proofing period to the functionality of the emulsifiers when used for breadmaking performance.     

Proofing of bread dough assisted by ohmic heating

Proofing of bread dough was studied under ohmic heating for a target temperature of 35°C. An experimental device based on PLC monitoring was developed to study the effect of heating rates and voltages on the proofing process. Conventional and ohmic heating-assisted proofing were compared; the results showed that the process itself had no impact on the proofing when identical heating rates (0.065°C·min^− 1) were used. However, increasing the heating rate could significantly reduce the time needed to reach an expansion ratio of 3 (from 122 min during conventional proofing to 65–70 min during ohmic heating in the range of 1–10°C·min^− 1). This was due to the shortening of the lag phase at the beginning of proofing (from 58 min during conventional heating to 20 min at 10°C·min^− 1 in ohmic heating). Results also showed that the voltage intensity had no significant effect on the proofing kinetics in the range of 50–150 V. The evolution of expansion ratios with proofing time could be fitted by a Gompertz model with a very high accuracy (R² > 0.999)     

The effect of different mixing processes on dough extensional rheology and baked attributes

BACKGROUND: Mixing is a significant part of the breadmaking process and is responsible for the development of the essential structure that will facilitate gas retention during proofing and the early stages of baking. The main objective of this study was to examine whether the dough extensional rheological and baking properties were affected from different mixers and energy inputs during mixing. RESULTS: It was found that extensional properties in uniaxial and biaxial extension were affected by the mixing equipment used and by the energy input used. Doughs mixed using a Farinograph had higher maximum resistance to uniaxial extension, higher P value and lower biaxial extensibility (Alveograph) and higher biaxial extensional viscosity than doughs mixed in a Stephan mixer (P < 0.01). The energy input was specific to each type mixing equipment and affected the biaxial extensional viscosity. Also, higher loaf volumes were achieved when higher energy inputs were used, whereas other baking properties were not affected. CONCLUSION: Altering the mixing equipment and the mixing speed affected the rheological properties of dough. Dough development during proofing as well as loaf volume was affected by the energy input levels and was increased by increasing the energy input and therefore the mixing time. Copyright © 2010 Society of Chemical Industry     

流态起酥油对冷冻面团烘焙特性的影响研究

使用冷冻面团生产面包具有经济、方便、快捷,产品质量稳定的特点,冷冻面团的主要缺点是:面团的醒发时间随着冷冻储存时间的延长而延长,且面包比容小.起酥油系统是提高冷冻面包面团储存稳定性的关键因素之一,流态起酥油具有良好的功能性和流动性,可以满足食品工业自动化生产的要求.研究了一种流态起酥油对冷冻面团烘焙特性的影响,结果表明在冷冻面团研究开发中使用流态起酥油可以很好地改善冷冻面团面包的烘焙特性,使得用冷冻面团制得的面包与新鲜面包在制作参数和口感上相比没有很大的区别,冷冻面团在冷冻储存期间烘焙品质的下降可以用一种专用于冷冻面团的起酥油系统来弥补.     

鲢鱼酶解产物对冷冻面团品质特性的影响

为研究鲢鱼酶解产物对冷冻面团品质的影响，在面团中加入2%的系列鲢鱼酶解产物，分析冻融处理前后（第0和4次冻融循环，－18 ℃冷冻18 h，4 ℃解冻6 h为一次冻融循环）面团醒发和焙烤特性、流变特性及显微结构等的变化。结果表明，添加酶解产物能抑制冻融后面团醒发时间延长和面包比容下降，其中30 min酶解产物（SCMH-30）效果最好，醒发时间（121 min）显著低于空白组（170 min），面包比容（1.72 mL/g）显著高于空白组（1.54 mL/g），说明其抗冻效果良好；与空白组新鲜面团相比，酶解产物组面团的拉伸强度降低，黏附性和延展性增大，可能与酶解产物中还原性肽的负面作用有关；冻融后所有面团的拉伸强度降低，黏附性和延展性增大，而抗冻性较好的海藻糖组和SCMH-30组面团的变化幅度相对较小。电镜观察表明添加SCMH-30削弱了面团面筋形成，但能较好地维持冻融后面团面筋结构稳定；粉质特性分析说明添加SCMH-30使面粉的面团形成时间、稳定时间、粉质指数均显著降低，弱化度显著上升，而加入葡萄糖氧化酶则可减轻其对面粉粉质特性的不利影响。研究结果为鲢鱼酶解产物在改良冷冻面团中的实际应用及其有效调控提供了理论依据。     

藜麦-小麦混合粉面团特性及藜麦馒头加工工艺

探讨不同比例的藜麦全粉对高筋小麦粉面团流变学特性的影响,确定藜麦全粉馒头中最佳的藜麦全粉添加比例并进行馒头加工工艺的优化。通过混合实验仪和吹泡仪对面团流变学特性进行测定,以馒头的感官评价和质构特性为评价指标,对藜麦全粉馒头的酵母添加量、发酵时间和醒发时间进行优化。结果表明：藜麦全粉馒头的最佳藜麦全粉添加量为15%;当酵母添加量0.75%、发酵时间100 min、醒发时间15 min时,藜麦全粉馒头的感官评价总分达到最高值86.58,比容达到最高值3.02 mL/g,同时,硬度、咀嚼性和胶着性分别达到最低值9.76、45.53 N和6.66 N。     

马铃薯全粉对比萨饼底加工工艺及品质的影响

研究马铃薯全粉对比萨面团流变学特性、发酵能力和比萨饼底质构特征、感官品质的影响。结果表明:马铃薯全粉能提高小麦粉的吸水率,缩短面团的形成时间,但会导致比萨面团的稳定时间缩短,弱化度增加;马铃薯全粉的添加量与面团的拉伸阻力、延伸度、最大拉伸比例和拉伸面积呈极显著负相关;马铃薯全粉能够提高面团的发酵能力和弹性,但会导致比萨饼底的硬度增加,感官品质略有下降,因此综合考虑确定马铃薯全粉的最佳添加量为15%;并进一步通过单因素和正交试验确定马铃薯比萨饼底的最佳原料配方为马铃薯全粉添加量15%、加水量60%、酵母添加量1.2%;在最佳原料配方的基础上确定马铃薯比萨的最佳工艺条件为醒发温度38℃、醒发湿度75%、醒发时间30 min、烘烤温度200℃、烘烤时间15 min,所得比萨的硬度为4 166.493 g,感官品质最佳。     

Effect of temperature and consistency on wheat dough performance

The effects of the dough consistency (DC; 300–700 BU), temperature of mixing (16–32 °C) and temperature along fermentation (15–35 °C) on the wheat bread dough performance during mixing, proofing, cooking and cooling have been studied through a central composite experimental design. Farinograph responses revealed the significant role of DC (α < 0.001) and mixing temperature (MT) (α < 0.001) on wheat bread dough elasticity. Fermentation responses obtained from the rheofermentometer showed that the DC induces a significant positive linear effect on dough development, whereas gas development was mainly governed by the fermentation temperature. The wheat bread dough behaviour subjected to a dual mechanical shear stress and temperature constraint showed that DC had a significant linear and positive effect on the starch gelatinisation and gelling process. Therefore, breadmaking is highly governed for DC, namely dough hydration, which has a direct consequence on the mixing, fermenting, cooking and cooling performance of the wheat bread dough.     

Assessment of Bread Dough Expansion during Fermentation

The aim of this work was to investigate different methods of measuring the expansion of bread dough during fermentation and to develop a mathematical model to describe the variation of dough volume. Dough was prepared with wheat flour, salt, yeast, and selected amount of water (56%, 58%, and 60% w/w flour basis). Proving time was 1 h and proving temperature investigated were 25, 30, and 35°C. Dough volume was measured with three methods: (1) vertical expansion in a flask, (2) horizontal expansion between two plates, and (3) free expansion method. Volume was measured either using displacement transducer or from image analysis of pictures taken during expansion. All the methods allowed monitoring the increase in dough volume as a function of proving time. Small differences were observed between the three methods. Free expansion shows a faster start of expansion in comparison with the two other methods. Expansion curves have been fitted with a modified Gompertz model (Romano et al., J Food Eng 83:142–148, 2007). They exhibited three phases: a lag phase, followed by a linear phase (constant expansion rate), and finally a phase with a decreasing expansion rate. Statistical analysis of the set of data showed that the proving temperature had a significant effect on the different parameters calculated (volume expansion ratio, expansion rate), while the water content had no significant effect.     

Comparison of rheological, fermentative and baking properties of gluten-free dough formulations

This paper examines the fundamental rheological properties, capability of CO₂ retention during proofing, and baking behaviour of gluten-free (GF) dough. Maize flour, maize starch, rice flour, and buckwheat flour formulations are compared. Apple pectin is used as the structuring agent. Rheologically, the GF dough formulations can be defined as physical gels of different viscoelasticity and structural networking. The curves of CO₂ retention in the GF dough best fit with the asymmetric transition sigmoidal function. Some correlations between characteristic parameters of the transition sigmoids versus rheological parameters of the GF dough, the spread parameter n of Cole–Cole model and the shear-thinning consistency index k, were found. In baking tests, extending the proofing time improved the taste, aroma, and mouth feel of gluten-free breads, particularly when a sourdough step was applied or flaxseed was added to the formulation.     

醒发工艺对豌豆挂面品质的影响研究

探讨了面团醒发和面带醒发两种醒发方式及其醒发时间对豌豆挂面蒸煮品质、质构特性和感官品质的影响。结果表明:相比于面带醒发,虽然面团醒发的豌豆挂面煮熟干物质损失率比较高,但其质构特性和感官评分更好。面团醒发和面带醒发均在45 min时的豌豆挂面综合品质最好。     

Assessment of proofing of bread dough in the microwave oven

 The effects of different proofing times in the microwave oven on the quality of microwave baked breads were investigated. The proofing height of the dough, specific volume and the firmness of the breads were found to be dependent on proofing time. When emulsifiers were added, the optimum proofing condition in the microwave oven was found to be 6 minutes at 10% power. The effects of different emulsifiers on the properties of the dough and, the volume and the firmness of the microwave-baked breads were compared. DATEM, Lecimulthin M-45 and Purawave were the three emulsifiers used. Purawave was found to be the most effective emulsifier on bread quality. Received: 5 July 2000 / Revised version: 6 September 2000     

A study on relationships between durum wheat semolina properties,technological mixing parameters and the properties of dough after mixing

Partial least square regression analysis was used to study the correlation between X variables (semolina quality, hydration level and mixing time) and Y variables, which were, in a first model, dough consistency during mixing, and, in a second model, dough properties after mixing (strength, elasticity, density) and leavening (maximum volume). The first model showed a predictive residual sum of squares (PRESS) of 2.98 and a predictive R² (Q²) of 0.92, and highlighted the key role of hydration and mixing time on dough consistency. The second model had the best PRESS (8.25) and Q² (0.94) values for dough volume and indicated that the volume increased with increasing mixing time until the dough consistency decreased of 20–30%. Dough volume was primarily affected by hydration. The model indicated that maximum volume after leavening, corresponding to optimum mixing time, was obtained with a soft and elastic dough, with a low‐density value.     

Novel materials and surface investigations for optimizing dough carrier interactions

In this study, different proofing basket materials were investigated regarding their adhesion to dough, their starting point of stickiness, and their microbiological contamination. First, the materials were checked for their adhesive forces according to a stickiness determination method developed by Chen and Hoseney. Then the change of the adhesive forces of proofing basket materials and dough with time was investigated. The effect of relative air humidity and proofing temperature on the starting point of stickiness was examined. It was found that with increasing temperature the time for the dough starting point of stickiness decreases. Also, the demand for a low bioburden of a proofing basket was measured with a proofing cycle. For simulation of industrial requirements of materials this proofing cycle was repeated up to seven times. Adhesive film test and counting of colony-forming units were used to characterize the materials.     

Predictive Models for the Survival/death of Campylobacter jejuni and Salmonella Typhimurium in Poultry Scalding and Chilling

ABSTRACT: Predictive models for the survival/death of Campylobacter jejuni and Salmonella Typhimurium during poultry scalding and chilling, as functions of temperature (50 to 60 °C), chlorine level (0 to 50 ppm) and water age (0, 10 h for scalding; 0, 8 h for chilling), were evaluated and developed using the data from previous study. As primary models, the Weibull distribution, exponential, logistic, and Gompertz models were compared. The secondary models were developed by modifying the Davey and polynomial models. Mean Square Errors ( MSE ) and the plots of predicted in contrast to observed survivors showed a good fit and prediction. The Weibull distribution-based secondary model was selected due to its fewer parameters and better prediction ( MSE s < 0.4) compared to the other models.     

Influence of yeast and frozen storage on rheological, structural and microbial quality of frozen sweet dough

The aim of the present study was to investigate the effect of yeast content and frozen storage (9 weeks at −40 °C) on the structural and rheological parameters, and fermentative activity of frozen sweet dough. Two types of dough were studied (to estimate dough shelf life): simple yeasted dough (SY) and double yeasted dough (DY). Fermentative activity (yeast viability, gassing power, and dough volume), rheological and textural parameters were assessed for frozen sweet doughs.These effects were explored by different and complementary methods: Fourier transform infrared (FTIR), dynamic rheology, texture profile analysis (TPA) and differential scanning calorimetry (DSC).The data showed that the longer the frozen storage time at −40 °C, the higher the decreased of frozen sweet dough quality. The rheological attributes such as hardness, ΔS, springiness, tan δ and yeast activity declined significantly during frozen storage. This modification led to lower specific volume of frozen sweet dough during proofing.The observed changes of the frozen sweet doughs rheological properties after thawing may be attributed to the damage on the gluten cross-linking, mainly produced by the ice crystallization during frozen storage. The storage effect was particularly concentrated in the first 27 days of storage.