冰结构蛋白影响冷冻面团及面包体系发酵烘焙与热力学特性的研究

研究了冰结构蛋白(ice structuring protein,ISP)作为新型冷冻食品添加剂在三种面团及面包体系,包括冷冻面团面包、预烘焙冷冻面包和新鲜面团面包中的应用,并探索了其对冷冻面团及面包体系发酵烘焙与热力学特性产生的影响。结果表明:ISP可增大冷冻面团面包的比容,经-18℃冻藏14d的ISP强化面团可得到与新鲜面团面包比容接近的结果;ISP有软化面包质地的作用,对经长时间冻藏的样品效果更显著;含有ISP的面包冻藏过程中水分含量保持相对稳定,而对照样增大趋势明显;ISP的引入致使面团体系糊化焓增大。     

抗冻蛋白对预发酵冷冻面团发酵流变特性和馒头品质的影响

运用F4发酵流变仪、质构仪等研究冻藏和冻融循环下抗冻蛋白对预醒发冷冻面团发酵流变学特性和馒头品质的影响。结果表明:随着冻藏时间的延长和冻融循环次数的增加,冷冻面团馒头的比容减小,硬度和咀嚼性明显增大,弹性和回复性下降。冷冻面团的最大发酵高度、气体总释放量和气体释放最大高度均明显下降。说明冻藏和冻融循环严重影响了酵母的产气能力和面团的持气性,与冻藏和冻融循环过程中重结晶和大冰晶的形成有关。添加抗冻蛋白的冷冻面团馒头品质得到明显改善,说明抗冻蛋白能够减缓冷冻面团馒头冻藏和冻融循环过程中品质下降。     

冷冻面团发酵技术在中式食品中的应用II．冰结构蛋白对鲜酵母及包子类冷冻面团流变发酵特性的影响

应用F3 流变发酵仪和动态流变仪研究冰结构蛋白(ISP)对冻藏0、1、2、3、4 周鲜酵母发酵特性和冷冻面团动态流变学特性的影响。结果表明：随着冻藏时间延长,所有酵母样品发酵过程中气体释放曲线最大高度H′m、产生CO2 气体总体积V总及面团最大膨胀高度Hm 均逐渐降低,冷冻面团的弹性模量(G′)和黏性模量(G 〞)逐渐下降,冷冻面团包子比容显著减小。引入冰结构蛋白(ISP)后,冻藏时间相同时,酵母发酵过程中的H′m、V 总及Hm 均有所增大,G′和G 〞下降趋势减缓,冷冻面团包子比容明显大于空白组,说明ISP 能够抑制冻藏过程中冰晶的形成和重结晶,减弱冰晶对酵母及面筋蛋白质网络结构的破坏,同时也说明ISP 能够增强面筋蛋白质网络结构的强度,提高面筋蛋白质对冰晶破坏的抵抗力。     

海藻酸丙二醇酯对全麦冷冻面团冻藏稳定性和烘焙特性的影响

本文研究了海藻酸丙二醇酯（Propylene glycol alginate,PGA）对全麦冷冻面团冻藏期间稳定性的影响,并探究了冷冻面团烘焙面包品质的变化。将0.3%的PGA加入全麦面团,通过测定冷冻面团冻藏1、2、3、4和5周后发酵特性、流变特性、蛋白质二级结构、微观结构以及面包的比容、质构特性、内部纹理结构和老化程度等,研究冷冻面团冻藏期间的稳定性。结果表明,随着冻藏时间的延长,添加PGA的冷冻面团在冻藏5周后具有较好的保水性,其发酵特性及流变特性相对于对照组均有所改善。冻藏5周后,对照组与PGA组其面包比容分别下降了19.872%和14.153%;面包硬度分别升高了64.186%和36.386%;气孔表面积分率分别下降了3.497%和2.300%;老化焓值分别上升了65.142%和42.416%。添加PGA能延缓冷冻面团冻藏期间β-折叠含量的上升和β-转角相对含量的下降。电镜扫描图（SEM）显示,随着冻藏时间的延长,PGA组的冷冻面团孔洞数目相比对照组明显减少且大小均匀,面筋网络结构完整性和连续性提高。研究结果表明PGA可以有效地延缓冷冻面团在冻藏期间的品质劣变,维持冷冻面团的稳定性并提高面包的烘焙特性。     

海藻酸钠对冷冻面团面包烘焙特性的影响

研究添加不同比例(0.1%、0.3%、0.5%和0.7%)海藻酸钠对冷冻面团面包烘焙特性的影响。结果表明,添加海藻酸钠能提高冷冻面团的持水率,减少冷冻面团醒发时间;增大面包的比容,降低面包的硬度和咀嚼性,提高弹性,改善冷冻面团面包的品质。感官评定显示,冻藏不同天数后,添加0.3%的海藻酸钠面包感官评分值最高。     

酶制剂在现烤面包生产中的应用研究

对两种酶制剂(α-淀粉酶、木聚糖酶)在冷冻1 d和3 d面团中的应用进行了研究。结果表明,随着冻藏时间的延长,面团的发酵力、酵母存活率、面包比容、面包柔软性均呈下降趋势;与对照相比,α-淀粉酶、木聚糖酶对面团的发酵特性和面包品质改善作用明显;冷冻1 d时,α-淀粉酶添加量为0.4 g/kg或木聚糖酶为0.8 g/kg时面团的酵母存活率、面包比容、面包柔软性最佳,α-淀粉酶添加量为0.6 g/kg或木聚糖酶添加量为0.4 g/kg时发酵力最佳;冷冻3 d时,α-淀粉酶添加量为0.6 g/kg时面团的酵母存活率、面包比容、面包柔软性最佳,α-淀粉酶添加量为0.8 g/kg时酵母发酵力最佳,木聚糖酶添加量为1.2 g/kg时面包柔软性最佳,添加量为0.8 g/kg时酵母存活率、面包比容、酵母发酵力最佳。     

胶原抗冻肽的制备及在冷冻面团中的应用

抗冻肽是一类通过抑制冰晶生长使生物有机体免受冰冻伤害的多肽。文中采用酶法制备了高热滞活性的胶原抗冻肽,并考察了该抗冻肽对冷冻面团酵母存活率、发酵时间、馒头比容、质构及感官评分的影响。结果表明:胶原抗冻肽显著改善了冷冻面团的品质,当其添加量为0.3%时,面团经21 d冻藏后,酵母存活率从43%增加到54.5%;醒发时间缩短了33.3%,为60 min;馒头比容从1.74 m L/g增加到2.11 m L/g,上升了27.1%;馒头的硬度和咀嚼性显著减小,其回弹性、黏性、弹性均增加;同时冷冻面团的外观较好,感官总分达到55.5分。     

海藻糖和卡拉胶寡糖对冷冻面团冻藏稳定性和烘焙特性的影响

为了提高冷冻面团和面包的产品品质，将不同比例的海藻糖(1%、1.5%、2%,质量分数)和卡拉胶寡糖(0.3%、0.5%、0.8%,质量分数)加入面团，通过测定冻藏0、2、4周后冷冻面团的发酵特性、流变特性、水分分布、蛋白质二级结构、微观结构以及面包的比容、质构和内部纹理结构特性，研究冷冻面团冻藏期间的稳定性及面包烘焙特性。结果表明，随着冻藏时间的延长，添加海藻糖和卡拉胶寡糖的冷冻面团在冻藏4周后，其发酵特性及流变特性相对于对照组均有所改善。冻藏4周后，对照组、海藻糖-1.5%组、卡拉胶寡糖-0.5%组α-螺旋相对含量分别下降了45.73%、27.13%、15.71%;β-折叠相对含量升高了31.32%、15.51%、13.79%。电镜扫描图显示，随着冻藏时间的延长，海藻糖和卡拉胶寡糖组的冷冻面团相比对照组具有更致密的网络结构。对照组、海藻糖-1.5%组、卡拉胶寡糖-0.5%组在冻藏1个月后其面包比容分别下降了30.86%、21.48%、15.80%。综上，卡拉胶寡糖相对于海藻糖对冷冻面团冻藏稳定性及烘焙特性具有更好的保护效果，可作为一种新型抗冻剂用于冷冻面团生产中。     

冷冻速率对面团发酵和烘焙性质的影响

研究了冷冻速率对冷冻面团体系中酵母发酵(包括酵母产气力、酵母存活率)和面团微结构的影响;以及对冷冻面团烘焙性质的影响(包括面包比容,面包评分和面包保质期).结果显示冷冻速率同时影响酵母活力和面团的超微结构,进而影响面包的品质和体积,综合考虑,确定面团在-32℃下快速冷冻至-18℃(冷冻速率约-5℃/min),并在-18℃下冻藏,较适合冷冻面团的生产.     

辛烯基琥珀酸淀粉酯对冷冻面团品质及馒头品质影响的研究

本试验向面团中添加辛烯基琥珀酸淀粉酯,提高了冷冻面团品质及成品馒头的品质。通过正交试验得出最佳添加量为0．25％,醒发时间13min,最长冻藏时间为20d。     

Effect of enzymatic crosslinking on the handling properties of dough as a function of NaCl levels for CWRS varieties,Pembina and Harvest

The effects of transglutaminase (TG) and glucose oxidase (GO) on the handling properties of model bread dough were examined at both normal (2% wt. by flour) and reduced (1% wt.) sodium chloride (NaCl) levels using two Canada Western Red Spring (CWRS) cultivars; Pembina and Harvest. The reduction of NaCl level had negative effects on dough rheology and stickiness, however, the inclusion of GO (0.001 and 0.01% by flour weight) or TG (only at the 0.5% by flour weight inclusion) was able to improve dough strength and reduce stickiness. GO appeared to be more effective than TG (at 0.01%) at equivalent concentrations for improving dough‐handling properties. Flour cultivar had significant effects; Harvest flour (weaker) was more impacted by salt reduction and enzyme inclusion compared to Pembina flour (stronger). Crosslinking assays showed significant differences in glutenin macropolymer (GMP) content in dough prepared with GO, and dough prepared with different flours. Additionally, significantly fewer free thiol groups were found in dough produced with GO compared to dough without any enzymes and those with TG. GO appears to have potential for use as a bread improver to reduce stickiness and improve the strength of bread dough produced at lower salt concentrations, especially for dough prepared with weaker flour cultivars.     

不同水对面团性质影响

通过在等量面粉中分别加入5种不同的水制成面团,测定其形成湿面筋含量、色泽及质构性质并进行比较。结果表明:去离子水不适于制作面团;加农夫山泉(矿物质水)和自来水制作面团性质略有改善,但色泽变差;加盐水制作面团粘性小,面团形成湿面筋含量增加、延伸性好、色泽好;加碱水可加速和面进程,产生淡黄色外观,但不能添加过量,否则会恶化面团品质。     

冷藏面团生产工艺

冷藏面团是指将预先调制好的各种生面团置于一种特殊的包装容器中,在冷藏条件下可储藏1～3个月的方便主食产品,产品最大的特点就是:营养、卫生、方便.从冷藏面团产品配方、生产设备及工艺、微生物控制和包装形式等四个方面作了详细的介绍,为食品生产厂家提供了一种新型的方便主食生产技术.     

冷冻面团中影响面团筋力因素

面团筋力影响冷冻面团稳定性,而面团筋力又受到面团加水量,面粉种类,添加剂等影响。可通过选择面粉种类,改变加水量,添加添加剂等手段提高冻冷面团稳定性。     

Enzymatic cross-linking to improve the handling properties of dough prepared within a normal and reduced NaCl environment

This research examines the use of three enzymes [glucose oxidase (GOX), hexose oxidase (HOX), and xylanase (XYL)] and their combinations [GOX–XYL and HOX–XYL] on the dough handling properties of CDC Plentiful and Stettler wheat cultivars prepared at reduced (1.0% wt. by flour) and normal (2.0% wt. by flour) NaCl levels. Properties investigated include dough rheology, stickiness, and ratio of resistance to extension and extensibility. The inclusion of XYL and its combinations with GOX and HOX increased the stickiness, yielded lower dough strength indicated by rheology, and reduced the ratio of resistance to extension and extensibility. The inclusion of oxidative enzymes yielded a stronger dough, where HOX addition to dough had the lowest stickiness values and highest |G*| values, whereas GOX addition led to the highest ratio of resistance to extension—extensibility. NaCl only had minor effects overall on dough strength and stickiness for the cultivars studied. Overall, superior dough handling properties were observed with oxidative enzyme addition (GOX and HOX) suggesting that the increased crosslinking that occurs could aid in improving low sodium bread dough properties.     

面筋对冷冻面团品质的影响

就面筋对冷冻面团品质的影响进行研究,主要考察不同的面筋添加量、不同的时间指标以及成品馒头品质的变化等方面对冷冻面团品质的影响规律.结果表明:面团较好的醒发时间为15 min,冷冻时间为4d,面筋添加量为0.9%时,面团的粉质特性较好,成品馒头的评分最高.这为利用面筋来改良冷冻面团的品质,为实际生产实践选取合适的食品添加剂的应用奠定了理论基础.     

Dough aeration and rheology: Part 1. Effects of mixing speed and headspace pressure on mechanical development of bread dough

A laboratory‐scale Tweedy‐type mechanical dough development mixer was modified to monitor work inputs of dough during mixing through a computerised data acquisition system. Recorded torque showed a curve that increased to a peak about midway through mixing. Using this system, the effects of mixing speed and pressure on the development of doughs made from strong and weak flours mixed to a work input of 40 kJ kg⁻¹ were studied. Mixing was characterized in terms of peak torque and torque at the end of mixing (end torque), and in terms of the number of blade revolutions at these two reference points. The peak torque and the end torque both increased with increasing mixing speed. The peak torque increased with increasing mixer headspace pressure, but the end torque did not. The number of blade revolutions to both the point of peak torque and to the end of mixing decreased with increasing mixing speed for both flours, implying dough development at higher speeds was more efficient. Increasing headspace pressure reduced the number of revolutions to the peak, but not to the end of mixing. These results provide evidence that achieving dough development is not independent of mixing speed in Tweedy‐type mixers, and that dough aeration, as affected by mixer headspace pressure, affects dough rheology and hence development in the mixer. Copyright © 2005 Society of Chemical Industry     

Mixing properties of fibre-enriched wheat bread doughs: A response surface methodology study

Fibre-enriched baked goods have increasingly become a convenient carrier for dietary fibre. However, the detrimental effect of fibres on dough rheology and bread quality continuously encourages food technologists to look for new fibres. The effect of several fibres (Fibruline, Fibrex, Exafine and Swelite) from different sources (chicory roots, sugar beet and pea) on dough mixing properties when added singly or in combination has been investigated by applying a response surface methodology to a Draper-Lin small composite design of fibre-enriched wheat dough samples. Major effects were induced on water absorption by Fibrex that led to a significant increase of this parameter, accompanied by a softening effect on the dough, more noticeable when an excess of mixing was applied. Conversely, Exafine increased water absorption without affecting the consistency and stability of dough, which even improved when combined with Swelite. Fibruline showed little effect on dough mixing parameters, but showed synergistic effects with pea fibres. The overall result indicates that the use of an optimised combination of fibres in the formulation of fibre-enriched dough allow improving dough functionality during processing.     

冷藏发酵工艺对面团及油条品质的影响

以无铝油条预混粉为原料制作冷藏面团,考察面团在不同冷藏条件下的发酵能力及制作成油条的品质变化,研究不同冷藏温度、冷藏时间及前发酵时间对面团发酵及油条品质的影响。发现前发酵时间、冷藏温度及冷藏时间对油条感官品质及质构品质均有影响,除前发酵60 min外,随冷藏时间增加,感官评分先增加后减小;前发酵时间相同的条件下,冷藏温度越高,面团发酵越快,到达发酵终点用时越短;相同冷藏温度条件下,前发酵时间越长,面团醒发越快,到达发酵终点所需时间越短;油条质构特性指标显示硬度与剪切力变化一致,与弹性指标变化相反。结果表明,油条面团经前发酵40 min在2℃温度下冷藏1~3 d,油条感官品质及质构特性较好,此条件下,油条冷藏面团的货架期为3 d。     

DEVELOPMENT OF DYNAMIC MODULUS AND CELL OPENING OF DOUGH DURING BAKING

The dynamic shear modulus (elastic and viscous modulus) development of dough during baking was studied. Flooded parallel plate geometry was used to monitor the rheological changes of commercially available canned doughs (bread dough, bun dough and biscuit dough). The normal force exerted on the upper plate by the expanding dough was measured to study the cell‐opening event. The dough‐baking process was simulated in a rheometer oven. The morphology of baked dough was studied using a scanning electron microscope to elucidate the effect of ingredients and process parameters on the properties of the final baked product. Three stages of modulus development were observed during the baking process: bubble growth and packing, rapid expansion/starch gelatinization and final curing. The cell opening coincided with the sudden rise in modulus caused by starch gelatinization. The rate at which starch gelatinization takes place controls the temperature of the cell opening. The type and concentration of various ingredients have a greater effect on the modulus and on the cell opening than the heating rates. Frequency dependence was observed during baking, but the effect on modulus development diminished at higher frequencies.