食品酶制剂改善冷冻面团贮藏稳定性的研究

应用F3发酵流变仪、质构仪研究了葡萄糖氧化酶和谷氨酰胺转胺酶对冷冻面团贮藏稳定性的影响.空白面团含有葡萄糖氧化酶面团和含有谷氨酰胺转胺酶面团于-18℃冷冻贮藏7,21,35 d,研究发现：三种面团经冷冻贮藏发酵高度均有所降低,产气能力下降;葡萄糖氧化酶和谷氨酰胺转胺酶抑制了冷冻贮藏对面团发酵高度、产气和持气能力的破坏.葡萄糖氧化酶和谷氨酰胺转胺酶稳定了面团流变学特性的变化.添加葡萄糖氧化酶和谷氨酰胺转胺酶冷冻面团面包比容增加、硬度减小;面包瓤更柔软、光滑、富有弹性,面包感官评分高.     

冷冻面团的研究进展

冷冻面团作为一种半成品,通过冷冻贮藏可以维持面团性能,延长面团保存期,被广泛应用于食品连锁加工过程中.本文综述了影响冷冻面团品质的因素,探讨了当前国内冷冻面团研究存在的难点,旨在为我国冷冻面团的发展提供参考.     

Effects of milk proteins and gums on quality of bread made from frozen dough

BACKGROUND: Mixtures of milk proteins and gums incorporated into bread formulations may enhance the quality of bread and retard the deterioration of frozen dough. Our objective was to investigate the effects of mixtures of milk proteins (casein (C) and whey protein (W)) and gums (sodium alginate (A) and κ‐carrageenan (K) on the quality of bread made from frozen dough. We hypothesized that bread containing milk proteins and gums would be of improved quality. Milk proteins improve texture, moisture retention and specific volume, and reduce the size of ice crystals, while gums incorporated into the bread improve moisture retention, control water mobility and prevent the growth of ice crystals, so we hypothesized milk proteins and gums would suppress the quality deterioration of bread during frozen storage. RESULTS: We found that mixtures of milk proteins and gums proved effective with regard to the maintenance of the baking quality of frozen dough. Breads containing CA had a higher specific loaf volume than the control bread. The addition of WK enhanced crumb firmness during extended frozen storage. In sensory evaluation, the addition of WA and CA contributed to the improvement of baking quality, taste, texture and acceptability. CONCLUSION: These findings are consistent with the hypothesis that mixtures of milk proteins and gums improved baking quality by reducing the deterioration of frozen dough. These results indicate that the addition of CA and WA improved the bread quality and WK could effectively be used as an anti‐staling agent in bread. Copyright © 2009 Society of Chemical Industry     

Water dynamics in fresh and frozen yeasted dough

Water is an integral part of wheat flour dough-the amount, physical state, and location of water are crucial to the formation of a dough that will hold gas and produce an open, aerated crumb structure in the final product. This has been understood for centuries by craft bakers, who were highly attuned to the "feel" of dough in their hands. In the 20th century, empirical instruments were invented that simulated part of the breadmaking process, and their limited predictive capacity made them valuable quality control tools. During the latter decades of the 20th century the cost and availability of advanced instrumental methods for characterizing foods improved dramatically, and facilitated a "fundamental science" approach to food research. The physicochemical mechanisms by which water exerts such a strong influence on the character of dough are now better understood. This review contrasts the empirical and fundamental view points, and summarizes recent knowledge about the roles of water in the manufacture of fresh and frozen yeasted dough.     

面团的玻璃化储存

由于面团在冷冻储存过程中受到结晶与再结晶的影响,产生结构松弛和水份迁移,品质显著下降。实现面团的玻璃化储存是解决问题的最佳方案。通过加入合适添加剂,可提高面团玻璃化转变温度,实现一般冷冻储存温度（-18℃）下的面团玻璃化储存。分析了各种玻璃化转变温度测定方法和添加剂在提高面团玻璃化转变方面的应用。     

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。     

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.     

后发酵冷冻面团成品品质影响因素的研究

主要对后发酵冷冻面团的品质变化进行了研究,在醒发室温度和湿度恒定的条件下,研究发酵时间和添加剂对冷冻面团所得馒头的比容、色度等品质的影响。并通过正交实验确定最佳的后醒发时间为25min,添加剂组合为:单甘酯0.37%,Vc添加量0.08%,抗冻剂0.08%,     

冷冻面团品质改良综述

较系统地介绍了国内外冷冻面团的研究开发现状,综述了常用添加剂(乳化剂、酶制剂、氧化剂、磷酸盐类、糖类等)对冷冻面团的品质的影响,并对我国冷冻面团的发展前景进行了展望。      

影响冷冻面团质量的因素

主要探讨了冷冻面团加工过程中工艺流程的选择、冻结前的处理、冻结条件,冻藏条件和解冻方法对冷冻面团质量的影响以及冷冻面团加工中基本原料的选择和添加剂的种类对面团质量的影响。     

未发酵冷冻甜面团面包储存期间的质量变化

冷冻面团技术是面包生产的一种新工艺,在烘烤前利用冷冻技术来处理面包坯或半成品,能够延长面包面团的货架储存期.选取不同冷冻储藏期内的冷冻面团,制作成面包并分析它们的比容、高径比、表皮和内部组织色泽及柔软度等指标,观察未发酵冷冻甜面团及其面包产品的品质特性.结果显示,在冷冻期间的前3～4周内,由冷冻面团制作成的甜面包品质急速降级.并在以后长达70天的冷冻储藏期间内趋于不可逆转的稳定状态.在进一步的研究中发现,使用一种以水溶性米糠多糖为乳化载体的冷冻甜面团改良剂能够使冷冻甜面团面包在长迭70天的冷冻储藏期间呈现出相当满意的产品质量特性.     

Disulphide interchange in dough proteins

Appreciable disulphide interchange has been found between wheat proteins and cystamine when the latter was incorporated into doughs. If the extent of the protein-protein reaction is of the same order it has been calculated that interchange of this magnitude would be enough to cross-link the glutenin into a continuous structure. Cysteamine was more reactive than cystamine in the disulphide interchange reaction.     

冷冻工艺条件对发酵面团中抗冻酵母活性的影响

研究了冷冻面团的冷冻终结温度、冻藏温度、冻藏时间对抗冻酵母活性的影响,得出最有利于抗冻酵母活性保持的冷冻工艺条件：冷冻终结温度-18℃,冻藏温度应与冷冻终结温度保持一致,贮存时间不超过30d为宜。     

Effect of carrot (Daucus carota) antifreeze proteins on the fermentation capacity of frozen dough

Carrot (Daucus carota) antifreeze proteins have strong anti-recrystallization ability and potential uses in food industry. In this study, the effects of carrot concentrated protein supplementation containing 18.3% carrot antifreeze protein on the fermentation capacity of frozen dough were evaluated. Adding carrot concentrated protein to frozen dough increased the retention capacity of the dough, decreased mortality of the yeast, caused a thermal-hysteresis phenomenon during freezing–thawing cycle, and retarded the crystal forming. The application of carrot concentrated protein in frozen dough was proved to be a promising improver for the frozen dough fermentation.     

焙烤冷冻面团专用油脂的制备

利用棕榈硬脂代替氢化油作基料,开发适用于焙烤冷冻面团的专用油脂生产技术及配方.将棕榈硬脂与大豆油按7:3比例混合进行酯交换反应,得到酯交换油脂用于制备焙烤冷冻面团专用油脂.通过单因素及正交实验确定的O/W型专用油脂最佳制备条件为:复合乳化剂(Tween80和SE比例为1:1)添加量12%(总重),乳化温度75℃,乳化时间1 min,油水比例4:6.在最佳制备条件下,O/W型专用油脂的乳化稳定性为95%,黏度为175 Pa·8.     

冷冻面团发酵特性的研究

以小麦高筋粉为原料,采用预发酵、未发酵、二次发酵3种发酵方式制作冷冻面团,研究不同发酵方式对冷冻面团理化特性的影响。结果表明,发酵方式影响了水的流动性和半结合水的含量,3种面团相比较,二次发酵面团相对较软,预发酵面团相对较硬;不同的发酵方式对于其面团内的面筋网络和酵母细胞的破坏有显著影响。     

冷冻面团中酵母抗冻保护剂的优选

为改善冷冻面团品质,减少低温对酵母的损害,对常见的几种酵母抗冻保护剂进行配方优化。单因素试验测定冷冻7 d后酵母存活率和面团发酵力,筛选出保护剂及其添加量水平,再运用二次回归正交旋转组合设计进行优选试验,在对存活率影响试验中,因素主次顺序为：海藻糖＞甘油＞脯氨酸;在对发酵力影响试验中,因素主次顺序为：海藻糖＞脯氨酸＞甘油。验证得到最优试验条件为：海藻糖、甘油和脯氨酸添加量分别为2.23%、3.43%和1.55%。在此条件下,酵母存活率和面团发酵力分别为85.86%和322 mL。     

冷冻面团馒头品质改良研究进展

为了研究食用碱添加量对不同冷冻杂粮（小麦、荞麦、玉米、绿豆）面团品质的影响,本文设计了0%、1%、2%、3%、4%、5%（以100 g冷冻杂粮面团为基准）食用碱添加量分别加入到小麦面团、荞麦面团、玉米面团、绿豆面团中,在−30 ℃条件下冷冻8 h,在−18 ℃的条件下冷冻1 d,然后在25 ℃下解冻30 min。然后分别测定冷冻面团的失水率、持水率、pH、质构特性、水分分布以及利用扫描电子显微镜（SEM）对冷冻面团表面网络结构和蛋白质结构的变化进行研究。结果表明,食用碱添加量与冷冻面团的失水率呈负相关,可以显著（P<0.05）影响冷冻面团的pH;在食用碱添加量为4%时,各个冷冻杂粮面团的弹性达到最大值,小麦面团、荞麦杂粮面团、玉米杂粮面团、绿豆杂粮面团的A₂₁分别达到48.189±1.509、45.652±2.202、43.585±2.472、43.743±1.155,说明食用碱可以抑制水分迁移,进而保持良好的持水性,且能有效改善冷冻杂粮面团面筋蛋白网络结构和品质,进一步提高冷冻杂粮面团品质。本文研究食用碱对冷冻杂粮面团特性的影响,以期为冷冻杂粮面团的品质改善以及现代化生产提供一定的理论依据。

     

酵母和加工条件对冷冻面团生产的影响

综述了酵母和加工条件对冷冻面团生产的影响,介绍了如何通过选择酵母种类、改善配方、改进制作方法及控制冷冻解冻条件等来改善冷冻面团的稳定性.