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.     

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。     

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%,     

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.     

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。     

抗冻性面包酵母选育及其在冷冻面团中应用

冷冻面团技术代表了当今世界面包生产的主流,它的应用得到了人们的广泛关注。控制冷冻面团的质量需要从多方面考虑,其中选择抗冻性面包酵母为问题的关键。研究发现,面包酵母的抗冻性可能与耐酒精度相关联,本文通过耐酒精度实验,选育出了抗冻性面包酵母S.cerevisiae X—003,并对其在冷冻面团中的应用进行了研究。     

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。     

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.     

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.     

低聚木糖对面团热机械特性及冷冻面团发酵流变特性的影响研究

采用Mixolab酶流变分析仪和流变发酵仪研究了低聚木糖对面团热机械特性和对冷冻面团发酵流变特性的影响,结果表明低聚木糖有强化面筋、增加面团耐揉性和耐蒸煮性的作用。引入低聚木糖会使流变发酵仪中的气体释放曲线和面团发展曲线的最大高度以及面团的持气率较空白组有不同程度的提高。     

冷冻面包面团的稳定性研究

制备冷冻面团时添加不同的添加剂,研究这些添加剂对冷冻面包面团品质的影响。结果表明,单独添加适量的溴酸钾或二乙酰酒石酸单双甘油酯,对制成面包的比容和柔软度均有一定的改善效果;以溴酸钾、二乙酰酒石酸单双甘油酯、活性面筋、魔芋精粉为正交试验的四个因素,每个因素设定三个水平,进行正交试验,当添加量分别为:溴酸钾30mg/kg、二乙酰酒石酸单双甘油酯0.3%、活性面筋3.0%、魔芋精粉0.1%时,冷冻面团的稳定性显著提高。     

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。     

Influence of surfactants on rheological characteristics of dough and quality of parotta

The effect of the surfactants glycerol monostearate (GMS), lecithin, diacetyl tartaric acid esters of monoglycerides (DATEM), polyoxyethylene sorbitan monostearate (PS‐60) and sodium stearoyl‐2‐lactylate (SSL) on the rheological characteristics of dough and quality of parotta was studied. Use of the surfactants increased stability as measured by the farinograph, valorimeter value, extensograph ratio figure and extensograph area, indicating an increase in the strength of the dough. Surfactants reduced the mixograph peak height, mixograph area, apparent biaxial extensional viscosity, compressive stress, force decay parameter, hardness and adhesiveness, and increased the cohesiveness of dough. The values for peak viscosity increased with DATEM, PS‐60 and SSL and decreased with GMS and lecithin. Among the surfactants tested, SSL and PS‐60 brought about the greatest improvement in the quality of parotta, followed in decreasing order by DATEM, lecithin and GMS.     

Storage and transport of frozen dairy products

The characteristics of frozen dairy foods and the importance of freezing as a preservative are discussed and the need for an effective temperature profile required for various products considered. The progress of the product from factory to consumer is traced in detail and the cold store and supply vehicles described.     

变性淀粉对冷冻面团水分特性的影响

探讨了醋酸酯马铃薯淀粉对冷冻面团水分特性的影响。面团中分别添加不同量的醋酸酯马铃薯淀粉,利用脉冲核磁共振仪测定面团特水力。结果表明:醋酸酯马铃薯淀粉显著增加了冷冻面团持水力,且持水力随醋酸酯马铃薯淀粉添加量的增加而增大;添加量为15%时,持水力达到最大值;与淀粉面团相比,醋酸酯马铃薯淀粉面团中不可冻结水的相对面积增大,不可冻结水的弛豫时间显著降低,这表明添加醋酸酯马铃薯淀粉减弱了水分子的移动性,使面团中水分相对难冻结,减轻了面团冻结过程中的结构损伤。     

冻结和冻藏对冷冻面团流变学以及汤包皮质构特性的影响

研究了冻结温度、冻藏温度、冻藏时间对冷冻面团流变学特性和汤包皮质构特性的影响。实验结果表明,冻结改变了面团的流变性质,降低了面团的弹性;并且-18℃下冻结对汤包皮TPA参数的影响比-30℃的影响大。-30℃的冻藏温度对面团的粘弹性影响较大,而不同冻藏温度对汤包皮的TPA参数影响不大;冻藏时间对面团粘弹性、面团拉伸特性以及汤包皮的TPA参数影响大。