面包老化抑制因素研究

随着经济水平提高,面包已悄悄走进我们的生活;但是,老化面包口感差,易掉屑且香味丧失,不为广大消费者所接受。为此,需要究面包老化机理,并从理论上寻找抑制面包老化方法,提高面包质量。该文综述近年来国内外对面包老化研究成果,从水分、淀粉结晶、添加剂、淀粉酶、贮存和温度几方面论述抑制面包老化方法;并对抑制面包老化,全面提高面包质量研究趋势进行展望。     

面包老化的影响因素及其控制途径

面包是一类食用良好、营养丰富、容易消化吸收、受大众欢迎的烘焙食品。但面包老化现象直接造成了经济损失,阻碍了面包工业的发展。综述了面包老化的机理,影响面包老化的因素以及控制面包老化的途径,以期能对未来的面包老化研究具有一定的参考作用。     

面包老化抑制因素的研究

在西方国家,面包是餐桌上的主食,面包的质量与人们的健康和幸福息息相关.随着经济水平的提高,面包已经悄悄走进了我们的生活.但是,老化的面包口感差,易掉屑且香味丧失,不为广大消费者所接受.我们需要研究面包老化的机理,并从理论上寻找抑制面包老化的方法,提高面包的质量.本文综述了近年来国内外对面包老化的研究结果,从水分、淀粉结晶、添加剂、淀粉酶、贮存和温度几方面论述了抑制面包老化的方法.并对抑制面包老化,全面提高面包质量的研究趋势进行了展望.     

面包老化抑制因素的研究

在西方国家，面包是餐桌上的主食，面包的质量与人们的健康和幸福息息相关。随着经济水平的提高，面包已经悄悄走进了我们的生活。但是，老化的面包口感差，易掉屑且香味丧失，不为广大消费者所接受。我们需要研究面包老化的机理，并从理论上寻找抑制面包老化的方法，提高面包的质量。本文综述了近年来国内外对面包老化的研究结果，从水分、淀粉结晶、添加剂、淀粉酶、贮存和温度几方面论述了抑制面包老化的方法。并对抑制面包老化，全面提高面包质量的研究趋势进行了展望。     

面包新鲜度量化指标的测定及研究

利用先进的物性测试仪对面包储存期间的物性参数进行了测定,得出了面包老化的物性参数变化规律,探讨了面包老化的机理,分析了面包老化过程中硬度与弹性的相关性,确定了面包老化的定量物性参数范围,为面包老化定性分析向定量参数分析转变作了有益的探索。     

主配料对面包老化的影响研究

通过实验系统研究了乳化剂SSL、水、油脂对面包老化及烘焙体积的影响。水、油做为面包主配料,对面包老化起着显著的延缓作用,乳化剂SSL是一种理想的面包抗老化剂。它们对增加面包烘焙体积有着显著的正面效果,体积与老化速率间的线性相关表明,这三种配料均通过增加面包体积而延缓了面包老化。     

几种有关面包硬化的因素

面包老化变硬是令人头痛的问题。食品行业的科技人员经多年研究,认为下述因素同面包老化变硬有关。1．淀粉。淀粉在面包的组成中比例最高,因此它的变化对面包的老化变硬起主     

影响面包老化因素及抗老化途径

该文综述近年来国内外有关面包老化研究成果,介绍影响面包老化主要因素,并从改变原辅料、添加酶制剂、乳化剂和亲水性胶体等方面论述抑制面包老化方法。     

青麦仁面包老化过程中品质分析

通过测定面包老化过程中的品质变化,分析了青麦仁面包老化过程中的品质变化规律。结果显示:随着老化时间的增长,面包的水分含量逐渐下降;水分活度呈现先降低后升高、再降低;面包的比容下降,老化达到第5天后,面包比容下降趋势减缓;青麦仁面包的各项感官指标均下降;面包芯色泽和面包表皮色泽下降;青麦仁面包的硬度上升,弹性下降;青麦仁面包中多分子层结合水向单分子层水转化,水分的总量在减少;在第5天后微生物卫生指标超标。     

γ-聚谷氨酸对夹心面包货架期的影响

人们在研究面包老化时,对水分的的迁移和分布做了大量的研究,发现面包水分的变化是老化的一个关键因素,面包中水分的损失加速了面包的老化进程。γ-聚谷氨酸可以结合面包中的水分,减缓面包在储藏状态中水分的流失,因此在同等储藏条件下可以延长面包的储藏期。利用NMR测定技术,结合电镜技术、酸价检测及感官评定分析在储藏期中面包品质的变化,分析面包中的水分变化,综合弛豫特性分析、质构特性分析、酸价测定、环境扫描电镜分析和感官评价可知,未添加γ-聚谷氨酸的夹心面包、仅果酱中添加γ-聚谷氨酸的夹心面包、仅面包中添加γ-聚谷氨酸的夹心面包和两组分均添加γ-聚谷氨酸的夹心面包的最佳品质保持时间分别为3、5、6、7d。说明γ-聚谷氨酸的添加,可以提高面包在储藏期中的品质质量,抑制面包的老化,延长面包的储藏期。     

Effect of chitosan on physical and chemical processes during bread baking and staling

The objective of this research was to investigate the effect of chitosan on the interaction of water with bread ingredients and on the rate of staling. The changes in freezable bound water and total water contents in bread crumb were assessed by differential scanning calorimetry from water melting and evaporation endothermic peak areas. It was found that freezable water content and total water content in bread crumb decrease during staling more rapidly in the presence of chitosan. The weak interaction of freezable water with protein and starch polymeric chains in bread crumb becomes stronger, but the interaction of nonfreezable bound water with protein and starch molecules in bread crumb becomes weaker in the course of staling during bread storage. Two stages of bread crumb staling were indicated. Chitosan increases the rate of bread staling during both stages. It was suggested that during bread staling chitosan increases water migration rate from crumb to crust, prevents amylose-lipid complexation, and increases dehydration rate both for starch and gluten.     

The Effect of Non‐Gluten Proteins on the Staling of Bread

As part of our studies on the mechanisms of bread staling, starch bread was used as a research tool that enables us to gain insights into the individual contributions that starch and gluten have on staling. Reconstitution experiments have demonstrated that bread of equivalent specific loaf volume stales at the same rate irrespective of protein concentration, or type of protein. However, other properties of bread, such as specific loaf volume, may be altered by specifically changing the protein component in the flour.     

Effects of native and enzymatically hydrolysed soya and oat lecithins in starch phase transitions and bread baking

The effects of oat and soya lecithins and their hydrolysates on crystallisation of wheat starch gel and on bread structure were studied. In baking studies the lecithins were compared with commonly used commercial emulsifiers. Soya lecithin hydrolysate retarded starch gel crystallisation and bread staling as effectively as the best commercial emulsifiers. The oat lecithins were interesting. They did not affect significantly the starch gel crystallisation but both of them retarded bread staling much more effectively than the soya lecithin. Oat lecithins were as good as the commercial Amidan indicating that glycolipids in oat lecithins slowed bread staling. © 1998 SCI.     

嗜热真菌耐热木聚糖酶对面包品质的改善

研究了纯化的耐热木聚糖酶对面包品质及老化的影响，探讨了耐热木聚糖酶影响面包发酵及烘烤过程的作用机理。适量添加木聚糖酶的面包体积显著增加且面包芯的组织结构优良，同时老化变缓：本试验条件下，添加纯酶1．5mg／kg为最适酶添加量，体积增加43％，硬度减小44％，老化速度放缓近一半。     

Effect of loaf specific volume on the rate and extent of staling in bread

The quantitative relationships between loaf specific volume and the rate and extent of staling in bread as measured by changes in crumb elastic modulus have been examined. The results show that loaf specific volume is a major factor in determining both the rate and extent of staling, both of which decrease in a linear manner, over the range studied, as loaf volume increases. Only two factors have been found that have a significant influence on these curves, the basic breadmaking process and the storage temperature. The influence of changes in loaf specific volume on staling characteristics is greater in bread prepared by bulk fermentation than in bread prepared by the Chorleywood Bread Process. Bread made by the Chorleywood Bread Process stales less rapidly than bread made by the conventional bulk fermentation process. The effect of loaf specific volume on the rate of staling is more marked as the storage temperature is lowered.     

Bread Staling: Updating the View

Staling of bread is cause of significant product waste in the world. We reviewed the literature of the last 10 y with the aim to give an up‐to‐date overview on processing/storage parameters, antistaling ingredients, sourdough technology, and measurement methods of the staling phenomenon. Many researchers have been focusing their interest on the selection of ingredients able to retard staling, mainly hydrocolloids, waxy wheat flours (WWF), and enzymes, but different efforts have been made to understand the molecular basis of bread staling with the help of various measurement methods. Results obtained confirm the central role of amylopectin retrogradation and water redistribution within the different polymers in determining bread staling, but highlighted also the importance of other flour constituents, such as proteins and nonstarch polysaccharides. Data obtained with thermal, spectroscopy, nuclear magnetic resonance, X‐ray crystallography, and colorimetry analysis have pointed out the need to encourage the use of one or more of these techniques in order to better understand the mechanisms of staling. Results so far obtained have provided new insight on bread staling, but the phenomenon has not been fully elucidated so far.     

Effect of Carbon Dioxide Atmosphere on Staling and Water Relations in Bread

The effect of Modified Atmosphere Packaging (MAP on staling and on water relations in bread was evaluated. Application of CO₂ in MAP delayed staling of bread. Water sorption of bread packed in CO₂ was reduced compared to fresh bread and to bread packed in air. A water activity of 0.75 was found to be the boundary between the multilayer and the free water range of the isotherm. Spoilage of bread (microbial growth and staling) took place only above this water activity. Inverse Gas Chromatography was found to be unsuitable for investigating the effect of CO₂ on bread at the higher water activities because equilibrium conditions could not be achieved at these water activities.     

MECHANISM AND THEORY OF STALING OF BREAD AND BAKED GOODS, AND ASSOCIATED CHANGES IN TEXTURAL PROPERTIES

Abstract. A critical review of the literature on the staling of bread has been presented with particular emphasis on developments during the last decade. The staling of bread has been discussed from a structural point of view with separate contributions due to starch retrogradation, a modification in the gluten structure and a partial re-distribution of moisture from the gluten to the starch fraction of the crumb. Both model systems and studies on the natural crumb are considered including the contribution to staling of macroscopic moisture re-distribution and deterioration in flavour volatiles. The staling of baked goods has also been reviewed and it is proposed that certain analogies from the bread situation might provide a suitable basis for an overall theory of cake staling. It seems possible that a considerable contribution to the staling of cake sponge may be due to changes undergone by the various proteins; the free moisture produced from the transforming proteins may be absorbed by the sugars and gelatinised starch. Retrogradation of starch appears to be less important than changes in the proteins during the staling of cake. Dehydration of the cake crumb is perceived to play an important role in the sensory evaluation of cake staleness.