Bread specific volume

Concerning bread, characteristics such as cell wall thickness, cell size, and uniformity of cell size affect the texture of bread crumb (Kamman, 1970) and also the appearance, taste perception, and stability of the final product (Autio and Laurikainen, 1997). Crumb elasticity can be predicted from its specific volume and is strongly affected by the amylose-rich regions joining partially gelatinized starch granules in the crumb cell walls (Scanlon and Liu, 2003). 

As the temperature is lowered further, a point is reached where many physical properties of the polymer, such as elastic moduli, viscosity, and specific volume, fall dramatically over a narrow temperature range. This is the glass transition temperature, Tg, which was discussed in Chapter 6. At this temperature, segmental motions of polymer molecules practically cease. It appears that the temperature of around -20°C, at which crumb firming rate becomes negligible, may correspond closely to the Tg of amy-lopectin at the water content of bread. 

Crumb firming is inversely proportional to specific volume of bread. Rate of crumb firming is at a maximum near (but not at) the freezing point of water and decreases as temperature is increased or decreased on either side. 

Kernel texture (38-47), Farinograph parameters (48-50), Alveograph parameters (48), Extensigraph parameters (50), Mixograph parameters (50), Zeleny sedimentation (38 0,51), SDS sedimentation (52, 53), bread loaf volume (48,49, 51, 54), water absorption (48,51) FermentabUity, hot water extract, specific gravity (in beer) (55-58), metabolizeable energy (59-62)... 

The specific volume of white bread is higher than that of rye bread (Table 15.53). The rye crumb is stronger and less elastic, suggesting that the pentosans can not fully condensate for the lack... 

Food products may include frozen produce, canned produce, pasta, sauces in jars, prepared meals or pizzas. It is important to work closely with the manufacturer, in working out the best types of ingredients to use, depending on the manufacturing facilities available. For example, frozen fruit and vegetable processors require a specific size and quality, pasta and bread manufacturers will have their specific requirement of the variety and grade of wheat. They require consistent quality and volume so as to be able to produce a consistent end product. As with restaurants, it is important to build a good relationship with your processor and to keep the manufacturer informed of any potential problems. This allows them to take other action to ensure their production does not suffer. 

So what do we call all this stuff around us We know specific names This is a table, that is a loaf of bread, and water comes out of the faucet. But to a chemist, all of this—and everything else—is broadly classed as matter, anything that has mass and occupies space (that is, has volume). This definition is so broad that it doesn t help you understand nature very well. So, in this chapter, matter is examined in greater detail so that you can begin to organize it into categories and classes that are more easily understood. Let s start by dividing matter into its three common physical states solid, liquid, and gas. 

Another application o f x ylanases is the use of this enzyme in poultry diets. Depression in weight gain and feed conversion efficiency in rye-fed broiler chicks has been associated with intestinal viscosity (24). The efficiency of xylanases in improving the quality of bread has also been demonstrated. The introduction of A. niger var. awamori xylanase into bread dough resulted in an increase in specific bread volume. This is further enhanced when amylase in combination with xylanase is used (25). 

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