The biochemistry of rye bread

While rye and wheat are genetically close enough to interbreed (the resulting hybrids are known as triticale), there are some substantial differences in the biochemistry of wheat and rye that can drastically affect the bread making process. A key issue is amylases--while wheat amylases are generally not heat-stable and have no effect on the stronger wheat gluten, rye amylase remains active at substantially higher temperatures. Since rye gluten is not particularly strong, the main structure of the bread is based on complex polysaccharides, including rye starch and pentosans, and the amylases in the flour can break down the resulting structure, inhibiting the rise of the dough.

There are two common solutions to that. The traditional manner, acidification, uses Lactobacillus cultures in a naturally derived sourdough starter to inactivate the rye amylases, which cannot function in an acidic environment, and to help gelatinize the starches in the dough matrix. In areas where obtaining wheat has traditionally been impractical because of marginal growing conditions or supply line difficulties, this has been the most important technique to creating lighter breads. As a byproduct of this intentional cultivation of lactic acid and acetic acid from the sourdough bacteria, standard baker's yeast is not often used, since Saccharomyces cerevisiae is known to be rather intolerant of acid environments. (Commercial yeast can, however, still be used; recipes substituting citric acid or vinegar and commercial yeast for the sourdough culture are sometimes used in baking trades.)

In areas where high-gluten hard wheat is readily available, on the other hand, the need for a complex polyculture of bacteria and yeast can often be reduced or removed by adding a large proportion of hard wheat flour to the rye flour; the added gluten compensates for amylase activity on the starch in the bread, allowing it to retain its structure as it cooks. (The Jewish rye bread tradition in the United States is based upon this mixing of grains.) The use of high-gluten wheat flour also makes possible multi-grain breads such as the "rye and Indian" bread of the American colonies, which combined rye and wheat with cornmeal in one loaf.

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С hemical process

In a "scientific" sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by somebody. Such a chemical process commonly involves a chemical reaction of some sort. In an "engineering" sense, a chemical process is a method intended to be used in manufacturing or on an industrial scale (see Industrial process) to change the composition of chemical(s) or material(s), usually using technology similar or related to that used in chemical plants or the chemical industry.

Neither of these definitions is exact in the sense that one can always tell definitively what is a chemical process and what is not; they are practical definitions. There is also significant overlap in these two definition variations. Because of the inexactness of the definition, chemists and other scientists use the term "chemical process" only in a general sense or in the engineering sense. However, in the "process (engineering)" sense, the term "chemical process" is used extensively. The rest of the article will cover the engineering type of chemical process.

Although this type of chemical process may sometimes involve only one step, often multiple steps, referred to as unit operations, are involved. In a plant, each of the unit operations commonly occur in individual vessels or sections of the plant called units. Often, one or more chemical reactions are involved, but other ways of changing chemical (or material) composition may be used, such as mixing or separation processes. The process steps may be sequential in time or sequential in space along a stream of flowing or moving material. For a given amount of a feed (input) material or product (output) material, an expected amount of material can be determined at key steps in the process from empirical data and material balance calculations. These amounts can be scaled up or down to suit the desired capacity or operation of a particular chemical plant built for such a process. More than one chemical plant may use the same chemical process, each plant perhaps at differently scaled capacities.

Such chemical processes can be illustrated generally as block flow diagrams or in more detail as process flow diagrams. Block flow diagrams show the units as blocks and the streams flowing between them as connecting lines with arrowheads to show direction of flow.

In addition to chemical plants for producing chemicals, chemical processes with similar technology and equipment are also used in oil refining and other refineries, natural gas processing, polymer and pharmaceutical manufacturing, food processing, and water and wastewater treatment.

 

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Monopolistic competition

Monopolistic competition is a form of imperfect competition where many competing producers sell products that are differentiated from one another (that is, the products are substitutes but, with differences such as branding, are not exactly alike). In it, a firm takes the prices charged by its rivals as given but ignores the impact of its own prices on the prices of other firms. In monopolistic competition, firms can behave like monopolies in the short run, including using market power to generate profit. In the long run, other firms enter the market and the benefits of differentiation decrease with competition; the market becomes more like perfect competition where firms cannot gain economic profit. However, in reality, if consumer rationality/innovativeness is low and heuristics is preferred, monopolistic competition can fall into natural monopoly, at the complete absence of government intervention. At the presence of coercive government, monopolistic competition will fall into government-granted monopoly. Unlike perfect competition, the firm maintains spare capacity. Models of monopolistic competition are often used to model industries. Textbook examples of industries with market structures similar to monopolistic competition include restaurants, cereal, clothing, shoes, and service industries in large cities. The "founding father" of the theory of monopolistic competition was Edward Hastings Chamberlin in his pioneering book on the subject Theory of Monopolistic Competition (1933). Joan Robinson also receives credit as an early pioneer on the concept.

Monopolistically competitive markets have the following characteristics:

· There are many producers and many consumers in a given market, and no business has total control over the market price.

· Consumers perceive that there are non-price differences among the competitors' products.

· There are few barriers to entry and exit.

· Producers have a degree of control over price.

The long-run characteristics of a monopolistically competitive market are almost the same as in perfect competition, with the exception of monopolistic competition having heterogeneous products, and that monopolistic competition involves a great deal of non-price competition (based on subtle product differentiation). A firm making profits in the short run will break even in the long run because demand will decrease and average total cost will increase. This means in the long run, a monopolistically competitive firm will make zero economic profit. This gives the amount of influence over the market; because of brand loyalty, it can raise its prices without losing all of its customers. This means that an individual firm's demand curve is downward sloping, in contrast to perfect competition, which has a perfectly elastic demand schedule.

Major characteristics

There are six characteristics of monopolistic competition (MC):

· product differentiation

· many firms

· free entry and exit in long run

· Independent decision making

· Market Power

· Buyers and Sellers have perfect information.