Starch mashing

The basic raw materials for the production of beer are sweet worts formed by en2ymatic hydrolysis of cereal starches. The principal cereal is barley which, after malting, is also the source of en2ymes that hydroly2e starches, glucans, and proteins. In some countries, eg, Germany, the mash biH consists... 

Infusion Method. Infusion is a classic method for top-fermented beers and is used for ad British types. The whole mash is heated graduady from mashing-in to mashing-off with holding times for the degradation of protein and starch. No part of the mash is boiled and the malt, therefore, must be well-modified to assure the breakdown of ad soluble substances. Because no boiling takes place there is no physical breakdown of the malt, and consequentiy infusion is not as effective as decoction despite the better protection of the enzymes. 

Wort. Wort is the Hquid drained off the mash tun containing maltose, a grain sugar derived from the conversion of starch during the mashing process by the action of the organic enzyme, maltase, found in badey malt. 

Particle size and cooking condition for the grain slurry vary depending on the type of distilled spirit that is to be produced. In the case of com grain fermentations, distillers use small size, high temperature, and low beer gallonage (higher starch concentrations) for neutral spirits production at 120—170°C and 76—91 L/0.03 m. Bourbon distillates call for low temperatures (100—150°C) and thinner mash of 95—115 L/0.03 m (saccharified starch slurries) out of flavor considerations. (0.03 m is approximately a bushel). 

Yeast (qv) metabolize maltose and glucose sugars via the Embden-Meyerhof pathway to pymvate, and via acetaldehyde to ethanol. AH distiUers yeast strains can be expected to produce 6% (v/v) ethanol from a mash containing 11% (w/v) starch. Ethanol concentration up to 18% can be tolerated by some yeasts. Secondary products (congeners) arise during fermentation and are retained in the distiUation of whiskey. These include aldehydes, esters, and higher alcohols (fusel oHs). NaturaHy occurring lactic acid bacteria may simultaneously ferment within the mash and contribute to the whiskey flavor profile. 

In the case of complex carbohydrates the glycemic index is a measure of how quickly the carbohydrate is broken down. An example is to compare potato starch and polydextrose. Both are polymers of dextrose but potato starch in the form of mashed potato is rapidly broken down and causes a surge in blood sugar, i.e. it has a high glycemic index. In contrast, polydextrose, which has the dextrose units linked 1 - 6, a link that is rare in nature, is only 25% metabolised and has a very low glycemic index. 

When the consumption of iodine is the same in two successive tests and a sample of the mixture is no longer coloured by iodine the saccharification is complete. Usually 75-80 per cent of the starch taken is converted into sugar. The rest of the starch is only broken down into dextrins, which are, however, also saccharified in the course of the subsequent fermentation. The volume of the mash is measured in a cylinder, and from the result of the final maltose titration the sugar content is calculated. For the C02-determination 10 c.c. are retained (cf. p. 402). 

Traditionally, com is dry-milled and suspended in boiling water to free the carbohydrate-rich starch compound from the nonstarch, cellulose biomass. The starch and cellulose components at this stage carry through the process. The non-convertible cellulose biomass is later separated. The milled com-water slurry, called mash, is boiled for about 1 hour. Enzymes such as a-amylase can be added to the process to help prevent gellation of starch. 

It is generally accepted that each hydrocolloid affects the pasting and rheological properties of starch-based systems, like mashed potato, in a different way (Chaisawang and Suphantharika,... 

Alvarez, M. D., Canet, W., Fernandez, C. (2007a). Effect of modified starch concentration and freezing and thawing rates on properties of mashed potatoes (cv. Kennebec). J. Sci. FoodAgric., 87,1108-1122. 

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