Maltose lactic acid bacteria

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. 

Williamson s medium L Contains ui opped beer, maltose, yeast extract, liver extract, casein hydrolysate, either polymyxin or phenylethanol with CO atmosphere (25 Q, supports lactic acid bacteria. Polymyxin suppresses gram-negative bacteria. Phenylethanol supports Pediococcus rather than Lactobacillus... 

Salivary a-amylase is a protein that contributes to the enamel pellicle (Sect. 12.1.3). More importantly, it attaches bacteria, especially streptococci, to teeth surfaces. Thus, following a meal rich in carbohydrates, amylopectin, amylase, and glycogen are digested to maltose at the surface of many oral bacteria. The maltose is taken into the cytosol by a phosphoenolpyruvate transporter homologous to the fructose transporter of S. mutans. Within these bacteria, the maltose is digested to two molecules of glucose 6-phosphate and metabolized to lactic acid. Thus, twice as much acid is produced per mole maltose than per mole sucrose and it contributes to tooth demineralization even if less sucrose is consumed. 

The organic acids generated by fermenting bacteria such as acetic, lactic, hydroxya-cetic, formic, pyruvic, etc., are the main flavor precursors. Acetic add is considered the main acid. It improves dough characteristics, speeds up fermentation, and affects final bread properties. It is generated mainly from maltose and other simpler carbohydrates. 

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