Sucrose enzymatic oxidation

Two important enzymatic oxidations have been very well known since early times. One is the conversion of alcohol into acetic acid by bacterium acetic in presence of air (the process is now known as quick-vinegar process) (Scheme-3) and the second one is the conversion of sucrose into ethyl alcohol by yeast (Scheme-4) (this process is used for the manufacture of ethyl alcohol). 

Several other sensors are available that arc based on the voltammetric measurement of hydrogen peroxide produced by enzymatic oxidations of other species of clinical interest. These analytes include sucrose, lactose, ethanol, and (.-lactate. A (Afferent enzyme is. of course, required for each species. In some cases, enzyme electrodes can be based on measuring oxygen or on measuring pH as discussed in Section 23F-2. 

For preservation of food it is mandatory to inhibit enzymatic activity completely if the storage temperature is below the phase transition temperature Tg or Tg (cf. 0.3.3). With help of a model system containing glucose oxidase, glucose and water as well as sucrose and maltodextrin (10 DE) for adjustment of Tg values in the range of — 9.5 to — 32 °C, it was found that glucose was enzymatically oxidized only in such samples that were stored for two months above the Tg value and not in those kept at storage temperatures below T ... 

Neoglycosylation of proteins was also applied to the modification of the psychrophilic Atlantic cod trypsin the applicability of psychrophilic enzymes is limited because of their lower thermodynamic stability, despite their higher catalytic rate. It has been shown that the thermodynamic stability could be enhanced appreciably by covalent chemical modification with an oxidized sucrose polymer without affecting the enzymatic activity. The acquired stability of cod trypsin was found to be on par with the mesophilic porcine trypsin.40... 

Invertase (EC 3.2.1.26) catalyzes the hydrolysis of P-fructofuranosides and has been used in analytical chemistry (biosensors), in confectionary, and in the production of inverted syrup (1). Invert sugar syrup, which can be obtained by acid or enzymatic hydrolysis of sucrose, is a valuable commercial product especially in countries where the main sources of sugar are beet or cane. With acid hydrolysis, the final syrup is often contaminated with colored oxidation compounds, which arise from cyclization of hex-oses at low pH and high temperatures (2-4). Such a problem does not occur... 

The physical methods described above tend to be more accurate for pure sucrose solutions than complex industrial sugar solutions for the latter, chemical methods are more accurate. Chemical methods are broadly divided into those based on (i) colorimetric reactions, (ii) enzymatic reactions, (iii) oxidation-reduction properties, or (iv) chromatography separations. 

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