Plants complex, acidic oligosaccharides from

Carbohydrates are ubiquitous. Every organism contains some carbohydrate. Carbohydrates can range from a simple monosaccharide to a large complex polysaccharide. Polysaccharides in combination with proteins, lipids, and nucleic acids play an important role in many plant and animal metabolic systems. Carbohydrates have many roles in food systems, where they function to provide flavor, structure, and texture to food and nutritional benefits to the consumer. This chapter attempts to address the role of common plant monosaccharides, oligosaccharides, and polysaccharides as ingredients in food systems by discussing their occurrence in plants, commercial processing, functionality, food uses, and healthful properties. 

Several feruloyl esterases have been purified and characterized (Table 1). However, comparison of their properties is difficult as the range of natural and synthetic substrates used to characterize these enzymes is diverse and the enzyme assays are not unifomi. The substrates range in size and complexity from small, soluble esters such as feruloylated oligosaccharides isolated from plant cell walls and phenolic acid methyl esters or synthetic feruloylated arabinosides to larger, more complex and often less soluble substrates such as feruloylated polymeric plant cell wall fractions (28). The only criterion used in all cases is the release of free ferulic acid or another hydroxycinnamic acid by hydrolysis of an ester bond. Specificity, as defined by Ae rate of catalysis (kca divided by the Michaelis constant gives the best indication of preferred substrates. However, hydrolysis of polymeric substrates is more complicated since not all of the esterified substituents are chemically equal, and effects such as decreased solubility and steric hindrance further complicates any results obtained. Therefore, these data should not be extrapolated to obtain kinetic constants. 

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