Microbial Enzymatic Production Of High Activity Of Dietary Fiber

Corn cortex, which is a byproduct in corn starch production, contains a great deal of dietary fiber and a low content of phytic acid. What's more, It is easy to improve the properties of corn cortex through chemical or biological methods. So corn cortex is a kind of very good raw material to process the dietary fiber (DF).In this study, microbial enzyme method and chemical method were adopted to remove starch and protein existed in corn cortex separately. The microbial enzyme method has many advantages in the moderate conditions, the maintenance of natural structure of fiber and a strong specialty, and the active contents such as soluble fiber and hemi-cellulose can be protected effectively to improve the physiological activity of the DF. On the contrary, the chemical methods lead to a drastic removal of starch and protein but a poor selectivity on substrates, and the hemi-cellulose in corn cortex could dissolve in an alkali solution, which makes soluble fiber and hemi-cellulose having important physiological activities lost. From the results of the test, it can be easily concluded that microbial enzyme method is prior to chemical method in preparation of the DF.Some research results have showed that unsolvable contents of DF mainly act on intestines to arouse mechanical vermiculation and the soluble contents primarily affect the metabolism function. The composite proportion of soluble contents in the DF is an important factor affecting the physiological functions of the DF.So the corn cortex DF obtained from the above is decomposed by xylanase and cellulase in order to change the chemical structure and relative content of the polymer composing the natural DF. By this technique, the soluble hemi-cellulose and cellulose polysaccharides whosemolecular weight lie in 31560-136960 are obtained, and these soluble components have better soluble properties and more active terminals on its surface. These add some new functions or properties to the DF or fortify those intrinsic but weak functions, which include two aspects: the physiological functions contributing to human health and the technological properties applied into food.Through the study above, the process that high activities soluble dietary fiber can be acquired effectively through the microbial enzyme method has been concluded. This processing method would be applied to the industrialized production.