Review of direct chemical and biochemical transformations of starch.

Starch is an important natural sustainable resource for various industries. Via chemical and biochemical one-step transformations it may be converted into numerous products or promising substances for different applications. All starch-based products may be divided into five main groups: carbon based materials, small organic molecules, starch depolymerization products, products with retained polymer chains but changed supramolecular structure, and modified starch. Some of the products are well-known and traditionally manufactured from starch in industrial scale. Other materials, like mesoporous carbon or nanosized starch particles, are just coming to market, and still require more thorough investigation and tuning of the preparation, treatment, and application procedures. Approaches for preparation of the novel greener composite or homogeneous carbon based materials, nanoparticles, heterocycles, organic acids, polyols from starch, are given in details. Recent improvements in starch hydrolysis, molecular or supramolecular modifications are also summarized in this review.