Granular starch is utilized in many food and industrial applications due to its universal abundance, relatively low cost (Whistler, 1984), and ability to impart a broad range of functional properties to food and nonfood products (Jane, 1995; BeMiller, 2007).
Current annual production (in millions of tons) for the primary starch sources follows the order: corn (46.1), cassava (9.1), wheat (5.15), and potato (2.45) (Röper and Elvers, 2008). However, most starches in their native form have limitations that make them less than ideal for the diversity of desired applications. For this reason, most granular starch utilized as a food or industrial ingredient is first modified (chemically and/or physically), while yet in the granular form, to alter and improve the physical properties of starch polymers in accordance with the intended end use.
Starch, including native and particularly modified types, accounts for more than 85% of all hydrocolloids used in food systems worldwide (Wanous, 2004). Some of the major industrial applications for various modified food starches are summarized in Table 1.
| Industry | Modified starch types |
| Adhesive | British gums, yellow dextrins |
| Food | Distarch phosphates, distarch adipates, hydroxypropyl starches, starch acetates, starch octenylsuccinates, monostarch phosphates, hydroxypropylated distarch phosphates, phosphorylated distarch phosphates, acetylated distarch phosphates, acetylated distarch adipates, thinned (via use of acid or alkaline hypochlorite solution) versions of the above, oxidized starches, pregelatinized versions of the above, white dextrins |
| Glass fiber | Cationic starches, benzylated starches |
| Papermaking | Hydroxyethyl starches, cationic starches, acid-thinned versions of the above, oxidatively thinned starches, graft copolymer products |
| Pharmaceutical | Hydroxyethyl starches, carboxymethyl starches, starch acetates, distarch phosphates, acid-modified (thin-boiling) starches and acid-modified versions of the above, oxidized starches |
Focused and comprehensive discussions of traditional commercial starch modification practices and modified starch applications are provided by Rutenberg and Solarek (1984) and Wurzburg (1986a), and specific reagents and reagent levels allowed for the production of modified starches for use in food are summarized by Xie, Liu, and Cui (2005). This modified starch series provides a synopsis of the current level of understanding of starch reactivity (granular and molecular aspects), advances in starch modification processes, and an overview of the physical changes that result from starch modification, with emphasis on recent scientific literature.