Starch botanical origin

Starch is isolated from plant sources by various methods (Ratnayake and Jackson, 2003 Zobel, 1992). The method of starch isolation depends on the nature and composition of the raw material source. Most food starches are isolated and purified on a commercial scale and then used as ingredients by food manufacturers. Commercial food starches are generally classified based on both botanical origin and functionality. With the increasing availability of modified starches prepared for specific food applications, starch manufacturers tend to emphasize and market starch with a secondary focus on botanical source. In fact, for food... 

Starch granules are composed of two types of a-glucan, amylose and amylopectin, which represent approximately 98-99% of the dry weight. The ratio of the two polysaccharides varies according to the botanical origin of the starch. 

Modification, which involves the alteration of the physical and chemical characteristics of the native potato starch to improve its fimctional characteristics, can be used to tailor it to specific food applications. The rate and efficacy of any starch modification process depend on the botanical origin of the starch and on the size and structure of its granules. This also includes the surface structure of the granules, which encompasses the outer and iimer surface depending on the pores and channels, which cause the development of the so-called specific surface (Juszczak, 2003). Potato starch modification can be achieved in three different ways physical, conversion, and chemical (derivatization) (Table 10.6). 

Paste properties of native starches from different botanical origins have been reviewed.92,133 Relevant to practical usage of starch, the most important paste properties are viscosity, texture, paste transparency, resistance to shear and tendency to retrograde. In terms of texture, the translucent potato starch pastes can be described as cohesive, long-bodied, stringy and rubbery. Other root, tuber and waxy starches give pastes of similar texture to that of potato starch, but are generally less cohesive. On the other hand, pastes from common cereal starches are opaque and can be described as noncohesive and short- and heavy-bodied. These and other properties of several native starches are summarized in Table 8.1. 

Various refinements of starch content analysis have been reported. The methods are based on starch hydrolysis, followed by polarimetry,305 high-pressure liquid chromatography306 or reaction with glucose oxidase/peroxidase.307,308 An iodine reaction can be used to determine the botanical origin of starch.309 The molecular weight distribution is determined by size-exclusion chromatography.310,311... 

Starch is a fine white powder that is odorless and tasteless. It is composed of very small spherical or elliptical granules. The botanical origin of the starch material determines the granule shape and size, and these characteristics are summarized in Table 1. It is insoluble in... 

Selected Properties of Various Botanical Origin Starches... 

Bergot R, 1993. Digestibility of native starches of various botanical origins by rainbow trout (Oncorhynchus mykiss). In Kaushik S.J., Luquet P.,Fish Nutrition in Practice, IV Int Symp. Fish Nutrition and Feeding, Les colloques , 61, INRA Editions, Paris, 857-865. 

Starch occurs as discrete granules whose size and shape depends on its botanical origin. However, all stareh granules have a semi-crystalline structure, hydrated only to a very small extent, insoluble in cold water, and very dense. 

The botanical origin of most starches is readily identified on the basis of granule size and shape, the form and position of the hilum, and the... 

Starch is a natural, renewable and biodegradable polymer produced by many plants as a source of stored energy. It is the second most abundant biomass material in nature and is found in plant roots, stalks, crop seeds, and staple crops such as rice, corn, wheat, tapioca and potato. Depending on their botanic origin, starch raw materials have different conversion factors, size, shape and chemical content. It consists of mainly two glucosidic macromolecules amylose and amylopectin. 

Guinesi L.S., da R6z A.L., Corradini E., Mattoso L.H.C., de Teixeira E., da S. Curvelo A.A. Kinetics of thermal degradation applied to starches from different botanical origins by non-iso-thermal procedures, Thermochim. Acta 447 (2006) 190. 

Thermoplastic starch (TPS) is an attractive source for the development of biodegradable plastics. It is one of the lowest cost biodegradable materials currently available in the global market (Mathew and Dufresne 2002 Shen et al. 2009). It can be found in the form of discrete semicrystalline particles, whose size, shape, morphology, and composition depend on the botanical origin (com, potato, maize. 

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