Starch value chains

The biorefinery concept that has emerged is analogous to today s petroleum refineries. However, many current endeavors focus on single technologies and feedstock such as starch or vegetable oils that could compete with food or feed. We need to create flexible, zero-waste biorefineries that can accept a variety of low-value local feedstock. Biorefineries will then be able to compete with existing industries (Clark et al., 2012). Further down the value chain the development of green chemistry fills the gap between the sustainable resource and the product (Poliakoff and License, 2007). 

Starch from ae su kernels in a dent background consists of 51-60% amylose, as determined by the blue value procedure (Table 3.6), with the amylose percentage increasing with increasing kernel age.57 Yeh et al.,90 in contrast, reported that ae su reduced amylose concentration from 65% for su to 28% for ae su, based on SEC separation of starch polysaccharides isolated from kernels in a sweet com background. Three fractions were obtained (Table 3.7). The first two were loosely-branched, similar to the amylopectin fractions in ae. Amylose from the third peak fraction was similar in iodine staining to that from normal however, some short chain length amylose as... 

The mature kernel phenotype for the triple mutant ae du su is similar to that for su (Table 3.3). Sugar concentrations of mature272 and immature270 ae du su kernels are higher than those of either of the single mutants or the double mutants ae du or ae su, while starch concentration is similar to that in su and the two double mutants. The amylose percentage is close to that of normal when measured by either the blue value test (Table 3.6) or SEC (Table 3.7). However, in contrast to normal, a major proportion of the branched polysaccharide is smaller than typical amylopectin (as is that of ae su), and it elutes from an SEC column at an intermediate position (Table 3.7). The absorbance maximum and absorptivity (extinction coefficient) of the branched polysaccharide-iodine complexes are similar to those for ae and ae su, and are characteristic of loosely-branched polymers. The absorbance maximum of the amylose-iodine complex is similar to that of normal, du, or su, but the absorptivity is lower than for either (Table 3.7). No short chain amylose has been found in ae du su starch.90... 

The iodine affinities, blue values, max, beta-amylolysis limits and branch chain length distributions are similar for the starch samples harvested at different stages (7 to 30 days DAF) of development of waxy rice grains,331 japonica rice328 and indica rice.332 The gelatinization temperature of maize starch increases from 12 to 24 DAF, but is reduced at 36 DAF.333... 

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