Structures and Physicochemical Properties of Six Wild Rice Starches

Abstract

Starches from six wild rice cultivars were studied for their chemical structures and physicochemical properties and compared with a long-grain rice starch. The six wild rice starches were similar in morphological appearance, X-ray diffraction patterns, swelling power, and water solubility index but different in amylose content, beta-amylolysis limit, branch chain length distribution, thermal properties, and pasting properties. The structure of the wild rice amylopectins was close to that of waxy rice amylopectin with more branching and a larger proportion of short branch chains of degree of polymerization 6-12 as compared with that of amylopectin from rice starch with a similar amylose content. The differences in branch chain length distribution of amylopectin and amylose content were assumed to contribute to the differences in physicochemical properties among the six wild rice starches as well as to the differences between the wild rice starches and the rice starch.

Starch noodles: History, classification, materials, processing, structure, nutrition, quality evaluating and improving

“…Furthermore, the extent of retrogradation would depend on the amylopectin structure as the starches shared similar amylose content. Starch with a higher proportion of long chains in its amylopectin fraction tends to have a higher extent of retrogradation (Wang, Wang, & Porter, 2002). Therefore, this may be one of the reasons that the manufacturers of mung bean starch noodle tend to use LFS-isolated mung bean starch.…”

Structural, thermal and viscoelastic properties of potato starches

“…K. Pukhraj and K. Jyoti with the least amount of DP 6-7 showed a significantly higher setback than other starches. However, starch with a higher proportion of long chains in its amylopectin fraction has been suggested to have a higher extent of retrogradation (Wang, Wang, & Porter, 2002). The amount and molecular weight of amylose leached from the granules and the remnant of the gelatinized starch also play a significant role (Loh, 1992).…”

Physicochemical Properties of Starch and Flour from Different Rice Cultivars

“…There are many factors which influence the physicochemical properties of rice starch. Rice cultivars (Wang et al 2002;Sodhi and Singh 2003;Iturriaga et al 2004;Cameron et al 2007;Singh et al 2007;Zhong et al 2009;Lu et al 2009), rice starch composition and structure (Vandeputte and Delcour 2004;Park et al 2007;Ibáñez et al 2007;Tukomane and Varavinit 2008;Nakorn et al 2009;Matalanis et al 2009), additives (Seow et al 1996;Liang and King 2003;Mandala and Bayas 2004;Noisuwan et al 2007;Zhou et al 2007;Ohishi et al 2007;Wu et al 2009;Tian et al 2009;Banchathanakij and Suphantharika 2009;Viturawong et al 2008), processing method (Bao et al 2005;Devi et al 2009), and storage conditions can significantly influence the physicochemical properties of rice starch. On the other hand, many factors affect the physicochemical properties of rice flour or flour gels, such as rice cultivars (Iturriaga et al 2004), amylose content (Varavinit et al 2003), proteins (Teo et al 2000;Sun et al 2008;Marco and Rosell 2008), lipid and moisture (Dautant et al 2007), processing methods (Bao et al 2005;Ahmed et al 2007), prolamin (Baxter et al 2004), pH and phosphates (Wang et al 2000), hydrothermal treatment (Lai 2001), milling methods …”