The molecular structure and pasting properties of the starches from seven normal cultivars of barley were examined and compared with those of normal maize, rice and wheat starches. The bar ley starches had an actual amylose content of 24.3-27.9%. The starches had different pasting prop erties, such as maximum viscosity and breakdown, and different amylose gelatinization. A positive correlation was found between the maximum viscosity and the gelatinization degree of amylose, suggesting that low amylose gelatinization restrains the swelling of starch granules. The amylopec tins had a low iodine affinity (0.42-0.70 g/100 g) and resembled each other in chain-length distri bution with the individual peaks of B 1 and A chains. The amyloses had DPn of 810-1410 with 3.6-5.2 chains per molecule, indicating that barley amyloses differed in molecular structure with the cultivars. Among the cereal starches, barley starches were similar to wheat starch in amylose content and molecular structure, especially molecular size of amylose and chain-length distribution of amylopectin. Barley is one of the major cereals along with maize, rice and wheat, and is mainly used for livestock feed and raw material for the production of alcoholic beverages. Recently, barley has also been used as food, such as a rice substitute, and in breads and noodles. Starch is the main component of barley grains (65% by wet weight).1) However, structural characteristics of barley starches have been less well established compared with those of other major cereals such as maize,2,3) rice4-6) and wheat.7,8) We recently examined the molecular structure of starches from some barley cultivars with different amylose content, one waxy (0% amylose), two low-amylose (2 and 11% amylose), two normal (23 and 25% amylose) and two high amylose (33 and 41% amylose) barley starches.9,10) The barley amylopectins from starches with differ ent amylose content were similar in molecular structure, while the amyloses had different molecu lar structures. The amyloses from the normal culti vars were similar in size to those of high-amylose cultivars but smaller than those of low-amylose cultivars. To date there is only limited literature in which the molecular structure of normal barley starches is examined9-12) although many varieties are cultivated. Moreover, in most studies,13-18) their structural analyses were conducted using whole starch. In this study, seven normal barley starches were characterized in molecular structure of frac tionated amylose and amylopectin and starch pasting properties in order to elucidate both similarities and differences among the normal varieties.
CITATION STYLE
Yoshimoto, Y., Hanashiro, I., Takenouchi, T., & Takeda, Y. (2001). Molecular Structure and Pasting Properties of Normal Barley Starches. Journal of Applied Glycoscience, 48(4), 307–316. https://doi.org/10.5458/jag.48.307
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