Effects of Compositional and Granular Properties on the Pasting Viscosity of Rice Starch Blends

Abstract

The changes in swelling power and pasting properties of suspensions of starch blends were studied in dependence on starch composition and at various isothermal temperatures (Tiso). Samples were prepared by mixing rice starches from Kaoshiung Sen 7 (KSS7, a high‐amylose‐content variety) and Taichung waxy 70 (TCW70, a waxy variety). Generally, mixing these starches at a comparable ratio caused significant decrements in overall swelling power, onset temperature of gelatinization or viscosity rise, and final viscosity of hot pastes after 30 min of isothermal stirring. Notable increases in the peak and conclusion temperatures of gelatinization and in the peak viscosity of the pastes were also observed. Generally, all viscosity parameters of the blends showed two linear dependencies on the starch composition, the graphs intersecting at a critical starch composition depending on the parameters concerned. The onset temperature of viscosity increase was related to the volume fraction of swollen granules when they were just closely packed in suspension. The volume fraction of KSS granules was smaller than that of TCW70. In addition, the rate of viscosity increase and the peak viscosity of the starch suspensions could be well described in terms of the swelling power (Q) when Q ≤ ∼27, and depending on the Tiso examined. From the photomicrographs of starch suspensions, the extensive shear‐induced disintegration of TCW70 granules in the co‐existence of rigid KSS7 granules was evident and in turn responsible for the reduced final viscosities of the hot pastes obtained from starch blends.

A comparison in rheological, thermal, and structural properties between Indian Basmati and Egyptian Giza rice flour dispersions as influenced by particle size

“…Basmati and Giza rice flours without sieving showed significantly different PV values, which was 1226 and 1467 BU, respectively. Similar values of peak viscosities for rice starch and its blends have been reported (Chen, Lai, & Lii, 2003). The higher PV of Giza rice is most probably associated with the higher amount of total starch and lower amount of amylose content compared to Basmati rice.…”

Effects of relative granule size and gelatinization temperature on paste and gel properties of starch blends

“…One possibility investigated in the present study is the mixing of different starches. Starch blends, instead of pure starches, can be used to impart desired properties such as improved pasting behavior (Chen, Lai, & Lii, 2003;Obanni & BeMiller, 1997), texture (Karam, Grossmann, Silva, Ferrero, & Zaritzky, 2005;Saito, 1980;Sugimoto, 1992), and freeze-thaw stability/low syneresis (Karam et al, 2005;Stute & Kern, 1994;White, Abbas, & Johnson, 1989).…”

Effects of lactic acid fermentation on FT-IR and pasting properties of rice flour

“…The pasting behavior is helpful for understanding the textural change and retrogradation potency of applied products (Chen, Lai, & Lii, 2003). The pasting properties can be measured using various instruments such as the Brabender Amylograph, the Brookfield Viscometer and most recently the Rapid Visco Analyser (RVA) (Yun & Quail, 1999).…”