Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment

Abstract

Glutinous rice flour (GRF) and glutinous rice starch (GRS) were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05). Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G') and loss modulus (G") values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry.

Effect of heat treatment of rye flour on rye‐wheat steamed bread quality

“…2. A similar result was published by Qin et al (2016), and they found that dry heating increased the viscosity of rice flour. The loss modulus (G″) represented the viscous characteristics and the capacity of the dough to resist flow.…”

“…The improvement of G ″ reflected that heat treatment caused increase in the viscosity of mixed dough. A similar result was published by Qin et al (2016), and they found that dry heating increased the viscosity of rice flour. HTHP treatment and steaming treatment significantly increased the viscosity in mixed dough with yeast, while the viscosity in mixed dough with Laomian all improved for three heat treatments methods and was in order of mRFh > mRFs > mRFe > mRF > WF.…”

“…The storage modulus (G 0 ) reflected the elasticity of the dough and the ability to recover to its original state after being deformed. The obvious increase in elastic modulus indicated that starch particles absorbed internal water from the gluten to swell and fix in the gluten network during heat treatment (Qin et al, 2016). The value of tan d denotes viscoelasticity of dough (Tronsmo et al, 2003).…”

“…HTHP treatment and steaming treatment significantly increased the viscosity in mixed dough with yeast, while the viscosity in mixed dough with Laomian all improved for three heat treatments methods and was in order of mRFh > mRFs > mRFe > mRF > WF. The obvious increase in elastic modulus indicated that starch particles absorbed internal water from the gluten to swell and fix in the gluten network during heat treatment (Qin et al, 2016). The water required by starch was transferred from the gluten network; consequently, the network structure had better viscoelasticity with the gradual loss of water.…”

“…It is a promising method due to safety, simplicity, no environmental pollution and low cost (Qiu et al, 2015). Much research has been shown that heat treatment leads to increase in cereal flour viscosity (Sun et al, 2014a,b;Qiu et al, 2015) and dough elasticity (Qin et al, 2016). These factors produce positive effects on specific volume and hardness of final product.…”