The high percent of starch in the milled rice have great effects on the eating quality of the cooked rice. Breeding rice with improved eating quality has long been the major objective in rice breeding programs. Starch pasting viscosity tested by Rapid Visco Analyser (RVA) serves as an important index in estimating the eating quality of rice. However, its utility in a rice breeding program has received few attention and has not been fully demonstrated. In the present study, the F 2:3 and F 3:4 seeds deriving from the Zhefu 49×Zhefu 728 were consecutively measured the RVA profiles of brown rice flour based on single-plant. The clustering analysis with different kinds of parameters of RVA suggested that once a line with desired RVA profile was selected in F 2:3 , the probability to select this kind of RVA profile from its F 3:4 progenies was as high as 51.8%. The present result was in agreement with genetic result that RVA profile parameters had a high heritability. Therefore, breeding better eating quality of rice can be accelerated with the assistance of RVA instrument.
Pasting properties are among the most important characteristics of starch, determining its applications in food processing and other industries. Pasting temperature derived from the Rapid Visco-analyser (RVA) (Newport Scientific), in most cases, is overestimated by the Thermocline for Windows software program. Here, two methods facilitating accurate measurement of pasting temperature by RVA were described. One is to change parameter setting to ‘screen’ the true point where the pasting viscosity begins to increase, the other is to manually record the time (T1) when the pasting viscosity begins to increase and calculate the pasting temperature with the formula of (45/3.8)×(T1–1)+50 for rice flour. The latter method gave a manually determined pasting temperature which was significantly correlated with the gelatinization temperature measured by differential scanning calorimetry.
