Different Characteristics of Annealed Rice Kernels and Flour and Their Effects on the Quality of Rice Noodles

Abstract

In this study, the characteristics of indica rice kernels (IRK) and flour (IRF) annealed in different conditions were evaluated, and the quality of rice noodles made with these IRK and IRF was determined. Native IRK and IRF were annealed in deionized water at a kernel or flour to water ratio of 1:3 (w/v) and temperatures of 50, 55, 60, and 65 °C for 12 and 24 h. Annealing increased the paste viscosity of IRK while decreasing that of IRF. Both annealed IRK and IRF exhibited increases in the gelatinization enthalpy change and relative crystallinity. Annealed IRK gel showed higher hardness, and annealed IRF gel displayed greater springiness. Unlike native rice noodles, annealed IRK noodles exhibited denser pores, while annealed IRF noodles exhibited a looser microstructure. With increasing annealing temperature and time, both annealed IRK and IRF noodles showed enhanced tensile properties. Rice noodles made from IRF annealed at 65 °C for 12 h exhibited a fracture strain of 2.7 times that of native rice noodles. In brief, IRK and IRF exhibited different degrees of susceptibility to annealing. Annealing had more significant effects on IRF than IRK. This study highlights the possibility of using annealed IRK and IRF in rice noodles.

Physicochemical and Functional Properties of Vermicelli Made of Modified White Rice, Brown Rice, and Black Rice

“…The micrograph structure of vermicelli flour showed a pleasing and porous appearance, consistent with findings reported by Sittipod and Shi [36]. However, Zhang [11] reported a different micrograph structure for vermicelli flour from indica rice flour, resembling a honeycomb-like structure with wide pores. This disparity may be attributed to differences in annealing temperature, time, and rice varieties.…”

“…Flour with such pasting properties will result in a hardness of 3.16N and adhesiveness of 2.65 mJ with an unidentified fracture value. Annealing treatment on rice flour increased the hardness and springiness of the resulting vermicelli [11]. The pasta formation of rice flour and modified vermicelli flour occurred between minutes 6-9 (Figure 2).…”