Characterization of the physical properties of electron-beam-irradiated white rice and starch during short-term storage

Abstract

Electron-beam irradiation (EBI) is a cold sterilization technology used in the irradiation processing of food, including rice. Herein, the effects of EBI on the swelling power, color, pasting, and sensory properties of white rice after short-term storage were analyzed. Samples were electron-beam irradiated at 0, 2, 4, 6, or 8 kGy and stored at 25 °C or 37 °C for up to 75 days. Results showed that swelling power and major pasting viscosities (including peak, breakdown, and setback viscosities) at both storage temperatures decreased with increased irradiation dose. Negative correlations were also observed between the major viscosities of pasting properties and irradiation dose at both storage temperatures. During sensory evaluation, extremely low scores for rice hardness, appearance, taste, and overall acceptability were obtained for rice subjected to high EBI dose (>4 kGy). However, rice stored at 37 °C showed lower performance than rice at 25 °C in terms of the abovementioned parameters. By contrast, the sensory properties at irradiation doses between 2 and 4 kGy were better than those of the control group at both storage temperatures. All these findings indicated the potential of low-dose (<4 kGy) EBI as pretreatment for improving the quality of white rice during storage.

Effect of heat and γ‐irradiation on fungal load, pasting, and rheological characteristics of three whole and dehulled millets during storage

“…Similar findings were observed by Du et al. (2019) with the electron beam γ‐irradiated white rice and the starch during 75 days of storage. The decreased peak viscosity may be due to the inferior crystalline structure of samples, amylopectin with shorter branch chain length, and starch granule integrity (Srichuwong & Jane, 2007).…”

“…The breakdown viscosity was decreased with the increase in heat and γ‐irradiation at 1 kGy and 2.50 kGy (Table 1). A similar report was observed with electron beam γ‐irradiated white rice under short‐term storage (Du et al., 2019). Generally, amylose may influence the breakdown viscosity; for example, decreased breakdown viscosity in our study may be due to the influence of heat and γ‐irradiation treatments on the less formation of a molecular network within the granules (Bhupender et al, 2013).…”

“…These physical treatments collectively prevented the fungal spore formation; for example, a study demonstrated the reduction in molds, yeast, and insects growth at a low to medium dose of γ‐irradiation (Chen et al., 2015). Another study showed the low amylose content, gelatinization temperature, and the textural parameters with the increase in the γ‐irradiation (Du et al., 2019). To date, very few studies are available on the technological, functional, and microbiological properties of millets for long‐term storage.…”