Effects of electron beam irradiation on microbiological and organoleptic qualities of powdered red pepper and ginger

摘要

Electron beam (EB) was applied to study the sterilizing techniques for powdered red pepper and ginger by determining their quality over gamma radiation (GR) from the microbiological and organoleptic points of view. The samples showed high microbial loads, such as lO~5-10~6 CFU/g in total aerobic bacteria, negligible levels in yeasts & molds and 10~2 CFU/g in coliforms. EB irradiation at 5 kGy resulted in the reduction of microbial loads by 2 to 3 log cycles, thereby decreasing the levels of total bacteria to 10~2-10~3 CFU/g and resulting in negative in coliforms. Decimal reduction doses (D_(10) value) on the initial bacterial loads in red pepper were 1.50-1.54 kGy in EB and 1.68-1.80 kGy in GR, while powdered ginger showed 1.30-2.27 kGy in EB and 1.45-2.77 kGy in GR, respectively. EB and GR showed a similar effect on microbial decontamination for both samples. Microbial populations in stored samples for 4 months at room temperature were not remarkably different from the initial loads in all samples. Irradiation caused little changes in Hunter's color parameters, but that were changable during storage. Sensory evaluations on color and odor of powdered samples indicated that no significant differences were observed among the all samples compared. These results revealed that EB irradiation at optimal dose levels for microbial control was not detrimental to the sensory quality of powdered red pepper and ginger.